Chu Weibin, Zheng Qijing, Akimov Alexey V, Zhao Jin, Saidi Wissam A, Prezhdo Oleg V
Department of Chemistry and Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States.
Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
J Phys Chem Lett. 2020 Dec 3;11(23):10073-10080. doi: 10.1021/acs.jpclett.0c03080. Epub 2020 Nov 12.
Synergy of nonadiabatic molecular dynamics with real-time time-dependent density functional theory has led to significant progress in modeling excited-state dynamics in nanoscale and condensed matter systems over the past decade. Nonadiabatic coupling (NAC) is the central quantity in such simulations, and its accurate and efficient evaluation is an enduring challenge in time-dependent Kohn-Sham theory, particularly in conjunction with planewave basis sets and projector augmented-wave (PAW) pseudopotentials because of the complexity of the PAW "all-electron" wave function. We report a method for rigorous evaluation of the NAC with PAW wave functions and demonstrate an efficient approximation to the rigorous NAC that gives comparable accuracy. As a validation, we intensely examine the NAC matrix elements calculated using both pseudo- and all-electron wave functions under the PAW formalism in six representative systems. The approximate NAC obtained with pseudowave functions is close to the exact all-electron NAC, with the largest deviations observed when subshell d-electrons are involved in the transitions. The developed approach provides a rigorous and convenient methodology for the numerical computation of NAC in the Kohn-Sham theory framework.
在过去十年中，非绝热分子动力学与实时含时密度泛函理论的协同作用在模拟纳米尺度和凝聚态物质系统中的激发态动力学方面取得了显著进展。非绝热耦合（NAC）是此类模拟中的核心量，其准确而高效的计算是含时Kohn-Sham理论中一项长期存在的挑战，特别是在结合平面波基组和投影增强波（PAW）赝势时，由于PAW“全电子”波函数的复杂性。我们报告了一种用PAW波函数严格计算NAC的方法，并展示了一种对严格NAC的有效近似，其精度相当。作为验证，我们在六个代表性系统中深入研究了在PAW形式体系下使用赝波函数和全电子波函数计算得到的NAC矩阵元。用赝波函数得到的近似NAC接近精确的全电子NAC，当亚壳层d电子参与跃迁时观察到的偏差最大。所开发的方法为Kohn-Sham理论框架下NAC的数值计算提供了一种严格且便捷的方法。
