Dissociative-attachment cross sections for excited and ground electronic states of SO₂

Absolute cross sections for dissociative attachment of electrons to the ground and electronically excited states have been measured using the relative flow technique. The excited molecules were prepared by laser optical pumping and their fraction was determined from the reduction in the dissociative attachment signal from the ground state. The cross sections for the excited state were determined by normalizing to this fraction. The success of this experiment should lead to similar measurements on other molecules.