S. P. Singh and Dhananjai Yadav
The intrinsic properties of orthorhombic Hamiltonians have enabled derivation of transformation relations for Hamiltonian parametersexpressed in various related axis systems. In this paper the standardization transformations are used to obtain alternative physically equivalent yet numerically distinct parameter sets for transition metal ions (Ni2+, Mn2+, Cr3+, Fe3+) in various hosts showing orthorhombic or lower site symmetry. Out of six alternative sets one parameter set satisfies the standardization criteria. Importantly, the standardized sets should be used for direct comparisons. Various non-standard ZFS parameter (ZFSP) sets for transition metal ions in crystals are standardized. The ratio of λ = E/D or λ’ = B22 / B20 is limited to the standard range (0, ± 1/3) or (0, ± 1), respectively. The
calculated alternative sets are presented for seven transition metal ion complexes considered. The results enable more reliable analysis, comparison, and fitting of ZFSP sets from EPR spectra for transition metal ions in various crystals.
Keywords: A. Inorganic compounds, A. Optical materials, D. Defects, D. Electron paramagnetic resonance (EPR)