Reaction of CH₂Cl radical with O₂ in solid para-hydrogen: Infrared spectrum of gauche-CH₂ClOO radical

Irradiation of a para-hydrogen (p-H₂) matrix containing chloroiodomethane (CH₂ClI) and O₂ at 3.3 K with light at 290 nm yielded infrared absorption lines at 750.1/745.6, 891.7, 1004.6, 1090.7, 1241.3, 1315.6, 1427.8, and 2988.7 cm⁻¹, which are assigned to the gauche-chloromethylperoxy radical (gauche-CH₂ClOO). Further irradiation of the matrix at 240 nm selectively diminished these features. The assignments are based on the photolytic behavior and comparisons of the observed vibrational wavenumbers and IR intensities with those predicted with the B3LYP/aug-cc-pVTZ method. The irradiation of CH₂ClOO at 240 nm was found to induce cleavage of the O–O bond to produce CH₂ClO, but not cleavage of the C–Cl bond to produce the Criegee intermediate CH₂OO.