Li_2SO_4溶液中离子间的缔合相互作用:基于密度泛函理论和分子动力学模拟的研究  

Ions-associated Interaction in Li_2SO_4 Aqueous Solution: A Density Functional Theory and Molecular Dynamics Simulations Investigation

作　　者：夏斐斐 胡俊 杨凤丽 郑纯智 房春晖[2] 曾德文[3] 易海波[4] XIA Fei-fei;HU Jun;YANG Feng-li;ZHENG Chun-zhi;FANG Chun-hui;ZENG De-wen;YI Hai-bo(School of Chemical and Environmental Engineering, Jiangsu University of Technology, Changzhou ,213001, China;Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810008, China;College of Chemistry and Chemical Engineering, Central South University, Changsha,410083, China;College of Chemistry and Chemical Engineering, Hunan University, Changsha ,410082, China)

机构地区：[1]江苏理工学院化学与环境工程学院,江苏常州213001 [2]中国科学院青海盐湖研究所中国科学院盐湖资源综合高效利用重点实验室,青海西宁810008 [3]中南大学化学化工学院,湖南长沙410083 [4]湖南大学化学化工学院,湖南长沙410082

出　　处：《盐湖研究》2018年第1期39-47,共9页Journal of Salt Lake Research

基　　金：国家自然科学基金项目(21406020)

摘　　要：基于密度泛函理论,使用B3LYP/aVDZ方法对[Li_2SO_4(H_2O)_n]~0(n=0~10、18)水合团簇的结构和性质进行了系统地研究,并结合Car-Parrinello分子动力学(CPMD)模拟了不同浓度的Li_2SO_4溶液结构,目的在于理解在Li_2SO_4溶液中离子间缔合相互作用及可能存在的物种。研究发现,对于[Li_2SO_4(H_2O)_n]~0(n=0~10、18)水合团簇,双配位单齿螯合接触离子对结构比双配位双齿螯合接触离子对结构更稳定,溶剂共享离子对结构最不稳定。同时,CPMD模拟结果表明,在3.09和3.17 mol/kg的Li_2SO_4溶液中,双配位单齿螯合接触离子对结构仍然是主要物种。以上结果表明在饱和的Li_2SO_4溶液(3.16 mol/kg)中,Li^+和SO_4^(2-)离子间的相互缔合作用主要以双配位单齿螯合接触离子对结构的物种存在,而具有双配位双齿螯合离子对结构的物种占少数,溶剂共享离子对结构几乎不存在。In this paper, the structures and properties of [Li2 SO4 （ H2 O） n ] 0 （ n = 0 - 10,18 ） hydrated clusters are systematically investigated by B3LYP/aVDZ methods based on density functional theory to understand the ion-associated interactions and the main species in Li2 SO4 aqueous solution. Meanwhile, the Li2 SO4 aqueous solutions in different concentrations are also studied by using Car-Parrinello molecular dynamics （CPMD） simulation. It is noted that bis-bidentate contact ion pairs are less stable than bis-monodendate contact ion pairs for [ LieSO4 （H2O） n ] 0 （ n = 0 - 10,18） clusters, and the solvent-shared ion pairs are the least stable structures. The CPMD simulation results show that bis-monodendate contact ion pairs are the main species in 3.09 and 3.17 mol/kg Li2SO4 aqueous solutions. It could be considered that the ions-associated interaction between Li ＋ and SO4 2- exists mainly as bis-monodendate contact ion pairs in saturated Li2 SO4 aqueous solution （3.16 mol/kg） ,while bis-bidentate contact ion pairs are of minority, solvent-shared ion pairs can be almost neglected.

关 键 词：离子缔合 离子水合 接触离子对 溶剂共享离子对 密度泛函理论 分子动力学模拟 

分 类 号：O641.5[理学—物理化学]