Unified calculations of the optical band positions and spin-Hamiltonian parameters for V²⁺ ions in CdCl₂ crystal

Abstract

The eight optical spectral band positions and three spin-Hamiltonian parameters (g factors g_//, g_⊥ and zero-field splitting D) of V²⁺ ions in trigonal CdCl₂ crystal are calculated together from the complete diagonalisation (of energy matrix) method (CDM) based on the two-spin-orbit-parameter model (also called the cluster approach). In the model, differing from the usual one-spin-orbit-parameter model in the conventional crystal-field theory (where only the contribution to spin-Hamiltonian parameters due to the spin-orbit parameter of central dⁿ ion is considered), both the contributions from the spin-orbit parameter of central dⁿ ion and that of ligand ions are taken into account. The calculated results show reasonable agreement with the experimental values. The local lattice relaxation in the vicinity of V²⁺ ion due to the introduction of V²⁺ impurity is acquired from the calculations. The calculations of spin-Hamiltonian parameters from the CDM based on the one-spin-orbit-parameter and those from the perturbation theory method based on the two-spin-orbit-parameter model are also made for comparison. The results are discussed.

Keywords:

• optical spectrum
• electron paramagnetic resonance
• crystal- and ligand-field theory
• defect structure
• CdCl₂:V²⁺

Acknowledgements

This project is supported by the Initial Foundation of Mianyang Normal University (Grant No. MQD2011A05), the Key Foundation of Mianyang Normal University (Grant No. 2011A16) and the Science and Technology Development Foundation of China Academy of Engineering Physics (Grant No. 2012A0302015 and 2012B0302050).