THE POSSIBLE ROLE OF CLO3 ISOMERS IN RELATION TO STRATOSPHERIC OZONE

After considering all possible connectivities for structural isomers o f molecular formula ClO3 on the doublet ROHF/6-31G(d) potential energy surface, four minimum energy structures were identified and studied f urther at some or all of the ROHF, UHF, CIS, UMP2, RMP2, and QCISD(T) levels of theory using various basis sets ranging in quality from 6-31 G(d) to 6-311+G(3df). Among the four ClO3 isomers (and alternative ele ctronic states for two of them), only the ground state (2A1) C3v struc ture was found to be stable at all correlated levels of theory. In par ticular, the isomers with connectivities ClOOO and OClOO are found to be unstable at the RMP2 and QCISD(T) levels of theory (6-31G(d) basis set). The implications of these results to the chemistry of stratosphe ric ozone depletion are discussed. In addition, predictions of a varie ty of physical properties of C3v ClO3 (2A1) were made, including vibra tional spectra and thermochemical tabulations based on G2 energy data.