Laboratory of Computational Science and Modelling, Institute of Materials, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
J Chem Phys. 2018 Mar 14;148(10):102301. doi: 10.1063/1.4990536.
Generalized Langevin Equation (GLE) thermostats have been used very effectively as a tool to manipulate and optimize the sampling of thermodynamic ensembles and the associated static properties. Here we show that a similar, exquisite level of control can be achieved for the dynamical properties computed from thermostatted trajectories. We develop quantitative measures of the disturbance induced by the GLE to the Hamiltonian dynamics of a harmonic oscillator, and show that these analytical results accurately predict the behavior of strongly anharmonic systems. We also show that it is possible to correct, to a significant extent, the effects of the GLE term onto the corresponding microcanonical dynamics, which puts on more solid grounds the use of non-equilibrium Langevin dynamics to approximate quantum nuclear effects and could help improve the prediction of dynamical quantities from techniques that use a Langevin term to stabilize dynamics. Finally we address the use of thermostats in the context of approximate path-integral-based models of quantum nuclear dynamics. We demonstrate that a custom-tailored GLE can alleviate some of the artifacts associated with these techniques, improving the quality of results for the modeling of vibrational dynamics of molecules, liquids, and solids.
广义朗之万方程 (GLE) 恒温器已被非常有效地用作一种工具，用于操纵和优化热力学系综的采样和相关的静态特性。在这里，我们表明可以为从恒温轨迹计算得出的动力学特性实现类似的、精湛的控制水平。我们开发了用于衡量 GLE 对谐振子哈密顿动力学干扰的定量指标，并表明这些分析结果可以准确预测强非谐系统的行为。我们还表明，在很大程度上可以修正 GLE 项对相应微正则动力学的影响，这为使用非平衡朗之万动力学来近似量子核效应提供了更坚实的基础，并有助于提高使用朗之万项来稳定动力学的技术对动力学量的预测。最后，我们讨论了在基于近似路径积分的量子核动力学模型中使用恒温器的问题。我们证明，定制的 GLE 可以缓解这些技术相关的一些伪影，从而提高分子、液体和固体振动动力学建模的结果质量。
