Photolysis of O2 dispersed in solid neon with far-ultraviolet radiation

Abstract

Irradiation at 173 or 143 nm of samples of ¹⁶O₂ or ¹⁸O₂ in solid Ne near 4 K produced many new spectral lines in absorption and emission from the mid-infrared to the near-ultraviolet regions. The major product was ozone, O₃, that was identified with its mid-infrared and near-ultraviolet absorption lines. Oxygen atoms were formed on photolysis of O₂ and stored in solid neon until the temperature of a sample was increased to 9 K, which enabled their migration and combination to form O₃ and likely also O₂. O₂ in five excited states and O in two excited states detected through the emission spectra indicate that complicated processes occurred in solid Ne after far-ultraviolet excitation. For the transition ¹D₂ → ³P_1,2 of O, the lifetime was determined to be 5.87 ± 0.10 s; the lifetime of the upper state of an unidentified transition associated with an emission feature at 701.7 nm was determined to be 2.34 ± 0.07 s.