LaOX:Ho^(3+)体系的荧光光谱及其配位场解析

FLUORESCENCE SPECTRA AND THEIR COORDINATION FIELD ANALYSIS OF LaOX:Ho^(3+) PHOSPHORS(X- = Cl^-,Br^-)

合成了LaOX:Ho^(3+)磷光体(X^-=Cl^-,Br^-),测定了该体系在室温和液氮温度下的荧光光谱;基于双层点电荷配位场模型,计算了Ho^(3+)离子在LaOX系列基质中的配位场微扰能级,给出其荧光光谱的理论归属;这套能级与实测光谱吻合较好,并对~5I_8→~5G_6超灵敏跃迁激发带的“鞍形”结构、~5I_8→~5G_6及(~5S_2,~5F_4)→~5I_8跃迁峰的温度效应提出合理解释。

LaOX:Ho^(3+) phosphors (X~=Cl-,Br-) were synthesized and their fluorescence spectra at room temperature and liquid nitrogen temperature were measured. Based on the Double Sphere Coordination Point Charg eField (DSCPCF) model, the coordination field perturbation energy levels of Ho3+ ions doped in LaOX matrixes were calculated and the corresponding spectra assigned. The energy levels calculated agree well with the spectra observed. And the theoretical assignments bring out a resonable explanation for the 'Saddle-shaped' excitation band of 5I8-5G6 hypersensitive transition and the temperature effect on 5I8-5G6 and (5S2,5F4)-5I8 transition bands. By comparison with Point Charge Field (PCF) model, DSCPCF model makes Bm2 decrease slightly, while Bm4 and especially Bm6 increase greatly. It is this correction that overcomes the shortcoming of PCF model in certain degree.