Dissociation of multiply ionized carbonyl sulfide due to electron impact

Abstract

The dissociation of singly to triply ionized carbonyl sulfide has been studied through electron impact ionization at an electron energy of 200 eV. Two- and three-dimensional covariance mapping techniques are used, accompanied by a focusing time-of-flight mass spectrometer. The absolute cross sections for the various dissociation channels of up to triply ionized carbonyl sulfide (OCS) have been obtained. The unstable OCS dications dissociate mostly into ion pairs, while the OCS trications dissociate into ion triple or ion pair with comparable probabilities. The total single ionization cross section agrees with the result of the binary-encounter-Bethe method. A metastable decay trace corresponding to OCS2+→CO++S+ is observed on the covariance map.