Excitation and Emission Spectra of Cs2NaLnCl6 Crystals Using Synchrotron Radiation |
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Authors: | Peter A. Tanner Chang-Kui Duan Bing-Ming Cheng |
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Affiliation: | 1. Department of Biology and Chemistry , City University of Hong Kong , Kowloon, Hong Kong S.A.R., Peoples' Republic of China bhtan@cityu.edu.hk;3. Department of Biology and Chemistry , City University of Hong Kong , Kowloon, Hong Kong S.A.R., Peoples' Republic of China;4. Institute of Modern Physics , Chongqing University of Post and Telecommunications , Chongqing, Peoples' Republic of China;5. National Synchrotron Radiation Research Center , Hsinchu, Taiwan |
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Abstract: | ABSTRACT The visible emission and vacuum ultraviolet excitation spectra of the series Cs2NaLnCl6 (Ln = Y, Nd, Sm, Eu, Tb, Er, Yb) and Cs2NaYCl6:Ln3+ (Ln = Sm, Er) have been recorded using synchrotron radiation at room temperature, and in some cases at 10 K. The excitation spectra comprise features associated with charge transfer, excitation from the valence to conduction band, and impurity bands. No d–f emissions were observed for these Ln3+ ions, so that the emission bands comprise intraconfigurational 4f N –4f N transitions and impurity bands, whose natures are discussed. Theoretical simulations of the f–d absorption spectra have been included. The comparison with data from the synchrotron at Desy enables a comprehensive account of the ground (or vibrationally excited ground for Ln2+) states of the Ln3+ 4f N , Ln3+ 4f N?15d, and Ln2+ 4f N+1 configurations relative to the valence and conduction bands of Cs2NaLnCl6, for which the band gaps are between 6.6 and 8.1 eV. |
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Keywords: | 4f–5d spectra charge transfer energy levels excitation spectra lanthanide ion spectral intensities |
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