15min:

MICHAEL J. FERGUSON, GIOVANNI MELONI, HARRY GOMEZ AND DANIEL M. NEUMARK, Department of Chemistry, University of California, Berkeley, CA 94720 and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.

The anion photoelectron spectra of ClH₂^- and ClD₂^- were measured at 299 nm, accessing the prereactive van der Waals well on the ground state Cl + H₂ potential energy surface, as well as the low-lying spin-orbit excited states resulting from the interaction of Cl (²P_3/2) and Cl^* (²P_1/2) with H₂. The photoelectron spectra are dominated by two relatively narrow peaks corresponding to the transitions to the neutral Cl H₂ and Cl^* H₂ complexes both are shifted toward higher electron binding energy relative to atomic chlorine due to the solvent shift by the hydrogen. Another feature in the spectra is the relative broadening of ClD₂^- versus ClH₂^-. The broadening of the ClD₂^- peaks may have its origins in the excited state transitions. The broadening may also be in part due to the presence of two nuclear spin species, as opposed to one in ClH₂^-. Only ClH₂^- (ortho) was generated in this experiment, while ClD₂^- had both ortho and para complexes generated.