The visible emissions of molecular oxygen in rare gas solids

Abstract

The vacuum ultraviolet‐excited emission spectra of molecular oxygen in low temperature rare gas solids have been recorded and analyzed. The observed transitions have been reassigned using isotopic substitution and are found to be C ³Δ_u→X ³Σ_g⁻ in argon and krypton and c ¹Σ_u⁻→a ¹Δ_g in xenon. These transitions have not been observed in the gas phase and the transition origins established here confirm previous tentative assignments of vibrational numberings of the upper states by Herzberg and Degan, respectively. The emission in xenon is very unusual for a solid phase spectrum in that emission occurs from several excited vibrational levels, which are apparently being populated directly by intersystem crossing. It is also unusual in that the lower state of the emission is not the ground state. No significant chemical interaction between the molecule and the rare gas is seen for any of the observed states.