AN EXPERIMENTAL-STUDY ON THE PHOTOCHEMISTRY AND VIBRATIONAL SPECTROSCOPY OF 3 ISOMERS OF CL2O2 ISOLATED IN CRYOGENIC MATRICES

Chloryl chloride, ClClO2, isolated in cryogenic matrices is subjected to photolysis, producing chlorine chlorite, ClOClO, which in turn is c onverted into dichlorine peroxide, ClOOCl. ClOClO is also formed by th e reactions C1 + OClO and ClOCl + O. The products are identified by me ans of FTIR spectroscopy using Cl-35/37 and O-16/18 isotopic shifts, w ith the aid of vibrational spectra of related molecules and results of ab initio calculations. The thresholds for photodecomposition of ClOC lO, ClClO2, and ClOOCl isolated in an argon matrix are above wavelengt hs of 665, 610 and 360 nm, respectively. Two dissociation channels are observed for both ClOClO and ClOOCl. For ClOClO they are (i) Cl + OCl O, leading to ClClO2;and (ii) 2ClO, yielding ClOOCl. For ClOOCl they a re (i) ClOO + Cl, resulting in Cl-2 + O-2, and (ii) 2ClO, giving rise to ClOClO. The observation of two photolysis paths for ClOOCl is of im portance for the catalytic ozone depletion in the polar stratosphere. Irradiation of ClClO2 isolated in a neon matrix resulted in Cl-2 + O-2 as the only products. The UV spectra of ClClO2 in the gas phase and i n a neon matrix are reinvestigated. Lower limits for the integral band strengths of ClOClO and ClOOCl are derived relative to those of ClClO 2. The vibrational data of this study, in conjunction with results of submillimeter spectroscopic investigations, are used to calculate a ge neral valence force field for ClOOCl.