Reaction of CH2Cl radical with O-2 in solid para-hydrogen: Infrared spectrum of gauche-CH2ClOO radical

Abstract

Irradiation of a para-hydrogen (p-H-2) matrix containing chloroiodomethane (CH2ClI) and O-2 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 wave-numbers 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. (C) 2020 Published by Elsevier B.V.