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Akagi, Hiroshi; Oba, Hironori; Yokoyama, Keiichi; Yokoyama, Atsushi; Egashira, Kazuhiro*; Fujimura, Yo*
no journal, ,
We have proposed a laser isotope separation method, utilizing rotational coherence of a simple molecule. In the scheme, photoexcited molecules are isotopically separated by difference of rotational period between them. To illustrate this method, two-pulse photodissociation of mixed 
Br
/
Br isotopes has been investigated theoretically. Additionally, we have shown that this method is effective for heavy isotopes, based on mass dependence of the isotope enrichment factor. The contrast ratio, which is defined as a ratio of the maximum enrichment factor to the minimum enrichment factor, does not depend on mass of the chosen isotopes significantly. Hence we conclude that the present method is effective for heavy isotopes.
Kasajima, Tatsuya; Yokoyama, Keiichi; Matsuoka, Leo; Yokoyama, Atsushi
no journal, ,
no abstracts in English
Hosaka, Koichi; Itakura, Ryuji; Yokoyama, Keiichi; Yamanouchi, Kaoru*; Yokoyama, Atsushi
no journal, ,
In intense laser fields, molecules are decomposed into fragments through a number of competing dissociative ionization pathways. We investigate the dissociative ionization dynamics of ethanol in intense laser fields with photoelectron-photoion coincidence momentum imaging. The channel-specific photoelectron spectra reveal the electronic states prepared just afterionization, depending both on the decomposition pathways and on the temporal profile of laserpulses.
in the B 
(0
) stateMatsuoka, Leo; Yokoyama, Keiichi; Kasajima, Tatsuya; Yokoyama, Atsushi
no journal, ,
no abstracts in English
beamHarries, J.; Teraoka, Yuden; Yoshigoe, Akitaka
no journal, ,
A supersonic N molecular beam was used to irridate a clean Al(111) surface, and nitrogen uptake monitored using synchrotron-radiation X-ray photoelectron spectroscopy. Previous work showed that the threshold kinetic energy for reaction was 1.8 eV. The uptake curve for a 2.0 eV beam was nearly linear, indicating that a protective nitride layer is not formed, and suggesting that nitrogen penetrates into the bulk. A depth-profile generated from angular-specific spectra reveals that this is indeed the case.
Hashimoto, Masashi; Oba, Hironori; Akagi, Hiroshi; Saeki, Morihisa; Yokoyama, Atsushi
no journal, ,
no abstracts in English
Gejo, Tatsuo*; Kuniwake, Miki*; Homma, Kenji*; Harries, J.; Oura, Masaki*; Sullivan, J. P.*; Azuma, Yoshiro*
no journal, ,
Exciting an inner-shell electron of a molecule to just-above or just-below its ionisation limit provides a system where the Born-Oppenheimer principle is no longer valid, and a valuable opportunity for studying the interaction of the unstable ion core and a low-energy electron. When the ion core undergoes Auger decay and fragments, the initially excited electron can be recaptured. It is the aim of this research to understand what happens in the case of the water molecule, by (1) detecting excited H atoms produced when the electron is captured by an outgoing proton. (2) detect the Lyman-
radiation produced when these excited H atoms decay, and (3) analysing the energy of low-energy Auger electrons emitted when the electron is captured by an O
or O
fragment.