用AIM理论研究水体系中K~+与水分子之间的成键

碱金属中的钾离子与水分子形成的K+-H2O团簇在生物体钾离子通道的选择中起到了重要的作用。本文用Car-Parrinello动力学方法(CPMD)和AIM理论对团簇中钾离子与水分子形成的键进行研究。结果表明钾离子与一、二两个水合层中的水分子均发生作用。在300K时,第一水合层钾离子的配位数为5.10,键能为11.99 kcal/mol。因为K+-H2O之间形成的较强的键,所以第一水合层中离子与水的结合在250K~350K时很稳定。

Ion-water Bonding of K+ Solvation in Water: An Atoms-in-Molecules Perspective

The alkali ion -water bonding, such as K ＋ , plays a key role on understanding the selectivity of biological ion channels, Using the combination of Car - Parrinello molecular dynamics simulation and the Atoms- In -Molecules theory, we investigated the K^＋ -water bonding in solution. The results indicated that K ^＋ bonds with the water molecules in the first and second hydration shells. In the first hydration shell at 300K, the K^＋ -water coordination numbers is 5.10, and the bond strengths is 11.99 kcal/mol. Because of their strong ion - water bonding, the first hydration shells of alkali ions K^＋ is stable in the temperature range from 250K to 350K.