| Abstract
| - The geometries, vibrational spectra, and relative energies ofHBrO2, ClBrO2, and BrBrO2 isomershave beenexamined using various density functional (BLYP, SVWN, and B3LYP)methods. A comparison of thedensity functional results for HBrO2 isomers with singlesand doubles coupled-cluster theory which incorporatesa perturbational estimate of the effects of connected triplesexcitation [CCSD(T)] shows that B3LYP resultsare in excellent agreement in predicting the geometries, vibrationalspectra, and relative energies and shouldyield reasonable results for ClBrO2 and BrBrO2isomers. The results also show interesting trends forHBrO2,ClBrO2, and BrBrO2 isomers. The peroxideform, XOOBr, is found to be the lowest energy structureamongthe isomers. The heats of formation at 0 K for HOOBr, ClOOBr, andBrOOBr are estimated to be 8.6, 38.9,and 46.1 kcal mol-1, respectively.Increase in halogenation tends to destabilize the peroxidethermodynamically.We examine the implication for the formation of XBrO2isomers from atmospheric cross reactions ofHOx,ClOx, and BrOxspecies.
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