Studies of EPR parameters and defect structures for the tetragonal Ni2+centers in AgX (X=Cl, Br) crystals from the two-mechanism model

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	Studies of EPR parameters and defect structures for the tetragonal Ni2+centers in AgX (X=Cl, Br) crystals from the two-mechanism model
	W. Fang; X. X. Wu; W. C. Zheng
	2009
发表期刊	Radiation Effects and Defects in Solids
ISSN	1042-0150
卷号	164 期号:2 页码:125-131
摘要	The high-order perturbation formulas of electron paramagnetic resonance (EPR) parameters (g factors g, g and zero-field splitting D) based on the two-mechanism (the crystal-field (CF) mechanism and the charge-transfer (CT) mechanism, the latter is neglected in the CF theory) models for 3d8 ions in tetragonal octahedral clusters are established from a cluster approach. By using these formulas and the parameters obtained from the optical spectra, the EPR parameters g, g and D of the tetragonal Ni2+ centers in AgX (X=Cl, Br) crystals are calculated. The results are in reasonable agreement with the experimental values. The calculations show that the sign of the EPR parameter QCT [Q= g(=g-gs), g (=g-gs) or D, where gs 2.0023 is the value of free electron] due to CT mechanism is the same as that of the corresponding QCT due to the CF mechanism in both AgCl: Ni2+ and AgBr: Ni2+ crystals, but the relative importance of the CT mechanism (characterized by QCT/QCF) for Q= g, g and D is 7%, 8% and 1.4% in AgCl: Ni2+, respectively, and those in AgBr: Ni2+ are 46%, 56% and 44%, respectively. It appears that for the 3dn MX6 clusters in crystals with ligands of large atomic number, the theoretical explanations of the EPR parameters should take both CF and CT mechanisms into account. The defect structures of the tetragonal Ni2+ centers in AgX (X=Cl, Br) crystals are also obtained from the calculations. The results are discussed.
部门归属	[fang, wang; zheng, wen-chen] sichuan univ, dept mat sci, chengdu 610064, peoples r china. [wu, xiao-xuan] civil aviat flight univ china, dept phys, guanghan, peoples r china. [zheng, wen-chen] chinese acad sci, int ctr mat phys, shenyang, peoples r china.;zheng, wc (reprint author), sichuan univ, dept mat sci, chengdu 610064, peoples r china;zhengwc1@163.com
关键词	Electron Paramagnetic Resonance Crystal- And ligAnd-field Theory Defect Structure Ni2++ Agcl Agbr Atomic Screening Constants Electron-spin-resonance Gyromagnetic Factor Scf Functions Spectra Ions Transition Cr3++
URL	查看原文
WOS记录号	WOS:000263573800007
引用统计	被引频次：2[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/31890
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	W. Fang,X. X. Wu,W. C. Zheng. Studies of EPR parameters and defect structures for the tetragonal Ni2+centers in AgX (X=Cl, Br) crystals from the two-mechanism model[J]. Radiation Effects and Defects in Solids,2009,164(2):125-131.
APA	W. Fang,X. X. Wu,&W. C. Zheng.(2009).Studies of EPR parameters and defect structures for the tetragonal Ni2+centers in AgX (X=Cl, Br) crystals from the two-mechanism model.Radiation Effects and Defects in Solids,164(2),125-131.
MLA	W. Fang,et al."Studies of EPR parameters and defect structures for the tetragonal Ni2+centers in AgX (X=Cl, Br) crystals from the two-mechanism model".Radiation Effects and Defects in Solids 164.2(2009):125-131.