论文标题
通过分子动力学模拟，计算致密原子流体的平衡三粒子熵
Computation of the equilibrium three-particle entropy for dense atomic fluids by molecular dynamics simulation
论文作者
论文摘要
我们通过分子动力学模拟计算了对数周的chandler-andersen流体熵的两个和三粒子的贡献。使用新方法来简化计算，计算了三粒子相关函数和熵。结果在质量上类似于Lennard-Jones系统。我们观察到三粒子贡献中的数值不稳定。先前在使用传统方法时已经检测到了这种现象，因此在计算中可能是固有的。虽然可以通过外推过程去除统计波动的效果，但由于有限箱大小而导致的离散误差更难表征。通过正确选择垃圾箱尺寸，可以在任何状态下，即使接近冰点，可以实现三粒子熵贡献的良好估计。我们观察到，尽管随着冻结的冻结，三粒子贡献的幅度与两粒子的贡献相比显着增加，但由于两个物体和三体术语对超出熵的高估而引起的误差超过了与单独的两个身体术语近似过量熵所诱导的误差。
We have computed the two and three-particle contribution to the entropy of a Weeks-Chandler-Andersen fluid via molecular dynamics simulations. The three-particle correlation function and entropy were computed with a new method which simplified calculation. Results are qualitatively similar to Lennard-Jones systems. We observed a numerical instability in the three-particle contribution. This phenomenon has been previously detected when the traditional method is used, thus it is likely to be intrinsic in the computation. While the effect of statistical fluctuations can be removed through an extrapolation procedure, the discretization error due to finite bin size is more difficult to characterize. With a correct choice of the bin size, a good estimate of the three-particle entropy contribution can be achieved at any state, even close to the freezing point. We observed that, despite the fact that the magnitude of the three-particle contribution increases significantly compared to the two-particle contribution as freezing is approached, the error induced from overestimation of the excess entropy by the two and three-body terms exceeds that induced by approximating the excess entropy with the two body term alone.
