DOI： 10.1063/1.5058101

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DOI： 10.1103/PhysRevA.98.052514

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DOI： 10.1103/physreva.98.052514

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Physics Publishing  

Cross sections for the formation of H(2p) atom in photoexcitation were measured for H2 in the lowest rotational level in the energy range of the doubly excited states for examining contribution of the non-adiabatic transition between the 1Σu - 1Πu doubly excited states.

DOI： 10.1088/1742-6596/875/4/032037

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1088/1742-6596/875/4/032002

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Physics Publishing  

Synopsis A new experimental apparatus was developed for electron-impact multi-coincidence measurements at high energy resolution. A new monochromator which was designed to take the space charge effect into account was developed. It is shown that the new monochromator is able to produce a monochromatized electron beam with high current and a high energy resolution which is sufficient to carry out the multi-coincidence measurements.

DOI： 10.1088/1742-6596/875/7/062021

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

Double-electron excitations in electron collisions with NH3 are investigated in the range of the outer valence and inner valence excitations by means of angle-resolved electron-photon coincidence measurements. Double-electron and single-electron excitations are termed double and single excitations, respectively, in this article. It is found that the dissociative double excitation resulting in H(2p) formation becomes more dominant over the dissociative single excitation at 100-eV incident energy as the electron scattering angle increases just from 8 degrees. to 15 degrees. This remarkable domination is not expected from the independent particle model and strongly supports the double-excitation mechanism through the electron correlation induced by the penetration of the incident electron depth into the valence orbitals of a NH3 molecule.

DOI： 10.1103/PhysRevA.96.012706

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

Double-electron excitations in electron collisions with NH3 are investigated in the range of the outer valence and inner valence excitations by means of angle-resolved electron-photon coincidence measurements. Double-electron and single-electron excitations are termed double and single excitations, respectively, in this article. It is found that the dissociative double excitation resulting in H(2p) formation becomes more dominant over the dissociative single excitation at 100-eV incident energy as the electron scattering angle increases just from 8 degrees. to 15 degrees. This remarkable domination is not expected from the independent particle model and strongly supports the double-excitation mechanism through the electron correlation induced by the penetration of the incident electron depth into the valence orbitals of a NH3 molecule.

DOI： 10.1103/PhysRevA.96.012706

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER  

Absolute grand total cross sections for electron scattering from N-2 are obtained in the energy range from 20 eV down to 5 meV with very narrow electron energy width of 9 meV using the threshold-photoelectron source. Total cross sections obtained in the present study are compared with the previous experimentally obtained results. At the very-low energy region below 50 meV, the present total cross sections are somewhat smaller than those reported by the Aarhus group [S.V. Hoffmann et al., Rev. Sci. Instrum. 73, 4157 (2002)], which has been the only experimental work that provided the total cross sections in the very-low energy region. The energy positions of the peaks in the total cross sections due to the (2)Pi(g) shape resonance are obtained with higher accuracy, due to the improved uncertainty of the energy position in the present measurement compared to the previous works. The resonance structure in the total cross sections due to the Feshbach resonances of N-2 at around 11.5 eV are also observed. Analysis of the resonant structure was carried out in order to determine the values of resonance width of Feshbach resonances of N-2.

DOI： 10.1140/epjd/e2017-80069-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevA.93.063423

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

The absolute values of the cross section for formation of a 2p atom pair in the photoexcitation of H-2 and D-2 are measured against the incident photon energy in the range of doubly excited states by means of the coincidence detection of two Lyman-alpha photons. The cross-section curves are explained only by the contribution of the doubly excited Q(2) (1)Pi(u)(1) state. The isotope effect on the oscillator strengths of 2p + 2p pair formation for H-2 and D-2 from the Q(2) (1)Pi(u)(1) state is almost the same as that on the oscillator strengths of 2s + 2p pair formation from the Q(2) (1)Pi(u)(1) state obtained by our group [T. Odagiri et al., Phys. Rev. A 84, 053401 (2011)]. This channel independence indicates that both isotope effects are dominated by the early dynamics of the Q(2) (1)Pi(u)(1) state, before reaching the branching point into 2p + 2p pair formation and 2s + 2p pair formation.

DOI： 10.1103/PhysRevA.93.063423

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

Absolute total cross sections for electron scattering from He, Ne, Ar, Kr and Xe at very low electron energies obtained using the technique employing the threshold-photoelectron source are presented. Comparison of the measured cross section for noble gas atoms with those of theoretical results are made.

DOI： 10.1063/1.4968638

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DOI： 10.1088/1742-6596/635/1/012030

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1088/1742-6596/635/11/112016

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IOP PUBLISHING LTD  

We have measured the emission spectrum of gaseous hydrogen molecules in the far ultraviolet spectral range over the large interval of excitation energies between 11 eV and 17 eV. This regime is governed by singly excited electronic states below the ionization threshold. While these features have been already investigated separately in the past, the completeness of the present measurements allows a very intuitive representation of the participating molecular effects and their respective correlations. It also contains the first complete investigation of the Condon diffraction bands visible for hydrogen through transitions into the ground state continuum.

DOI： 10.1088/1742-6596/635/11/112130

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

The angular correlation functions (ACFs) of a pair of Lyman-alpha photons emitted from H fragments in the photodissociation of a hydrogen molecule are measured at a 33.66-eV incident photon energy and at hydrogen gas pressures of approximately 0.1 and 1 Pa. The ACFs are measured for both opposite and nonopposite arrangements of the two photon detectors. It turns out that the experimental ACFs involve neither the contribution of the reactions H(n = 2) + H-2 nor the contribution of the cascade from H(n >= 3) to H(2p) fragments. Thus the experimental ACFs are those for primary H(2p) pairs following the photodissociation of H-2. The experimental ACFs are compared with (i) the theoretical ACF for entangled pairs of H(2p) atoms, where the magnetic quantum number of each hydrogen atom is indefinite, and (ii) the theoretical ACF for H(2p) pairs with definite magnetic quantum number of each hydrogen atom relative to the internuclear axis [the former entangled state of H(2p) pairs is a sum of the latter pair states with definite magnetic quantum number]. In the theoretical ACF in (ii), the disentanglement in H(2p) pairs during the dissociation is considered. The experimental ACFs show a similar tendency in angular dependence to the theoretical ACF for entangled H(2p) pairs. However, there still remains a considerable difference in the variation magnitude between those experimental and theoretical ACFs. The experimental ACFs show the reverse tendency in angular dependence to the theoretical ACF for H(2p) pairs with definite magnetic quantum number of each hydrogen atom relative to the internuclear axis. We thus conclude that the pair of H(2p) atoms in the photodissociation of H-2 is unlikely to be in the definite states of magnetic quantum number of each hydrogen atom relative to the internuclear axis, i.e., unlikely to be in the components of the entangled state of H(2p) pairs.

DOI： 10.1103/PhysRevA.90.043405

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

Absolute total cross sections for electron scattering from He and Ne are obtained in the energy range from 20 eV down to below 10 meV with a very narrow electron energy width of 6-8 meV using the threshold-photoelectron source. Total cross sections obtained in the present study generally agree well with those obtained in the previous experiments for both He and Ne above 100 meV, where several experimental works have been reported. Comparison of the present cross sections with the theoretical cross sections which have been regarded as the "standard" cross sections shows very good agreement even at very low energies below 10 meV, which confirms the validity of theoretical cross sections. The scattering lengths for electron scattering from He and Ne are also determined from the present total cross sections using the modified effective range theory. The resonant structures in the total cross sections due to Feshbach resonances of He and Ne are also observed. Analysis of the resonant structure was carried out based on the spin-dependent resonant scattering theory in order to determine the values of natural width of Feshbach resonance of Ne.

DOI： 10.1103/PhysRevA.89.022709

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

A new experimental technique for the total cross section measurements of ultra-low energy electron collisions with atoms and molecules utilizing the synchrotron radiation is presented. The technique employs a combination of the penetrating field technique and the threshold photoionization of rare gas atoms using the synchrotron radiation as an electron source in order to produce a high resolution electron beam at very low energy. Absolute total cross sections for electron scattering from He, Ne, Ar, Kr, and Xe in the energy region from extremely low electron energy to 20 eV are presented.

DOI： 10.1063/1.4866926

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IOP PUBLISHING LTD  

Absolute total cross sections for electron scattering from He and Ne at electron energies ranging from 6 meV to 20 eV were obtained with the experimental technique employing the threshold-photoelectron source. The measured tot a I ross sections were compared with previous experimental and theoretical cross sections.

DOI： 10.1088/1742-6596/488/4/042015

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER INST PHYSICS  

The absolute cross sections for the formation of the H(2s) and H(2p) atoms, sigma(2s) and sigma(2p), respectively, in photoexcitation of CH4 and NH3 were measured in the range of the incident photon energy 15-48 eV for studying superexcited states of the molecules. The same superexcited states were found to contribute to the sigma(2s) and sigma(2p) cross sections. It was concluded that the non-adiabatic transitions play a significant role during the dissociation of the superexcited states and ionic states. (C) 2013 AIP Publishing LLC.

DOI： 10.1063/1.4826460

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

The cross sections for emission of two fluorescence photons from a pair of excited fragments in photoexcitation of H2O have been measured as a function of the incident photon energy using the photon-photon coincidence technique. The cross section increased in the range 30-45 eV, i.e. in the vicinity of the double ionization potential of H2O. The increase of the cross section was attributed to three-body neutral dissociations of a water molecule via multiply excited states: H2O** -> H(2p) + OH** -> H(2p) + H(2p) + O(P-3). Some multiply excited states of H2O were also found in the cross section curve around 65 eV.

DOI： 10.1088/0953-4075/45/21/215204

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER  

A new experimental technique for the measurements of the total cross section for electron scattering from atoms and molecules at very low energy is described. Momentum transfer cross sections for scattering from Ar, Kr and Xe at very low energies were carefully derived using the modified effective range theory from the recently measured total cross sections, which were obtained with a new experimental technique utilizing the threshold photoelectron source. A significant discrepancy between the momentum cross sections derived from the present analysis and those determined in the previous electron swarm studies was found at energies below 100 meV. The findings emphasize the need of further high precision experiments in the very low energy region as well as re-analysis of the previous swarm data.

DOI： 10.1140/epjd/e2012-20629-0

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IOP PUBLISHING LTD  

Total cross sections for electron scattering from Ar, Kr, Xe and N-2 at electron energies ranging below thermal energy to 20 eV with high-energy resolution obtained are presented. A new experimental technique which employs a combination of the penetrating field technique and the threshold photoionization of rare gas atoms using the synchrotron radiation as an electron source in order to produce a high resolution electron beam at very low energy was developed for the measurements. The lowermost energy of the present measurement reaches to the cold electron collisions regime, where the de Broglie wavelength of an electron becomes much lager than the typical size of target.

DOI： 10.1088/1742-6596/388/4/042004

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

Absolute total cross sections for electron scattering from Ar and Xe at electron energies ranging from 7 meV to 20 eV were obtained with the experimental technique employing the threshold-photoelectron source. The measured total cross sections are in good agreement with those obtained by other groups down to 100 meV, above which several experimental works have been reported. Scattering lengths for electron scattering from Ar, Kr, and Xe were determined from the present total cross sections and our recent results for Kr using the modified effective range theory. The values of the scattering length obtained in the present analysis differ from the values determined from the previous swarm experiments and beam experiments. The resonant structures in the total cross sections due to Feshbach resonances of Ar, Kr, and Xe with an improved energy resolution were also measured. Analyses of the resonant structure were carried out based on the spin-dependent resonant scattering theory in order to determine the values of the natural width of Feshbach resonances of Ar, Kr, and Xe precisely.

DOI： 10.1103/PhysRevA.84.062717

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

The cross sections for the formation of the metastable atomic hydrogen in the 2s state in photoexcitation of H-2 and D-2 were measured as a function of the incident photon energy in the range of the doubly excited states with their symmetries of the electronic states, (1)Sigma(+)(u) or (1)Pi(u), being resolved. It has turned out from the comparison with the cross-section curves for other dissociation processes and the theoretical calculation [J. D. Bozek et al., J. Phys. B 39, 4871 (2006)] that the Q(2)(1) Pi(u) (1) doubly excited state of H-2 dissociates into both H(2s) + H(2p) and H(2p) + H(2p). The dissociation dynamics of this state has been discussed in terms of the nonadiabatic transition during neutral dissociations.

