Photolysis of Matrix-Isolated Dichlorine Monoxide: Infrared Spectra of ClClO and (ClO)2

Abstract

In situ photolysis of matrix-isolated dichlorine monoxide, Cl2O, at 20°K, produced eight bands near 960 cm−1 and a quartet near 375 cm−1. Growth plots for the high-frequency features during photolysis show that three distinct molecules are produced. Oxygen and chlorine isotopic shifts indicate that ClClO, with a structure like those of the nitrosyl halides, is most probably responsible for absorptions between 962 and 952 cm−1 as well as for the 377–368-cm−1 quartet. In addition, bands at 982 and 945 cm−1 are attributed to (ClO)2, in which pairs of ClO molecules are weakly linked. Thus (ClO)2 resembles the nitric oxide dimer rather than H2O2 or O2F2. The observed frequencies indicate that the vibrational frequency of ClO itself is probably near 970 cm−1 rather than 853 cm−1 as deduced earlier from electronic spectra.