【web開催】第87回KPSIセミナー "Dynamics of molecular rotational wave packets induced by intense ultrashort pulsed laser fields​"

Dynamics of molecular rotational wave packets induced by intense ultrashort pulsed laser fields​

Dr. Shinichi Fukahori ( Graduate School of Arts and Sciences, The University of Tokyo)

Abstract

     When molecules are exposed to an intense ultrashort laser pulse, a superposition of the rotational eigenstates called a rotational wave packet (RWP) is created by the impulsive rotational Raman transition. Dynamics of the RWP of linear molecules has been extensively investigated, and it has been known that the molecular axis distribution evolves in time periodically and the alignment of the molecular axis with respect to the laser polarization direction is achieved under the field-free condition at the rotational revival times. 
    In the present study, we examine the RWP dynamics of H₂O. H₂O is one of the simplest non-linear molecules whose moments of inertia along the principal axes are different to each other, and this type of molecules is classified as an asymmetric top. Based on the dependence of the tunnel ionization probability of H₂O on the angle between the molecular axis and the laser polarization axis, the RWP dynamics is investigated by the pump-probe measurement of the yield of the molecular ions, H₂O⁺, in which the RWP is created by the pump laser pulse and the ionization is induced by the probe laser pulse.