Nonexponentialities in the Ultrafast Electron-Transfer Dynamics in the System Oxazine 1 in N,N-Dimethylaniline

Transient absorption experiments with probing in the blue part of the spectrum (440−500 nm) are performed for the electron-transfer system oxazine 1 in N,N-dimethylaniline. The experiments with high time resolution of better than 20 fs show pronounced modulations due to high-frequency wave packet motion (600 cm -1) in the excited electronic state of the oxazine 1 molecule before electron transfer. Additionally, modulations due to wave packet motion in the product state of oxazine 1 after complete charge separation are observed. The absorption transients related to the electron transfer from N,N-dimethylaniline to oxazine 1 are clearly nonmonoexponential with time constants of 30 and 80 fs. This behavior points to a strong adiabaticity of the electron-transfer reaction with a high relevance of nuclear motions.