The EPR Zero-Field Splitting D and its Pressure and Temperature Dependence for Trigonal Mn2+ Centers in [Zn(H2O)6](BF4)2:Mn2+ Crystal

2006 ◽  
Vol 61 (5-6) ◽  
pp. 289-292 ◽  
Author(s):  
Hong-Gang Liu ◽  
Xiao-Xuan Wu ◽  
Wen-Chen Zheng ◽  
Lv He

The EPR zero-field splitting D (= b02 ) and its pressure and temperature dependence for trigonal Mn2+ centers in low and room temperature phases in [Zn(H2O)6](BF4)2 :Mn2+ crystal are studied by a high-order perturbation formula based on the dominant spin-orbit coupling mechanism. From the studies, the local trigonal distortion angles, the local angular compressibilities and the local angular thermal expansion coefficients for Mn2+ centers in both phases of the [Zn(H2O)6](BF4)2 crystal are estimated. The results are discussed

2004 ◽  
Vol 59 (12) ◽  
pp. 961-963 ◽  
Author(s):  
Wen-Chen Zheng ◽  
Yang Mei ◽  
Xiao-Xuan Wu ◽  
Qing Zhou

By using the spin-orbit coupling mechanism and the empirical superposition model, the zero-field splittings D of Mn2+ ions on both Mg2+ sites in hexagonal 6H-RbMgF3 crystal are calculated from the structural data of both Mg2+ sites. The calculated results of both methods confirm the suggestion that Mn2+ in 6H-RbMgF3 occupies the Mg2+ (I) site (which has D3d site symmetry) and the zero-field splitting D of 6H-RbMgF3: Mn2+ is explained reasonably.


1972 ◽  
Vol 27 (7) ◽  
pp. 1082-1093
Author(s):  
R Krieger ◽  
J Voitländer

AbstractThe zero-field splitting and g-values of manganocene and chromocene have been calculated. The wave functions were obtained by means of a self-consistent charge extended Huckel method. The calculated values g||=2.0034 and g⊥ = 2.0033 of manganocene agree fairly well with the experi­mental results obtained from ESR measurements. The very large computed zero-field splitting D= -0.24 cm-1 explains that there has been observed only one ESR transition though mangano­cene is in a spin-5/2 state. For chromocene no ESR transition has been found until now. We therefore studied the splitting of the orbitally degenerate ground state by the combined action of spin-orbit coupling and low-symmetry perturbation. The predicted splitting is strongly dependent on the magnitude of the rhombic distortion compared to the spin-orbit interaction. The g-values are highly anisotropic, with g|| =2.49 and g⊥ =1.97


1989 ◽  
Vol 163 ◽  
Author(s):  
P. Emanuelsson ◽  
W. Gehlhoff ◽  
P. Omling ◽  
H. G. Grimmeiss

AbstractThree different Electron Paramagnetic Resonance (EPR) signals, one trigonal and two orthorhombic, which originates from iron-indium pairs in silicon are investigated. It is shown that the two orthorhombic spectra can be explained as transitions within the two doublets of a S=3/2 system with a large zero-field splitting. The temperature dependence of-the intensities reveals that the newly discovered spectrum corresponds to the lower doublet and that the zero-field splitting is 9.8 ± 2.0 cm-1.


2010 ◽  
Vol 645-648 ◽  
pp. 403-406 ◽  
Author(s):  
Andreas Scholle ◽  
Siegmund Greulich-Weber ◽  
Eva Rauls ◽  
Wolf Gero Schmidt ◽  
Uwe Gerstmann

In non-annealed 6H-SiC samples that were electron irradiated at room temperature, a new EPR signal due to a S=1 defect center with exceptionally large zero-field splitting (D = +652•10-4 cm-1) has been observed under illumination. A positive sign of D demonstrates that the spin-orbit contribution to the zero-field splitting exceeds by far that of the spin-spin interaction. A principal axis of the fine structure tilted by 59° against the crystal c-axis as well as the exceptionally high zero-field splitting D can be qualitatively understood by the occurrence of additional close-lying defect levels in defect clusters resulting in comparatively large second-order spin-orbit coup¬ling. A tentative assignment to vacancy clusters is supported by the observed annealing behavior.


1994 ◽  
Vol 49 (11) ◽  
pp. 1013-1015 ◽  
Author(s):  
Jia-Jun Chen ◽  
Mao-Lu Du ◽  
Zhao-Ming Li

Abstract This paper presents a cluster approach to the zero-field splitting (ZFS) of the ground state 3A2(F) of d8 ions with tetragonal symmetry, in which not only the spin-orbit coupling of the central transition-metal-ion but also that of ligands contributes. For some pseudo-tetragonal Ni(II) com­ pounds the calculated values of the ZFS parameter follow the order Cl-> Br-> I-. This agrees with the experimental finding, while the pure crystal field approach considering only the coupling of central metal ion yields the opposite trend.


2005 ◽  
Vol 60 (1-2) ◽  
pp. 91-94
Author(s):  
Yang Mei ◽  
Wen-Chen Zheng ◽  
Xiao-Xuan Wu ◽  
Qing Zhoua

The EPR parameters (zero-field splitting D and g factors g‖, g⊥) of Cr3+ in a NaInS2 crystal are calculated from high-order perturbation formulas based on the two spin-orbit coupling parameter model for the EPR parameters of 3d3 ions in trigonal octahedral sites. In the calculations, both the contribution to EPR parameters from the spin-orbit coupling parameter of the central 3d3 ion and that of ligands are considered. From the calculations it is found that, to explain reasonably the EPR parameters, the local structure (in particular the local trigonal distortion angle θ ) in the vicinity of the Cr3+ impurity is different from the corresponding structure in the host crystal. The change of the local angle θ with temperature is also obtained from the temperature dependence of zero-field splitting. The results are discussed.


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