Polarization dependence of dissociative ionization of ethanol by intense laser irradiation

Akagi, Hiroshi; Otobe, Tomohito; Itakura, Ryuji; Hosaka, Koichi*; Yamanouchi, Kaoru; Yokoyama, Atsushi

In the present work, ethanol molecules are irradiated with a circularly-polarized intense laser field (I = 1.4 10 W/cm), and the produced electron and ion are measured in coincidence. The channel-specific photoelectron spectra correlated with the C-C and C-O dissociation channels are similar to that correlated with the parent ion, showing the series of distinctive ATI peaks. These are the signature representing that the electronic ground state of parent ions is initially prepared upon the ionization, and then, the subsequent electronic excitation leading to the C-C or C-O dissociation takes place within the same laser pulse. For the linear polarization with similar laser field intensity (1.7 10 W/cm), the ATI series is also observed, but less pronounced. This means that the electronic excitation of the parent ion is more efficiently induced in the circularly polarized laser field than in the linearly polarized one.