DOI： 10.1103/PhysRevA.84.053401

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

The electron energy loss spectrum of H(2)O in coincidence with detecting Lyman-alpha photons (CoEELS) has been measured at the incident electron energy of 100 eV and electron scattering angle of 8 degrees in the inner valence range in order to investigate the formation and decay of the doubly excited states. The present CoEELS has been compared with that at the infinite incident electron energy and 0 degrees electron scattering angle, which was derived from the density of the dipole oscillator strength of H(2)O for the emission of the Lyman-alpha photons against the incident photon energy (Nakano et al 2010 J. Phys. B: At. Mol. Opt. Phys. 43 215206). It is remarkable that there exists a large difference in shape between these CoEELSs. This difference has turned out to be attributed to the noticeable contribution of the forbidden doubly excited states at 100 eV incident electron energy and 8 degrees scattering angle. They lie at 25.0 and 27.4 eV and have been found out in this study. The differential cross sections for the excitation to the superexcited states resulting in H(2p) formation have been obtained at 100 eV and 8 degrees and compared with those at the infinite energy and 0 degrees. The electron collisions at 100 eV and 8 degrees enhance the dissociative double excitation against the dissociative single excitation as compared with the electron collision at the infinite energy and 0 degrees.

DOI： 10.1088/0953-4075/44/17/175207

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記述言語：英語   出版者・発行元：AMER PHYSICAL SOC  

In this Reply to the preceding Comment by Sancho and Plaja, we point out the difference between the coincidence time spectrum of two Lyman-alpha photons measured by us and their theoretical one.

DOI： 10.1103/PhysRevA.83.066102

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

The differential cross sections of the dissociative double excitations resulting in H(2p) formation in 80 eV electron collisions with H-2 have been measured at electron scattering angles of 3, 20, 30 and 40 degrees by means of angle-resolved electron energy loss spectroscopy in coincidence with detecting Lyman-alpha photons. The doubly excited states of H-2 involved in this study are the optically allowed Q(1) (1)Pi(u)(1) and Q(2) (1)Pi(u)(1) states and the forbidden state at 26 eV, which has not been assigned so far and is temporarily referred to as the F state in this study. At a 3. electron scattering angle the differential cross section of the dissociative excitation to the forbidden F state is the largest among those for the three doubly excited states and decreases with increasing the electron scattering angle more rapidly than those for the allowed Q(1) (1)Pi(u)(1) and Q(2) (1)Pi(u)(1) states. The differential cross sections for the forbidden and allowed states do not differ quite so much, which may show that the forbidden F state is a dissociative state rather than an autoionizing state. The effective generalized oscillator strengths for H(2p) formation have been compared with the dipole oscillator strengths according to the limit theorem.

DOI： 10.1088/0953-4075/44/6/065203

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

We have constructed and made available atomic and molecular (AM) numerical databases on collision processes such as electron-impact excitation and ionization, recombination and charge transfer of atoms and molecules relevant for plasma physics, fusion research, astrophysics, applied-science plasma, and other related areas. The retrievable data is freely accessible via the Internet. We also work on atomic data evaluation and constructing collisional-radiative models for spectroscopic plasma diagnostics. Recently we have worked on Fe ions and W ions theoretically and experimentally. The atomic data and collisional-radiative models for these ions are examined and applied to laboratory plasmas. A visible M1 transition of W26+ ion is identified at 389.41 nm by EBIT experiments and theoretical calculations. We have small non-retrievable databases in addition to our main database. Recently we evaluated photo-absorption cross sections for 9 atoms and 23 molecules and we present them as a new database. We established a new association "Forum of Atomic and Molecular Data and Their Applications" to exchange information among AM data producers, data providers and data users in Japan and we hope this will help to encourage AM data activities in Japan.

DOI： 10.1063/1.3585809

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

An experimental technique for the measurement of the total cross section for electron scattering from atoms and molecules at high resolution is described. The total cross sections for electron scattering from Kr in the energy range from 14 meV to 20 eV obtained with the technique are also reported. The present technique employs a combination of the penetrating field technique and the threshold photoionization of rare-gas atoms using synchrotron radiation as an electron source in order to produce a high-resolution electron beam at very low energy. The characteristics of the electron sources were determined by measuring the ionizing photon energy dependence of photoelectron yield. Absolute total cross sections for electron scattering are obtained by the attenuation method. The measured absolute values of the total cross sections for electron scattering from Kr agree with those obtained by other groups down to 175 meV, above which several experimental works have been reported. Below 175 meV, the present results generally agree with theoretical cross sections down to 14 meV. The resonant structures in the total cross sections due to Kr- (4p(5)5s(22)P(3/2)) and the Kr- (4p(5)5s(22)P(1/2)) Feshbach resonances are also reported. The resolution of the present setup has been estimated from a fit of the measured profile of the Kr- (4p5(5)s(22)P(3/2)) resonance by the theoretical curve obtained from the resonant scattering theory.

DOI： 10.1103/PhysRevA.82.062707

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

The cross sections for the emission of Lyman-alpha fluorescence in the photoexcitation of H(2)O have been measured as a function of the incident photon energy in the 14-60 eV range, i.e. the outer-and inner-valence ranges. Four superexcited states have been found, two of which are doubly excited states, one is a singly excited state and one a state including electron configurations of both single and double excitations. The gross feature of the superexcited states of H(2)O resulting in the formation of excited hydrogen atoms has been obtained by combining the present results and the cross section curves of the Balmer fluorescences (Kato et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 3127). The breakdown of the independent electron model has been indicated in the inner-valence range of H(2)O, and the degree of breakdown has been compared among CH(4), NH(3) and H(2)O ten-electron molecules.

DOI： 10.1088/0953-4075/43/21/215206

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER PHYSICAL SOC  

We have measured the coincidence time spectra of two Lyman-alpha photons emitted by a pair of H(2p) atoms in the photodissociation of H(2) at the incident photon energy of 33.66 eV and at the hydrogen gas pressures of 0.40 and 0.02 Pa. The decay time constant at 0.02 Pa is approximately half the lifetime of a single H(2p) atom, 1.60 ns, while the decay time constant at 0.40 Pa is in agreement with the lifetime of a single H(2p) atom. It turns out that the decay faster than the lifetime of a single H(2p) atom originates from the entanglement in the pair of H(2p) atoms. We have demonstrated an effect of entanglement on atomic decay.

DOI： 10.1103/PhysRevA.82.040101

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

A photoelectron spectrum of H2O has been recorded at a resolution of 2 meV under Doppler-free conditions. Complex rotational structures appear in the individual vibrational states of the electronic (X) over tilde (+) B-2(1) and (A) over tilde (+) (2)A(2) states in H2O+. The rotational structures are analyzed and well reproduced using a spectator orbital model developed for rotationally resolved photoelectron spectroscopy.

DOI： 10.1021/jp102496n

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

The differential cross sections for the dissociative single and double excitations resulting in H(2p) formation with the excitation energy of 19-46 eV in electron-CH4 collisions have been measured as a function of electron scattering angle in the range 4 degrees-48 degrees at 80 eV incident electron energy by means of angle-resolved electron energy-loss spectroscopy in coincidence with detecting Lyman-alpha photons. This is the first measurement of the differential cross sections for the dissociative double excitations as a function of electron scattering angle in electron-molecule collisions. Their fractions have been compared with those at the optical limit calculated from the density of the dipole oscillator strength for the emission of Lyman-alpha photons previously measured by our group. The dissociative double excitations in 80 eV electron collisions seem to be brought about in a very different way from those at the optical limit where they arise from the electron correlation in a methane molecule. The differential cross sections have also been discussed in terms of momentum transfer, leading to a universal curve.

DOI： 10.1088/0953-4075/43/15/155208

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER INST PHYSICS  

A novel method of spectroscopy for highly excited states of molecules in the valence excitation range has been established through the detection of metastable hydrogen atoms in the 2s state formed by photoexcitation. The detector for the metastable hydrogen atom is composed of a stack of parallel plate electrodes that creates a localized electric field and triggers the emission of the Lyman-alpha photon from the atom and a chevron pair of microchannel plates that detects the photon. For linear molecules, the angle-resolved detection of the metastable hydrogen atom enables us to measure cross sections in which electronic symmetries of highly excited molecular states are resolved. Such symmetry-resolved cross section measurements were carried out for doubly excited states of H(2). (C) 2010 American Institute of Physics. [doi:10.1063/1.3436653]

DOI： 10.1063/1.3436653

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE BV  

Angle-resolved energetic-ion yield spectra have been measured in the 0 Is excitation region of N2O. Franck-Condon analysis based on ab initio two-dimensional potential energy surfaces of the core-excited Rydberg states reproduces well the observed vibrational excitations specific to the individual Rydberg states. The irregular Rydberg behavior in the Sigma-symmetry absorption spectrum is attributed the valence-Rydberg coupling in light of the second moment analysis. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2006.12.071

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

After inner shell excitation the ultrafast fragmentation of small molecules can proceed on a time scale similar to that of the Auger decay. In this case the nuclear motion affects the observed electron spectrum in various ways. The best known example is the Doppler splitting of atomiclike Auger lines, but non-parallel potential surfaces are equally important. Using an electron energy ion momentum coincidence experiment and an ab initio calculation of potential curves, we discuss the main features seen in the non-coincident and coincident resonant Auger spectrum by decay of the F (1s) -> 6a* core excited state of CH3F.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

At the high resolution electron spectroscopy end station of BL27 at SPring-8 in Japan we replaced the conventional gas-cell with a Doppler free gas-jet source. Such a device was constructed in such a way that the gaseous molecules, or atoms, travel perpendicularly to the direction of observation of the electron energy analyzer, so that the Doppler broadening is removed. This apparatus has been tested and proved successfully for resonant Auger emission of Ne 1s(-1)3p and H2O O 1s(-1)2b(2) and O 1s(-1)4a(1).
In the experiment on Ne, electrons of about 811 eV of energy are observed with a width of 63 meV. Such narrow width allows to resolve terms of inner-valence excited states of the series Ne+ 2s2p(5)(P-1,P-3)np S-2, P-2, D-2; and also to extract the natural lifetime widths of states that can undergo further Auger decay.
This Doppler-free technique was also applied in H2O, to study the Auger decay from the O 1s(-1)2b(2) and O 1s(-1)4a(1) core-excited states. The Doppler-free system allows to resolve the vibrational structure in the final Auger state, thus to investigate details of nuclear dynamics in the core excited state.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：KLUWER ACADEMIC/PLENUM PUBL  

Differential cross sections (DCS) for elastic scattering and electronic and vibrational excitation of CF(3)I by electron impact have been measured using electron energy loss spectroscopy (EELS). Differential oscillator strengths are derived from EELS measurements and compared with photo-absorption cross sections. Assignments have been suggested for each of the observed absorption bands incorporating both valence and Rydberg tranistions. Vibrational structure in each of these bands is observed for the first time.

DOI： 10.1007/0-387-27567-3_4

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER INST PHYSICS  

We report experimental results for electron scattering from perfluorocyclobutane, c-C4F8, obtained from measurements in our two laboratories. A set of differential, integral, and momentum transfer cross sections is provided for elastic scattering for incident electron energies from 1.5 to 100 eV. Inelastic scattering (vibrational excitation) cross sections have been measured for incident electron energies of 1.5, 2, 5, 6, and 7 eV. In order to investigate the role of intermediate negative ions (resonances) in the scattering process we have also measured an excitation function for elastic scattering and vibrational excitation of the ground electronic state of C4F8 for incident energies between 0.6 and 20 eV. These results are compared with the limited amount of data available in the literature for scattering from this molecule. (C) 2004 American Institute of Physics.

