Investigation of the Zero-Field Splitting of d8 Ions in Pseudo-tetragonal Ni(II) Compounds

1994 ◽  
Vol 49 (11) ◽  
pp. 1013-1015 ◽  
Author(s):  
Jia-Jun Chen ◽  
Mao-Lu Du ◽  
Zhao-Ming Li
Keyword(s):  
Metal Ion ◽  
Tetragonal Symmetry ◽  
Zero Field ◽  
Central Metal ◽  
Spin Orbit Coupling ◽  
Cluster Approach ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Central Transition ◽  
Ion Yields

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.

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
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Coupling Mechanism ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Thermal Expansion Coefficients ◽  
Perturbation Formula ◽  
Expansion Coefficients

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

EPR Parameters and Local Atom-position Parameters for Co2+ Ions in CdS and CdSe Semiconductors

2004 ◽  
Vol 59 (11) ◽  
pp. 783-786 ◽  
Author(s):  
Wen-Chen Zheng ◽  
Xiao-Xuan Wu ◽  
Yang Mei ◽  
Jian Zi
Keyword(s):  
Coupling Parameter ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Cluster Approach ◽  
Zero Field Splitting ◽  
Trigonal Symmetry ◽  
Epr Parameters ◽  
Impurity Centers ◽  
Atom Position

The EPR parameters (zero-field splitting D and g factors gII, g⊥) of Co2+ ions in CdS and CdSe semiconductors are calculated from the high-order perturbation formulas based on the cluster approach for a 3d7 ion in trigonal symmetry. These formulas include the contribution to the EPR parameters from both the spin-orbit coupling parameter of the 3d7 ion and that of the ligand. From the calculations, the local atom-position parameters u (which are different from the corresponding values in the host crystals) for the Co2+ impurity centers in both semiconductors are estimated. The results are discussed

Zur paramagnetischen Elektronenresonanz metallorganischer Sandwich-Verbindungen, Teil I / The magnetic resonance properties of some sandwich compounds, part i

1972 ◽  
Vol 27 (7) ◽  
pp. 1082-1093
Author(s):  
R Krieger ◽  
J Voitländer
Keyword(s):  
Zero Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Degenerate Ground State ◽  
Resonance Properties ◽  
Rhombic Distortion ◽  
Combined Action ◽  
Low Symmetry

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

Synthesis and Characterization of the Heptanuclear [MnIII 6 CoIII]3+ Triplesalen Complex: Evidence for Exchange Pathways Involving Low-spin CoIII

2010 ◽  
Vol 65 (3) ◽  
pp. 295-303 ◽  
Author(s):  
Erich Krickemeyer ◽  
Veronika Hoeke ◽  
Anja Stammler ◽  
Jürgen Schnack ◽  
Hartmut Bögge ◽  
...  
Keyword(s):  
Exchange Interaction ◽  
Metal Ion ◽  
Magnetic Measurements ◽  
Variable Temperature ◽  
Molecular Structures ◽  
Magnetic Data ◽  
Zero Field ◽  
Central Metal ◽  
Zero Field Splitting ◽  
Isotropic Exchange

The reaction of the tert-butyl-substituted triplesalen ligand H6talent-Bu2 with MnII(OAc)2・ 4H2O and K3[CoIII(CN)6] results in the formation of the heptanuclear complex [{(talent-Bu2 )- (MnIII(MeOH))3}2{CoIII(CN)6}](PF6)2(OAc)・11MeOH ([MnIII6 CoIII](PF6)2(OAc)・11MeOH, 1 ・11MeOH), which has been characterized by FT-IR spectroscopy, elemental analysis, ESI-MS, single-crystal X-ray diffraction, and magnetic measurements. The molecular structure of the [MnIII6 CoIII]3+ complex is closely related to the already published analogs [MnIII6CrIII]3+ and [MnIII6 FeIII]3+. Variable-temperature variable-field and μeff vs. T magnetic data have been analyzed in detail by full-matrix diagonalization of the appropriate spin-Hamiltonian consisting of isotropic exchange, zero-field splitting, and Zeeman interaction, taking into account the relative orientation of the D tensors. This allowed a careful inspection of the MnIII-MnIII exchange interaction involving a diamagnetic central metal ion. A satisfactory reproduction of the magnetic data required the incorporation not only of an exchange interaction between the MnIII ions belonging to one triplesalen half unit, but also of an exchange coupling between MnIII ions belonging to different triplesalen subunits. Satisfactory reproduction of the experimental data has been obtained for the parameter set J1 = −(0.50±0.04) cm−1, J2 = +(0.05±0.02) cm−1, and D = −(2.5±0.5) cm−1. A detailed analysis of the J1 coupling taking into account the molecular structures of the three available heptanuclear complexes [MnIII6MIII]3+ (M = Cr, Fe, Co) indicates that the exchange interaction between the MnIII ions belonging to the same triplesalen subunit involves not only an exchange pathway through the central phloroglucinol unit but also an exchange pathway through the central metal ion.

