水溶液中Al^(3+)第三水化层对Al(H_2O)_6^(3+)水交换特性影响的密度泛函理论研究  

Density functional theory study of the influences of the third hydration shell on the characteristics for the water-exchange reactions of Al(H_2O)_6^(3+)(aq) in aqueous solution

作　　者：侯晓霞[1] 董绍楠 张婧[1] 毕树平[1] 

机构地区：[1]南京大学化学化工学院,南京210023

出　　处：《环境化学》2016年第2期246-253,共8页Environmental Chemistry

基　　金：国家自然科学基金(21177054)资助~~

摘　　要：针对水溶液中铝离子第三水化层(hydration shell)对Al(H_2O)^(3+)_6动态水交换反应特性的影响,本文采用密度泛函理论(Density functional theory,DFT)在B3LYP/6-311+G(d,p)基组水平上进行了研究.探讨了第三水化层对第一到第二水化层水交换反应速率常数k^(1-2)_(ex)以及第二到三水化层水交换反应速率常数k^(2-3)_(ex)的影响.研究结果表明,在第三水化层添加不同数目水分子时相应于k^(1-2)_(ex)和k^(2-3)_(ex)的活化能垒变化均不大,表明第三水化层对水交换反应速率常数k^(1-2)_(ex)和k^(2-3)_(ex)影响不大,采用第二水化层就可以较好处理Al(H_2O)^(3+)_6的真实溶剂效应.The influences of the third hydration shell on the dynamic characteristics for the water-exchange reactions of Al（H2O）6^3＋（aq） complexes in aqueous solution were investigated by density functional theory（DFT） calculations on the basis of B3LYP/6-311＋G（d,p）. The effects of the third hydration shell on the water-exchange reaction rate constant between the first and second hydration shells kex^1-2 and the water exchange rate constant between the second and third hydration shells kex2-3 were examined. DFT calculation results show that the activation energy barriers for both kex^1-2 and kex^2-3 changes only slightly when different number of water molecules were considered in the third hydration shell. This indicates that the third hydration shell has little influence on the water-exchange rate constants kex^1-2 and kex^2-3. It is satisfactory to account the explicit solvent effects with two hydration shells for Al（H2O）6^3＋（aq） complexes in aqueous solution.

关 键 词：Al(H2O)6^3+ 水交换反应 密度泛函理论(DFT) 第三水化层 

分 类 号：X131.2[环境科学与工程—环境科学]