This paper presents a cluster approach to the calculation of the g factor in RX:V 2+ (R=Na,K,Rb; X=Cl,Br), in which not only the contribution due to the spin-orbit coupling of the central transition-metal ion but also that of the ligands are included. The calculated results agree well with the available experimental data. The results show that the contribution to the g shift due to the spin-orbit coupling of the ligands is small in RCl:V 2+ but is about 80% of that of the central transition-metal ion in RBr:V 2+

Theoretical investigation of the g factor in RX:V2+ (R=Na,K,Rb;X=Cl,Br).

sichuan normal univ,inst solid state phys,chengdu 610066,peoples r china. acad sinica,int ctr mat phys,shenyang,peoples r china. sichuan normal univ,dept phys,chengdu,peoples r china.;chen, jj (reprint author), sichuan teachers coll,dept phys,nanchung 637002,peoples r china

Investigation on the gyromagnetic factor of ni(ii), v(ii), and cr(iii) in csmgx3 (x=cl,br,i)

A complete diagonalization (of energy matrix) method based on the cluster approach (where the covalence effect due to the admixture between the orbitals of the central d(n) ion and that of ligands is considered) was applied to calculate the spin-Hamiltonian parameters (g factors, g(parallel to) and g(perpendicular to), and hyperfine structure constants, A(parallel to) and A(perpendicular to)) for two Cu2+ centers in ZnGa2O4 spinel at the temperature T approximate to 110 K. In both Cu2+ centers, Cu2+ ions occupy the trigonally-distorted octahedral sites 16d and the octahedrons undergo the static Jahn-Teller distortions from trigonal to tetragonally-elongated and tetragonally-compressed, respectively. The calculated spin-Hamiltonian parameters of the elongated Cu2+ center show good agreement with the experimental values and those of the compressed Cu2+ center are close to the observed values. The better agreement of spin-Hamiltonian parameter between calculation and experiment for the compressed Cu2+ center can be acquired by considering a small admixture of vertical bar d(x2-y2)> state to the vertical bar d(z2)> ground state due to the vibrational motion of ligands. The defect structures of both Cu2+ centers (characterized by the ligand displacements a(1) and a(2), respectively) in ZnGa2O4 spinel were also determined from the calculation.

Studies on the spin-Hamiltonian parameters of two Cu2+ centers and their defect structures due to Jahn-Teller effect for Cu2+-doped ZnGa2O4 spinel

Investigations of electron-paramagnetic-resonance parameters of trigonal (CrO4)4−, (MnO4)3− and (FeO4)2− clusters in Y2SiO4:Cr4+, Ba3(VO4)2:Mn5+ and K2CrO4:Fe6+ crystals

Investigations of the optical and EPR spectra for (NiX6)4− (X=Cl, Br, I) clusters

A perturbation expression of the gyromagnetic factor of d3 ions is derived considering the spinorbit coupling of the ligand ions and taking into account all the excited states besides 4T2 state. The molecular orbital coefficients are determined by means of a semiempirical method in estimating the g-shift. The results show that the contribution of the spin–orbit coupling of the ligand ions to the g-shift must be considered for ligand ions possessing large spin–orbit coupling constants. The g-shifts of CsVX3 are calculated and the results agree well with experimental data.



Ein Storungsausdruck des gyromagnetischen Faktors von d3-Ionen wird abgeleitet, wobei die Spin–Bahn-Kopplung der Ligandenionen berucksichtigt wird, sowie alle angeregten Zustande, neben dem 4T2-Zustand. Die Molekularorbital-Koeffizienten werden mittels einer halbempirischen Methode fur die Berechnung der g-Verschiebung bestimmt. Die Ergebnisse zeigen, das der Beitrag der Spin–Bahn-Kopplung der Ligandenionen zur g-Verschiebung fur Ligandenionen mit grosen Spin–Bahn-Kopplungskonstanten berucksichtigt werden mus. Die g-Verschiebungen von CsVX3 werden berechnet und die Ergebnisse stimmen gut mit experimentellen Werten uberein.

Mao-Lu Du

Papers

Gyromagnetic Factor and Spin–Orbit Coupling of Ligands in CsVX3 (X = Cl, Br, I)