As an efficient molecular simulation method, the smoothed molecular dynamics (SMD) method introduces background mesh and mapping process into molecular dynamics (MD) procedure to suppress high-frequency modes, so that a much larger time step than that of MD can be adopted. SMD method can achieve a nice overall accuracy, but local atomic disorders cannot be described very well with original SMD method for smoothing out high-frequency motions. An improved SMD method with two kinds of high-order shape functions is proposed. A parameter indicating the smoothing degree in SMD method is also presented to assess the mapping process. The efficiency and the accuracy of the improved method are discussed in detail, and the proposed method is validated with several examples. The results demonstrate obvious improvement in accuracy, and more high-frequency atomic motions can be captured. When the high-order SMD method is coupled with the MD method, the non-physical phonon reflection, which may occur at the interface in the coupling of MD and original SMD method, will decrease remarkably even if no transition scheme is employed.

中文翻译：

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一种改进的具有高阶形函数的平滑分子动力学方法

作为一种有效的分子模拟方法，平滑分子动力学（SMD）方法将背景网格和映射过程引入分子动力学（MD）过程中以抑制高频模式，因此可以采用比MD大得多的时间步长。SMD 方法可以达到很好的整体精度，但是用原始的 SMD 方法不能很好地描述局部原子紊乱来平滑高频运动。提出了一种具有两种高阶形状函数的改进SMD方法。还提供了指示 SMD 方法中平滑度的参数以评估映射过程。详细讨论了改进方法的效率和准确性，并通过几个例子验证了所提出的方法。结果表明准确率明显提高，并且可以捕捉到更多的高频原子运动。当高阶 SMD 方法与 MD 方法耦合时，即使不采用过渡方案，MD 与原始 SMD 方法耦合时在界面处可能发生的非物理声子反射也会显着减少。