DISSOCIATIONS OF STATE-SELECTED C2H+2, H2S+ AND D2S+ IONS STUDIED BY PHOTOELECTRON-PHOTOION COINCIDENCE SPECTROSCOPY

It is shown that C2H+2 (ÃΣg+) ions dissociate by H loss with zero kinetic energy release at a threshold near 17.3 eV, although the thermochemical dissociation limit is probably lower. H2S+ and D2S+ dissociate from the Ã2A1 states to S+ + H2 with 90 ± 20% conversion of excess energy to relative translation. The B̃ 2B2 states of these ions fragment predominantly by H or D atom loss, with a maximum of 30% kinetic energy release. © 1979.