DOI： 10.1063/1.1782174

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMERICAN PHYSICAL SOC  

Fragmentation of the SF6 molecule upon F 1s excitation has been studied by resonant photoemission. The F atomiclike Auger line exhibits the characteristic Doppler profile that depends on the direction of the photoelectron momentum relative to the polarization vector of the radiation as well as on the photon energy. The measured Doppler profiles are analyzed by the model simulation that takes account of the anisotropy of the Auger emission in the molecular frame. The Auger anisotropy extracted from the data decreases with an increase in the F-SF5 internuclear distance.

DOI： 10.1103/PhysRevLett.91.213003

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMERICAN PHYSICAL SOC  

The resonant Auger spectrum from the decay of F 1s-excited CF4 is measured. Several lines exhibit a nondispersive kinetic energy as the exciting photon energy is tuned through the resonance region. The F 1s(-1) atomiclike Auger line is split into two components due to the emission of Auger electrons by a fragment in motion, when electron emission is observed along the polarization vector of the light. This Doppler splitting is direct evidence that the core excitation leads to T-d-->C-3v symmetry lowering, by elongation of a specific C-F bond preferentially aligned along the polarization vector of the incident photon.

DOI： 10.1103/PhysRevLett.90.233006

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMERICAN PHYSICAL SOC  

Using very high resolution achieved by the Doppler-free resonant Raman Auger technique, we have resolved the lowest terms of the series of inner-valence excitations 2s2p(5)(P-1,P-3)np S-2, P-2, and D-2 in Ne+. The measured Auger anisotropic parameters and branching ratios help to establish the assignments of these levels. The measured lifetime widths are in reasonable agreements with ab initio calculations available in the literature.

DOI： 10.1103/PhysRevLett.90.153005

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

A Doppler-free electron spectroscopy apparatus that consists of a high-resolution electron spectrometer and a molecular beam source has been installed on beamline 27SU at Spring-8 in Japan. The apparatus is described and the Auger resonant Raman spectra of neon atoms recorded at the 1s -> 3p excitation and those of water molecules recorded at the O 1s -> 2b(2) excitation are presented to demonstrate the performance.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

Low-energy satellite bands accompanying the C 1s mainline have been investigated both for randomly-oriented and fixed-in-space CO2 molecules. We find that these satellite bands are resonantly enhanced at the same photon energy as the shape resonance of the mainline and more enhanced for the E-symmetry parallel transition than the II-symmetry perpendicular transition. Our observations contradict the predictions based on the shake-up model and agree with predictions given by the photoelectron-impact model which assumes the dominance of final state correlations arising from the interaction between a primary photoelectron and a valence electron.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

The experimental studies for electron-polyatomic molecule collision are reviewed in connection with the plasma processing and environmental issues. Recent developments in electron scattering experiments on the differential cross section measurements for various processes such as elastic scattering, vibrational, and electronic excitations are summarized from high to low energy regions (1-100 eV). The need for cross-section data for a broad variety of molecular species is also discussed because there is an urgent need to develop an international program to provide the scientific and technological communities with authoritative cross sections for electron-molecule interactions.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMERICAN PHYSICAL SOC  

The angular distributions of the spin-orbit state resolved S 2p photoelectrons of SF6 have been measured in the vicinity of the shape resonances. Relative partial photoionization cross sections of SF, into the (S 2p(3/2))(-1) and (S 2p(1/2))(-1) states, and the asymmetry parameters of the S 2p(3/2) and S 2p(1/2) photoelectrons are presented. Enhancement of the photoionization cross section into the (S 2p(1/2))(-1) state at the (S 2p(1/2))(-1) 2t(2g) resonance has been observed. The excitation photon energy dependence of the asymmetry parameter shows a broad dip at about the photon energies of the resonances. Continuum multiple-scattering calculation of the asymmetry parameters for the (S 2p(3/2))(-I) and (S 2p(1/2))(-1) states of SF6 reproduces this behavior.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

Resonant Auger transitions from the 2p(-1)4s photo-excited states in Ar to the 3p(-1)3s(-1)4s levels and the subsequent Auger decay to the 3p(4) states of Ar2+ are studied by means of angle-resolved electron spectroscopy. The branching ratios and the values of the angular anisotropy parameter beta are determined for the emitted electrons. The angular correlation between the two electrons emitted in the sequential transitions in the cascade are also measured in the coincidence experiment. All the experimental data are compared with MCDF calculations which include electron correlations in the initial, intermediate and final states of the cascade. It is found that although the electron energies are very well reproduced by the calculations, the calculated anisotropy parameters and angular correlation parameters for some of the transitions disagree with the experiment.

DOI： 10.1088/0953-4075/34/1/308

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROYAL SWEDISH ACAD SCIENCES  

Angular distribution of C2+ ions produced in C4+(ls(2)) + He --> C2+(ls(2)2s(2)) + He2+ at collision energy of 270 and 470 eV are presented. Measurements have been carried out with an experimental setup for the state selective differential cross section measurements of electron capture processes which utilizes the 14.5GHz Caprice Electron Cyclotron Resonance (ECR) ion source at RIKEN. It is found that results of calculations based on the potential, which was obtained from the previous experimental results at 1520 eV, do not reproduce the present experimental results at 270 and 470 eV.

DOI： 10.1238/Physica.Topical.092a00339

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：AMER INST PHYSICS  

We have measured the angular distributions of the resonant Anger and the second-step Anger electrons ejected in the processes Ar*(2p(5)3s(2)3p(6)((2)p(0))4s, J(0) = 1) --> Ar*(+)(2p(6)3s(2)3p(5)(P-1(1)) 4s P-2(1/2,3/2)) + e(1)(-) and Ar*(+)(2p(6)3s3p(5)(P-1(1))4s P-2(1/2,3/2)) --> Ar++(2p(6)3s(2)3p(4) P-3(0,1,2)) + e(2)(-), respectively, and the angular correlations between these two electrons. Based on these results, we discuss a key role of the lifetime interference effect in the angular distribution of the second-step Auger electrons and the extraction of the Auger amplitudes from the experimental data. The experimental results are compared with the multi-configuration Dirac-Fock calculations.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROYAL SWEDISH ACAD SCIENCES  

In order to study the charge transfer processes between highly charged ions and atoms or molecules in the collisional energy range of below 100 eV/q, an experimental setup for the state selective differential cross section measurement of multi-electron capture processes was prepared. The apparatus is set at the 30 degrees beam line of the RIKEN 14.5 GHz Caprice ECR ion source. Highly charged ions extracted from the ion source at 2 keV/q into the beam line, are decelerated down to 10-100 eV/q and then energy selected by a double hemispherical analyzer A typical current of 300 pA was achieved for the energy selected 40 eV/q Ar6+ beam with an energy width of 0.3 eV/q. The energy distribution of scattered ions for 36.6 eV/q (7.3 eV/u) Ar8+-N-2 collisions at scattering angles from 0 degrees to 10 degrees has been measured.

DOI： 10.1238/Physica.Topical.080a00377

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROYAL SWEDISH ACAD SCIENCES  

Using a photon-ion merged-beam technique, we studied the photoionization of multiply charged Xeq+ (q = 1-3) ions in the 4d excitation region (50-140eV). Relative yield spectra of photoions created by single (q-->q+1) and double (q-->q+2) photoionization were measured as a function of photon energy. A broad ''4d giant resonance'' peak with some preceding discrete peaks appears in each total ion spectrum. The intensities of discrete peaks observed at around 4d ionization threshold strongly depend on the target charge state. Those for Xe3+ target are very strong, whereas those for Xe+ are weak. Peaks due to 4d-->5p transition, which cannot occur in the neutral Xe case, has also been observed for each ion-target. The experimental spectrum for Xe+ has been analyzed by a multiconfiguration Dirac-Fock calculation This calculation shows that results observed may be explained in terms of the correlation of valence and excited orbitals, and the effect of 4f-orbital collapse, of which the degree varies strongly with the change of the effective nuclear charge.

DOI： 10.1088/0031-8949/1997/T73/042

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記述言語：英語   出版者・発行元：AMER PHYSICAL SOC  

A series of resonant Auger-electron spectra excited at selected photon energies across the O 1s -> Rydberg resonances in O(2) has been measured. Applying a spectator-electron shake relaxation model originally introduced for atomic resonant Auger-electron spectra, and using, to a large extent, the assignments for the core-excited resonances available from the literature, many of the observed spectator Auger-electron final states are assigned in terms of cationic Rydberg series. Vice versa the resonant Auger-electron spectra are used for consistency tests of the literature assignments for the core-excited intermediate Rydberg states. For some of the latter, alternative assignments are proposed for reasons discussed.

DOI： 10.1103/PhysRevA.78.022516

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記述言語：英語   出版者・発行元：AMER INST PHYSICS  

We report on an experimental and theoretical investigation of x-ray absorption and resonant Auger electron spectra of gas phase O(2) recorded in the vicinity of the O 1s ->sigma* excitation region. Our investigation shows that core excitation takes place in a region with multiple crossings of potential energy curves of the excited states. We find a complete breakdown of the diabatic picture for this part of the x-ray absorption spectrum, which allows us to assign an hitherto unexplained fine structure in this spectral region. The experimental Auger data reveal an extended vibrational progression, for the outermost singly ionized X (2)Pi(g) final state, which exhibits strong changes in spectral shape within a short range of photon energy detuning (0 eV>Omega>-0.7 eV). To explain the experimental resonant Auger electron spectra, we use a mixed adiabatic/diabatic picture selecting crossing points according to the strength of the electronic coupling. Reasonable agreement is found between experiment and theory even though the nonadiabatic couplings are neglected. The resonant Auger electron scattering, which is essentially due to decay from dissociative core-excited states, is accompanied by strong lifetime-vibrational and intermediate electronic state interferences as well as an interference with the direct photoionization channel. The overall agreement between the experimental Auger spectra and the calculated spectra supports the mixed diabatic/adiabatic picture. (C) 2008 American Institute of Physics.

DOI： 10.1063/1.2831920

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記述言語：英語   出版者・発行元：AMER PHYSICAL SOC  

We present an experimental observation of the electronic Doppler effect in resonant Auger spectra upon core excitation slightly above the carbon K edge of the CO molecule. Thus the electronic Doppler effect has been identified in above-threshold excitation, and in a transition of Pi symmetry. Ab initio calculations of the potential energy curves of the relevant states of CO and the wave packet technique have been employed to provide a theoretical background to the experimental studies. The weak feature around 299.4 eV in the photoabsorption spectrum, whose decay has been investigated by the present experiment, is assigned to double (core-valence) excitations to C 1s shake-up states vertical bar 1s(C)(-1)1 pi(-1)pi(*2)> with a strong dissociative character, and the Doppler splitting of the atomic peak has been reproduced by the simulation.

DOI： 10.1103/PhysRevA.76.062704

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記述言語：英語   出版者・発行元：AMER PHYSICAL SOC  

We present experimental evidence for pronounced electron transfer from C to F(+) happening during the breakup of CH(3)F(+) ions in gas phase produced by resonant photoemission following F 1s -> 6a(1)(*) core excitation of CH(3)F. We measured the momentum of the ionic fragments in coincidence with the F KVV Auger electrons that show a Doppler shift reflecting the motion of the F nucleus. The correlation between Doppler shift and ion momentum is opposite for the F(+) and the CH(2)(+) fragments, indicating that CH(2)(+) is produced by electron transfer from C to F(+), after the Auger electron emission from excited moving F. This finding is rationalized by calculations of the potential energy curves of the main states involved in the excitation and decay processes.

DOI： 10.1103/PhysRevA.76.052705

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Methane and deuteromethane molecules were core ionized using synchrotron radiation, and the ionic fragments from the molecular dissociation were detected in coincidence with the Auger electrons. The electron - ion coincidence spectra are analysed in terms of partial ion yields and ion kinetic energy distributions, both as functions of electron kinetic energy. The dependence of the fragmentation patterns on the electronic character of the Auger final states as well as on the excess energy available for dissociating the molecule is studied. The analysis reveals marked differences in the dissociation of the 2a(1)(-2) and 2a(1)(-1) 1t(2)(-1) states, interpreted as an `excess- energy- dependent' concerted dissociation process for the 2a(1)(-2) state and an ` electronic- state- dependent' sequential process for the 2a(1)(-1) 1t(2)(-1) state.

