Suzuki Yasumitsu, Abedi Ali, Maitra Neepa T, Gross E K U
Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
Department of Physics and Astronomy, Hunter College and the City University of New York, 695 Park Avenue, New York, New York 10065, USA.
Phys Chem Chem Phys. 2015 Nov 21;17(43):29271-29280. doi: 10.1039/c5cp03418c.
We study the exact nuclear time-dependent potential energy surface (TDPES) for laser-induced electron localization with a view to eventually developing a mixed quantum-classical dynamics method for strong-field processes. The TDPES is defined within the framework of the exact factorization [A. Abedi, N. T. Maitra, and E. K. U. Gross, Phys. Rev. Lett., 2010, 105, 123002] and contains the exact effect of the couplings to the electronic subsystem and to any external fields within a scalar potential. We compare its features with those of the quasistatic potential energy surfaces (QSPES) often used to analyse strong-field processes. We show that the gauge-independent component of the TDPES has a mean-field-like character very close to the density-weighted average of the QSPESs. Oscillations in this component are smoothened out by the gauge-dependent component, and both components are needed to yield the correct force on the nuclei. Once the localization begins to set in, the gradient of the exact TDPES tracks one QSPES and then switches to the other, similar to the description provided by surface-hopping between QSPESs. We show that evolving an ensemble of classical nuclear trajectories on the exact TDPES accurately reproduces the exact dynamics. This study suggests that the mixed quantum-classical dynamics scheme based on evolving multiple classical nuclear trajectories on the exact TDPES will be a novel and useful method to simulate strong field processes.
我们研究了用于激光诱导电子局域化的精确含时核势能面（TDPES），以期最终开发出一种用于强场过程的混合量子 - 经典动力学方法。TDPES是在精确因子分解框架内定义的[A. 阿贝迪、N. T. 梅特拉和E. K. U. 格罗斯，《物理评论快报》，2010年，第105卷，123002]，并且包含了在标量势中与电子子系统和任何外部场耦合的精确效应。我们将其特征与常用于分析强场过程的准静态势能面（QSPES）的特征进行了比较。我们表明，TDPES的规范无关分量具有类似于平均场的特征，非常接近QSPES的密度加权平均值。该分量中的振荡被规范相关分量平滑掉，并且两个分量都需要用来产生作用在原子核上的正确力。一旦局域化开始出现，精确TDPES的梯度会跟踪一个QSPES，然后切换到另一个，这类似于QSPES之间表面跳跃所提供的描述。我们表明，在精确TDPES上演化一组经典核轨迹能够准确地再现精确动力学。这项研究表明，基于在精确TDPES上演化多个经典核轨迹的混合量子 - 经典动力学方案将是一种模拟强场过程的新颖且有用的方法。
