Time-dependent wave packet study on trans-cis isomerization of HONO driven by an external field

The present paper is devoted to a full quantum mechanical study of the cis -> trans isomerization of HONO. In contrast to our previous study [Richter , J. Chem. Phys. 120, 6072 (2004)], the dynamics is now performed in the presence of an external time-dependent field in order to be closer to experimental conditions. A six-dimensional dipole surface is computed. Using a previously developed potential energy surface [Richter , J. Chem. Phys. 120, 1306 (2004)], all eigenstates up to 4000 cm(-1) are calculated. We simulate the dynamics during and after excitation by an electromagnetic pulse whose parameters are chosen to efficiently trigger the isomerization. Our investigations show that there is a selective isomerization pathway.