团簇分子[Zn-(CH_3CH_2OH)_n]~(2+)的荧光光谱研究及理论光谱验证

通过荧光光谱实验和理论计算对金属离子在乙醇溶液中的微团簇结构进行了研究。荧光光谱实验发现在275~330 nm范围存在较强的乙醇分子荧光峰,当加入盐离子(Zn~(2+))后该处荧光强度逐渐变弱,说明盐的加入对乙醇体系的荧光效率产生了影响,破坏了原有乙醇分子之间的作用,使得其刚性结构发生改变,荧光效率降低,同时Zn~(2+)与乙醇分子通过溶剂化作用形成了新的微团簇,在350~380 nm之间出现了新峰。通过对团簇结构Zn-(H_2O)_n]~(2+)(n=1~3)进行优化比较,得到了相对精确及运算成本较低的密度泛函理论B3LYP方法,并应用于Zn~(2+)在乙醇溶液中团簇结构计算。结果表明体系的第一溶剂化层存在着n=1~6的微团簇分子,且最多为6。比较理论计算荧光光谱与实验荧光光谱,进一步说明了Zn~(2+)与乙醇形成了新的微团簇及计算方法的可行性。

[Zn-(CH3 CH2 OH)n ]2+ Clusters Probed with Fluorescence Spectroscopy and Computation

In this paper the cluster structures of Zn-(CH 3 CH 2 OH)n ]2+ have been investigated with spectroscopic experiment and theoretical calculation.According to the fluorescence spectroscopy experiments,the fluorescence peak of ethanol molecules was found between 275~330 nm.A new peak appeared between 350~380 nm after the metal ions (Zn2+ )was added into etha-nol solution due to the generation of new clusters of molecules,and the original fluorescence peak of ethanol molecules became weak owing to the destroyed structure of ethanol molecules induced by Zn2+ .The cluster structures of Zn2+ in water solution were investigated by using different methods.By comparing the results,a more accurate and fast B3LYP method of DFT was found and applied to optimize the possible structures of Zn-(CH 3 CH 2 OH)n ]2+ .The results suggested that the first solvation shell of the system is up to six ethanol molecules,and thermodynamic parameters also shows the six kinds of molecular clusters which are likely in the solution.Moreover compared the theoretical fluorescence spectroscopy with experimental fluorescence spectroscopy,new clusters Zn-(CH 3 CH 2 OH)n ]2+ have been generated,with Zn-(CH 3 CH 2 OH)n ]2+ (n=1~3)as main con-structions.