Shu Yinan, Zhang Linyao, Sun Shaozeng, Truhlar Donald G
Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States.
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, People's Republic of China.
J Chem Theory Comput. 2020 Jul 14;16(7):4098-4106. doi: 10.1021/acs.jctc.0c00409. Epub 2020 Jun 9.
Electronically nonadiabatic dynamics methods based on a self-consistent potential, such as semiclassical Ehrenfest and coherent switching with decay of mixing, have a number of advantages but are computationally slower than approximations based on an unaveraged potential because they require evaluation of all components of the nonadiabatic coupling vector. Here we introduce a new approximation to the self-consistent potential that does not have this computational drawback. The new approximation uses time-derivative couplings evaluated by overlap integrals of electronic wave functions to approximate the nonadiabatic coupling terms in the equations of motion. We present a numerical test of the method for ethylene that shows there is little loss of accuracy in the ensemble-averaged results. This new approximation to the self-consistent potential makes direct dynamics calculations with self-consistent potentials more efficient for complex systems and makes them practically affordable for some cases where the cost was previously too high.
基于自洽势的电子非绝热动力学方法，如半经典埃伦费斯特方法和具有混合衰减的相干开关方法，具有许多优点，但计算速度比基于非平均势的近似方法慢，因为它们需要评估非绝热耦合矢量的所有分量。在此，我们引入一种新的自洽势近似方法，该方法不存在此计算缺陷。新的近似方法使用通过电子波函数的重叠积分评估的时间导数耦合来近似运动方程中的非绝热耦合项。我们对乙烯进行了该方法的数值测试，结果表明系综平均结果的精度几乎没有损失。这种新的自洽势近似方法使得对于复杂系统使用自洽势进行直接动力学计算更加高效，并且对于一些此前成本过高的情况在实际中也变得可行。
