Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
J Chem Phys. 2010 Oct 28;133(16):164101. doi: 10.1063/1.3499947.
We present a new method for introducing stable nonequilibrium velocity and temperature gradients in molecular dynamics simulations of heterogeneous systems. This method extends earlier reverse nonequilibrium molecular dynamics (RNEMD) methods which use momentum exchange swapping moves. The standard swapping moves can create nonthermal velocity distributions and are difficult to use for interfacial calculations. By using nonisotropic velocity scaling (NIVS) on the molecules in specific regions of a system, it is possible to impose momentum or thermal flux between regions of a simulation while conserving the linear momentum and total energy of the system. To test the method, we have computed the thermal conductivity of model liquid and solid systems as well as the interfacial thermal conductivity of a metal-water interface. We find that the NIVS-RNEMD improves the problematic velocity distributions that develop in other RNEMD methods.
我们提出了一种在异质系统分子动力学模拟中引入稳定非平衡速度和温度梯度的新方法。这种方法扩展了早期使用动量交换交换操作的反向非平衡分子动力学 (RNEMD) 方法。标准的交换操作可以产生非热速度分布，并且难以用于界面计算。通过在系统的特定区域对分子进行非各向同性速度缩放 (NIVS)，可以在保持系统线性动量和总能量的情况下在模拟的区域之间施加动量或热通量。为了测试该方法，我们计算了模型液体和固体系统的导热系数以及金属-水界面的界面导热系数。我们发现，NIVS-RNEMD 改善了其他 RNEMD 方法中出现的有问题的速度分布。
