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Journal Articles

Charge transfer cross sections of slow multiply charged neon ions in collisions with noble gas atoms

Kusakabe, Toshio*; Shirai, Toshizo*

Plasma and Fusion Research (Internet), 9(Sp.2), p.3401119_1 - 3401119_4, 2014/07

We have measured the single- and multiple-charge transfer cross sections of Ne$$^{q+}$$ ions (q = 2 $$sim$$ 6) in collisions with Ne, Ar, Kr and Xe atoms at 2 kV in acceleration voltage. The multiply charged neon ions were extracted from a compact electron beam ion source called micro-EBIS using a strong ring permanent magnet. The cross sections of charge transfer were determined based on an initial growth rate method. In the Ne$$^{5+}$$ + Ar, Kr and Xe, and Ne$$^{6+}$$ + Ne, Ar and Xe collisions, five fold-charge transfer cross sections were derived. In the Ne atoms, the double-charge transfer of Ne$$^{2+}$$ ions, triple-charge transfer ofNe$$^{3+}$$ ions, and four fold-charge transfer of Ne$$^{4+}$$ ions are the so-called symmetric resonant charge transfer processes. The present data in these collisions are found to be in good accordance with the previous data of Kaneko et al.

Journal Articles

Charge-transfer cross sections of slow doubly and triply charged carbon ions from CO and CO$$_{2}$$ molecules

Kusakabe, Toshio*; Shiota, Kenji*; Shirai, Toshizo*

Plasma and Fusion Research (Internet), 8(Sp.1), p.2401145_1 - 2401145_4, 2013/11

no abstracts in English

Journal Articles

Energy levels and spectral lines of tungsten, W III through W LXXIV

Kramida, A. E.*; Shirai, Toshizo*

Atomic Data and Nuclear Data Tables, 95(3), p.305 - 474, 2009/05

 Times Cited Count:145 Percentile:8(Physics, Atomic, Molecular & Chemical)

The energy levels and spectral lines of multiply ionized tungsten atoms, W$$^{2+}$$ through W$$^{73+}$$, have been compiled. Experimental data on spectral lines and energy levels exist for the spectra of W III through W VII, W XXVIII through W LI, W LIII, and W LV through LXV. For W VIII, the four lowest energy levels were derived from the series limits of W VII. For W LXIV (Na-like) and W LVI (K-like), we supplement experimental data on energy levels and wavelengths with predicted values found by accurate interpolations and extrapolations along the isoelectronic sequences. For W LXXIII (He-like) and W LXXIV (H-like), theoretical data on energy levels and line wavelengths are compiled. For WIII, we include experimentally determined radiative transition probabilities where available. The ground state configurations and terms were determined for all stages of ionization. A value of ionization energy is included for each ion.

Journal Articles

Spectral data for gallium; Ga I through Ga XXXI

Shirai, Toshizo*; Reader, J.*; Kramida, A. E.*; Sugar, J.*

Journal of Physical and Chemical Reference Data, 36(2), p.509 - 615, 2007/06

 Times Cited Count:42 Percentile:14.51(Chemistry, Multidisciplinary)

Journal Articles

Analytic cross sections for electron impact collisions with nitrogen molecules

Tabata, Tatsuo*; Shirai, Toshizo*; Sataka, Masao; Kubo, Hirotaka

Atomic Data and Nuclear Data Tables, 92(3), p.375 - 406, 2006/05

 Times Cited Count:47 Percentile:7.06(Physics, Atomic, Molecular & Chemical)

no abstracts in English

Journal Articles

Compilation of wavelengths, energy levels, and transition probabilities for W I and W II

Kramida, A. E.*; Shirai, Toshizo*

Journal of Physical and Chemical Reference Data, 35(1), p.423 - 683, 2006/03

 Times Cited Count:49 Percentile:12.54(Chemistry, Multidisciplinary)

Energy levels, wavelengths, and transition probabilities of the first and second spectra of tungsten, W I and W II, have been compiled. Wavelengths of observed transitions and energy levels derived from those wavelengths have been obtained from a critical evaluation of the available literature. Measured transition probabilities for some of the observed transitions have been compiled from the published literature.

