摘要
推导了晶体中立方(Oh对称)的3d3八面体基团的g因子的高阶微扰公式;其中,既包括了传统的晶场机制(涉及与d—d跃迁光谱有关的晶场激发态与基态的相互作用)的贡献,也包括了以前在晶体场理论中被忽略的荷移机制(涉及与电荷转移光谱有关的荷移激发态与基态的相互作用)的贡献。采用这个公式和由CaZrO3∶Mn4+晶体光谱所得的参量,文章计算了该晶体的g因子(也包括了d—d跃迁光谱),计算结果与实验值能很好地吻合一致。计算中发现,荷移机制对g因子移动Δg(≈g-2.0023)的贡献在符号上与晶场机制的贡献相反,但大小已达到晶场机制贡献的62%。这表明,对晶体中高价态的3d3离子(如Mn4+和Fe5+)八面体基团,合理地解释其g因子(或其他电子顺磁共振谱参量)应同时考虑晶场机制和荷移机制的贡献。
The complete high-order perturbation formula of g factor for 3d3 ions in cubic octahedral site was derived. In the formula, both the contribution ΔgCF to g-shift Δg(=g-gs, where gs=2. 002 3) due to crystal-field (CF) mechanism (related to the interactions of CF excited states with the ground state) and that (ΔgCT) due to charge-transfer (CT) mechanism (related to the interactions of CT excited states with the ground state, which is omitted in crystal-field theory) are included. By using the formula and the parameters obtained from the optical spectra of CaZrO3 : Mn^4+ crystal, the g factor of CaZrO3 : Mn^4+ was calculated. The result is consistent with the experimental value The calculations show that the contribution is opposite in sign and about 62% in magnitude compared with the contribution ΔgCF. It appears that both CF and CT mechanisms should be considered in the calculation of g factor for the high valence 3d^3 (6 g. , Mn^4+ and Fe^3+ ) ions in crystals.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2008年第8期1705-1707,共3页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(10274054)
民航总局民航飞行技术与飞行安全科研基地项目资助