摘要
用高温固相法合成了NaLn(PO3)4∶1.0%(原子分数)Ce3+(Ln=La,Gd)两种粉末发光材料,在合肥国家同步辐射实验室(NSRL)测得两种样品中Ce3+的真空紫外光谱。根据真空紫外光谱图,得到了两种稀土偏磷酸盐中所掺Ce3+离子5d轨道的能级分裂图。结合NaLa(PO3)4和NaGd(PO3)4的单晶结构数据,发现随着Ln-O平均键长的减小,Ce3+离子5d轨道的晶场劈裂(εcfs)、重心位移(εc)和总的红移(total red-shift,D)均增大。根据配体极化模型,计算了两种化合物中掺杂Ce3+离子的有效平均键长(Reff)和光谱极化率(αsp),发现随着平均键长Rav(Ln-O)变短,Ce3+离子的光谱极化率(αsp)也随之减小。
Two powder samples NaLn (PO3)4 : 1. 0at % Ce^3+ (Ln = La, Gd) were synthesized by the solid- state reaction method. The VUV luminescence spectra at room temperature were measured at NSRL. On the basis of VUV excitation spectra of Ce^3+ ions in both samples, the energy level diagram of Ce^3+ ions was proposed. Combined the VUV excitation spectra of Ce^3+ and the structural parameters of NaLn (PO3)4 (Ln = La, Gd) single crystals, it was found that thetotal total bond crystal field splitting ( εefs), centroid shift ( ε e), redshift D (A) increased as the average Ln - O lengths [Rav(Ln - O)] became shorter. According to the ligand polarization model, the effective average Ce- O bond length (Reff) and the spectroscopic polarizability (αsp) were also calculated. And it was obtained that the spectroscopic polarizability (α sp) decreased when the Ray (Ln - O) shortened.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2008年第2期225-228,共4页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金(20571088)
广东省科技计划项目(2006B14801001)资助