Quantum Origin of Anomalous Isotope Effects

本项目重点研究氧原子(O)与分子氧（O2）的复合反应形成臭氧（O3）的量子动力学，以研究平流层臭氧异常大同位素富集现象。为了降低计算成本并仍然捕获相关的量子效应，将开发一个合适的近似层次。整个臭氧形成过程将用两步能量转移机制来表示。第一步，亚稳臭氧分子（O3*）的形成，将用全量子反应散射的形式描述。第二步，通过第三体碰撞稳定O3*，将使用近似的半经典方法进行处理。这种方法应该提供对第一步中的零点能量效应和第二步中的对称效应的适当描述。该项目将涉及与美国和国外其他理论和实验小组的合作。更好地了解O3中的异常同位素效应可能导致更好地了解其在大气中的产生和损失。该奖项将为一名博士后研究员和本科生提供教育和培训。其他更广泛的影响包括公开讲座，重点关注当地和区域环境问题，开发量子化学和分子动力学研究生课程，并将研究纳入本科和研究生课程。该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。

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).