Misiewicz Jonathon P, Elliott Sarah N, Moore Kevin B, Schaefer Henry F
Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia.
Phys Chem Chem Phys. 2018 Mar 14;20(11):7479-7491. doi: 10.1039/c7cp08582f.
Stabilized Criegee intermediates (SCI) are formed during the ozonolysis of unsaturated hydrocarbons and have been implicated in the formation of hydroxyl radicals and aerosols. Previous theoretical research [S. Jørgenson and A. Gross, J. Phys. Chem. A, 2009, 113, 10284-10290] computed the rate constants for addition of ammonia to simple SCIs, but reported a wide distribution of quantum chemical energies, depending on the basis set used. We report optimized geometries for these reactions at the CCSD(T)/ANO2 and CCSD(T)/ANO1 levels, and CCSD(T)/CBS energies with perturbative quadruples corrections. We find the inclusion of perturbative quadruples corrections elevates the energy of the transition state by 0.76-0.88 kcal mol relative to the reactants, which qualitatively changes the reaction surface. We calculate rate constants and find that Jørgenson and Gross previously overestimated the rate constants for ammonia addition to SCIs, but were within an order of magnitude. This supports the previous conclusion of Vereecken et al. [L. Vereecken, H. Harder and A. Novelli, Phys. Chem. Chem. Phys., 2012, 14, 14682-14695] that ammonia addition to SCIs is a negligible sink of Criegee intermediates.
稳定的克里吉中间体（SCI）在不饱和烃的臭氧分解过程中形成，并与羟基自由基和气溶胶的形成有关。先前的理论研究[S. 约根森和A. 格罗斯，《物理化学杂志A》，2009年，113卷，10284 - 10290页]计算了氨与简单SCI加成反应的速率常数，但报告了量子化学能量的广泛分布，这取决于所使用的基组。我们报告了在CCSD(T)/ANO2和CCSD(T)/ANO1水平下这些反应的优化几何结构，以及带有微扰四重校正的CCSD(T)/CBS能量。我们发现，相对于反应物，包含微扰四重校正会使过渡态的能量升高0.76 - 0.88千卡/摩尔，这在定性上改变了反应表面。我们计算了速率常数，发现约根森和格罗斯之前高估了氨与SCI加成反应的速率常数，但误差在一个数量级之内。这支持了韦勒肯斯等人[L. 韦勒肯斯、H. 哈德和A. 诺维利，《物理化学化学物理》，2012年，14卷，14682 - 14695页]先前的结论，即氨与SCI的加成是克里吉中间体一个可忽略不计的汇。
