REMPI THRESHOLD PHOTOELECTRON-SPECTRA OF THE CIS AND TRANS ROTATIONAL ISOMERS OF JET-COOLED META-CHLOROPHENOL

The cis and trans rotational isomers of jet-cooled m-chlorophenol have been studied by two-colour (1 + 1') laser threshold photoelectron spectroscopy. The adiabatic ionisation energy (I(a)) for each isomer was obtained from the positions of the respective zeroth vibrational peaks in the threshold photoelectron spectra. This yielded I(a) values of 8.655 +/- 0.001 eV for the cis isomer and 8.682 +/- 0.001 eV for the trans isomer. Additionally a provisional assignment of the vibrational structure observed in the ion current spectrum (S1 state) and the threshold photoelectron spectra (D0 state) has been made on the basis of comparison with the known ground state vibrational frequencies of the neutral molecule.