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Itakura, Ryuji; Hosaka, Koichi*; Yamanouchi, Kaoru*; Yokoyama, Atsushi
no journal, ,
By the photoelectron-photoion coincidence momentum imaging, channel-specific photoelectron images of ethanol and oxygen molecules ionized in intense laser fields are obtained at different laser field intensities and pulse durations for clarifying their electronic excitation mechanisms.
Akagi, Hiroshi; Itakura, Ryuji; Hosaka, Koichi*; Yamanouchi, Kaoru; Yokoyama, Atsushi
no journal, ,
When a molecule is exposed to circularly-polarized laser fields, dissociation processes following ionization proceed differently from the case of linearly polarization. In the present work, ethanol molecules are irradiated with a circularly-polarized intense laser field (I = 1.4
10
W/cm
, 
800 nm), and the produced electron and ion are measured in coincidence. Under the present experimental conditions, Keldysh parameter 
is calculated to be 2.6, suggesting the multiphoton ionization is expected to be dominant. The relative yields of C
H
OH
, CHOH, and CH
C with respect to the parent ion are 0.36, 0.31, and 0.01, which correspond to only 0.5, 0.4, and 0.2 of those for the linear polarization with similar laser field intensity (1.710 W/cm.
Kasajima, Tatsuya; Tsubouchi, Masaaki; Matsuoka, Leo; Yokoyama, Keiichi; Yokoyama, Atsushi
no journal, ,
no abstracts in English
OHarries, J.; Gejo, Tatsuo*; Kuniwake, Miki*; Homma, Kenji*; Oura, Masaki*; Sullivan, J. P.*; Azuma, Yoshiro*
no journal, ,
Photo-excitation of the O 1s electron in HO can lead to the production of neutral, excited H atoms. Knowledge of the excited state distribution provides information on the dissociation dynamics process. Excitation of the O 1s electron leads to a HO
ion core. Auger decay subsequently leads to HO
, which dissociates, and one of the fragments can capture the initially excited electron. If this fragment is H, excited neutral H atoms are formed. In this research we use pulsed synchrotron radiation as the excitation source, and detect the UV fluorescence emitted when the excited H atoms decay. Analysis of the decay lifetimes leads to information on the excited state distribution.
Yokoyama, Keiichi; Matsuoka, Leo; Akagi, Hiroshi; Kasajima, Tatsuya; Tsubouchi, Masaaki
no journal, ,
Pure rotational transition shows evenly spaced line spectra, the rotational comb, when the molecule is diatomic and has a closed-shell electronic structure. Let us consider irradiating an optical frequency comb tuned to the rotational comb. We studied numerically the dynamics of the molecular rotation in such a irradiation. As a result, the dynamics was found to obey the diffusion equation within the quantum mechanics. Also, we found that an isotope-selective excitation based on this scheme is a novel example of coherent control effective even at high temperature.