Far-infrared spectroscopy of the H₂-O₂ van der waals complex

Abstract

We report the far infrared spectrum of H₂–O₂ at 80 K in the vicinity of the pure rotational bands of H₂. Sharp peaks were observed, which correspond to end-over-end rotational transitions of the H₂–O₂ molecular complex, that are superimposed over broad collision induced absorptions. We find that the maximum value of the end-over-end rotational quantum number that is bound is seven, which is two more than supported by a recently reported ab initio H₂–O₂ potential energy surface. The rotational spectrum reported here should therefore greatly help in refining this surface, which is used to calculate scattering processes relevant to the chemistry occurring in interstellar molecular clouds.