Investigations on the local structure and EPR parameters for the trigonal Nd³⁺centre in CdS

Abstract

The local structure and the electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants) for the trigonal Nd 3+ centre in CdS are theoretically investigated by considering the local lattice relaxation. The impurity Nd 3+ is found not to occupy exactly the host Cd 2+ site, but to suffer a shift of about 0.31Å away from the sulphide triangle along the C 3 axis due to size and charge mismatch. The theoretical EPR parameters based on the above impurity axial displacement are in good agreement with the observed values. The local structure and the EPR parameters are discussed for this centre.

An investigation on the defect structures and spin Hamiltonian parameters for the two orthorhombic Ti3+ centers in ZnWO4

“…For 3d n transition-metal ions in tetrahedral CF environments [25][26][27], the expressions A R 4 ( ) E (27/16) Dq and A R 2 ( ) E12 A 4 have been proved valid and are reasonably utilized in this work. So, the SHPs, particularly the axial and perpendicular anisotropies Δg [ ¼(g xx þ g yy )/2 À g zz ] and δg ( ¼g xx Àg yy ) are closely correlated with the orthorhombic CF parameters and the local distortion in the vicinity of the impurity.…”

Theoretical Investigations for the Defect Structure and the Spin Hamiltonian Parameters of Divalent Cobalt in LiMgPO₄

“…Here Ā2 and Ā4 are the intrinsic parameters related to the reference (average) distance R (≈ 2.070 Å) [19,20]) taken as the average of the six effective impurity-ligand distances R'nH. For 3d n ions in octahedral environments [27][28][29], the expressions Ā4 ≈ 3Dq/4 and Ā2 ≈ 10.8 Ā4 have been proved reliable in many crystals and are used in the present calculations. From the Slater-type selfconsistent field functions [30,31] and the distance R, the integrals Sdpt ≈ 0.0113 and Sdpe ≈ 0.0374 are calculated.…”

Investigations of spin Hamiltonian parameters and local structures for three Cr(CN)63− centres in NaCl at three temperatures

“…Utilizing the local geometry and the superposition model [21,22], the rhombic CF parameters are expressed as follows:…”