Intermolecular and Intramolecular Excited State Charge Transfer

Abstract

A primary mechanism of energy relaxation and chemical change in organic molecules in excited electronic states is charge transfer. 1 The charge transfer process can be intermolecular, involving an excited molecule and a neighboring molecule, one serving as an acceptor and the other as a donor molecule, or intramolecular , involving a charge redistribution in the excited molecule which produces a very large excited state dipole moment. In our investigations of the dynamics of these various charge transfer processes, a picosecond laser pulse was used to excite the molecules of interest. The charge transfer dynamics were monitored by a variety of techniques, including transient absorption of the excited charge transfer complex (exciplex) or ion radicals by a time delayed picosecond pulse, and fluorescence from the exciplex and from the initially excited molecule using a picosecond streak camera for detection.