School of Chemistry and Chemical Engineering and Ministry of Education Key Laboratory of Scientific and Engineering Computing, Shanghai Jiao Tong University , Shanghai, 200240, China.
J Chem Inf Model. 2017 Jul 24;57(7):1599-1608. doi: 10.1021/acs.jcim.7b00206. Epub 2017 Jul 12.
Calcium and magnesium ions play important roles in many physicochemical processes. To facilitate the investigation of phenomena related to these ions that occur over large length and time scales, a coarse-grained force field (CGFF) is developed for MgCl and CaCl aqueous solutions. The ions are modeled by CG beads with characteristics of hydration shells. To accurately describe the nonideal behavior of the solutions, osmotic coefficients in a wide range of concentrations were used as guidance for parametrization. The osmotic coefficients were obtained from the chemical potential increments of water calculated using the Bennett acceptance ratio (BAR) method. The result CGFF accurately reproduces experimental osmotic coefficients, densities, surface tensions, and cation-anion separations of calcium chloride and magnesium chloride solutions at molalities up to 3.0 mol/kg. As a preliminary application, the force field is applied to simulate aggregations of sodium dodecyl sulfate (SDS) in calcium chloride solution, and the simulation results are consistent with experimental observations.
钙离子和镁离子在许多物理化学过程中发挥着重要作用。为了促进对这些离子在大长度和时间尺度上发生的相关现象的研究，我们为 MgCl 和 CaCl 水溶液开发了一种粗粒化力场 (CGFF)。离子用具有水化壳特征的 CG 珠模拟。为了准确描述溶液的非理想行为，在广泛的浓度范围内使用渗透压系数作为参数化的指导。渗透压系数是通过使用 Bennett 接受率 (BAR) 方法计算的水化学势增量获得的。CGFF 准确地再现了实验渗透压系数、密度、表面张力和氯化钙和氯化镁溶液的阳离子-阴离子分离，摩尔浓度高达 3.0 mol/kg。作为初步应用，该力场被应用于模拟十二烷基硫酸钠 (SDS) 在氯化钙溶液中的聚集，模拟结果与实验观察结果一致。
