Dispersed fluorescence from CO(B 1Σ +) excitation in He and Ar

Abstract

Two striking effects were observed between 158 and 175 nm in the dispersed laser-induced fluorescence spectrum resulting from excitation of CO(B 1Σ +). In the presence of Ar the intensity of the CO(X 1Σ +, ν′→A 1Π, ν′=0) progression was doubled. Also, an unresolved emission appeared over the entire spectrum. The former is attributed to a COAr complex that undergoes an electronically non-adiabatic transition. Since collisionally induced intersystem crossing can account for only a fraction of the broadband emission, we speculate that most of this feature originates from a metastable triatomic complex.