Spectroscopy of the Rydberg states of SO in a supersonic jet

Abstract

A supersonic nozzle with an internal discharge is described and shown to be a flexible and efficient method of generating cold free radicals in a molecular beam. This is used in conjunction with a time-of-flight mass spectrometer (modified to allow use with the discharge nozzle) to take 2 + 1 multiphoton ionization spectra of three Rydberg states of the SO radical. The low temperatures obtained in the jet allow the regular/inverted nature of the states to be unambiguously determined. These states also show an Ω-dependent predissociation which is interpreted in terms of singlet–triplet mixing.