Femtosecond Infrared and Visible Spectroscopy of Photoinduced Intermolecular Electron Transfer Dynamics and Solvent−Solute Reaction Geometries: Coumarin 337 in Dimethylaniline

We present time-resolved infrared and visible spectroscopic data that reveal the relative orientations of donor and acceptor molecules in the 〈τ ET 〉 = 4 ps intermolecular electron transfer between dimethylaniline solvent and coumarin 337 solute. Although consideration of the dipolar attraction suggests the two species are most likely to be aligned with their molecular long axes parallel, the electron transfer occurs between species with their long axes perpendicular.