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

机译：使用频率相关的恒温器模拟水中的量子零点效应

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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.
机译：像水这样的分子具有的振动模式的零点能量远高于室温。结果，液体的经典分子动力学模拟大大低估了具有较高零点温度的模式的能量，这由于非谐效应而转化为对共价原子间距离的低估。零点效应可以使用路径积分分子动力学模拟来恢复，但是这些运算在计算上是昂贵的，这使得它们与从头算分子动力学模拟的结合成为一个挑战。从计算简单的角度来看，作为路径积分方法的替代方法，可以设想一种恒温器的设计，该恒温器能够在其相应的零点温度下平衡并维持不同的振动模式。最近，Ceriotti等人。 [物理牧师102，020601（2009）]引入了一个框架，该框架可使用具有相关噪声的定制兰格文方程，该方程可用于经典分子动力学模拟中的量子涨落。在这里，我们表明可以将带有抑制噪声的广义Langevin方程与Nose-Hoover恒温器结合使用，以对液态水的独立模式有效地施加零点温度。与路径积分分子动力学模拟相比，使用我们简单而廉价的方法，我们对所有原子对相关函数都达到了极好的一致性。

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  • 来源
    《Physical review》 |2013年第13期|134207.1-134207.11|共11页
  • 作者

    Sriram Ganeshan; R. Ramirez; M. V. Fernandez-Serra;

  • 作者单位

    Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA;

    Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain;

    Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA;

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  • 正文语种 eng
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  • 关键词

    computational modeling; simulation; hydrogen bonding; hydrophilic effects;

    机译：计算建模;模拟;氢键;亲水作用;

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