QUANTUM HARMONIC TRANSITION-STATE THEORY - APPLICATION TO ISOMERIZATION OF STILBENE IN LIQUID ETHANE

A harmonic quantum transition slate theory, suggested recently by Poll ak and Gershinsky [in Lectures an Stochastic Dynamics, edited by W. Lu tz and T. Poeschel, Lecture Notes in Physics (Springer Verlag, New Yor k, 1997)], is applied for the first time to a realistic reacting syste m. The isomerization of trans-stilbene in the gas phase and in the pre sence of dense liquid ethane solvent is investigated. We find that the overall quantum effect at room temperature is rather small. The quant um correction to the classical reaction rate estimate is approximately 23% for gas phase stilbene at room temperature. The addition of the d ense solvent lowers the correction down to 13%, thus making the reacti ng system even more ''classical,'' justifying the extensive use of cla ssical molecular dynamics in investigating this reaction. (C) 1998 Ame rican Institute of Physics.