Yang Zhong-Zhi, Li Xin
Department of Chemistry, Liaoning Normal University, Dalian 116029, PR China.
J Phys Chem A. 2005 Apr 28;109(16):3517-20. doi: 10.1021/jp051106p.
A systematic study on monovalent ions in water clusters and in aqueous solution is presented for providing insight into their solvation structures, charge distributions, binding energies, as well as dynamic and thermodynamic properties in terms of the atom-bond electronegativity equalization method fused into molecular mechanics (ABEEM/MM) that is to take ABEEM charges into the Coulomb term in MM. For hydrated systems of M+(H2O)n, M+ being Li+, Na+, and K+, as well as X-(H2O)n, X- being F-, Cl-, and Br-, with n = 1-6, parameters for the effective interaction between the ion and the water molecules were determined, so as to reproduce the experimental or ab initio results. The corresponding parameters were tested with molecular dynamics (MD) simulations of these ions in liquid water and with solvation free energy calculations using the perturbation technique. The results of aqueous ionic solution simulations with the ABEEM/MM force field provide a reasonable description of many important properties, which are in good agreement with the experimental measurements. This work demonstrates that the combination of ABEEM/MM-MD provides a powerful tool in analyzing solvation processes of monovalent ions in water.
本文对水团簇和水溶液中的单价离子进行了系统研究，旨在通过将原子键电负性均衡方法融入分子力学（ABEEM/MM），即把ABEEM电荷纳入MM中的库仑项，来深入了解它们的溶剂化结构、电荷分布、结合能以及动力学和热力学性质。对于M+(H2O)n（M+为Li+、Na+和K+）以及X-(H2O)n（X-为F-、Cl-和Br-）的水合体系，n = 1 - 6，确定了离子与水分子之间有效相互作用的参数，以重现实验或从头算结果。通过这些离子在液态水中的分子动力学（MD）模拟以及使用微扰技术的溶剂化自由能计算，对相应参数进行了测试。使用ABEEM/MM力场对离子水溶液进行模拟的结果，合理地描述了许多重要性质，与实验测量结果吻合良好。这项工作表明，ABEEM/MM - MD的结合为分析水中单价离子的溶剂化过程提供了一个强大的工具。
