Molecular Symmetry and Two-Photon Spectroscopy

Abstract
Two-photon polarization spectroscopy is an established method for making excited state symmetry assignments in randomly oriented samples. The relationship between the two-photon absorption process and the symmetry of the excited state, as established by previous theoretical developments, is illustrated in terms of the principles of the interaction between polarized light and oriented symmetric molecules. A description of the experimental methodology is presented and several applications for which this method has been used in vibronic coupling studies are discussed.