Direct diabatization and analytic representation of coupled potential energy surfaces and couplings for the reactive quenching of the excited 2Σ+ state of OH by molecular hydrogen.
Direct diabatization and analytic representation of coupled potential energy surfaces and couplings for the reactive quenching of the excited 2Σ+ state of OH by molecular hydrogen.
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DOI：
10.1063/1.5111547
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发表时间：
2019-09
期刊：
影响因子：
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通讯作者：
Yinan Shu;Joanna Kryven;A. G. Sampaio de Oliveira-Filho;Linyao Zhang;Guoliang Song;Shaohong L Li;R. Meana-Pañeda;Bina Fu;J. Bowman;D. Truhlar
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作者：
Yinan Shu;Joanna Kryven;A. G. Sampaio de Oliveira-Filho;Linyao Zhang;Guoliang Song;Shaohong L Li;R. Meana-Pañeda;Bina Fu;J. Bowman;D. Truhlar
我们利用扩展的多组态准简并微扰理论、四重非绝热分子轨道和构型均匀性建立了电子非绝热反应OH*+H2→H2O+H的势能面及其耦合的整体三态非绝热表示，其中*表示对A2Σ+态的电子激发。为了实现计算的非绝热耦合的符号一致性，我们开发了一种称为簇生长算法的图形处理单元加速算法。在得到一致的非绝热耦合符号后，我们将非绝热矩阵元(由非绝热势能和非绝热耦合组成)拟合到解析表示式中。绝热势能面是通过对角化3×3非绝热势能矩阵得到的。将拟合的非绝热矩阵元与计算的非绝热矩阵元、原始计算的绝热势能面和由拟合产生的绝热势能面进行了比较，结果表明，当前的拟合对于动力学研究来说是足够精确的，它可以用于量子或半经典动力学计算。
We have employed extended multiconfiguration quasidegenerate perturbation theory, fourfold-way diabatic molecular orbitals, and configurational uniformity to develop a global three-state diabatic representation of the potential energy surfaces and their couplings for the electronically nonadiabatic reaction OH* + H2 → H2O + H, where * denotes electronic excitation to the A 2Σ+ state. To achieve sign consistency of the computed diabatic couplings, we developed a graphics processing unit-accelerated algorithm called the cluster-growing algorithm. Having obtained consistent signs of the diabatic couplings, we fit the diabatic matrix elements (which consist of the diabatic potentials and the diabatic couplings) to analytic representations. Adiabatic potential energy surfaces are generated by diagonalizing the 3 × 3 diabatic potential energy matrix. The comparisons between the fitted and computed diabatic matrix elements and between the originally computed adiabatic potential energy surfaces and those generated from the fits indicate that the current fit is accurate enough for dynamical studies, and it may be used for quantal or semiclassical dynamics calculations.