Nonadditivity of ab initio pair potentials for molecular dynamics of multivalent transition metal ions in water
Nonadditivity of ab initio pair potentials for molecular dynamics of multivalent transition metal ions in water
复制标题
水中多价过渡金属离子分子动力学从头算对势的非加和性
DOI：
10.1063/1.452130
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发表时间：
1987
影响因子：
4.4
通讯作者：
A. Rahman
中科院分区：
文献类型：
--
作者：
L. Curtiss;J. W. Halley;J. Hautman;A. Rahman
本文报道了Fe ~（2+）和Fe ~（3+）离子与水相互作用的从头算分子轨道对势。使用从头算对势对Fe 2+和Fe 3+在水中的溶剂化壳层的静态结构进行分子动力学计算给出了物理上不正确的结果，即，配位数为8，而不是实验观察到的6。对于水中的二价过渡金属离子，其他工作者也遇到了这个问题。通过计算两个水分子与阳离子相互作用的三体能量，我们表明问题的起源最有可能是在对势的可加性假设中，即，忽略多体力报告了近似考虑三体力的经验势，并给出水中Fe 2+和Fe 3+的配位数为6。
Ab initio molecular orbital pair potentials for the interaction of Fe2+ and Fe3+ ions with H2O are reported. Molecular dynamics calculations of the static structure of the solvation shell of Fe2+ and Fe3+ in water using the ab initio pair potentials gives physically incorrect results, i.e., the coordination numbers are eight instead of six as observed experimentally. This problem has also been encountered by other workers for divalent transition metal ions in water. By computing three‐body energies from the interaction of two water molecules with the cations, we show that the origin of the problem is most likely in the assumption of the additivity of the pair potentials, i.e., neglect of many‐body forces. Empirical potentials are reported which take approximate account of the three‐body forces and give coordination numbers of six for both Fe2+ and Fe3+ in water.