Mapped interpolation scheme for single-point energy corrections in reaction rate calculations and a critical evaluation of dual-level reaction path dynamics methods
Mapped interpolation scheme for single-point energy corrections in reaction rate calculations and a critical evaluation of dual-level reaction path dynamics methods
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DOI：
10.1021/jp9842493
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发表时间：
1999-02-25
影响因子：
2.9
通讯作者：
Truhlar, DG
中科院分区：
文献类型：
--
作者：
Chuang, YY;Corchado, JC;Truhlar, DG
测试了将高级电子结构数据合并到反应路径动力学计算中的三个过程。在一种方法中，用带有内插单点能量的变分过渡态理论VTST-ISPE，用高能级理论沿着低能级反应路径计算的少量额外能量被用来修正反应的经典能量轮廓。在第二个过程中，我们前面介绍的带内插优化修正的变分过渡态理论(VTST-IOC)，对能量、频率和转动惯量的更高水平的修正是基于在比反应路径更高的水平上重新优化的驻点几何结构。第三种方法称为内插优化能量法(IOE)，除了省略了频率校正外，它与IOC类似。用CH3+H‘H-->、CH3’+H(R1)、OH+H‘H->、HOH’+H(R2)和OH+H‘CH3 HOH’+CH3(R3)三个氢转移反应，通过与包括多维隧道效应在内的全变分过渡态理论计算的反应速率的比较，验证了该方法的正确性。我们提出了一种非常有效的方案来进行VTST-ISPE计算，这是因为它的计算成本较低而广受欢迎。通过对具有8对高能级和低能级的反应R_1-R_3的计算，我们还表明，只在静止点处有较高能级数据的VTST-IOC是一种比整个反应路径上具有较高能级能量的VTST-ISPE更可靠的双能级程序。尽管在IOE方案中没有对反应路径上的频率进行修正，但结果仍然比VTST-ISPE的结果好，这表明了在最高水平优化几何构型的重要性。
Three procedures for incorporating higher level electronic structure data into reaction path dynamics calculations are tested. In one procedure, variational transition state theory with interpolated single-point energies, which is denoted VTST-ISPE, a few extra energies calculated with a higher level theory along the lower level reaction path are used to correct the classical energetic profile of the reaction. In the second procedure, denoted variational transition state theory with interpolated optimized corrections (VTST-IOC), which we introduced earlier, higher level corrections to energies, frequencies, and moments of inertia are based on stationary-point geometries reoptimized at a higher level than the reaction path was calculated. The third procedure, called interpolated optimized energies (IOE), is like IOC except it omits the frequency correction. Three hydrogen-transfer reactions, CH3 + H'H --> CH3H' + H (R1), OH + H'H --> HOH' + H (R2), and OH + H'CH3 HOH' + CH3 (R3), are used to test and validate the procedures by comparing their predictions to the reaction rate evaluated with a full variational transition state theory calculation including multidimensional tunneling (VTST/MT) at the higher level. We present a very efficient scheme for carrying out VTST-ISPE calculations, which are popular due to their lower computational cost. We also show, on the basis of calculations of the reactions R1-R3 with eight pairs of higher and lower levels, that VTST-IOC with higher level data only at stationary points is a more reliable dual-level procedure than VTST-ISPE with higher level energies all along the reaction path. Although the frequencies along the reaction path are not corrected in the IOE scheme, the results are still better than those from VTST-ISPE; this indicates the importance of optimizing the geometry at the highest possible level.