Collision-induced dissociation of CS2+ to S2+ at kilovolt laboratory energies

Abstract

Collision-induced dissociation (CID) of CS2 + molecular ions to S2 + ions at laboratory collision energies ranging from 1 to 6 keV energy has been studied by mass analyzed ion kinetic energy spectrometry (MIKES) utilizing a reversed geometry tandem mass spectrometer. The dissociation proceeds via four energetically distinct pathways which are strongly dependent upon the kinetic energy of the ion and on the nature of the collision gas. CID with argon neutrals is dominated at all energies by the lowest energy threshold reaction, which is endothermic by about 6 eV, whereas the energetics of the process differ and are strongly dependent on the ion kinetic energy when lighter collision gases (He, H2 and D2) are used for collisional activation. The most probable energy transfer from kinetic to internal modes is 11 ± 2 eV for these collision gases. A highly endothermic channel with kinetic energy loss of ~41 ± 4 eV opens up when the energy of the ions is reduced to 3 keV and less. At 1 keV ion energy, there is a small contribution to the total CID from a highly exothermic channel (kinetic energy release of 47 ± 5 eV) that is observed with all collision gases under low pressure conditions in the collision cell.