Experimental and theoretical study on p-chlorofluorobenzene in the S, S1 and D states

Abstract

The geometric structures and vibration frequencies of para-chlorofluorobenzene (p-ClFPh) in the first excited state of neutral and ground state of cation were investigated by resonance-enhanced multiphoton ionization and slow electron velocity-map imaging. The infrared spectrum of S0 state and absorption spectrum for S1 ← S0 transition in p-ClFPh were also recorded. Based on the one-color resonant two-photon ionization spectrum and two-color resonant two-photon ionization spectrum, we obtained the adiabatic excited-state energy of p-ClFPh as 36302±4 cm−1. In the two-color resonant two-photon ionization slow electron velocity-map imagin spectra, the accurate adiabatic ionization potential of p-ClFPh was extrapolated as 72937±8 cm−1 via threshold ionization measurement. In addition, Franck-Condon simulation was performed to help us confidently ascertain the main vibrational modes in the S1 and D0 states. Furthermore, the mixing of vibrational modes between S0 → S1 and S1 → D0 has been analyzed.