ISOMERIZATION OF STILBENE IN THE GAS-PHASE - THEORETICAL-STUDY OF ISOTOPIC AND CLUSTERING EFFECTS

This paper presents a continuation of our previous theoretical studies on the rate of isomerization of trans-stilbene from the first excited electronic state based on the potential energy surface of Vachev et a l. [J. Phys. Chem. 99, 5247 (1995)]. Harmonic RRKM computations and mo lecular dynamics and Monte Carlo based classical rates are presented f or deuterated isotopes of stilbene as well as hexane clusters of stilb ene of varying size. Good agreement with experiment is found for energ y dependent rates of d(12) vs h(12) stilbene. However, we find that th e rate for d(2) stilbene is greater than for d(10) stilbene in contrad iction to the experimental observations. For the hexane clusters we fi nd that addition of hexane molecules causes a systematic decrease in t he rate, in agreement with experiment. (C) 1997 American Institute of Physics.