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应用新一代可极化分子力场——原子-键电负性均衡浮动电荷分子力场ABEEM/MM,结合精密量子化学方法,构建了精确的Mn2+-H2O相互作用的势能函数,确定了相关参数.将该势能函数用于计算[Mn(H2O)n]2+(n=1～12)的结构和结合能,得到了与量子化学一致的结果.进一步对Mn2+水溶液进行ABEEM/MM动力学模拟,得到的Mn2+–O径向分布函数的第一和第二最高峰分别处于0.218和0.435nm处,积分得到第一和第二水合层的配位水分子数分别为7.03和17.74;对于O–Mn2+–O角度分布函数,其第一和第二最高峰分别位于80°和140°附近,这些结果与实验和其他理论方法的结果有很好的一致性.Mn2+的极化作用使得第一水合层中水分子的键长明显增长,键角明显减小;而Mn2+对第二水合层及外层水分子的结构影响较小.分析体系的电荷分布表明,与ABEEM-7P纯水相比,Mn2+水溶液中参与形成氢键的氢原子和孤对电子的电荷变化较大,且Mn2+和其邻近的水分子间存在明显的电荷转移.
The potential energy function of the accurate Mn2 + -H2O interaction was constructed by using the new generation of polarized molecular field-atom-bond electronegativity equilibrium floating charge molecular force field ABEEM / MM combined with the precision quantum chemistry method. The correlation parameters The potential energy function was used to calculate the structure and the binding energies of [Mn (H2O) n] 2+ (n = 1 ~ 12), and the results were consistent with those obtained by quantum chemistry.A further study on the ABEEM / MM kinetics of Mn2 + , The first and the second peak of the Mn2 + -O radial distribution function were obtained at 0.218 and 0.435 nm, respectively, and the number of coordinated water molecules of the first and the second hydration layers were respectively 7.03 and 17.74. For O- Mn2 + -O angle distribution function, the first and second highest peak are located in the vicinity of 80 ° and 140 °, respectively, these results are in good agreement with the experimental and other theoretical methods.The polarization of Mn2 + makes the first hydration The bond length of water molecules obviously increased and the bond angle decreased obviously, while Mn2 + had little effect on the structure of the second hydration layer and the outer water molecules.The charge distribution of the system showed that compared with the ABEEM-7P pure water, Hydrogen atoms and lone pair electrons involved in hydrogen bonding in Mn2 + aqueous solution Vary widely, the presence of significant charge transfer between adjacent and Mn2 + and water molecules.