Following the relaxation dynamics of photoexcited aniline in the 273-266 nm region using time-resolved photoelectron imaging

Time-resolved photoelectron imaging was used to investigate the relaxation dynamics of electronically excited aniline in the gas-phase following ultraviolet irradiation in the 273-266 nm region. We find that at all wavelengths studied, excitation is predominantly to the long-lived (>1 ns) S1(pp*) state, which exhibits ultrafast intramolecular vibrational redistribution on a <1 ps timescale. At excitation wavelengths centred on resonant transitions in the aniline absorption spectrum that have previously been assigned to the higher lying S2(3s/ps*) state, we also see clear evidence of this state playing a role in the dynamics. However, we see no indication of any non-adiabatic coupling between the S1(pp*) and S2(3s/ps*) states over the range of excitation wavelengths studied.