A correlation diagram model for interpreting propensity rules in collision induced vibrational relaxation

Propensity rules for collision induced vibrational energy transfer are derived by a correlation diagram technique similar to that used by Woodward and Hoffman to treat symmetry restrictions in concerted reactions. A rough quantification is accomplished by an ad hoc generalization of the modified SSH breathing sphere model. Predicted relative transfer rates agree qualitatively and, in some cases, quantitatively with those observed for collisions of benzene, aniline, and pyrazine with inert atoms.