EPR and Optical Absorption Studies of VO²⁺-Doped Diammonium Hexaaqua Magnesium(II) Sulfate

ABSTRACT

Electron paramagnetic resonance (EPR) studies of VO²⁺ impurity ion in single crystals of diammonium hexaaqua magnesium(II) sulfate are carried out at 9.5 GHz (X-band) at room temperature. Different spin-Hamiltonian parameters are determined. VO²⁺ is expected to enter the lattice substitutionally. Superhyperfine splitting is also observed. An EPR study of a powder sample is done that supports the data obtained from single crystal studies. Optical absorption studies are also performed at room temperature. The crystal field parameter (D_q), tetragonal parameters (D_s and D_t), and various bonding parameters are evaluated to estimate the covalency and nature of bonding of VO²⁺ with its different ligands.

KEYWORDS:

• crystal field
• distortion
• optical absorption
• spin Hamiltonian

ACKNOWLEDGMENTS

The authors are thankful to Dr. T. K. Gundu Rao, R.S.I.C., I.I.T., Mumbai, for recording of EPR spectra. One of the authors (AKS) is thankful to the University Grants Commission for financial assistance in the form of a minor research project.

Notes

^a Present study.