Kinetic models for stilbene photoisomerization: Comparison of theory and experiments

摘要

Torsional correlation times fortranstocisisomerization of stilbene in solution are calculated using Fokkerndash;Planck and diffusional models for the barrier crossing process. Hydrodynamic interactions and the solventhyphen;dependent potential of mean force are incorporated into the calculations. Both convective effects and hydrodynamic interactions are found to have a significant impact on the isomerization rate of stilbene in alkane solvents near room temperature. It is found that the potential barrier between thetransand 90deg; states definitely has to be below 1200 cmminus;1, the latest experimental value of this quantity, in order to explain the observed photoisomerization rate. The dependence of the rate on friction is calculated and various improvements to our model and their relative importance are discussed.