Spectral line

Quantum mechanics

Perpendicular

Crystal (programming language)

Materials science

Nuclear magnetic resonance

Perturbation (astronomy)

Crystal structure

Atomic physics

Computer science

Electron paramagnetic resonance

Physical chemistry

Polarization (electrochemistry)

Physics

Hyperfine structure

Mathematics

Molecular physics

Tetragonal crystal system

Condensed matter physics

Geometry

Crystallography

Chemistry

Programming language

physica status solidi (b)

The EPR g-factors g∥, g⟂ and hyperfine structure constants A∥, A⟂ for a tetragonal Co2+ centre, i.e., Co(H2O)2Cl4 centre, in NH4Cl crystal are calculated from the perturbation formulas based on a cluster approach. In these formulas, the parameters related to the contributions from the configuration interaction, the covalency effect and the low-symmetry crystal field can be obtained from the optical spectra and the structural model and data of the studied system. The core polarization constant κ in the calculation formulas of hyperfine constants is used as an adjustable parameter. The calculated results are in good agreement with the observed values.

Theoretical Investigations of theg-Factors and Hyperfine Structure Constants for a Tetragonal Co2+ Centre in NH4Cl Crystal