DOI： 10.1088/0953-4075/40/18/008

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記述言語：英語   出版者・発行元：AMER PHYSICAL SOC  

We have measured the vibrationally resolved partial cross sections sigma(')((v1),v(2)('),v(3)(')) and asymmetry parameters beta(')((v1),v(2)('),v(3)(')) for N-c and N-t K-shell photoionization of the N2O molecule in the sigma* shape resonance region above the N-t and N-c K-shell ionization thresholds. N-c K-shell photoionization of the N2O molecule predominantly causes the excitation of the quasisymmetric vibrations (v(1)(')), whereas N-t K-shell photoionization causes both quasisymmetric and quasiantisymmetric vibrations (v(1)(') and v(3)(')) to be excited. The shape resonance energy in the N-c K-shell photoionization increases with an increase in v(1)('). The beta(')((v1),0,0) curves for the N-c K-shell photoionization exhibit maxima at energies close to the shape resonance energies for the individual values of v(1)('). The shape resonance energy in the N-t K-shell photoionization decreases with an increase in v(1)(') and slightly increases with an increase in v(3)('). The beta(')((v1),0,0) curves show a significant state dependence in the region of the shape resonance, with the curves shifting to lower energy as v(1)(') increases. The vibrational state dependence of the cross sections sigma(')((v1),v(2)('),v(3)(')) and asymmetry parameters beta(')((v1),v(2)('),v(3)(')) are well reproduced by the theoretical calculations using the multichannel Schwinger configuration interaction (MCSCI) method, including both the N-c and N-t ion states.

DOI： 10.1103/PhysRevA.76.012506

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記述言語：英語   出版者・発行元：AMER INST PHYSICS  

The valence character of O 1s -> Rydberg excited O-2 is investigated by means of participator Auger decay spectroscopy, performed at selected photon energies across the K-shell resonance region, and by means of partial ion yield x-ray absorption spectroscopy. For several of the excitation energies studied, the authors find substantial sigma(*)((4)Sigma(-)(u),(2)Sigma(-)(u)) valence character being mixed with ns sigma and np sigma ((4)Sigma(-)(u),(2)Sigma(-)(u)) Rydberg states. An experimental indication of a coupling between the channels associated with quartet and doublet ion cores is considered and discussed. New spectroscopic constants are derived for the singly ionized X (2)Pi(g) state of O-2 based on the observation of at least 20 vibrational sublevels. (C) 2007 American Institute of Physics.

DOI： 10.1063/1.2723745

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Vibrationally resolved N-c and N-t K-shell photoelectron spectra of the dinitrogen oxide have been studied experimentally and theoretically. Vibrational frequencies for the N-c and N-t ls ionized states obtained from the 2D potential surfaces computed by the CCSD(T) method within the equivalent core approximation reasonably agree with the experimental values. Experimental relative intensities of the vibrational structure are reasonably reproduced by the multi-channel Schwinger configuration interaction method (MCSCI) with the computed 2D potential surfaces. Improved relaxed geometries of these core-hole states are obtained from fitting the experimental spectra using the MCSCI calculations and regarding the bond lengths as fitting parameters. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2007.02.057

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DOI： 10.1088/0953-4075/40/12/019

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DOI： 10.1103/PhysRevA.75.012716

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記述言語：英語   出版者・発行元：AMER INST PHYSICS  

The photoelectron shake-up satellite spectra that accompany the C1s and O1s main lines of carbon monoxide have been studied by a combination of high-resolution x-ray photoelectron spectroscopy and accurate ab initio calculations. The symmetry-adapted cluster-expansion configuration-interaction general-R method satisfactorily reproduces the satellite spectra over a wide energy region, and the quantitative assignments are proposed for the 16 and 12 satellite bands for C1s and O1s spectra, respectively. Satellite peaks above the pi(-1)pi(*) transitions are mainly assigned to the Rydberg excitations accompanying the inner-shell ionization. Many shake-up states, which interact strongly with three-electron processes such as pi(-2)pi(*2) and n(-2)pi(*2), are calculated in the low-energy region, while the continuous Rydberg excitations are obtained with small intensities in the higher-energy region. The vibrational structures of low-lying shake-up states have been examined for both C1s and O1s ionizations. The vibrational structures appear in the low-lying C1s satellite states, and the symmetry-dependent angular distributions for the satellite emission have enabled the Sigma and Pi symmetries to be resolved. On the other hand, the potential curves of the low-lying O1s shake-up states are predicted to be weakly bound or repulsive. (c) 2006 American Institute of Physics.

DOI： 10.1063/1.2346683

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Angle-resolved ion yield (ARIY) spectroscopy has been carried out on high-temperature N2O molecules. From spectra recorded at 300 K (room temperature) and at 700 K, symmetry-resolved absorption profiles of the N 1s(-1) 3 pi and 0 1s(-1) 3 pi resonances have been extracted from molecules in the vibrational ground state and in bending-vibration excited states. The spectra show dramatic differences, and the Renner-Teller effect becomes more evident for the vibrationally excited molecules. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2006.07.009

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

O K-shell photoionization of the CO2 molecule causes antisymmetric vibrations v '(3) in the core-ionized molecule. The v '(3)-resolved partial cross sections sigma(+)(v ' 3) and asymmetry parameters beta(v ' 3) are measured in the Sigma(u) shape resonance region above the O K-shell ionization threshold of the CO2 molecule. Neither the shape resonance energy in sigma(+)(v ' 3) nor the value of beta(v ' 3) shows v '(3)- dependence. This v '(3)- independent nature is attributed to the fact that v '(3) vibrations do not cause any change of the size of the potential box responsible for the formation of the shape resonance. Multiple scattering calculations employing the v '(3)-dependent fixed-nuclei approximation reproduce well the measured v '(3)-resolved partial cross sections.

DOI： 10.1088/0953-4075/39/17/021

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

We have measured the vibrationally resolved partial cross sections sigma(nu'1) and asymmetry parameters beta(nu'1) for C K-shell photoionization of the CO2 molecule in the Sigma(u) shape resonance region above the C K-shell ionization threshold. The positions of both the maxima of sigma(nu'1) and the minima of beta(nu'1) move towards the C K-shell threshold with increasing symmetric stretching vibrational excitation nu('1) in the C 1s single-hole state. Calculations employing the relaxed-core Hartree-Fock approach reproduce the observed vibrational effects.

DOI： 10.1088/0953-4075/39/14/012

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

The C K-shell photoelectron mainline of C2H2 molecules have been measured at photon energies 295-350 eV. The gerade and ungerade symmetries of the core-ionized states, 1 sigma(g) and 1 sigma(u), are resolved. Resonance enhancement is found only in the log photoionization cross-section and assigned to the sigma(u)(*) shape resonance. The photoelectron asymmetry parameter takes a minimum value at the shape resonance energy. The shape resonance energy decreases with increase in the vibrational quantum number. No correlational shape resonance appears in the 1 sigma(u) photoionization channel, suggesting that the channel coupling is negligible. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2006.01.070

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

High-resolution electron spectrometry is used to investigate inner-valence Auger transitions in Ne+. The following series of transitions have been observed: Ne+ 2s(1)2p(5)(P-1,P-3)np -> Ne2+ 2S(2)2p(4) (3)p, D-1 and Ne+ 2s(0)2p(6)(S-1)np -> Ne2+ 2s(1)2p(5) (1,3)p. In addition, we have observed a new series of valence inter-multiplet Auger transitions Ne+ 2s(1)2p(5)(P-1)np -> Ne2+ 2s(1)2p(5) P-3. The initial states of these transitions were populated by the resonant Auger decay of photoexcited Ne 1s(-1)np resonances. Thus, the investigated transitions constitute the second step in an Auger cascade process. The photon energy was chosen to effectively populate Rydberg states of Ne+ with n = 4-10. The energy positions, quantum defects, relative intensity and angular distribution parameters of the Ne+ Auger electron emission have been determined. Experimental results are compared with multi-configuration Dirac-Fock calculations carried out as a part of this study.

DOI： 10.1088/0953-4075/39/6/004

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Vibrationally resolved C and O 1s photoelectron spectra of carbon monoxide have been measured in the photon energy range between 300 and 440 eV and between 550 and 702 eV, respectively. The intensity ratios of the vibrational components vary slowly, approaching the sudden limit. From the spectra in the sudden lit-nit, the information about the potential curves for the C 1s and O 1s ionized states are extracted. The experimental potential curves thus obtained are reproduced well by the present ab initio calculations based on the symmetry adapted cluster-confliguration interaction method. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2005.09.094

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DOI： 10.1088/0953-4075/39/2/012

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記述言語：英語   出版者・発行元：AMER PHYSICAL SOC  

Symmetry-resolved x-ray absorption spectroscopy has been first carried out on high-temperature molecules. From the angle-resolved ion yield spectra of CO2 both at room temperature and at 430 degrees C, symmetry-resolved absorption profiles of the C 1s(-1)2 pi(u) and O 1s(-1)2 pi(u) resonances have been extracted for the vibrational ground state molecules and bending-vibration excited ones. The profiles change dramatically between them, and the Renner-Teller effect becomes more evident for the vibrationally excited molecules. The effects of the multimode vibronic coupling are suggested for the O 1s(-1)2 pi(u) and O 1s(-1)3s sigma(g) resonances.

DOI： 10.1103/PhysRevLett.95.203002

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

We have carried out a coincidence experiment between energy-resolved resonant Auger electrons and mass-resolved ions on CH3F molecules following F 1s and C 1s excitation to the lowest unoccupied C-F antibonding molecular orbital sigma(CF)(*). We found a strong enhancement of the F+ or CH+ ion production in coincidence with the F KVV and C KVV spectator Auger electrons, respectively, in the wide binding energy range of 28-36 eV. This site-selective ion production is interpreted as a consequence of the resonant Auger emission taking place in the transient region where the C-F elongation caused by the core excitation transforms the molecular valence orbitals gradually into nonoverlapping valence orbitals of each fragment.

DOI： 10.1103/PhysRevA.72.042704

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

Carbon 1s photoelectron spectra of methane are measured over a photon energy range between 480 eV and 1200 eV. Additional components appear between the individual symmetric stretching vibrational components and are attributed to the excitations of asymmetric stretching and bending vibrations due to recoil of the high-energy photoelectron emission. This recoil effect is the evidence for the violation of the Franck-Condon principle which states that neither the positions nor the momenta of the nuclei change during the ionization event.

DOI： 10.1103/PhysRevLett.95.133001

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Resonant photoemission from the fluoromethane (CH3F) molecule has been measured with photon energies scanning through the resonance in which a C or F Is electron is promoted to the lowest unoccupied molecular orbital sigma*(CF), The spectator Auger band with the lowest binding energy of similar to 27 eV is tentatively assigned to 2e(-2) 6a(1). The energy-resolved electron-ion coincidence experiments revealed that this state produces predominantly CH2+ ions both for C 1s and F 1s excitations, providing evidence that the spectator Auger decay to this state takes place within the molecular regime, where the valence electrons are delocalized over the entire molecule. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2005.06.125

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Vibrationally resolved carbon Is photoelectron spectra of methane are measured over a photon energy range between 300 and 480 eV. The intensity ratios of the vibrational components vary significantly, exhibiting a minimum at about 330 eV. The observed non-FC distribution is tentatively explained as a result of the internal inelastic scattering of the photoelectron on valence electrons, which leads to the loss of the photoelectron current that depends on the vibrational excitation of the residual ion. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2005.05.118

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

The Auger resonant Raman spectra of CO, arising from the transitions to the X and A final electronic states of CO+, have been recorded at photon energies corresponding to the vibrational excitations v(')=3,5, and 8 in the O 1s -> 2 pi resonance. The spectra are simulated within the model that takes into account both the lifetime-vibrational interference (LVI) and interference with the nonresonant photoemission. The spectroscopic parameters, omega(e), omega(e)x(e), Gamma and r(e), of the O 1s(-1)2 pi core-excited state, necessary for the simulation, have been derived by fitting the Franck-Condon simulation to the total ion yield spectrum, assuming a Morse potential for the O 1s(-1)2 pi state. Not only the LVI but also the interference with the nonresonant photoemission turn out to be significant.

