Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom.
J Chem Phys. 2012 Dec 14;137(22):22A548. doi: 10.1063/1.4765087.
In this article, we investigate the convergence of quantum dynamics calculations with coupled variationally optimized gaussian product basis functions, describing wavepacket motion on regions of molecular potential energy surfaces calculated on the fly. As a benchmark system, we model the radiationless decay of fulvene from its first electronic excited state through an extended S(1)∕S(0) conical intersection seam and monitor two associated properties: the spatial extent to which the conical intersection seam is sampled and the timescale and stepwise nature of the population transfer. We suggest that the fully variational description reviewed here (direct dynamics-variational multi-configuration gaussian) provides a way to balance accuracy against computational cost for molecules of comparable sizes by choosing the number of coupled gaussian product basis functions and a middle way forward between grid based and trajectory surface hopping approaches to non-adiabatic molecular quantum dynamics calculations.
在本文中，我们研究了量子动力学计算与耦合变分优化的高斯积基函数的收敛性，这些函数描述了在分子势能表面的区域上运动的波包，这些势能表面是实时计算的。作为一个基准系统，我们通过扩展的 S(1)∕S(0) 锥形交叉 seam 来模拟富烯从其第一电子激发态的无辐射衰减，并监测两个相关的性质：锥形交叉 seam 被采样的空间范围，以及人口转移的时间尺度和逐步性质。我们建议，这里回顾的完全变分描述（直接动力学-变分多构型高斯）通过选择耦合高斯积基函数的数量，为具有可比大小的分子提供了一种在准确性和计算成本之间取得平衡的方法，这是一种介于基于网格和轨迹表面跳跃方法之间的非绝热分子量子动力学计算的中庸之道。
