Recommendations for velocity adjustment in surface hopping

Data set for the paper. Abstract. This study investigates velocity adjustment directions after hoppings in surface hopping dynamics. Using fulvene and a protonated Schiff base (PSB4) as case studies, we investigate the population decay and reaction yields of different sets of dynamics with the velocity adjusted either in the nonadiabatic coupling, gradient difference, or momentum directions. For the latter, besides the conventional algorithm, we investigated the performance of a reduced kinetic energy reservoir approach recently proposed. Our evaluation also considered velocity adjustment in the directions of approximate nonadiabatic coupling vectors. While results for fulvene are susceptible to the adjustment approach, PSB4 is not. We correlated this dependence to the topography near the conical intersections. When nonadiabatic coupling vectors are unavailable, the gradient difference direction is the best adjustment option. If the gradient difference is also unavailable, a semiempirical vector direction or the momentum direction with a reduced kinetic energy reservoir becomes an excellent option to prevent an artificial excess of back hoppings. The precise velocity adjustment direction is less crucial for describing the nonadiabatic dynamics than the kinetic energy reservoir's size.本论文所用数据集。 摘要。本研究针对表面跳跃动力学（surface hopping dynamics）中的跃迁后速度调整方向展开探究。本研究以富烯（fulvene）与质子化希夫碱（protonated Schiff base，缩写为PSB4）为案例体系，针对分别采用非绝热耦合（nonadiabatic coupling）、梯度差（gradient difference）或动量方向进行速度调整的多组动力学模拟，考察其布居衰减与反应产率。针对动量方向调整方案，除传统算法外，本研究还探究了近期提出的约化动能储库方法（reduced kinetic energy reservoir approach）的性能表现。本评估还考虑了采用近似非绝热耦合矢量（approximate nonadiabatic coupling vectors）方向进行速度调整的方案。研究结果显示，富烯的动力学结果易受速度调整方案的影响，而PSB4则无此敏感性。我们将这一差异与锥形交叉（conical intersections）附近的势能面拓扑结构相关联。当无法获取非绝热耦合矢量（nonadiabatic coupling vectors）时，梯度差方向为最优的速度调整选择；若梯度差也无法获取，则采用半经验矢量方向或结合约化动能储库的动量方向，可有效避免人为的反向跃迁过量。相较于动能储库的尺寸，精准的速度调整方向对于非绝热动力学的模拟并非至关重要。