Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
J Chem Phys. 2019 Mar 14;150(10):104101. doi: 10.1063/1.5087160.
In the previous work of Cotton and Miller [J. Chem. Phys. 145, 144108 (2016)], an improved symmetrical quasi-classical (SQC) windowing model for the molecular dynamics treatment of electronically non-adiabatic processes was developed in order to extend the original SQC approach to the regime of weak-coupling between the electronic states. The improved SQC model-based on triangular-shaped window functions-handled the weak-coupling limit as intended and, as a bonus, was shown to be universally superior to the original square/histogram SQC windowing model over all coupling regimes, but only for treating systems of two electronic states, as no higher-dimensional generalization was evident. This paper, therefore, provides a generalized version for treating an arbitrary number of electronic states. By construction, the benefits of the two-state triangle model-seamless treatment of weak-coupling and improved accuracy in all coupling regimes-carry over to the generalized version. Far more significant, however, is that the new model provides vastly improved windowing statistics in higher dimensions, enabling the SQC simulation of electronically non-adiabatic processes involving many more relevant electronic states than was previously practical. Capabilities are demonstrated with respect to a 24 pigment trimer model of the Fenna-Matthews-Olson light-harvesting complex, as well as treating similar 48- and 96-electronic state model problems, illustrating the scaling properties of the new method.
在科顿和米勒的前期工作中 [J. Chem. Phys. 145, 144108 (2016)]，为了将原始 SQC 方法扩展到电子态之间弱耦合的区域，开发了一种用于处理电子非绝热过程的分子动力学的改进对称准经典（SQC）窗口模型。基于三角形窗口函数的改进 SQC 模型——处理弱耦合极限，并且作为额外的好处，在所有耦合区域中，都被证明优于原始的正方形/直方图 SQC 窗口模型，但仅适用于处理两个电子态的系统，因为没有明显的更高维概括。因此，本文提供了一种用于处理任意数量电子态的广义版本。通过构造，两态三角形模型的优势——弱耦合的无缝处理以及所有耦合区域的改进精度——可以转移到广义版本。然而，更重要的是，新模型在更高维度上提供了大大改进的窗口统计数据，使得 SQC 模拟能够处理比以前更实用的更多相关电子态的电子非绝热过程。通过 24 个色素三聚体模型的芬纳-马修斯-奥尔森光捕获复合物，以及处理类似的 48 个和 96 个电子态模型问题，展示了新方法的扩展性能。
