PICOSECOND RAMAN INVESTIGATIONS OF THE VIBRATIONAL ENERGY DEPENDENCE OF INTER-LIGAND ELECTRON TRANSPER IN TRANSITION METAL COMPLEXES

Author Institution: Department of Chemistry, Louisiana State UniversityTwo color picosecond Rsman spectroscopy has been utilized to measure the vibrational energy dependence of electron transfer. Above the classical barrier to inter-ligand electron transfer, vibrational relaxation completely quenches electron transfer from the excited vibrational states. Below the barrier the first direct measurements of inter-ligand electron hopping are reported in the excited electronic state of D3 symmetry complexes of polypyridyl Ru(ll). It was found that the rate of inter-ligand electron transfer from the thermalized vibrational states varied between $>10^{11} sec^{-1}$ and $< 10^{2} sec^{-1}$ depending on the chemical nature of the complex. The observed kinetics are rationalized in terms of recent electron transfer theory which describe the reaction dynamics through Franck-Condon factors weighted by the density of product vibrational states. Results for five complexes will be presented