标题： 使用频率依赖性恒温器模拟水中量子零点效应 显示英文标题

标题： Simulation of quantum zero-point effects in water using a frequency-dependent thermostat

摘要： 像水这样的分子具有零点能远高于室温的振动模式。 因此，它们液体的经典分子动力学模拟大大低估了具有更高零点温度的模式的能量，这由于非谐波效应导致共价原子间距离的低估。 可以使用路径积分分子动力学模拟来恢复零点效应，但这些模拟计算成本高昂，使其与从头算分子动力学模拟相结合成为一个挑战。 作为路径积分方法的替代方案，从计算简单的角度来看，人们会设想设计一种恒温器，能够将不同的振动模式平衡并保持在其相应的零点温度下。 最近， Ceriotti 等 (Phys. Rev. Lett. 102 020601 (2009)) 引入了一个框架，使用定制的Langevin方程和相关噪声，可用于在经典分子动力学模拟中包含量子涨落。 在这里，我们展示了可以将抑制噪声的广义Langevin方程与Nose-Hoover恒温器结合使用，以有效地在液态水的独立模式上施加零点温度。 使用我们简单且低成本的方法，我们相对于路径积分分子动力学模拟，在所有原子对关联函数方面取得了很好的一致性。 显示英文摘要

摘要： Molecules like water have vibrational modes with a zero-point energy well above room temperature. As a consequence, classical molecular dynamics simulations of their liquids largely underestimate the energy of modes with a higher zero-point temperature, which translates into an underestimation of covalent interatomic distances due to anharmonic effects. Zero-point effects can be recovered using path integral molecular dynamics simulations, but these are computationally expensive, making their combination with ab initio molecular dynamics simulations a challenge. As an alternative to path integral methods, from a computationally simple perspective, one would envision the design of a thermostat capable of equilibrating and maintaining the different vibrational modes at their corresponding zero-point temperatures. Recently, Ceriotti et al. (Phys. Rev. Lett. 102 020601 (2009)) introduced a framework to use a custom-tailored Langevin equation with correlated noise that can be used to include quantum fluctuations in classical molecular dynamics simulations. Here we show that it is possible to use the generalized Langevin equation with suppressed noise in combination with Nose-Hoover thermostats to efficiently impose a zero-point temperature on independent modes in liquid water. Using our simple and inexpensive method, we achieve excellent agreement for all atomic pair correlation functions compared to the path integral molecular dynamics simulation.