Photoinduced intermolecular electron transfer and off-resonance Raman characteristics of Rhodamine 101/N,N-diethylaniline

Abstract

The ultrafast photoinduced intermolecular electron transfer (PIET) reaction of Rhodamine 101 (Rh101+) in N,N-diethylaniline (DEA) was investigated using off-resonance Raman, femtosecond time-resolved multiplex transient grating (TG) and transient absorption (TA) spectroscopies. The Raman spectra indicate that the CC stretching vibration of the chromophore aromatic ring is more sensitive to ET compared with the CC stretching mode. The ultrafast photoinduced intermolecular forward ET (FET) from DEA to Rh101+∗ occurs on a time scale of τFET=425–560fs. The backward ET (BET) occurs in the inverted region with a time constant of τBET=46.16–51.40ps. The intramolecular vibrational relaxation (IVR) process occurs on the excited state potential energy surface with the time constant of τIVR=2.77–5.39ps.