Dissociative electron attachment to electronically excited CS₂

Abstract

Dissociative attachment of low-energy electrons to the electronically excited and bent ¹B₂ state of CS₂ is studied. The measurements are carried out in a crossed three-beam geometry in which a laser beam is used to prepare the excited molecules. The absolute cross sections for the formation of S⁻ and CS⁻ by dissociative attachment to the ¹B₂ excited state are determined by a measurement of the relative number density in the excited state. Based on the earlier observation of the formation of S₂⁻from the linear symmetric ground state of CS₂, an increase in the S₂⁻ cross section was expected from the bent excited state. However, S₂⁻is found to be absent from this state. Possible mechanisms are proposed to explain this counterintuitive result.