DOI： 10.1103/PhysRevA.72.022507

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

We employ a novel technique in which highly excited Rydberg states of Ne+ 2p(4n)p are populated via PCI-induced recapture of the near-threshold 1s photoelectron (De Fanis et al 2004 Phys. Rev. A 70 040702) to investigate valence inter-multiplet Auger transitions. The following series of the transitions have been observed: Ne+ 2p(4)(D-1)np(2) L -> Ne2+ 2p(4) P-3(J), Ne+ 2p(4)(S-1)np(2)P -> Ne2+ 2p(4) P-3(J) and Ne+ 2p(4)(S-1)np P-2 -> Ne2+ 2p(4) P-3(J). Their energy positions, quantum defects and the anisotropy parameters of the Auger electron emission have been determined. Experimental results are in good agreement with multi-configuration Dirac-Fock calculations carried out as a part of this study. The importance of interference effects for decays via naturally overlapping fine-structure components of the intermediate state is discussed.

DOI： 10.1088/0953-4075/38/13/015

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

We have set up a coincidence apparatus consisting of a high-resolution electron spectrometer and a k-resolving ion spectrometer. As an example for measurements performed with this apparatus, we present ion mass spectra that are coincident with energy-resolved resonant Auger electrons emitted from F 1s excited SF6 molecules and resonant Auger electron spectra that are coincident with mass-selected fragment ions, as a function of the detuning from the F(1s(-1))a(1g)* resonance in SF6. Significant changes of these spectra due to detuning suggest that a substantial fraction of the excess photon energy goes into fragmentation rather than into electron kinetic energy. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2005.01.009

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

The lowest-energy satellite bands accompanying the O 1s mainline Of CO2 molecule have been investigated, using angle-resolved photoelectron spectroscopy. The measurements were carried out at beamline 27 at SPring-8 in Japan with a high-resolution electron spectroscopy apparatus consisting of a hemispherical energy analyzer (SES-2002) combined with a gas cell. We found that the internal inelastic scattering is significant while the conjugate shake-up plays its role as well. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2005.01.172

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

The lowest-energy satellite bands accompanying the F 1s mainline of the SF6 molecule have been investigated using angle-resolved photoelectron spectroscopy. We found that a conjugate shake-up is dominant while the internal inelastic scattering also plays a significant role. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2005.01.059

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

We have carried out angle-resolved measurement for the C 1s photoelectron shakeup satellites of gaseous CO molecules, at unprecedented energy resolution, and resolved the vibrational structures for one (2)Sigma(+) and two (2)Pi bands. The present ab initio calculations for the potential curves of these shakeup satellite states and the relevant Franck-Condon analysis well reproduce the vibrational structures of these bands and confirm the assignments.

DOI： 10.1103/PhysRevLett.94.243004

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

DOI： 10.1016/j.elspec.2005.01.092

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

The relative photoion yield in the 4d photoionization of Eu+ has been measured with an energy resolution of E/Delta E similar or equal to 820. The obtained spectrum shows that the 4d 'giant resonance' of Eu+ is not a single peak but consists of many resonances. The result is compared with a recent theoretical calculation and our previous result which has been measured with lower resolution. The calculation well reproduces the experimental result in the region of E >= 140 eV, while some peaks are not corresponding in lower energy region. (c) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2005.01.209

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

High-resolution angle-resolved molecular resonant Auger emission from the F 1s excited states of the CF4, SiF4, and SF6 molecules are reported. A number of strong spectator lines resulting into the dissociative final states, whose anisotropy changes by changing the excitation photon energy, dominate the resonant Auger spectra. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2005.01.173

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記述言語：英語  

The vibrationally resolved C 1s single-hole ionization cross sections of H2CO are measured in the region of the σ* shape resonance. The energy of the shape resonance is pushed down by the excitation of the C-O stretching vibration v2′. Our calculations, which take account of elastic multiple scattering within the C-O potential box, show that the downward shift of the shape resonance energy is originated from the elongation of the characteristic internuclear C-O distance in the core-ionized molecule with an increase in v2′. The characteristic internuclear distance varies from R+(0,0,0)=1.198 up to R+(0,2,0)=1.415. In addition to the elastic multiple-scattering mechanism, the internal inelastic scattering of the C 1s photoelectron by valence electrons is suggested as a possible mechanism responsible for the enhancement of vibrational excitations through the shape resonance and near threshold. © 2005 The American Physical Society.

DOI： 10.1103/PhysRevA.71.052510

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

We have applied a high-resolution-electron-momentum-resolved-ion coincidence technique to the Auger emission from CF4 following the F 1s→ a(1)(*) excitation and found that the Auger electron emitted from the atomic F fragment during the ultrafast dissociation is backscattered by the residual fragment CF3. We find also that more than half of the excess energy goes into the vibrational excitation of the CF3 fragment.

DOI： 10.1103/PhysRevA.71.052704

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

Total cross sections (TCSs) are experimentally investigated for 0.8-600-eV electron and 0.7-600-eV positron scattering from c-C4F8 molecules using a linear transmission time-of-flight method, and a comparative study of the results is carried out in this paper. Electron-scattering differential cross sections (DCS) measurements carried out for energies 1.5-100 eV are used for a combined TCS and DCS discussion. These DCS results help to offer a better understanding of some of the structures observed in the TCSs. Fingerprints of a low-energy resonance, consistent with large electron attachment cross sections near 0 eV, have been observed below 2 eV where TCSs show a continually rising trend. Another resonance peak at similar to 8.5 eV, attributed to dissociative electron attachment with the production of fragmented ions, and a broader one at 16-40 eV, have also been observed. Except for the pronounced shoulder at similar to 40 eV, there is good qualitative agreement between the TCS result and the integrated cross-section results. Although electron TCSs are found to be generally larger than positron TCSs in the 3-120-eV ranges, these two TCSs, however, show a tendency towards merging above 120 eV.

DOI： 10.1103/PhysRevA.71.032717

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Shake-up satellite spectra accompanying the C 1s and O 1s photoelectron main lines of formaldehyde were studied by the combination of high-resolution X-ray photoelectron spectroscopy and accurate ab initio calculations. The symmetry adapted cluster-configuration interaction (SAC-CI) general-R method finely reproduced the details of the experimental spectra and enabled quantitative assignments for the seven satellite bands: some were newly interpreted. The shake-up transitions were mainly attributed to the valence excitations accompanying the inner-shell ionization. The Rydberg excitations were found to be minor. Three-electron processes such as 1s(-1)n(-2)pi*(2) and 1s(-1)pi(-2)pi*(2) were predicted in the low-energy region where the valence shake-up states such as 1s(-1)n-sigma*, pi-pi* exist. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2004.09.011

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記述言語：英語   出版者・発行元：AMER INST PHYSICS  

Vibrationally resolved spectra have been obtained for the lowest-lying cationic states X B-2(1), A (2)A(1), and B B-2(2) of the water molecule reached after participator resonant Auger decay of core-excited states. The angular distribution has been measured of the first four vibrational components of the X state in the photon energy regions including the O 1s-->4a(1) and the O 1s-->2b(2) core excitations, and for different portions of the vibrational envelope of the B state in the photon energy region including the O 1s-->2b(2) core excitation. For the X state, a large relative spread in beta values of the different vibrational components is observed across both resonances. For the B state, a very different trend is observed for the high binding energy side and the low binding energy side of the related spectral feature as a function of photon energy. A theoretical method based on the scattering K matrix has been used to calculate both the photoabsorption spectrum and the beta values, by taking both interference between direct and resonant photoemission and vibrational/lifetime interference into account. The numerical results show qualitative agreement with the trends detected in the experimental values and explain the conspicuous variations of the beta values primarily in terms of coupling between direct and resonant photoemission by interaction terms of different sign for different final vibrational states. (C) 2005 American Institute of Physics.

DOI： 10.1063/1.1850898

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記述言語：英語   出版者・発行元：AMER INST PHYSICS  

Resonance phenomena in the bending (010), symmetric (100), and asymmetric (001) stretching vibrational modes in water (H2O) molecules have been investigated by measuring differential cross sections (DCSs) at fixed energy losses of 0.43, 0.46, 0.49, and 0.51 eV while sweeping the impact energies from 1.6 to 10 eV, at angles 60degrees and 90degrees, using a crossed-beam method. No resonancelike enhanced features have been observed in the study of the (010) mode. In the DCSs for the combined (100+001) mode, a single broad hump was observed at each angle, whose position shifts towards the higher energy side with increasing scattering angle, a feature typical of the interference profiles previously observed in a study of the (301) vibrational mode. DCSs for the (001) mode exhibited a rather isotropic angular distribution with no evidence of resonances. However, enhancement of DCSs were indeed observed for the (100) mode, at the energy loss of 0.46 eV, which is attributable to the A(1) symmetry resonance that was studied by Seng and Linder [J. Phys. B 9, 2539 (1976)], with a typical s-wave characteristic angular distribution. Theoretical analysis based on the continuum multiple-scattering approach has been carried out to provide rationale to the experimental results. (C) 2005 American Institute of Physics.

DOI： 10.1063/1.1828048

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

We have investigated the lowest-energy satellite bands accompanying the F Is mainline of SiF4 molecule using angle-resolved photoelectron spectroscopy and separated the contributions from the direct shake-up and the conjugate shake-up. The direct shake-up satellites are resonantly enhanced by the shape resonance at the same kinetic energy as that of the mainline: the anisotropy parameter beta of the direct shake-up satellites drops in the vicinity of the shape resonance as for the mainline. The intensity of the conjugate shake-up satellites decreases monotonically with the increase in the photon energy: their beta value also varies monotonically as a function of the energy. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2004.11.123

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

The decay properties of an above-threshold resonance in core-ionized water, which is difficult to. identify with usual spectroscopic methods, have been analyzed by resonant Auger spectroscopy. The resonance is. shown to correspond to a doubly excited neutral state embedded in the O 1s ionization continuum. The main, result of the experiments is the assessment on the dissociative nature of the intermediate state, with a consequent fragmentation in H neutral plus O*H core excited. This dissociation takes place on the same time scale.. as electron decay, and therefore is categorized as an ultrafast. dissociation process.

DOI： 10.1103/PhysRevA.71.010703

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Ultrafast dissociation of the SF6 molecule following F 1s --> a*(1g) excitation has been studied by the coincident measurement of the kinetic energy of the resonantly emitted electron and the momentum of the fragment ion. The nuclear motion takes place on the same time scale as the Auger decay, leading to atomic-like F (1s)-Auger lines in the electron spectrum. De-tuning from the excitation resonance changes the ratio of the two time scales involved. We measured the shift of the atomic-like Auger line and the changes in the parameters that describe the corresponding ionic fragmentation dynamics as a function of the detuning energy. Our data are consistent with predictions based on electron spectroscopic measurements that resolved the Doppler-splitting of the Auger-line. We found that unlike in diatomic molecules a substantial fraction of the excitation energy remains in the neutral fragment(s).

DOI： 10.1088/0953-4075/38/1/001

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

We have obtained electron decay spectra following core excitation of NO2 below both the nitrogen and the oxygen K-edges. The resonant decay through participator processes is weak below the N K-edge, while is more intense below the O K-edge. The propensity rule stating that two valence electrons tend to participate in the decay with opposite spins was verified in the decay of the O1s --> 6a(1) core-excited state and the O1s --> 2b(1) core-excited state(s). Theoretical findings suggest that the relative ordering of the exchange-split core-excited components stems mainly from the valence-valence exchange interaction term being dominant over the core-valence one. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2004.10.045

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

We present a joint theoretical and experimental investigation of the N 1s photoionization of NO2 in the shape resonance region. The theoretical calculations, based on a single-channel relaxed-core Hartree-Fock approximation, predict that the shape resonance appears only in the A(1)-->B-2 transition and that the shape resonance energy of the N 1s(-1) (1)A(1) channel is about 2.6 eV lower in kinetic energy than that of the N 1s(-1) (3)A(1) channel, suggesting that the potential for the (1)A(1) channel is much more attractive than that for the (3)A(1) channel. Symmetry-selected cross sections measured by means of a multiple-ion coincidence imaging prove that the shape resonance appears only in the A(1)-->B-2 transition, as predicted by the calculation. The experimental partial cross sections for the N 1s(-1) (1)A(1) and (3)A(1) channels measured by means of conventional electron spectroscopy exhibit the shape-resonance maxima at photon energies of 416.3 and 415.9 eV, respectively, at corresponding kinetic energies of 3.0 and 3.3 eV, respectively, implying that the attractive potential for the (1)A(1) channel is overestimated in the single-channel approximation. The possible role played by correlation effects on the K-shell ionization of NO2 is discussed in terms of interchannel coupling between the main-line channels and, possibly, with additional excited target states.

