A transition-state based rotational sudden (TSRS) approximation for polyatomic reactive scattering.
A transition-state based rotational sudden (TSRS) approximation for polyatomic reactive scattering.
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DOI：
10.1063/1.5003226
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
Bin Zhao;U. Manthe
中科院分区：
文献类型：
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作者：
Bin Zhao;U. Manthe
引入了用于计算微分和积分横截面的基于过渡态的旋转突变 (TSRS) 近似。 TSRS 方法仅需要从消失的总角动量 (J = 0) 的反应散射计算中获得的数据。它是在量子过渡态框架内导出的，可以被视为现有 J 平移方案的概括和改进。 TSRS 方法假设激活的复合物突然衰减以及内坐标中整体旋转和运动的可分离性。根据车身固定框架的选择，可以衍生出 TSRS 的不同变体。 TSRS方法应用于计算H2O+H→H2+OH反应、逆反应H2+OH→H2O+H和H2O+Cl→HCl+OH反应的各种同位素异构体的积分截面。与精确的紧耦合计算和已建立的近似方案的比较表明，对于 H2O+H→H2+OH 反应和研究的所有同位素异构体，基于散射框架的 TSRS 近似比离心突然近似和标准 J 位移产生更准确的结果。对于H2+OH→H2O+H和H2O+Cl→HCl+OH反应，TSRS结果以及其他近似方案的结果与精确方案的结果非常吻合。通过分析过渡态几何惯性矩矩阵的不同贡献，使这些发现合理化。
A transition-state based rotational sudden (TSRS) approximation for the calculation of differential and integral cross sections is introduced. The TSRS approach only requires data obtained from reactive scattering calculations for the vanishing total angular momentum (J = 0). It is derived within the quantum transition state framework and can be viewed as a generalization and improvement of existing J-shifting schemes. The TSRS approach assumes a sudden decay of the activated complex and separability of the overall rotation and motion in the internal coordinates. Depending on the choice of the body fixed frame, different variants of the TSRS can be derived. The TSRS approach is applied to the calculation of integral cross sections of various isotopomers of the H2O+H→H2+OH reaction, the reverse reaction H2+OH→H2O+H, and the H2O+Cl→HCl+OH reaction. Comparison with accurate close-coupling calculations and established approximate schemes shows that a scattering frame based TSRS approximation yields more accurate results than the centrifugal sudden approximation and standard J-shifting for the H2O+H→H2+OH reaction and all isotopomers studied. For the H2+OH→H2O+H and the H2O+Cl→HCl+OH reactions, the TSRS results as well as the results of the other approximate schemes agree well with the exact ones. The findings are rationalized by an analysis of the different contributions to the moment of inertia matrix at the transition state geometry.