Physica B-Condensed Matter
The perturbation formula of g factor for 3d(7) ion in cubic octahedral crystals has been obtained from a cluster approach. In the formula, the parameters related to the configuration interaction and the covalency reduction effect can be obtained from the optical spectra of the crystal under study and so no adjustable parameters are applied. From the formula, the g factors for Co2+ in fluoroperovskites LiBaF3, KMBF3, KZnF3 and CsCdF3 are calculated. The calculated results are in agreement with the observed values. The g factor following the order of LiBaF3 : Co2+ < KMgF3 : Co2+ < KZnF3: Co2+ < CsCdF3 : Co2+ is also explained. (C) 2000 Elsevier Science B.V. All rights reserved.
关键词:
electron paramagnetic resonance;crystal- and ligand-field theory;Co2+;LiBaF3;KMgF3;KZnF3;CsCdF3;perovskite;transition;impurities;crystals
庞晶
,
靳玲花
,
应孝梅
量子电子学报
doi:10.3969/j.issn.1007-5461.2011.06.005
近年来,变系数非线性发展方程受到越来越多的关注. 2008年王明亮等提出了一种新的方法,即(G’/G)展开法.将(G’/G)展开法首次尝试应用到变系数非线性发展方程中,并以广义变系数Burgers方程为例,成功得到了在系数满足一定条件时新的精确解；又尝试将该展开法进行新的扩展,再一次对广义变系数Burgers方程求解,又成功得到了一些新解.实践证明,该展开法不仅易于求解常系数非线性发展方程,而且对变系数非线性发展方程仍很高效、简洁、实用,并且具有广泛的应用前景.
关键词:
非线性发展方程
,
精确解
,
(G’/G)展开法
,
广义变系数Burgers方程
冯庆江
,
杨世玲
量子电子学报
doi:10.3969/j.issn.1007-5461.2013.06.007
应用改进的G/G'展开法构造出Zhiber-Shabat(ZS)方程的20组精确解,这些解的类型主要包含双曲函数通解、三角函数通解和有理函数通解三种形式.对解的性质进行了相应分析,当对双曲函数通解中的参数取特殊值时,可以得到孤立波解.当对三角函数通解中的参数取特殊值时,可以得到对应的周期波函数解.实践证明,应用改进的G/G'展开法能够得到方程一些新的精确解,扩大了解的范围.
关键词:
非线性方程
,
改进的G/G'展开法
,
ZS方程
,
孤立波解
,
周期波解
冯庆江
,
肖绍菊
连铸
doi:10.3969/j.issn.1007-5461.2015.01.006
应用改进的G'/G2展开法构造出Zakharov方程的18组精确解,这些解主要包括双曲函数通解、三角函数通解和有理函数通解三种形式.当对双曲函数通解中的参数取特殊值时,可以得到孤立波解.对三角函数通解中的参数取特殊值时,可以得到对应的周期波函数解.实践证明,应用改进的G'/G2展开法能够得到Zakharov方程一些新的精确解,扩大了解的范围,这种方法对于研究非线性光学和量子光学具有非常广泛的应用意义.
关键词:
非线性方程
,
改进的G'/G2展开法
,
Zakharov方程
,
孤立波解
Optical Materials
The perturbation formulas of the EPR g factors g,, g and g. for a 4f(11) 1 ion in orthorhombic symmetry are established. In these formulas, the contributions to the g factors arising from the second-order perturbation terms and the admixture of various states are taken into account. The above formulas are applied to the orthorhombic Er3+ centers in YAG, YGG and LuGG garnets. By analyzing their g factors, we find that the polar angles theta(j)(') of the impurity-ligand bonds related to the Z axis of the crystals in these Er3+ centers are smaller than the host angles theta(j) in pure crystals, whereas the azimuthal angles, related to the X axis in the impurity centers are larger than the corresponding phi(j) in the hosts. The g factors and their anisotropies Delta g [= g(z) - (g(x) + g(y))/2] and delta g (= g(x) - g(y)) for Er3+ in the garnets based on the above local structural parameters are in good agreement with the observed values. In addition, the angular distortions Delta theta (= theta(j)(') - theta(j)) or Delta phi (= phi(j)(') - phi(j)) obtained by analyzing the EPR data in this work are different from Delta theta(2), or Delta phi(2) (for only the second set of ligands, i.e., j = 2) based on the superposition model crystal-field analysis in the previous work. The validity of the results is discussed. (c) 2004 Elsevier B.V. All rights reserved.
关键词:
electron paramagnetic resonance (EPR);defect structure;crystal-field;and spin hamiltonians;Er3+;garnets
Spectroscopy and Spectral Analysis
The complete high-order perturbation formula of g factor for 3d(3) ions in cubic octahedral site was derived. In the formula, both the contribution Delta g(CF) to g-shift Delta g(=g-g(s), where g(s) =2. 002 3) due to crystal-field (CF) mechanism (related to the interactions of CF excited states with the ground state) and that (Delta g(CT)) 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 CaZrO(3) : Mn(4+) crystal, the g factor of CaZrO(3) : 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 Delta g(CF). It appears that both CF and CT mechanisms should be considered in the calculation of g factor for the high valence 3d(3) (e. g., Mn(4+) and Fe(3+)) ions in crystals.
关键词:
electron paramagnetic resonance;g factor;charge transfer mechanism;crystal and ligand field theory;CaZrO(3);Mn(4+);atomic screening constants;scf functions;luminescence;manganese
