Defect model and spin-Hamiltonian parameters for the tetragonal Mo(5+) and W(5+) centers in Cs(2)ZrCI(6) and Cs(2)HfCI(6) crystals

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	Defect model and spin-Hamiltonian parameters for the tetragonal Mo(5+) and W(5+) centers in Cs(2)ZrCI(6) and Cs(2)HfCI(6) crystals
	W. C. Zheng; Y. Mei; W. Q. Yang
	2009
发表期刊	Philosophical Magazine
ISSN	1478-6435
卷号	89 期号:20 页码:1621-1628
摘要	The spin-Hamiltonian (SH) parameters (g factors g(parallel to), g(perpendicular to) and hyperfine structure constants A(parallel to), A(perpendicular to)) of tetragonal M(I)C(16)(-) (M(I) = Mo, W) centers in cubic Cs(2)MCl(6) (M = Zr, Hf): M(I)(5+) crystals are calculated from high-order perturbation formulas based on a two-mechanism model. These contain the contributions to SH parameters from both the crystal-field (CF) mechanism concerning the CF excited states and the charge-transfer (CT) mechanism concerning the CT excited states. In the calculations, two possible defect models are suggested for the tetragonal M(I)C(16)(-) centers. In model I, one Cl(-) ion shifts towards the M(I)(5+) impurity by Delta Z(I) along the C(4) axis due to electrostatic repulsion between the Cl(-) ion and a neighboring charge compensator, monovalent anion, at the interstitial site. In model II, two Cl(-) ions are displaced towards M(I)(5+) by Delta Z(II) along the C(4) axis due to the Jahn-Teller effect. The calculated results show that, to obtain a good fit between calculated and experimental SH parameters, the required displacement Delta Z(I) (which is about twice the displacement Delta Z(II)) is too large to be regarded as reasonable. Thus, model II seems more likely. The contributions of the CT mechanism to SH parameters are important and, for high valence state d(n) ions in crystals, the exact calculations of the SH parameters should take both CF and CT mechanisms (the latter is omitted in the widely used CF theory) into account.
部门归属	[zheng, w. c.; mei, y.; yang, w. q.] sichuan univ, dept mat sci, chengdu 610064, peoples r china. [yang, w. q.] chengdu univ informat technol, dept opt & elect, chengdu 610225, peoples r china. [zheng, w. c.] chinese acad sci, int ctr mat phys, shenyang 110016, peoples r china.;zheng, wc (reprint author), sichuan univ, dept mat sci, chengdu 610064, peoples r china;zhengwc1@163.com
关键词	Mo(5+) w(5+) Crystal Field Defect Structures Electron Paramagnetic Resonance Inorganic Materials Spectroscopy Atomic Screening Constants Single-crystals Up-conversion Scf Functions Transition Ions Excitation Complexes Spectrum Halides
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文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/32614
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	W. C. Zheng,Y. Mei,W. Q. Yang. Defect model and spin-Hamiltonian parameters for the tetragonal Mo(5+) and W(5+) centers in Cs(2)ZrCI(6) and Cs(2)HfCI(6) crystals[J]. Philosophical Magazine,2009,89(20):1621-1628.
APA	W. C. Zheng,Y. Mei,&W. Q. Yang.(2009).Defect model and spin-Hamiltonian parameters for the tetragonal Mo(5+) and W(5+) centers in Cs(2)ZrCI(6) and Cs(2)HfCI(6) crystals.Philosophical Magazine,89(20),1621-1628.
MLA	W. C. Zheng,et al."Defect model and spin-Hamiltonian parameters for the tetragonal Mo(5+) and W(5+) centers in Cs(2)ZrCI(6) and Cs(2)HfCI(6) crystals".Philosophical Magazine 89.20(2009):1621-1628.