Quantum mechanical studies of isomeric and conformeric structures of methyl‐chloro‐peroxide

Ab initio quantum mechanical studies are carried out for the isomeric structures and the torsional potential of methyl‐chloro‐peroxide. These species are important intermediates in the atmospheric reactions of methyl, methoxy, and methylperoxy radicals with chlorine dioxide, chlorine monoxide, and atomic chlorine, respectively. The calculations indicate that the peroxide form, CH₃OOCl, with a skew geometry for C, O, O, and Cl atoms, is the lowest minimum energy structure followed by CH₃OClO. The CH₃ClO₂ adduct is found to be much higher in energy. The calculated isomerization barriers are found to be relatively high to permit possible interconversion pathways. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004