THE INFLUENCE OF ELECTRIC FIELDS ON THE OPTICAL ABSORPTION OF MOLECULES

Author Institution: Institut fur physikalische Chemie, Universitat. MainzThe position and the intensity of electronic bands are influenced by an electric field. Pronounced changes in the position of absorption bands are mainly due to the dipole moment and polarizability of the molecule in the ground state and the change of the dipole moment and of the polarizability during the excitation process, and pronounced changes in intensity are due to the field dependence of the transition moment, which can be described by the transition polarizability. The effect of an external electric field on the optical absorption (electrochromism) of suitable molecules can be used to determine the dipole moment in the ground state, the change in dipole moment during the excitation process, the direction of the transition moment of the electronic band, and certain components of the polarizability in the ground and excited state and of the transition polarizability tensor. These data largely determine the strong solvatochromism (solvent-dependence of the position and intensity of electronic bands), which is observed in particular with molecules having large dipole moments