The REMPI spectra of o-, m- and p-bromofluorobenzene and the photodissociation of p-bromofluorobenzene

Abstract

The vibrations of o-, m- and p-bromofluorobenzene (BrFPh) in the first electronically excited state are studied by (1+1) resonance-enhanced two-photon ionization spectroscopy. The observed vibrational bands have been assigned on the basis of comparison with the results from theoretical calculations. The band origins of the S1←S0 electronic transitions of o-, m- and p-BrFPh, which were influenced by positive resonance effect and negative inductive effect, are found to be 36986.68cm−1, 36961.48cm−1 and 36223.20cm−1 respectively. Meanwhile, the potential barrier height (the energy of the crossing points between the bound S1 state and a repulsive state relative to the S1 minimum) of p-BrFPh is determined to be lower than 2815cm−1 (0.3490eV) by the REMPI spectra of bromine atom and p-BrFPh molecule.