Vassilev Peter, Louwerse Manuel J, Baerends Evert Jan
Divisie Scheikunde, afd. Theoretische Chemie, Vrije Universiteit Amsterdam, De Boelelaan 1083, Amsterdam 1081 HV, The Netherlands.
J Phys Chem B. 2005 Dec 15;109(49):23605-10. doi: 10.1021/jp044751p.
Ab initio density functional theory molecular dynamics simulations of the solvated states of the hydroxyl radical and hydroxide ion are performed using the Becke-Lee-Yang-Parr (BLYP) exchange-correlation functional (Becke, A. D. Phys. Rev. A 1988, 38, 3098. Lee, C.; Yang, W.; Parr, R. G. Phys. Rev. B 1988, 37, 785). The structures of the solvation shells of the two species are examined. It is found that the OH radical forms a relatively well-defined solvation complex with four neighboring water molecules. Three of these molecules are hydrogen bonded to the OH, while the fourth is hemibonded via a three-electron two-centered bond between the oxygen atoms of the OH and water. The activity and the diffusion mechanism of the OH radical in water is discussed in comparison with the OH- ion. Although the results are partially influenced by the tendency of the BLYP density functional to overestimate hemibonded structure, the present simulations suggest that the widely accepted picture of rapid diffusion of OH radical in water through hydrogen exchange reaction may need to be reconsidered.
使用Becke-Lee-Yang-Parr（BLYP）交换关联泛函（Becke，A. D.《物理评论A》1988年，第38卷，第3098页。Lee，C.；Yang，W.；Parr，R. G.《物理评论B》1988年，第37卷，第785页）对羟基自由基和氢氧根离子的溶剂化状态进行了从头算密度泛函理论分子动力学模拟。研究了这两种物质溶剂化壳层的结构。发现羟基自由基与四个相邻水分子形成了一个相对明确的溶剂化复合物。其中三个分子通过氢键与羟基相连，而第四个分子则通过羟基和水分子的氧原子之间的三电子双中心键半键合。与氢氧根离子相比，讨论了羟基自由基在水中的活性和扩散机制。尽管结果部分受到BLYP密度泛函高估半键合结构趋势的影响，但目前的模拟表明，广泛接受的羟基自由基在水中通过氢交换反应快速扩散的图景可能需要重新考虑。
