Hütter Michael, Ončák Milan
Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
J Chem Theory Comput. 2025 May 13;21(9):4397-4404. doi: 10.1021/acs.jctc.4c01717. Epub 2025 Apr 29.
We present an imaginary time path-integral formalism for molecular systems including nuclear and electronic degrees of freedom based on the previous work of [Schmidt, J. R.; Tully, J. C. 2007, 127, 094103]. To sample the resulting path integral expression efficiently, a path integral Monte Carlo scheme is proposed, allowing the computation of finite temperature equilibrium properties of molecular systems including multiple low-lying electronic states directly from ab initio potential energy surfaces. Finally, we show how this generalized approach in combination with the Monte Carlo scheme can reproduce exact results for a simple model system including nonadiabatic couplings as well as thermodynamic equilibrium properties of H and C. Our implementation of the algorithm is available as an open-source code.
基于[施密特，J.R.；塔利，J.C. 2007，127，094103]之前的工作，我们提出了一种适用于包含核自由度和电子自由度的分子系统的虚时路径积分形式。为了有效地对所得路径积分表达式进行采样，我们提出了一种路径积分蒙特卡罗方案，该方案允许直接从第一性原理势能面计算包含多个低电子态的分子系统的有限温度平衡性质。最后，我们展示了这种广义方法与蒙特卡罗方案相结合如何能够重现一个包含非绝热耦合以及氢和碳的热力学平衡性质的简单模型系统的精确结果。我们的算法实现以开源代码的形式提供。
