The role of symmetry in the mass independent isotope effect in ozone

Abstract

Understanding the internal distribution of "anomalous" isotope enrichments has important implications for validating theoretical postulates on the origin of these enrichments in molecules such as ozone and for understanding the transfer of these enrichments to other compounds in the atmosphere via mass transfer. Here, we present an approach, using the reaction NO₂^- + O₃, for assessing the internal distribution of the Δ¹⁷O anomaly and the δ¹⁸O enrichment in ozone produced by electric discharge. The Δ¹⁷O results strongly support the symmetry mechanism for generating mass independent fractionations, and theδ¹⁸O results are consistent with published data. Positional Δ¹⁷O and δ¹⁸O enrichments in ozone can now be more effectively used in photochemical models that use mass balance oxygen atom transfer mechanisms to infer atmospheric oxidation chemistry.