Optical absorption and fluorescence properties of trivalent lanthanide chlorides in high temperature molten LiCl-KCl eutectic

The absorption and fluorescence spectroscopic properties of all series of lanthanide elements (La, Ce, …, Yb, Lu) were investigated in high temperature molten LiCl-KCl eutectic. Based on absorption spectra, the molar absorptivities for major absorption bands of lanthanides (Ln) were determined by analyzing the calibration curves at various concentrations. Moreover, the nephelauxetic parameters, β, for lanthanides in molten LiCl-KCl salt were evaluated by comparing those for aqueous lanthanide ions. In addition, fluorescence spectra and lifetimes of lanthanide elements were obtained at various Ln(III) concentrations, and this is the first to systematically present fluorescence spectroscopic properties of the whole lanthanide elements in high temperature molten LiCl-KCl salt. Such absorption and fluorescence spectra can provide a fundamental basis for the understanding and development of various pyrochemical processes in molten LiCl-KCl eutectic.