High-Frequency EPR Spectroscopy of Large Metal Ion Clusters: From Zero Field Splitting to Quantum Tunneling of the Magnetization

1998 ◽  
Vol 31 (8) ◽  
pp. 460-466 ◽  
Author(s):  
Anne-Laure Barra ◽  
Louis-Claude Brunel ◽  
Dante Gatteschi ◽  
Luca Pardi ◽  
Roberta Sessoli
Keyword(s):  
Epr Spectroscopy ◽  
High Frequency ◽  
Quantum Tunneling ◽  
Metal Ion ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Ion Clusters

scholarly journals Abnormal Magnetic Moment and Zero Field Splitting of Some Nickel (II) Complexes

2017 ◽  
Vol 7 (1) ◽  
pp. 34
Author(s):  
Rajeev Ranjan ◽  
Navneet Sinha ◽  
Sahdeo Kumar ◽  
Chandra Mauleshwar Chandra ◽  
Shivadhar Sharma
Keyword(s):  
Magnetic Moment ◽  
Metal Ion ◽  
Free Ligand ◽  
Tetragonal Distortion ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Absorption Bands ◽  
Field Splitting ◽  
Zero Field Splitting Parameter ◽  
Splitting Parameter

<em>Some complexes of Ni(II) have been prepared with 2-thio-3-acetyl hydantoin (TAHN) and 2-formyl pyridine thiosemicarbazone (FPTS). On the basis of elemental analysis and molar conductivity, the complexes have been formulated as NiL<sub>2</sub>X<sub>2</sub>, where L = TAHN or FPTS and X = Cl<sup>–</sup>, Br<sup>–</sup>, NCS<sup>–</sup>, ClO<sub>4</sub><sup>–</sup>. The infrared spectra of complexes and free ligand reveal that the ligand TAHN is co-ordinated through sulphur and acetyl oxygen, while FPTS ligand co-ordinates through heterocyclic nitrogen and sulphur to Ni(II) metal ion. The magnetic moment of these complexes are found to be 3.20-3.25 B.M. The values are greater than value (2.828 B.M) corresponding to two unpaired electrons of a d<sup>8</sup>-system. The appearance of four absorption bands in their electronic spectra reveal, the tetragonal distortion in the octahedral symmetry of complexes. The zero field splitting parameter(D) and the other crystal field parameters like Dq<sub>(xy)</sub>, Dq<sub>(z)</sub>, Dt have been calculated. The results show that, the tetragonal distortion parameter (Dt) increases in the order of NCS<sup>– </sup>&lt; Cl<sup>–</sup> &lt; Br<sup>–</sup> while the zero field splitting parameter (D) also increases in the same order for both the planer ligands.</em>

Studies of EPR Parameters and Local Structure for Cr3+ in NaInS2 Crystal

2005 ◽  
Vol 60 (1-2) ◽  
pp. 91-94
Author(s):  
Yang Mei ◽  
Wen-Chen Zheng ◽  
Xiao-Xuan Wu ◽  
Qing Zhoua
Keyword(s):  
Local Structure ◽  
Coupling Parameter ◽  
Orbit Coupling ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Epr Parameters ◽  
Local Angle

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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