Investigation on the ultrafast relaxation dynamics of the S1 state of 3,4-difluoroaniline

Abstract

The ultrafast dynamics of 3,4-difluoroaniline is studied by time-resolved velocity map imaging and mass spectroscopy. Following the excitation with 299.6 or 291.8 nm to the S1 state, relaxation process with three decay components is explored. The hundreds-of-picosecond decay is attributed to the intersystem crossing to triplet state and the nanosecond decay represents the following relaxation of the triplet state. However, the dynamics in hundreds-of-femtoseconds for two excitations are different. We intend to designate it as the molecules leaving the Franck-Condon region at 299.6 nm and as the intramolecular vibrational energy redistribution at 291.8 nm with highly vibrational excitation.