The vibrational spectra of molecular ions isolated in solid neon. II. O+4 and O−4

Abstract

When a relatively concentrated Ne:O₂ sample is codeposited at ∼5 K with a beam of excited neon atoms, prominent infrared absorptions appear which are assigned to O⁺₄ and O⁻₄. Absorptions of O₃ and O⁻₃ are also present, and their product distributions in isotopic substitution experiments indicate that O‐atom production and reaction is a minor channel in this experimental system. Detailed isotopic substitution experiments require that both O⁺₄ and O⁻₄ possess two equivalent O₂ units. Analysis of the isotopic shifts strongly favors a planar trans configuration (C_2h) for both molecules. Several combination bands of O⁺₄ are observed, and give evidence regarding the position of ν₁(a_g), which is infrared inactive, and regarding perturbations by combinations of low‐frequency fundamentals. The mechanism of photodestruction of the ions in this system is also considered.