Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (11): 2535-2540.doi: 10.3866/PKU.WHXB20111006


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

WU Xiao-Jing1, DAI Yun1, ZHANG Nan1, LI Jing2   

  1. 1. School of Chemical Engineering, Hefei University of Technology, Hefei 230009, P. R. China;
    2. Institute for Geoanalysis of Anhui Province, Hefei 230001, P. R. China
  • Received:2011-06-17 Revised:2011-07-18 Published:2011-10-27
  • Contact: WU Xiao-Jing

Abstract: Fluorescence spectra of CaCl2, LiCl, and Ca(NO3)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 CaCl2 and LiCl are connected to methanol as clusters with good fluorescence properties. A strong increase in fluorescence intensity of CaCl2 and LiCl solutions was observed upon increasing their concentrations. The interaction between Ca(NO3)2 and methanol causes the fluorescence quenching of methanol. The results of the theoretical calculation show that [CaCl(CH3OH)n]+ and LiCl(CH3OH)n clusters strengthen the fluorescence intensity of the salt methanol solution and the oscillator strength of NO3- and the methanol clusters is almost zero. This illustrates the fluorescence quenching phenomenon of the NO3- anion and methanol.

Key words: Density functional theory, Salt/methanol cluster, Fluorescence quenching, Excitation wavelength


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