Gas phase EPR of vibrationally excited O2

Abstract

The gas phase electron paramagnetic resonance spectrum of vibrationally excited molecular O₂ has been obtained using a discharge sampling technique. Measurements of line intensities indicate vibrational temperatures up to 600°K with maintenance of a translational‐rotational equilibrium temperature of 300°K. Analysis of the O₂ spectrum allows a determination of the vibrational variation of the ``spin‐spin'' parameter, λ<sub>v</sub>, and the ``spin‐rotation'' parameter, γ_v. Combination of these values with previous microwave results for the v=0 state of O₂ gives much improved values for these parameters at the equilibrium inter‐nuclear distance of O₂. Further analysis of these results gives values for the first and second derivatives of the parameters with respect to internuclear distance.