Journal Articles

Atomic and molecular data activities for fusion research at JAERI

Kubo, Hirotaka; Sataka, Masao; Shirai, Toshizo

Journal of Plasma and Fusion Research SERIES, Vol.7, p.352 - 355, 2006/00

no abstracts in English

Journal Articles

Cross sections of charge transfer by slow doubly-charged carbon ions from various carbon containing molecules

Kusakabe, Toshio*; Shiota, Kenji*; Kubo, Hirotaka; Shirai, Toshizo*

Journal of Plasma and Fusion Research SERIES, Vol.7, p.237 - 239, 2006/00

no abstracts in English

Journal Articles

Production and compilation of charge changing cross sections of ion-atom and ion-molecule collisions

Imai, Makoto*; Shirai, Toshizo*; Saito, Manabu*; Haruyama, Yoichi*; Ito, Akio*; Imanishi, Nobutsugu*; Fukuzawa, Fumio*; Kubo, Hirotaka

Journal of Plasma and Fusion Research SERIES, Vol.7, p.323 - 326, 2006/00

no abstracts in English

Journal Articles

Compilation of wavelengths and energy levels of tungsten, W III through W LXXIV

Kramida, A. E.*; Shirai, Toshizo*

Journal of Plasma and Fusion Research SERIES, Vol.7, p.334 - 337, 2006/00

no abstracts in English

Journal Articles

Selective transition to the closely-lying states Cs(7$$D$$$$_{3/2}$$) and Cs(7$$D$$$$_{5/2}$$) by femtosecond laser pulses

Yamada, Hidetaka; Yokoyama, Keiichi; Teranishi, Yoshiaki*; Sugita, Akihiro; Shirai, Toshizo*; Aoyama, Makoto; Akahane, Yutaka; Inoue, Norihiro*; Ueda, Hideki*; Yamakawa, Koichi; et al.

Physical Review A, 72(6), p.063404_1 - 063404_5, 2005/12

 Times Cited Count:5 Percentile:69.63(Optics)

A demonstration of coherent quantum control for ultrafast precise selection of closely-lying states is reported. A phase-locked pair of femtosecond laser pulses is generated through a pulse shaper to excite the ground-state cesium atom to the Cs(7$$D$$$$_{3/2}$$) and Cs(7$$D$$$$_{5/2}$$) states by two-photon absorption. The excited state population is measured by detecting fluorescence from each spin-orbit state. By controlling the phase-difference of the pulse pair, an ultrafast precise selection is accomplished. The contrast ratio of the maximal to minimal selection ratio exceeds 10$$^3$$ with the delay less than 400 fs.

Journal Articles

Optimal control of ultrafast selection

Yokoyama, Keiichi; Teranishi, Yoshiaki; Toya, Yukio; Shirai, Toshizo; Fukuda, Yuji; Aoyama, Makoto; Akahane, Yutaka; Inoue, Norihiro*; Ueda, Hideki; Yamakawa, Koichi; et al.

Journal of Chemical Physics, 120(20), p.9446 - 9449, 2004/05

 Times Cited Count:5 Percentile:81.91(Chemistry, Physical)

Optimal laser control for ultrafast selection of closely-lying excited states, whose energy separation is smaller than the laser bandwidth, is reported on the two-photon transition of atomic cesium; Cs(6S $$rightarrow$$ 7D$$_{J}$$, J = 5/2 and 3/2). Selective excitation was carried out by pulse shaping of ultrashort laser pulses which were adaptively modulated in a closed-loop learning system handling eight parameters representing the electric field. Two-color fluorescence from the respective excited states was monitored to measure the selectivity. The fitness used in the learning algorithm was evaluated from the ratio of the fluorescence yield. After fifty generations, a pair of nearly transform-limitted pulses were obtained as an optimal pulse shape, proving the effectiveness of "Ramsey fringes" mechanism. The contrast of the selection ratio was improved by $$sim$$ 30 % from the simple "Ramsey fringes" experiment.

Journal Articles

Total cross sections for charge transfer by multiply charged neon and argon ions colliding with various hydrocarbons at keV energies

Kusakabe, Toshio*; Miyamoto, Yoshiharu*; Ishida, Rikiya*; Ito, Kojiro*; Kuroyanagi, Nobuhiro*; Nakai, Yota*; Shirai, Toshizo

Nuclear Instruments and Methods in Physics Research B, 205, p.600 - 604, 2003/05

 Times Cited Count:5 Percentile:57.71

no abstracts in English

Journal Articles

Extended description for electron capture in ion-atom collisions; Application of model potentials within the framework of the continuum-distorted-wave theory

Guly$'a$s, L.*; Fainstein, P. D.*; Shirai, Toshizo

Physical Review A, 65(5), p.052720_1 - 052720_9, 2002/05

 Times Cited Count:11 Percentile:48.67(Optics)

We perform an extension of the continuum-distorted-wave (CDW) approximation for single electron capture by introducing model potentials to describe the interaction of the active electron with the residual-target and projectile ions. The cross sections for electron transfer in collisions of bare and dressed projectile ions with H and He atoms are calculated and compared with experimental data and previous CDW calculations that make use of approximate analytical wave functions to represent the active electron initial and final states. For electron capture in proton-He collisions into definite final states the present calculations are in better agreement with experiments. We trace the differences in the results from both models to a different behavior at projectile scattering angles close to the Thomas peak.

