电荷转移机制对高价钒离子晶体EPR参量的影响

发布时间：2018-08-09 15:00

【摘要】：3d~1离子是重要的过渡金属离子,比如掺杂V4+离子的晶体是一类具有激光特性和非线性光学特性的晶体,因而对于掺杂材料性质的研究就显得非常有意义。前人研究发现掺杂材料的性质与杂质中心的缺陷结构密切相关,并且光谱和电子顺磁共振谱对杂质缺陷畸变有灵敏的依赖关系,因此,可以通过光谱和电子顺磁共振谱研究杂质离子在晶体中的光学和磁学性质与缺陷的关系。近年来,人们主要考虑晶体场(CF)机制并基于分子轨道理论和自旋哈密顿理论的方法,在处理掺杂金属离子的EPR参量和光谱性能方面取得了很大的进展。对于本文中研究的掺杂V4+离子价态比较高,电荷转移(CT)跃迁能相对较小,我们需要考虑CT机制对EPR参量的定量贡献。本文创新工作如下:(1)本文突破CF机制的限制,我们考虑了CT机制对EPR参量的贡献,推导出了3d1离子的高阶微扰公式。我们进一步完善了理论公式,并且还建立了对应参量之间的定量关系。(2)根据理论公式,解释了(10)×224SOVO:OH3KZn Cl晶体中掺V4+离子的g因子和超精细结构常数A,并获得了V4+中心缺陷结构的信息。(3)结合光谱数据研究了V4+杂质在(10)×224POVO:OH6Zn K晶体六配位八面体中的EPR参量,理论研究和实验结果一致,并且发现CT机制对g因子和A值的贡献与CF机制的三阶微扰项也有相同数量级的贡献。(4)通过数据分析说明CT机制对EPR参量的影响不能被忽略,这在理论上,对g因子和A值的理解有指导意义。
[Abstract]:3d~1 ion is an important transition metal ion, for example, the crystal doped with V4 ion is a kind of crystal with laser characteristics and nonlinear optical properties, so it is very significant to study the properties of doped materials. Previous studies have found that the properties of the doped materials are closely related to the defect structure of the impurity center, and that the spectra and EPR have sensitive dependence on the distortion of the impurity defects. The relationship between the optical and magnetic properties of impurity ions in crystals and defects can be studied by means of spectra and electron paramagnetic resonance spectroscopy. In recent years, based on the molecular orbital theory and spin Hamiltonian theory, great progress has been made in the treatment of the EPR parameters and spectral properties of doped metal ions based on the crystal field (CF) mechanism and the methods of molecular orbital theory and spin Hamiltonian theory. For the doped V4 ions studied in this paper, the valence state is high and the transition energy of charge transfer (CT) is relatively small. We need to consider the quantitative contribution of CT mechanism to EPR parameters. The innovations of this paper are as follows: (1) in this paper, we break through the limitation of CF mechanism, we consider the contribution of CT mechanism to EPR parameters, and derive the high-order perturbation formula of 3d1 ion. We further improve the theoretical formula and establish a quantitative relationship between the corresponding parameters. (2) according to the theoretical formula, The g factor and hyperfine structure constant A of V4 doped in (10) 脳 224SOVO:OH3KZn Cl crystal are explained, and the information of the central defect structure of V4 is obtained. (3) the EPR parameter of V4 impurity in the hexagonal octahedron of (10) 脳 224POVO:OH6Zn K crystal is studied by means of spectral data. The theoretical and experimental results are consistent, and it is found that the contribution of CT mechanism to g factor and A value is of the same order as that of CF mechanism. (4) the data analysis shows that the influence of CT mechanism on EPR parameters can not be ignored. In theory, the understanding of g factor and A value is instructive.
【学位授予单位】：四川师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O73

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