Argon matrix infrared spectra and vibrational analysis of the hydroperoxyl and deuteroperoxyl free radicals

Abstract

Matrix reactions of H and D atoms from a microwave discharge source with oxygen molecules diluted in argon have produced significantly higher yields of HO₂ and DO₂ than the previous photolysis methods. Oxygen isotopic enrichment confirmed the previous vibrational assignments to HO₂; significantly greater concentrations of DO₂ allowed observation of the weak 0–0 mode at 1123 cm⁻¹. Normal coordinate calculations using HO₂ and DO₂ oxygen isotopic frequencies gave excellent agreement with the observed data. The bonding in HO₂ is suggested to be largely covalent, in contrast to the ionic species ${\mathrm{Li}}^{+}{\mathrm{O}}_2^{-}$ .