Collisional behaviour with Ar of the Λ doublets of CH(X 2Π)N″= 15 produced in the two-photon dissociation of CH2CO at 279.3 nm

Abstract

Relaxation of the N″= 15 Λ doublets of CH(X ²Π) produced in the two-photon dissociation of ketene at 279.3 nm has been observed in the presence of Ar. An initially equilibrated nascent Λ doublet population is seen to be removed in such a way that the component of A″ symmetry (π orbital perpendicular to the plane of rotation) dominates. The application of recent theory describing collisions of ²Π diatomics with closed shell atoms is briefly discussed.