DOI： 10.1103/PhysRevA.70.062724

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Resonant and normal Auger electron spectra associated with an O1s initial vacancy of the O-2 molecule have been recorded using photon energies of 541.80, 541.97 and 650 eV. The resonant Auger spectra obtained at 541.80 and 541.97 eV are interpreted as composed essentially of two characteristic parts, one between 10 and 35 eV binding energy reminiscent to direct photoionisation, and another, above 35 eV, associated primarily with spectator decay of the intermediate core-hole state. The spectra above 35 eV owe some similarity to the ordinary Auger electron spectrum recorded at 650 eV, and an interpretation is made in terms of Rydberg series in the cation converging towards the dicationic ionisation limits. The interpretation is based on a relaxation model introduced earlier for atomic resonant Auger spectra. The assignments of the resonant spectra assume that the relevant intermediate neutral states at 541.80 and 541.97 eV governing the Auger decay are essentially the v = 0 and 1 vibrational components of the (O1s) ((4)Sigma(u)(-)) 4psigma Rydberg state. Arguments for this interpretation are given. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.cplett.2004.09.048

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

We use recapture of near-threshold photoelectrons by postcollision interaction with Auger electrons as an effective method for population of the high-Rydberg states of subvalence ionized Ne ions. The subsequent intermultiplet Auger transitions are detected by high-resolution electron spectrometry. The series of transitions 2p(4)(D-1)np D-2, F-2-->2p(4) P-3 up to n=20 are observed and identified with the help of multiconfiguration Dirac-Fock ob initio calculations.

DOI： 10.1103/PhysRevA.70.040702

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記述言語：英語   出版者・発行元：AMER INST PHYSICS  

We report experimental results for electron scattering from tetrafluoroethylene, C2F4, obtained from measurements in two laboratories. An extensive set of differential, integral, and momentum transfer cross sections is provided for elastic scattering for incident electron energies from 1 to 100 eV and inelastic (vibrational excitation) scattering for incident electron energies at 3, 6, 7.5, 8, and 15 eV, and for scattering angles ranging from 10degrees to 130degrees. To highlight the role of intermediate negative ions (resonances) in the scattering process we have also measured excitation functions for elastic scattering and vibrational excitation of the ground electronic state of C2F4 for incident energies between 1.5 and 20 eV. Our results are compared with recent theoretical calculations and a limited number of other experimental results. (C) 2004 American Institute of Physics.

DOI： 10.1063/1.1778386

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Recent developments are reviewed for the Doppler-free resonant Raman Auger spectroscopy studies of atoms and molecules on the beamline 27SU at Spring-8 in Japan. Using the Doppler-free technique, we have investigated the Ne+ excited states which are not accessible by direct photoemission. We have resolved the lowest two members (n = 3, 4) of the series of the inner-valence excitations 2s2p(5)(P-1.3)np S-2, P-2, and D-2 in Ne+ and established the assignments of these levels based on the measured Auger anisotropic parameters and branching ratios. Furthermore, the lifetime widths have been measured for some of these states as well as for 2s(0)2p(6)(S-1)np P-2 (n = 3, 4). We have also investigated vibrational motions in some Auger final states of H2O+. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elspec.2004.02.062

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

The VUV photoabsorption spectrum of tetrafluoroethylene is reported in the wavelength range; 115-320 nm (10.8-3.9 eV). The result is compared with high-energy electron energy loss spectra (EELS). Electrons of incident energy 100 and 30 eV are analysed post-interaction at scattering angles of 5degrees, 15degrees and 30degrees in the energy loss range; 3.0-15.7 eV. Both the photoabsorption and EELS measurements represent the highest resolution data yet reported. The spectra are found to be in good agreement with each other and generally consistent with previous experimental and theoretical work. New photoabsorption features are observed and Rydberg and vibrational assignments suggested. The He(I) photoelectron spectrum is recorded from 9.7 to 20.9 eV and compared to earlier work. New vibrational structure is observed in the first photoelectron band. Implications relevant to the production of CF(2) radicals by photon and electron impact are discussed. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.chemphys.2003.10.031

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DOI： 10.1103/PhysRevA.70.052504

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Electron impact dissociation of CH4 into non-emissive neutral fragments, i.e., CH3 and CH2 radicals, has been studied near threshold of the lowest excited states. The neutral fragments produced are discriminated by means of the threshold ionization technique, which is based on the difference in ionization threshold energy between the parent molecule (14.3 eV, CH4 + e -> CH3+ + H + 2e) and the produced fragments (9.8 eV, CH3 + e -> CH3+ + 2e). Electron impact ionization spectrum of the CH3 radical, which agrees well with the previous measurements, were obtained. The excitation function of CH3 and CH2 radicals by electron impact dissociation of CH4 showed that threshold energies for both CH3 and CH2 radical production were about 8.5 eV. Consideration from the comparison of the threshold energies for CH3 and CH2 radical production with the electron energy loss spectra of CH4; the dissociation channel of the lowest excited states into CH3 radicals play an important role, which is clearly different from the photodissociation.

DOI： 10.1238/Physica.Topical.110a00420

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記述言語：英語   出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD  

We have measured absolute elastic scattering cross sections for electron impact on ethylene. The experimental data have been obtained on two different, crossed-beam electron spectrometers and they cover the energy range from I to 15 eV and scattering angles between 10degrees and 130degrees. Both differential (in angle) and energy dependent cross sections have been measured and comparison is made with earlier data, and also with a number of recent theoretical calculations. (C) 2003 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0969-806X(03)00290-1

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

O 1s single-hole ionization cross sections of CO have been measured for v(')=0-2. The O 1s(-1)sigma(*) shape resonance moves up in energy with an increase in v('), opposite to the C 1s(-1)sigma(*) shape resonance observed previously. Theoretical calculations beyond the fixed-nuclei approximation reproduce these experimental results. The relationship between the v(')-dependent characteristic internuclear distance in the residual ion and the shape resonance energy is discussed.

DOI： 10.1103/PhysRevA.68.022508

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Angular differential energy gain spectra of C4+ and N4+-He collisions have been measured at the collision energy of 100 and 120 eV/q, respectively. In the case of C4+-He collisions, the oscillation structure in the angular differential cross section of the double-electron capture into the C2+(1s(2) 2s(2) S-1) state has been clearly observed. On the other hand, in the case of N4+-He collisions, the N3+(1s(2) 2p(2) S-1) product channel in single-electron capture process is dominant at the forward scattering angle and the N3+ (1s(2) 2p(2) D-1 and/or P-3) state becomes dominant at larger scattering angle. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0168-583X(02)01949-3

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Absolute differential cross sections (DCSs) for elastic and vibrationally inelastic scattering of electrons from CF3Cl and CF3Br have been determined by a crossed-beam experiment, in the energy range of 1.5-100 eV and over the scattering angles of 15degrees-130degrees. The relative flow method was applied to normalize these cross sections, using helium as a standard. The present results are compared with the previous ones for CF3H, CF4 and CF3I. An effect due to a long-range interaction of polar molecules has been observed in a systematic manner in elastic DCSs below 3 eV. Broad resonance structures where the vibrational cross sections are enhanced are observed at around 7 eV in both CF3Cl and CF3Br as experimentally confirmed previously in CF3H, CF4 and CF3I. The continuum multiple-scattering method is also employed to carry out the analysis.

DOI： 10.1088/0953-4075/36/9/314

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

We have measured absolute elastic scattering and vibrational excitation cross sections for electron impact on ethylene. The experimental data have been obtained on two different crossed-beam electron spectrometers and they cover the energy range from 1 to 1,00 eV and scattering angles between 10degrees and 130degrees. Both differential (in angle) and energy-dependent cross sections have been measured. The differential cross sections have also been analysed using a molecular phase shift analysis technique in order to derive the integral elastic and elastic momentum transfer cross sections. Comparison is: made with earlier data,where available, and also with a number of recent theoretical calculations.

DOI： 10.1088/0953-4075/36/8/314

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Out-of-plane nuclear motion stimulated in the core-excited state and symmetry breaking due to this nuclear motion have been investigated for B Is excitation in the BF3 molecule by a combination of three different experimental methods: angle-resolved ion-yield spectroscopy, vibrationally resolved resonant Auger electron spectroscopy and quadruple-ion coincidence momentum-imaging technique. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0301-0104(02)00903-5

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

Using very high resolution achieved by the Doppler-free resonant Raman Auger technique, we have resolved the lowest terms of the series of inner-valence excitations 2s2p(5)(P-1,P-3)np S-2, P-2, and D-2 in Ne+. The measured Auger anisotropic parameters and branching ratios help to establish the assignments of these levels. The measured lifetime widths are in reasonable agreements with ab initio calculations available in the literature.

DOI： 10.1103/PhysRevLett.90.153005

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

Angle-resolved resonant Auger-electron spectroscopy has been carried out on the nitrogen molecule at selected photon energies around 419 eV, where a 1s core electron and two valence electrons are promoted into the lowest unoccupied molecular orbital 1pi(g). Significant enhancement of a specific band, which cannot be disentangled in direct photoionization, is observed at a binding energy of 37.6 eV, with a value of the anisotropy parameter beta much smaller than 2. We assign this new band to the transition to a doubly excited cationic state of N-2, in which two of the excited valence electrons remain in the 1pi(g) orbital, proposing a "double spectator" type decay mechanism. This observation shows how to preferentially probe multiply excited configurations of cations using multiple resonant excitation.

DOI： 10.1103/PhysRevA.67.032504

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

We have studied angular correlations between resonant Auger electrons and successive second-step Auger electrons emitted in a cascade decay after photoexcitation of resonances 3d(5/2)(-1)5p in Kr and 4d(5/2)(-1)6p in Xe. Two spectrometers were used for the angle-resolved detection of the two electrons in coincidence. Angular correlations for several pairs of strong lines have been measured in both atoms. The experimental results are compared with multiconfiguration Dirac-Fock calculations which include electron correlations in the initial, intermediate and final states of the cascade. In general, good agreement between experiment and theory is obtained.

DOI： 10.1088/0953-4075/36/2/312

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

The electronic states of CF3I have been investigated using photon and electron energy loss spectroscopy from 4 to 20 eV (3 10 nm > lambda > 60 nm). Assignments have been suggested for each of the observed absorption bands incorporating both valence and Rydberg transitions. Vibrational structure in each of these bands is observed for the first time. Absolute photo-ab sorption cross-sections have also been measured and are compared with earlier measurements. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S1387-3806(02)00939-9

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Total cross-sections (TCSs) for electron and positron scattering from C3H4 isomers (allene and propyne) were measured using the linear transmission method in the range of 0.8-600 eV for electrons and 0.7-600 eV for positrons. Elastic cross-sections for electron scattering were also measured by a crossed-beam experiment in the range of 2-100 eV. Sharp resonance-like peaks were observed in the electron TCSs for propyne around 3.6 and 8 eV, and 2.5 and 11 eV for allene. The positron TCSs for these molecules were found to be smaller and much smoother than the electron TCSs. Clear differences in resonance positions and magnitudes between the two isomers can be viewed as an isomer effect. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0009-2614(02)01823-7

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記述言語：英語   出版者・発行元：INST NUCLEAR CHEMISTRY TECHNOLOGY  

A systematic analysis of the absolute differential cross sections (DCSs) for electron scattering by halogen-containing molecules CF3X (X = H, F, Cl, Br, I) has been performed with impact energy and scattering angle ranging from 1.5 to 100 eV and 15 to 130degrees, respectively. Three of the results of these experiments are described in the present report. Firstly, a clear difference is demonstrated in the elastic-scattering cross section angular distributions of polar and nonpolar molecules with the substitution of one of the F atoms in CF4 for a H, Cl, Br or I atom. Secondly, vibrational excitation spectra of the unresolved composite modes (mainly CF3 stretching) for CF3X reveal a common broad structure in the region from 7 to 9 eV due to shape resonance. The third result presented is the observation of a low-lying electronic state of CF3Cl, CF3Br, and CF3I. This feature is enhanced at lower incident energies and larger scattering angles. Also discussed are some preliminary results on the formation of negative and neutral fragments from SiF4 and CH4 by electron impact.

