Spectroscopic Theory of the Solvent Cage
The solvent cage concept of photochemistry is translated into spectroscopic language by an extension of the Born-Oppenheimer approximation. The intermolecular perturbation of the solute modes is taken as the barrier to viscous flow in the solvent cage. It was shown that novel phenomenological consequences in the spectroscopy of polyatomic molecules in rigid solvent matrices can be predicted. Explicit consideration was given to molecular torsional potentials, the Dushinsky potential, the hydrogen-bonding potential, and a variety of molecular potentials in the region of large intermolecular distortions.