Mass analyzed threshold ionization spectra of ethyl bromide

Abstract

Using one-color two-photon (1C2P) scheme, high-resolution mass analyzed threshold ionization MATI spectra of ethyl bromide have been recorded. Accurate values for the adiabatic ionization energy have been determined to be 83097±3 cm-1 and 85452±3 cm-1 for the X1 2E1/2 and X2 2E1/2 states of the cation， respectively, giving a splitting of 2355±6 cm-1. The ionic vibrational frequencies were also obtained, and the values were in agreement with high accuracy with the literature data. The spectra showed extensive excited vibrational structure as a result of wave packet evolving on the potential energy surface of the dissociative state in the time interval between the absorption of the two photons. The vibrational calibration was done based on the known vibrational frequencies of the neutral ethyl bromide. The spectrum was found to exhibit mainly vibrational modes involving the dissociation of the molecule, including some non-totally symmetric modes.