Eu3+:Ln2O2S(Ln=Lu,Y,Gd,La)晶体的角重迭参数计算

本文使用角重迭模型(AOM),针对Eu3+:Ln2O2S(Ln=Lu,Y,Gd,La)晶体系列,在考虑硫和氧两种不同格位的情况下,对f电子的全部四个角重迭参数eσ、eπ、eδ和eφ进行了计算,得到了一些基本规律,即中心离子与配位体之间的共价性大小次序为Lu～Y>Gd>La,并且Ln-O键的共价性要强于Ln-S键.

CALCULATION OF ANGULAR OVERLAP PARAMETERS FOR Eu3+:Ln2O2S(Ln=Lu,Y,Gd,La)CRYSTAL SERIES

Angular Overlap Model(AOM)is applied to Eu3+:Ln2O2S(Ln=Lu,Y,Gd,La)crystal series while two sorts of ligand(oxygen and sulfur with distance R1 and R2)are considered.The results show that the cova-lency between central ion and ligands varies in the order Lu~Y>Gd>La,and for σ-bonding the covalency of Ln-O bonding is larger than that of Ln-S bonding.Our conclusions also indicate that at least both parameters eσ and ex must be considered in practical calculationsions for this crystal series.If we only consider parameter eσ,larger deviation will occur,compared to some other crystals,such as GdVO4,LuVO4 and YVO4 where parameter eσ is dominant.This gives us a hint that the value of each parameter depends on the structure and components of the studied crystal.