Intramolecular vibrational energy relaxation. Decomposition of chemically activated alkylcyclobutanes

Abstract

FA-MEI WANG and B. S. RABINOVITCH. Can. J. Chem. 54, 943 (1976). This paper describes an approach to the study of intramolecular energy relaxation of highly vibrationally excited complex molecules. The features of the decomposition of a series of chemically activated alkylcyclobutanes are outlined, including variable selectivity of the initial, non-randomized state of excitation. It is shown how this can afford both a qualitative test of the postulate of internal energy randomization employed in the Rice-Ramsperger-Kassel-Marcus treatment of unimolecular reactions, as well as a quantitative measure of the rate of relaxation. The study of the first members of this series, ethyl and dimethyl cyclobutane, is described. As expected, the first members can provide a lower limit to'the relaxation rate, namely, X > 1012 s-1.

Dynamics of ethyl radical decomposition. 3. Effect of chemical activation vs. microcanonical sampling

“…The angular momentum vector defined by the principal moments of inertia for the critical configuration J7 is J = Jt = jtJ + jiJ + ji£ (23) There is a linear transformation between the components of J for the molecule and critical configuration body-fixed axes given by Jf = cJ 1 = cc (24) It is important to recognize that, regardless of the transformation matrix c, if P(JX) = P(Jy) = P(JZ) the relationship P{tPx) = P{>Py) = P(JPZ) is necessarily true.…”