REACTION FIELD MOLECULAR-DYNAMICS SIMULATION WITH FRIEDMANS IMAGE CHARGE METHOD
REACTION FIELD MOLECULAR-DYNAMICS SIMULATION WITH FRIEDMANS IMAGE CHARGE METHOD
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DOI：
10.1021/j100031a031
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发表时间：
1995-08-03
影响因子：
--
通讯作者：
HERMANS, J
中科院分区：
文献类型：
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作者：
WANG, L;HERMANS, J
弗里德曼的图像电荷方法已被实施在分子动力学模拟水滴系统来表示反应场。首先对有无反应场的纯水滴进行了模拟。分析了液滴的能量、径向分布函数、表面效应和介电常数。其次，计算了模型阳离子在有无反应场的不同水滴中的水合自由能。对于具有反应场的纯水滴，我们发现与液滴边界条件相关的固有问题，即，表面效应和液滴的低介电常数只能通过反应场部分地减轻。通过自由能计算，我们发现当阳离子位于液滴中心时，反应场能很好地代表长程相互作用。然而，在反应场中的阳离子的水合自由能取决于阳离子在液滴中的位置，以类似于没有反应场的方式。所有这些都表明，直接应用弗里德曼的图像电荷方法的液滴模拟是不成功的。在研究中，我们发现，通过忽略水分子与其像之间的相互作用，不对表面附近的水分子施加反应场，可以使水化自由能几乎与阳离子的位置无关。
Friedman's image charge method has been implemented in molecular dynamics simulations on water droplet systems to represent the reaction field. The simulation were first done on pure water droplets with and without the reaction field. The energy, radial distribution function, surface effects, and dielectric constant of the droplets were analyzed. Second, the hydration free energy of a model cation was calculated in different water droplets with and without the reaction field. For pure water droplets with the reaction field, we found that the inherent problems associated with droplet boundary conditions, i.e., the surface effects and the low dielectric constant of the droplets, can be only partly alleviated by the reaction field. From the free energy calculations, we found that the reaction field can well represent the long-range interaction when the cation is at the center of a droplet. However, the hydration free energy of the cation in the reaction field depends on the position of the cation in the droplet, in a similar way as without the reaction field. All this suggests that direct application of Friedman's image charge method to droplet simulations is not successful. In the study, we found that by neglecting the interaction between water molecules and their images and not applying the reaction field to the water molecules near the surface, the hydration free energy can be made almost independent of the position of the cation.