盐/甲醇体系荧光光谱的分析和指认  

Analysis and Assignment of the Fluorescence Spectra of a Salt/ Methanol System

作　　者：吴晓静[1] 代云[1] 张楠[1] 李静[2] 

机构地区：[1]合肥工业大学化学工程学院,合肥230009 [2]安徽省地质实验研究所,合肥230001

出　　处：《物理化学学报》2011年第11期2535-2540,共6页Acta Physico-Chimica Sinica

摘　　要：研究了CaCl_2、LiCl和Ca(NO_3)_2在甲醇溶液中的荧光光谱,并对溶液中可能的团簇构型采用密度泛函理论和含时(TD)密度泛函理论中的B3L-YP方法进行结构优化和激发能计算.实验结果表明CaCl_2和LiCl与甲醇形成了具有荧光性质的簇合物,且随着CaCl_2和LiCl浓度的增加溶液的荧光强度整体呈增强趋势,而Ca(NO_3)_2与甲醇相互作用使甲醇发生荧光猝灭.理论计算得到盐/甲醇溶液中可能存在多种簇合物,但能使甲醇溶液荧光增强的团簇构型主要为[CaCl(CH_3OH)_n]^+和LiCl(CH_3OH)_n,而NO_3^-与甲醇通过氢键作用形成簇合物的振荡强度几乎为零,解释了NO_3^-使甲醇发生荧光猝灭的现象.Fluorescence spectra of CaCI_2,LiCI,and Ca（NO_3）_2 in methanol were investigated and the structures and excitation energy of possible clusters were optimized by density functional theory（DFT） and time-dependent（TD） DFT theory with B3LYP method.Experimental results indicate that CaCI_2 and LiCI are connected to methanol as clusters with good fluorescence properties.A strong increase in fluorescence intensity of CaCI_2 and LiCI solutions was observed upon increasing their concentrations.The interaction between Ca（NO_3）_2 and methanol causes the fluorescence quenching of methanol.The results of the theoretical calculation show that[CaCI（CH_3OH）_n]~＋ and LiCI（CH_3OH）_n clusters strengthen the fluorescence intensity of the salt methanol solution and the oscillator strength of NO_3^- and the methanol clusters is almost zero.This illustrates the fluorescence quenching phenomenon of the NO_3^- anion and methanol.

关 键 词：密度泛函理论 盐/甲醇团簇 荧光猝灭 激发波长 

分 类 号：O645[理学—物理化学] O641[理学—化学]