摘要
用叠加模型分析晶场参量，用微扰法计算ＭｇＴｉＯ３晶体中Ｍｎ２＋和Ｆｅ３＋离子的零场分裂（ＺＦＳ）参量ｂ０２，ｂ０４和ｂ３４．将计算值与实验值比较，确定了３ｄ５离子的占位和移动．对于ＭｇＴｉＯ３：Ｍｎ２＋，Ｍｎ２＋可能替代Ｍｇ２＋离子，且不发生移动；对于ＭｇＴｉＯ３：Ｆｅ３＋，Ｆｅ３＋同时替代Ｍｇ２＋和Ｔｉ４＋离子，且分别向八面体中心移动０．００８９ｎｍ和０．０１６ｎｍ．
By means of the complete diagonalization of Hamiltonian matrix, we calculate the optical fine structure of Cr 3+ (Ⅰ) ion in LiNbO 3:Cr 3+ ,Mg 2+ , and then carefully analyze the zero field splittings and the R lines ( 2E→ 4A 2transition). According to the EPR and absorption spectra, we further study the substitutional sites for Cr 3+ (Ⅰ) and Cr 3+ (Ⅱ) ions in LiNbO 3:Cr 3+ ,Mg 2+ . The results indicate that Cr 3+ (Ⅱ) ions should be at the Nb 5+ sites and move 0.013±0.001nm along the C 3 axis towards the centre of the oxygen octahedron, and the calculated values of the zero field splitting parameter D and energies of the 2E and 4T 2states are both in good agreement with the experimental data. For Cr 3+ (Ⅰ), there exist two possibilities: at the Nb 5+ and Li +sites, both with moving along the C 3 axis about 0.049nm towards the center of the octahedron. The calculated results for the 2E state energy and the zero field splitting agree well with experimental ones.
出处
《四川师范大学学报（自然科学版）》
CAS
CSCD
1998年第3期288-292,共5页
Journal of Sichuan Normal University（Natural Science）
基金
四川省应用基础专项基金
四川省教委重点科研基金
关键词
占位
零场分裂
钛酸镁晶体
锰离子
铁离子
Zero field splitting
Ground state splitting
R lines
LiNbO 3:Cr 3+ ,Mg 2+
