MOLECULAR-DYNAMICS STUDY OF THE PICOSECOND PHOTOSTIMULATED CONFORMATIONAL DYNAMICS

The process of laser pulse excitation of isolated polyatomic molecules is studied using molecular dynamics computer simulation. A quantum theory describing the dynamics of laser excited electronic state of the molecule is combined with classical molecular dynamics simulation. The detailed computer simulation results on the laser excitation and subsequent IVR processes and conformational changes in jet-cooled stilbene molecule depending on the parameters of the laser pulse are presented. It is shown that only a limited set of modes is active during the excitation and another one take part in the IVR. The isomerization time at excess vibrational energy equal to 3050 cm-1 has been found to be 135 ps.