ION-COLLISION SPECTROMETRIC STUDY OF THE DISSOCIATION DYNAMICS OF S2+ AND CS+ RADICALS

Collision-induced dissociation experiments on ground-state S2+ and CS+ have been carried out using a crossed-beam ion translational energy spectrometer with a very high angular resolution (less-than-or-equal-to 10(-4) rad). The distributions of kinetic energies released upon dissociations S2+ --> S+ + S, CS+ --> S+ + C, and CS+ --> C+ + S in 3-keV collisions with N2 have been measured; dissociation channels have been identified with the aid of computer simulations of trajectories through the apparatus of ions possessing different center-of-mass kinetic-energy release (K(c.m.) components. In the case of S+ formation from S2+, dissociation occurs via excitation to repulsive S2+* electronic states, giving rise to K(c.m.) components of 1.5 and 2.0 eV; lower K(c.m.)values (0 and 0.3 eV) are obtained upon dissociation of a bound excited state of S2+ by a curve-crossing mechanism. Dissociation of CS+ occurs via rotational resonances, giving rise to narrow, symmetrical structure in the S+ translational energy spectrum; direct dissociation also occurs which yields relatively high K(c.m.) values due to the breaking of the strong C= S triple bond. The CS+ --> + S channel is considerably weaker.