期刊
JOURNAL OF CHEMICAL PHYSICS
卷 132, 期 13, 页码 -出版社
AMER INST PHYSICS
DOI: 10.1063/1.3314248
关键词
molecular electronic states; potential energy surfaces; quantum theory
资金
- NSF
- ONR
We present a new algorithm for mixed quantum-classical dynamics that helps bridge the gap between mean-field (Ehrenfest) and surface-hopping dynamics by defining a natural rate of decoherence. In order to derive this decoherence result, we have expanded the number of independent variables in the usual Ehrenfest routine so that mixed quantum-classical derivatives are now propagated in time alongside the usual Ehrenfest variables. Having done so, we compute a unique rate of decoherence using two independent approaches: (i) by comparing the equations of motion for the joint nuclear-electronic probability density in phase space according to Ehrenfest dynamics versus partial Wigner transform dynamics and (ii) by introducing a frozen Gaussian interpretation of Ehrenfest dynamics which allows nuclear wave packets to separate. The first consequence of this work is a means to rigorously check the accuracy of standard Ehrenfest dynamics. Second, this paper suggests a nonadiabatic dynamics algorithm, whereby the nuclei are propagated on the mean-field (Ehrenfest) potential energy surface and undergo stochastic decoherence events. Our work resembles the surface-hopping algorithm of Schwartz and co-workers [J. Chem. Phys. 123, 234106 (2005)]-only now without any adjustable parameters. For the case of two electronic states, we present numerical results on the so-called Tully problems and emphasize that future numerical benchmarking is still needed. Future work will also treat the problem of three or more electronic states.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据