Dissociative ionisation of CS2 and the formation of S2+

Photoelectron-photoion coincidence spectroscopy has been used to examine dissociative ionisation of CS2 from electronic states of CS: up to 27 eV, including the satellite states 3, 4, 6 and 10 whose decay has not been studied before. Branching ratios to the ions S+, CS+, S-2(+) and C+ have been determined throughout the range and kinetic energy release distributions have been deduced from peak shapes, allowing inferences on the states of the fragments. The choice of product channel is not strongly dependent on initial parent ion state identity. The products are formed in many different final states, but kinetic energy releases less than 3 eV are favoured, corresponding to formation of highly excited states of the products. In confirmation, optical emission has been found in coincidence with photoelectrons from formation of several inner valence states of the ions. Formation of S-2(+) occurs from several initial states of the parent ion and possible mechanisms are considered. It is concluded that a "quasi-statistical'' model may best describe the dissociation of CS: from the inner valence states. (C) 2001 Elsevier Science B.V. All rights reserved.