Ultraviolet Resonance Raman Studies of Electronic Excitations

Abstract

Electronic excitation of molecules often results in significant changes in chemical bonding and may initiate chemical reaction. This is particularly true for small molecules,because excitation of a single electron can be a major influence on the total bonding of the system. In such cases the bond lengths and the shape of a molecule may be very different in the excited state than in the ground state, or, indeed, the excited state potential may be dissociative or pre-dissociative. These bonding changes may cause the resulting absorption spectra to be very difficult to interpret because of spectral diffuseness, congestion due to the excitation of many degrees of freedom,or very different vibrational frequencies in the excited state from those of the ground state.