Ultrafast laser excitation and rotational de-excitation of cis-stilbene
*, Weifeng Wua,
, Hong Tanga
, and Roland E. Allenc
Bio-Informatics Institute, Chongqing University of Posts and Telecommunications,
Chongqing, 400065, P. R. China
Department of Physical Sciences, Nicholls State University, PO Box 2022, Thibodaux,
LA 70310, U. S. A.
Department of Physics, Texas A&M University, College Station, Texas 77843, U. S. A.
A realistic dynamical simulation is reported for ultrafast laser excitation and rotational
de-excitation of cis-stilbene. Upon irradiation by a laser pulse with a FWHM of 100 fs,
the molecule first rotates around its vinyl bond to about 90°, where an avoided crossing
leads to electronic de-excitation. The molecule then immediately twists back to about
- 60° within only about 80 fs, avoiding isomerization. The other principal dihedral angles,