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DOI： 10.1088/0953-4075/36/21/L02

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

Absolute differential cross sections (DCSs) for elastic and vibrationally inelastic scattering of electrons from C3H4 isomers (allene and propyne) have been determined by a crossed-beam experiment in the energy range 1.5-100 eV and over the scattering angles between 15degrees-130degrees. The relative flow method was applied to normalize these cross sections, using helium as a standard. Clear evidence of the strong isomer effect has been observed in DCSs for both elastic and vibrational excitation processes, and the isomer effect still conspicuously persists in total elastic cross sections. Two resonance regions where the vibrational cross sections are strongly enhanced are observed in both allene and propyne below a few eV, while both the DCSs become identical at higher energies, hence weakening the isomer effect. More details of the observed mode selectivity are discussed based on the selection rules for vibrational excitation via a shape resonance as well as on an argument based on the angular correlation.

DOI： 10.1103/PhysRevA.66.032714

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

High resolution spectra and angular anisotropy of the resonant Auger electron emission from the 4d(-1)6p photoexcited states in Xe are studied. The low energy part of the spectra which contains transitions to the 5s(1)5p(5)6p and 5s(0)5p(6)6p states of Xe(+) and the subsequent cascade Auger transitions to the 5s(2)5p(4) and 5s5p(5) states of Xe(2+) is investigated in detail. High resolution has enabled us to determine the values of anisotropy parameter beta for many individual resonant Auger transitions and for some second step transitions which had not been measured previously. The results are compared with the theoretical predictions based on the multiconfiguration Dirac-Fock approach.

DOI： 10.1088/0953-4075/35/15/307

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Absolute differential cross sections for elastic scattering from CF(3)I are reported between 15 and 60 eV and over scattering angles of 20 -130. Vibrational excitation cross sections for the composite stretching modes are shown to be preferentially enhanced at incident electron energies between 5 and 9 eV indicating the formation of short lived shape resonances.

DOI： 10.1088/0953-4075/35/15/303

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

The photon-ion merged beam technique has been used to measure the ionization cross sections of I-, Cs+, Be and Ba2+-ions in the energy region from 40 to 185 eV, which is dominated by photoexcitation from the 4d shell(4). Within the experimental accuracy, the total oscillator strengths for these ions and for the I+, I2+, Xe+ and Xe2+ ions, that were recently studied by some of the present authors, are identical, with the contribution from the 4d --> np or of resonances becoming more important with increasing nuclear charge and ionization stage, and with the maximum value of the continuum cross section increasing as the nuclear number is enlarged. The present data support the assumption that the 4f wavefunctions contract gradually with increasing ionization, both along isonuclear and isoelectronic sequences, for ionic charges ranging from -1 to +2.

DOI： 10.1088/0953-4075/35/13/301

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Absolute differential cross sections (DCSs) for electron impact excitation of electronic states Of CO2 in the 10.8-11.5 eV energy-loss range are reported. These data were obtained at the incident electron energies 20, 30, 60, 100 and 200 eV and over the scattered electron angular range 3.5degrees-90degrees. The accuracy of our experimental methods has been established independently by using several different normalization techniques at both Sophia and Flinders Universities. Generalized oscillator strengths were derived from our measured DCSs and then extrapolated to zero momentum transfer, in order to determine the optical oscillator strengths. These optical oscillator strengths, where possible, are compared with the results from previous measurements and calculations.

DOI： 10.1088/0953-4075/35/3/311

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

We present measured and calculated differential cross sections, as well as calculated integral cross sections, for elastic electron collisions with CH3F, CHF2F2, CHF3, and CF4. The calculated cross sections were obtained with the Schwinger multichannel method, and a Born-closure procedure was used to improve the differential cross sections for polar systems. Polarization effects were found to be relevant even for systems with moderately large permanent dipole moments, such as CH3F and CHF3. In general, there is good agreement between theory and experiment.

DOI： 10.1103/PhysRevA.65.022702

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記述言語：英語  

Angle-resolved resonant Auger spectra for the transitions Xe 3d5/2 -16p → 4d-2np are recorded with optical and electron energy bandwidths smaller than the lifetime widths Γ of the Auger initial and final states. All the multiplet structures are resolved for the ionic core 4d-2 of the spectator Auger final states and assigned as 4d-21S0np, 1D2np, 1G4np, 3P0,1,2np and 3F1,2,3np, n = 6, 7, by comparison with previous measurements and calculations for the corresponding normal Auger emission. The resonant Auger anisotropy parameters obtained from the angular distribution measurements agree well with those expected from the spectator model.

DOI： 10.1142/S0218625X0200194X

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Resonant Auger spectra of H2O are recorded with unprecedented resolution, for excitation energies tuned across the 0 1s --> 2b(2) resonance, Electron emission spectra for decay to the lb(2)(-1) final state show a partially resolved vibrational envelope whose overall appearance is photon energy dependent. Comparison with ab initio calculations indicates that the two-dimensional nuclear motion of the Auger final state can be controlled by sampling different portions of the potential curve and changing the nuclear motion in the core-excited state.

DOI： 10.1088/0953-4075/35/1/104

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Resonant Auger transitions from the 3d(-1)5p photoexcited states in Kr to the 4s(-1)4p(-1)5p and 4s(-2)5p levels and subsequent Auger decay to the 4p(4) and 4s4p(5) states of Kr2+ are studied by means of angle-resolved electron spectroscopy. The angular anisotropy parameters beta are determined for most of the prominent lines in the spectrum of emitted electrons. It is found that the first-step spectator transitions are strongly anisotropic, while the second-step participator transitions are almost isotropic. Extensive multiconfiguration Dirac-Fock calculations are performed which include correlations in all of the states involved. Noticeable improvements are achieved in comparison with early calculations. The energy position of the main spectral lines and their intensities are described satisfactorily. It turns out that the interference effects due to coherent excitation of resonances influence the anisotropy of the Auger emission significantly. The calculated beta parameters agree very well with the experiment.

DOI： 10.1088/0953-4075/34/19/307

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Using the photon-ion merged-beam technique, we have measured the absolute photoionization cross sections for Xe2+ and Xe3+ formation from Xe+ at selected energies between 80 and 140 eV, and utilized the absolute data to normalize our previously reported relative cross sections. The structure and energy dependence of the cross sections for Xe+ deviate from those of neutral Xe; however, the maximum total cross section for Xe+ is, within the experimental error, the same as for Xe.

DOI： 10.1088/0953-4075/34/17/309

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記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：IOP PUBLISHING LTD  

Angle-resolved resonant Auger spectra for the transitions Xe 3d(5/2)(-1)6p --> 4d(-2) np are recorded with optical and electron energy band widths narrower than the lifetime widths of the Auger initial and final states. All the multiplet structures are resolved for the ionic core 4d(-2) of the spectator Auger final states and assigned as 4d(-2) S-1(0) np, D-1(2) np, (1)G(4) np, P-3(0,1,2) np, and F-3(1,2,3) np (n = 6, 7) by comparison with previous measurements and calculations for the corresponding normal Auger emission. The resonant Auger anisotropy parameters obtained from the angular distribution measurements agree well with those expected from the spectator model.

DOI： 10.1088/0953-4075/34/11/103

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

A crossed-beam experiment has been performed to measure differential vibrationally inelastic cross sections for electron scattering from CO2 in the energy range from 1.5 to 30 eV over the scattering angles of 10-130 degrees. Near the (2)Pi (u) resonance at 3.8 eV, the angular and energy dependences of the differential cross sections (DCS) have been determined in detail. Absolute values are obtained by normalizing the inelastic cross sections to the elastic ones. To determine the intensity of the individual vibrational modes from the energy-loss spectra, a deconvolution procedure was employed. The DCS for the pure fundamental modes (010), (100), (001) and the overtone of (020) are reported in detail for the first time over wide ranges of impact energy and scattering angle.

DOI： 10.1088/0953-4075/34/10/308

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

We present absolute measurements of differential elastic electron scattering cross sections from benzene (C6H6) and hexafluorobenzene. (C6F6) The measurements have been performed in our two laboratories on different crossed-beam apparatuses for scattering angles between 10 degrees and 130 degrees. C6H6 at the Australian National University in the energy range from 1.1 to 40 eV, and C6F6 at Sophia University from 1.5 to 100 eV. The cross sections for both molecules, which are characterized by strong forward-angle scattering and large-angle oscillations, are favourably compared with recent theoretical calculations.

DOI： 10.1088/0953-4075/34/6/304

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DOI： 10.1103/PhysRevA.63.050703

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

The Anger emission following the resonant excitation of the BCl3 molecule has been investigated using monochromatized synchrotron radiation. The B Is excitation to the unoccupied Anti-bonding 4e' orbital enhances the shoulder structure in the low kinetic energy side of the photoemission from the 2e' valence bonding orbital. Based on a series of quantum mechanical calculations, this shoulder structure is interpreted as the dynamical Auger emission which reflects the B-Cl stretching nuclear motion and appears as a result of the purely multistate vibronic coupling effect among the Jahn-Teller split B 1s(-1)4e' E' states and the closely lying B 1s(-1)3a'(1) A'(1) state.

DOI： 10.1103/PhysRevLett.85.3129

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

We report absolute measurements, using the relative how technique, of low-to-intermediate energy (1.5-100 eV) differential cross sections (DCSs) for elastic electron scattering and vibrational excitation of nitrous oxide. These results, which have been undertaken independently in our two laboratories on different experimental apparatus, are compared in detail with each other and with previous experimental results and theoretical calculations. For elastic scattering the level of agreement between the DCSs from the two laboratories is generally very good. However, the agreement with recent theoretical calculations is rather poor, particularly at energies below 10 eV. For vibrational excitation DCS results have been measured at 2.4 and 8 eV-energies corresponding to the positions of two broad (2)Pi and (2)Sigma shape resonances respectively.

DOI： 10.1088/0953-4075/33/9/301

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Dissociative single and double photoionization of N-2 as a function of the exciting-photon energy has been investigated using monochromatized synchrotron radiation in the exciting photon energy range between 37 and 69 eV by dispersed VUV fluorescence spectroscopy (80 nm less than or equal to lambda fl less than or equal to 200 nm). Relative partial emission cross sections for N I and N II fluorescence have been recorded as a function of the exciting-photon energy. There is strong evidence that the precursors of dissociative single ionization with one of the fragments being excited are the N-2(+) 2 sigma(g)(-1) (2)Sigma(g)(+) state with its closely lying correlation stares only. An approximately linear excess energy dependence of the cross sections for the molecular double photoionization into the N-2(2+) D (1)Sigma(u)(+) state has been observed in the excitation spectrum of D (1)Sigma(u)(+) --> X (1)Sigma(g)(+) fluorescence in N-2(2+) close to its threshold. Evidence for dissociative double photoionization with excitation has been found.

DOI： 10.1088/0953-4075/33/3/316

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DOI： 10.1103/PhysRevA.61.060701

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DOI： 10.1088/0953-4075/33/13/101

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

We have determined the ratio of the s and d Auger-decay amplitudes and their phase difference for the resonant Auger transition 2p(3/2)(-1)4s --> 3s(-1)3p(-1)4s(P-2) from the measurement of the angular correlation between the resonant Auger emission and the subsequent second-step Auger emission, as well as the angular distribution measurements for these two electron:emissions. The analysis of the experimental data is based on the nonrelativistic LSJ coupling approximation.