Journal Articles

Analytic cross sections for electron collisions with hydrocarbons; CH$$_4$$, C$$_2$$H$$_6$$, C$$_2$$H$$_4$$, C$$_2$$H$$_2$$, C$$_3$$H$$_8$$, and C$$_3$$H$$_6$$

Shirai, Toshizo; Tabata, Tatsuo*; Tawara, Hiroyuki*; Ichikawa, Yukikazu*

Atomic Data and Nuclear Data Tables, 80(2), p.147 - 204, 2002/03

 Times Cited Count:63 Percentile:6.02(Physics, Atomic, Molecular & Chemical)

Cross sections for 138 processes of hydrocarbons in collisions with electrons, based on available literature sources, are critically compiled. The leterature has been surveyed to September 2000. A short comment is given for each measurement. The recommended data sets are presented in separate graphs for each process. Analytic fits to the recommended cross sections are also presented.

Journal Articles

Theoretical study on dielectronic recombination of O$$^{6+}$$ ions in metastable states

Zhao, L.-B.*; Shirai, Toshizo

Physical Review A, 64(5), p.052704_1 - 052704_6, 2001/11

A computational scheme, based on the theory of continuum-bound transitions of Bell and Seaton [J. Phys. B $${bf 18}$$, 1589 (1985)] and the close-coupling R-matrix approach, has been developed to treat dielectronic recombination (DR) in high-lying resonance energy regions. This scheme and our presented numerical method to compute DR in low-lying resonance energy regions [Phys. Rev. A $${bf 62}$$, 022706 (2000)] have been applied together to elucidate the experimental spectra of DR of O$$^{6+}$$ ions in the metastable $$1s2s,,^3S$$ and $$1s2s,,^1S$$ states. For comparison, a perturbative theoretical calculation of DR for O$$^{6+}$$ has also been accompanied. The reasonable representation of the general dielectronic spectral shape is yielded by both our close-coupling and perturbative calculations. However, both the methods do not reproduce the experimental double peak structure at $$sim$$ 6-8 eV. This shows that the further investigation on DR of this kind of ions is required both experimentally and theoretically.

Journal Articles

Analytic cross sections for electron collisions with CO, CO$$_{2}$$, and H$$_{2}$$O relevant to edge plasma impurities

Shirai, Toshizo; Tabata, Tatsuo*; Tawara, Hiroyuki*

Atomic Data and Nuclear Data Tables, 79(1), p.143 - 184, 2001/09

 Times Cited Count:36 Percentile:12.49(Physics, Atomic, Molecular & Chemical)

no abstracts in English

Journal Articles

Charge transfer in collisions of lithium ions with beryllium through oxygen ions at energies below 32 keV/amu

Suzuki, Shingo*; Shirai, Toshizo; Shimakura, Noriyuki*

Physica Scripta, T92, p.438 - 440, 2001/07

no abstracts in English

Journal Articles

Multiple-scattering analysis of triply differential cross sections for electron emission in energetic ion-atom collisions

Guly$'a$s, L.*; Fainstein, P. D.*; Shirai, Toshizo

Journal of Physics B; Atomic, Molecular and Optical Physics, 34(8), p.1473 - 1483, 2001/04

The role of multiple scattering events has been investigated in single ionisation of atoms induced by energetic ion impact. The triply differential cross sections has been evaluated as a function of projectile scattering angle for fixed values of the emitted electron energy and angle within the frame of the Distorted Wave Born approximation (DWB). It has been shown that the double scattering mechanism, which (sometimes) results in a characteristic double scattering peak at definite projectile scattering angle, provides a satisfactory description of the process in a wide region of electron ejection energies and angles. For low energy electron emission the role of higher orders is not negligible, and the quantum mechanical nature of the process is more emphasized. At an electron velocity equal to the projectile velocity the analogy to the mechanism of electron capture into bound states has also been investigated. In this region the DWB theory for ionisation corresponds to the Oppenheimer-Brinkman-Kramers (OBK) model for electron capture.

Journal Articles

Strong relativistic effects on dielectronic recombination of metaotable Li$$^{+}$$ ions

Zhao, L.-B.; Shirai, Toshizo

Physical Review A, 63(1), p.703_1 - 703_4, 2001/01

no abstracts in English

83 (Records 1-20 displayed on this page)