Electronic spectra and chemical reactivity

Perturbation theory suggests a close relationship between the electronic spectra of molecules and energy barriers to possible unimolecular and bimolecular reactions. Considering only v/sub max/, the vertical frequency of the lowest excited state (of the same multiplicity), a number of interesting correlations can be made. It is necessary (a) to compare only groups of related molecules and (b) to use elementary spectroscopic theory to identify the nature of the lowest excited state. The relationship between vis-UV spectra and the stability of isomers is discussed.