Resonant two-photon mass-analyzed threshold ionization of 2,5-difluoroaniline

We report the vibronic and cation spectra of 2,5-difluoroaniline. The band origin of the S1 ← S0 electronic excitation and adiabatic ionization energy are found to be 34 451 and 65 205 cm−1, respectively. The vibronic bands at 98, 220, 290, and 695 cm−1 result from the substituent-sensitive bending and those at 445, 535, and 730 cm−1 correspond to the in-plane ring deformation vibrations of this molecule in the electronically excited S1 state. The distinct features at 311, 334, 394, 498, and 738 cm−1 in the cation spectra result from the substituent-sensitive bending and in-plane ring vibrations in the D0 state.