Spectroscopic Closure Property and Franck–Condon Band Structuring

Abstract

A relationship is derived from evaluating the change in molecular equilibrium size on excitation from a moment analysis of the electronic spectrum. The method is applied to the ${}^1{L}_b{\leftarrow }^{1}A$ benzene spectrum. The agreement of the calculated bond lengthening with that derived from independent rotational analysis would seem to confirm the adequacy of a spectroscopic closure property for benzene.