MULTIDIMENSIONAL FRICTIONAL COUPLING EFFECT IN THE PHOTOISOMERIZATIONOF TRANS-STILBENE

A model based on two coupled generalized Langevin equations is propose d to investigate the trans-stilbene photoisomerization dynamics. In th is model, a system which has two independent coordinates is considered and these two system coordinates are coupled to the same harmonic bat h. The direct coupling between the system coordinates is assumed negli gible and these two coordinates influence each other through the frict ional coupling mediated by solvent molecules. From the Hamiltonian whi ch is equivalent to the coupled generalized Langevin equations, we obt ain the transition state theory rate constants of the stilbene photois omerization. The rates obtained from this model are compared to experi mental results in n-alkane solvents.