W.L. Feng

Studies of the spin-Hamiltonian parameters and the Jahn-Teller distortions for tetragonal Cu(H(2)O)(6)(2+) clusters in trigonal A(2)Mg(3)(NO(3))(12)center dot 24H(2)O (A = La, Bi) crystals

The anisotropic and isotropic spin-Hamiltonian parameters (g factors and hyperfine structure constants) of tetragonal Cu(H(2)O)(6)(2+) clusters due, respectively, to the static and dynamic Jahn-Teller effects for Cu(2+) in trigonal A(2)Mg(3)(NO(3))(12).24H(2)O (A=La, Bi) crystals are calculated from the high-order perturbation formulas based on the cluster approach. In the approach, the admixture between the d orbitals of 3d(n) ion and the p orbitals of ligand ion via covalence effect is considered. All of the calculated results are in agreement with the experimental values. The tetragonal elongations (characterized by DeltaR=R(parallel)-R( perpendicular)) of Cu(H(2)O)(6)(2+) cluster due to the Jahn-Teller effect in A(2)Mg(3)(NO(3))(12).24H(2)O crystals are acquired from the calculations. The results are discussed.

Theoretical investigation for the EPR g-factors of the mixed ground state in NaCl: Ag(2+) crystals

In this paper, it is considered that the local structure of the (AgCl6)4- cluster for the NaCl: Ag2+ crystal is of the axially elongational D4h symmetry which possesses the weaker rhombic distortion at <001> lattice site. The mechanism for an admixture of the 2A1g into the ground state 2B1g is taken into account. The electron paramagnetic resonance (EPR) g factors of NaCl: Ag2+ are studied by using the double spin-orbit coupling model and an approximation of a semiempirical molecular orbit. The EPR g factors for the NaCl: Ag2+ crystals are reasonably explained as well as the good agreement between the calculated values and the experimental data is obtained.