Mass analyzed threshold ionization of chlorobenzene and chlorobenzene center dot Ar-1

Mass analyzed threshold ionization (MATI) spectra of the Cl-35 and Cl-37 isotopomers of chlorobenzene have been recorded via different vibrational S-1 states. Most cationic states exhibit only a small isotopic shift of 2-4 cm(-1). The strongest isotope effect is observed for the 6a vibrational mode, which differs by about 6 cm(-1) for the two isotopomers. MATI spectra have also been recorded for the Van der Waals complex chlorobenzene Ar-1. Upper limits for the dissociation energies of the complex in its cationic state, as well as in its neutral states S-0 and S-1 could be determined. (C) 1997 Elsevier Science B.V.