DOI： 10.1103/PhysRevLett.83.5463

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Absolute differential cross-sections (DCS) for elastic electron scattering by N2O have been measured by a crossed-beam experiment with impact energies ranging from 1.5 to 100 eV and angles between 20 degrees and 130 degrees; DCS below 5 eV have been observed. A clear p-wave structure is observed for the first time in the DCS at 2.2 eV where a narrow intense shape resonance has been reported. A continuum multiple scattering (CMS) calculation has also been carried out. The CMS results and the reported theoretical DCS show much larger deviations near 5 eV than those at 2.2 eV from the present experimental values, indicating that an approximation of higher quality is needed to account for the DCS in the non-resonant region. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0009-2614(99)00701-0

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

We have investigated the P 2p photoabsorption of a D-3h symmetry molecule PF, using angle-resolved ion yield spectroscopy and analyzed it with the help of first-principles calculations within the framework of the DV-X alpha method. Nearly isotropic ionic fragmentation is observed irrespective of the symmetries of the excited states and interpreted using a model in which two axial P-F bonds and three equatorial P-F bonds are assumed to have roughly the same rupture probabilities via P 2p Auger decay. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0009-2614(99)00578-3

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

Total cross sections for electron (e(-)) and positron (e(+)) scattering from C3H8 and C3F8 have been measured from 0.8 to 600 eV and 0.7 to 600 eV, respectively. We have also investigated differential elastic cross sections by electron impact from 2.0 to 200 eV, and compared them with the present theoretical results. For e(-) scattering from C3H8, the cross sections are found to be larger by a factor of 2 than those of e(+) scattering below 20-30 eV. They show a large peak at 8 eV due to a shape resonance and a shoulderlike structure in the region of 20-40 eV. For e(-) scattering from C3F8, the cross sections are again larger by at least a factor of 2 than those of e(+) scattering below 50 eV, and they have two peaks at 4 and 8 eV, followed by a broad peak in the region of 20-40 eV. Some small structures overlie the broad hump. Both e(-) and e(+) impact cross sections for C3H8 and C3F8 quickly approach each other beyond 200 eV. From the differential cross section study, we have been able to provide more detailed information on shape resonances, and also we have carried out some analysis of resonances in vibrational excitation results. In general, the total and integrated elastic cross sections are in good qualitative and quantitative agreement. [S1050-2947(99)04403-0].

DOI： 10.1103/PhysRevA.59.2006

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DOI： 10.1063/1.479270

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DOI： 10.1088/0953-4075/32/13/102

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Photoion yields from doubly charged Xe ions were measured in the 4d-threshold energy region. The experiment was performed by a photon-ion merged-beam technique with synchrotron radiation as a light source. The measured spectrum mainly consists of strong 4d --> 5p transition lines at around 57 eV, a very broad peak at around 100 eV, and the preceding strong discrete peaks lying between 79 and 90 eV. The peak position of the broad peak changes very little from that in Xe+ photoion-yield spectra of Sane et al. The enhancement of discrete peaks in the Xe2+ spectrum implies a further collapse of nf-wavefunctions than that of Xe+.

DOI： 10.1088/0953-4075/31/18/011

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

The undispersed and dispersed vacuum ultraviolet fluorescence (lambda(F1) = 105-200 nm) after neutral photodissociation excitation of CO has been measured as a function of the exciting-photon energy in the region between 18.5 and 36 eV. The target-gas pressure dependence of the fluorescence intensities for energies below 23 eV was observed to be linear. For exciting photon energies above 23 eV photoelectron impact excitation of neutral CO from the ground to the CO(A (1) Pi) state causes a nonlinear pressure dependence of the undispersed fluorescence intensity. CO Rydberg states converging to the CO+ D and C states have been assigned on the basis of the recorded spectra. Previous assignments of the R-C(3s,4s,3p,4p) and R-D(3s,4s) Rydberg series could be supported and the identification of their vibrational levels have been considerably extended. Two new progressions (R-D(5s,6s)) have been assigned.

DOI： 10.1088/0953-4075/30/8/009

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記述言語：英語   出版者・発行元：AMER CHEMICAL SOC  

The dispersed fluorescence yields of excited photodissociation fragments of N2O are obtained by means of the two-dimensional fluorescence spectroscopy as a function of both the excitation energy (E(ex)) in the range 14.28-36.35 eV and the fluorescence wavelength (lambda(fl)) in the range 80-200 nm. Final dissociation products, dissociation limits, and correlation among different neutral dissociation channels are identified. In most cases of the neutral dissociation of superexcited states below 20 eV, neutral dissociation is shown to proceed via multichannel predissociation. The nd pi Rydberg states converging to N2O+(C-2 Sigma(+)) are shown to have the neutral dissociation channel with specific branching ratios for their decay. The neutral dissociation into N-2(a(1) Pi(g)) + O is shown to diminish at the threshold energy for the three-body neutral dissociation, Broad features of enhanced fluorescence above 20 eV are identified as multiply excited neutral states.

DOI： 10.1021/jp9620173

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記述言語：英語   出版者・発行元：ROYAL SWEDISH ACAD SCIENCES  

Using a photon-ion merged-beam technique, we studied the photoionization of multiply charged Xeq+ (q = 1-3) ions in the 4d excitation region (50-140eV). Relative yield spectra of photoions created by single (q-->q+1) and double (q-->q+2) photoionization were measured as a function of photon energy. A broad ''4d giant resonance'' peak with some preceding discrete peaks appears in each total ion spectrum. The intensities of discrete peaks observed at around 4d ionization threshold strongly depend on the target charge state. Those for Xe3+ target are very strong, whereas those for Xe+ are weak. Peaks due to 4d-->5p transition, which cannot occur in the neutral Xe case, has also been observed for each ion-target. The experimental spectrum for Xe+ has been analyzed by a multiconfiguration Dirac-Fock calculation This calculation shows that results observed may be explained in terms of the correlation of valence and excited orbitals, and the effect of 4f-orbital collapse, of which the degree varies strongly with the change of the effective nuclear charge.

DOI： 10.1063/1.119450

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DOI： 10.1063/1.474581

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Dispersed vacuum-ultraviolet fluorescence from neutral dissociation fragments in the wavelength range from 100-200 nm has been measured after photodissociation of CO as a function of the exciting photon energy between 18.5 and 29 eV. The decay channels of neutral dissociative excitation of the formed CO Rydberg states converging to the CO+ D and C states have been analysed. The vibrationally excited levels of the R(D)(ns) and R(D)((n + 1)s) Rydberg states preferentially dissociate into the fragments C I(2s(2)2p(n - 1)d/ns (2S+1)L(J))+ O I(2s(2)2p(4 2S+1)L(J)). Relative cross sections for the observed lines of C I and O I have been obtained. For the lines at 193, 167.5 and 156 nm estimations for absolute cross sections are presented. Evidence for superexcited states has been found in the exciting photon energy range between 24 and 27.5 eV.

DOI： 10.1088/0953-4075/29/16/011

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

The excitation function of the dissociative photoionization excitation (DIE) of N-2 has been measured with the detection technique of coincidence between photoion and fluorescence-photon using extreme-uv synchrotron radiation (SR) as an excitation source in the energy region of 35 - 65 eV and the detection direction parallel and perpendicular to the polarization vector of SR. The coincidence spectra obtained in this energy region show at least two qualitatively different structures originating from two different DIE processes. The major components of the DIE in the present energy region is ascribed to the dissociation of the 2 sigma(g)(-1 2)Sigma(g)(+) state which is strongly coupled with correlation states in the (2) Sigma(g)(+) symmetry.

DOI： 10.1016/0368-2048(96)02896-4

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

The excitation function of the dissociative photoionization excitation (DIE) of N-2 has been measured with the detection technique of coincidence between photoion N+ and a fluorescence photon emitted from an excited atom N* using extreme-UV synchrotron radiation (SR) as an excitation source in the energy region of 35-65 eV. The axis of the detection system was set at two angles, parallel or perpendicular with respect to the major axis of the elliptically polarized SR, in the present measurement. The coincidence spectra obtained in this energy region show at least two qualitatively different structures originating from two different ors processes. The major components of the DIE in the present energy region are ascribed to the dissociation of the 2 sigma(g)(-1 2)Sigma(g)(+) state which is strongly coupled with correlation states in the (2) Sigma(g)(+) symmetry. In addition, DIE from other precursor states in the Pi symmetry or dissociative photo-double ionization excitation (DDIE) was also observed.

DOI： 10.1088/0953-4075/29/9/017

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

The absolute photoabsorption cross sections (sigma(t)) and photoionization quantum yields (eta) of alkanes (C2H6 and C3H8) have been measured in the 50-120 nm region using synchrotron radiation as a light source and an ionization chamber combined with metallic thin film windows. We have evaluated the absolute photoionization cross sections (sigma(i)) and the total cross sections for non-ionizing processes, i.e., the neutral-dissociation cross sections (sigma(d)) following superexcitation. Several superexcited states have been revealed in these spectra.

DOI： 10.1016/0368-2048(96)02879-4

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Dispersed fluorescence of excited atomic fragments has been recorded after neutral photodissociation of CO as a function of the exciting-photon energy using photon-induced fluorescence spectroscopy. In the fluorescence wavelength range between 90 and 200 nm several lines have been detected which were not previously observed after neutral photodissociation of CO. The recorded relative partial emission cross sections show complicated structures due to resonance effects. The strength of the observed structures are strikingly different in the partial cross section functions.

DOI： 10.1016/0368-2048(96)02913-1

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Neutral dissociation of a superexcited N2O molecule has been studied by measuring dispersed vuv fluorescence spectra of dissociation fragments as a function of the excitation wavelength. Obtained spectra are presented as a two dimensional fluorescence excitation spectrum (2D-FES). The 2D-FES clearly shows the complex neutral dissociation behavior of superexcited states of N2O.

DOI： 10.1016/0368-2048(96)02914-3

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記述言語：英語   出版者・発行元：ELSEVIER SCIENCE BV  

Photoion kinetic energy spectra of O+ produced by the dissociative photoionization of O-2 have been measured as a function of photon wavelength in the vacuum-uv region. which have shown both the non-Franck-Condon population of the vibrational O-2(+)(B-2 Sigma(g)) states near the ionization thresholds via bath resonance-assisted photoionization and direct ionization.

DOI： 10.1016/0368-2048(96)02897-6

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記述言語：英語   出版者・発行元：IOP PUBLISHING LTD  

Dispersed VUV fluorescence emitted from photodissociation fragments in the wavelength range between 90 and 200 nm has been recorded following the neutral photodissociation of CO using monochromatized synchrotron radiation for exciting-photon energies close to the respective dissociation thresholds. Qualitatively different energy dependencies of the fluorescence intensities have been observed close to the thresholds. Atomic carbon fluorescence at wavelengths of 119, 128, 132.9, and 146 nm has been observed for the first time after neutral photodissociation with excitation of CO.

DOI： 10.1088/0953-4075/28/24/013

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記述言語：英語   出版者・発行元：AMERICAN PHYSICAL SOC  

DOI： 10.1103/PhysRevLett.74.239

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DOI： 10.1088/0953-4075/28/6/006

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記述言語：英語   出版者・発行元：AMER INST PHYSICS  

Collisional deexcitation cross sections of He(2 P-1) by Ne have been measured in a region of the mean collisional energy between 17 and 38 meV using a pulse-radiolysis method. Measured cross sections are in a range of 20-25 Angstrom(2) and increase with increasing collisional energy. The experimental cross sections are compared with the calculated ones for total and partial excitation transfer into highly excited Ne atoms. Fairly good agreement between calculated and experimental results indicates that in the deexcitation of He(2 P-1) the excitation transfer into Ne-*(6p(3), 5s(2), or 6S(4)) is important in the measured mean collisional energy region. It is also shown that a dipole-dipole interaction plays an important role in the excitation transfer from He(2 P-1) to Ne.

DOI： 10.1063/1.466800

Web of Science

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DOI： 10.1063/1.464834

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会議種別：ポスター発表  

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会議種別：ポスター発表  

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会議種別：ポスター発表  

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会議種別：ポスター発表  

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会議種別：ポスター発表  

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会議種別：ポスター発表  

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会議種別：ポスター発表  

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会議種別：ポスター発表  

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会議種別：ポスター発表  

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