We consider the vibronic properties of molecular Rydberg states in the strong coupling (degenerate) limit of the ion core, and show how the observed optical Rydberg spectrum for such a molecule is closely related to the Franckndash;Condon spectrum of its Jahnndash;Teller ion core, regardless of the symmetry labels attached to the Rydberg electronic species. These relationships permit the resolution of a quarterhyphen;century old paradox in the Rydberg spectrum of benzene and give rise to easily verifiable predictions concerning benzenersquo;s vibronic spectrum, which are applied to a recently discovered new Rydberg series. We further suggest that observed deviations from the idealized Rydberg case discussed here will reveal additional details about the coupling of Rydberg electronic and corehyphen;vibronic motion.
展开▼
