Quantum Origin of Anomalous Isotope Effects

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The focus of this project is on quantum dynamics studies of the recombination reaction of oxygen atoms (O) and molecular oxygen (O2) to form ozone (O3), in order to study the anomalously large isotopic enrichment of stratospheric ozone. A hierarchy of suitable approximations will be developed in order to reduce computational costs and still capture the associated quantum effects. The overall ozone formation process will be represented using a two-step energy transfer mechanism. The first step, formation of metastable ozone molecules (O3*), will be described with a fully quantum reactive scattering formalism. The second step, stabilization of O3* by third body collisions, will be treated using an approximate semi-classical method. This approach should provide a proper description of the zero-point energy effect during the first step and of symmetry effects during the second step. The project will involve partnerships with other theoretical and experimental groups in the U.S. and abroad.A better understanding of the anomalous isotope effects in O3 could lead to an improved understanding of its production and loss in the atmosphere. This award will provide for the education and training of a postdoctoral researcher and undergraduate students. Other broader impacts include public lectures focused on local and regional environmental issues, development of a graduate course on quantum chemistry and molecular dynamics, and integration of the research into undergraduate and graduate courses. This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).