@Article{JPhysChemA_110_7547, author = {S. Pag{\`e}s and B. Lang and E. Vauthey}, title = {{Ultrafast Excited State Dynamics of the Perylene Radical Cation Generated upon Bimolecular Photoinduced Electron Transfer Reaction}}, journal= {J. Phys. Chem. A}, ISSN = {1089-5639}, volume= {110}, number= {24}, pages = {7547-7553}, url = {http://pubs.acs.org/cgi-bin/abstract.cgi/jpcafh/2006/110/i24/abs/jp0615252.html}, eprint= {http://www.unige.ch/sciences/chifi/publis/refs_pdf/ref00818.pdf}, doi= {10.1021/jp0615252}, abstract = {{The ultrafast ground state recovery (GSR) dynamics of the radical cation of perylene, Pe$^{•+}$, generated upon bimolecular photoinduced electron transfer in acetonitrile, has been investigated using pump-pump-probe spectroscopy. With 1,4-dicyanobenzene as electron acceptor, the free ion yield is substantial and the GSR dynamics of Pe$^{•+}$ was found to depend on the time delay between the first and second pump pulses, $\Delta${\em t}$_{12}$, i.e., on the “age” of the ion. At short $\Delta${\em t}$_{12}$, the GSR dynamics is biphasic, and at $\Delta${\em t}$_{12}$ larger than about500 ps, it becomes exponential with a time constant around 3 ps. With {\em trans}-1,2-dicyanoethylene as acceptor, the free ion yield is essentially zero and the GSR dynamics of Pe$^{•+}$ remains biphasic independently of $\Delta${\em t}$_{12}$. The change of dynamics observed with 1,4-dicyanobenzene is ascribed to the transition from paired to free solvated ion, because in the pair, the excited ion has an additional decay channel to the ground state, i.e., charge recombination followed by charge separation. The rate constants deduced from the analysis of these GSR dynamics are all fully consistent with this hypothesis.}}, year = {2006} }