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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Quantum Wave Packet Study of Nonadiabatic Effects in O(~1D) + H_2 -> OH + H
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Quantum Wave Packet Study of Nonadiabatic Effects in O(~1D) + H_2 -> OH + H

机译：O（〜1D）+ H_2-> OH + H中非绝热效应的量子波包研究

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We develop a wave packet approach to treating the electronically nonadiabatic reaction dynamics of O(~1D) + H_2 -> OH + H, allowing for the 1~1A' and 2~1A' potential energy surfaces and couplings, as well as the three internal nuclear coordinates. Two different systems of coupled potential energy surfaces are considered, a semiempirical diatomics-in-molecules (DIM) system due to Kuntz, Niefer, and Sloan, and a recently developed ab initio system due to Dobbyn and Knowles (DK). Nonadiabatic quantum results, with total angular momentum J = 0, are obtained and discussed. Several single surface calculations are carried out for comparison with the nonadiabatic results. Comparisons with trajectory surface hopping (TSH) calculations, and with approximate quantum calculations, are also included. The electrostatic coupling produces strong interactions between the 1~1A' and 2~1A' states at short range (where these states have a conical intersection) and weak but, interestingly, nonnegligible interactions between these states at longer range. Our wave packet results show that if the initial state is chosen to be effectively the 1A' state (for which insertion to form products occurs on the adiabatic surface), then there is very little difference between the adiabatic and coupled surface results. In either case the reaction probability is a relatively flat function of energy, except for resonant oscillations. However, the 2A' reaction, dynamics (which involves a collinear transition state) is strongly perturbed by nonadiabatic effects in two distinct ways. At energies above the transition state barrier, the diabatic limit is dominant, and the 2A' reaction probability is similar to that for 1A'', which has no coupling with the other surfaces. At energies below the barrier, we find a significant component of the reaction probability from long range electronic coupling that effectively allows the wave packet to avoid having to tunnel through the barrier. This effect, which is observed on both the DIM and DK surfaces, is estimated to cause a 10% contribution to the room temperature rate constant from nonadiabatic effects. Similar results are obtained from the TSH and approximate quantum calculations.
机译：我们开发了一种波包方法来处理O（〜1D）+ H_2-> OH + H的电子非绝热反应动力学，考虑到1〜1A'和2〜1A'的势能面和耦合，以及三个内部核坐标。考虑了耦合势能表面的两种不同系统，一种是基于Kuntz，Niefer和Sloan的半经验分子内双原子（DIM）系统，另一种是由于Dobbyn和Knowles（DK）而开发的从头算系统。获得并讨论了总角动量J = 0的非绝热量子结果。进行了几次单表面计算，以与非绝热结果进行比较。还包括与轨迹表面跳变（TSH）计算以及近似量子计算的比较。静电耦合在短距离（其中这些状态具有圆锥形交点）之间在1〜1A'和2〜1A'状态之间产生强相互作用，而在较长范围内，这些状态之间的相互作用微弱但不可忽略。我们的波包结果表明，如果将初始状态选择为有效的1A'状态（在绝热表面上发生插入以形成产物），那么绝热和耦合表面结果之间的差异就很小。无论哪种情况，反应概率都是能量的相对平坦的函数，除了共振振荡。然而，非绝热效应以两种截然不同的方式强烈干扰了2A'反应动力学（涉及共线过渡态）。在高于过渡态势垒的能量处，非绝热极限占主导地位，2A'反应概率与1A''类似，后者与其他表面没有耦合。在势垒以下的能量处，我们发现远程电子耦合的反应概率中有很大一部分，有效地使波包避免通过势垒隧穿。在DIM和DK表面上都观察到这种效应，据估计可导致非绝热效应对室温速率常数的10％贡献。从TSH和近似量子计算中也获得了相似的结果。

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