Stress-Induced Trigonal Crystal-Field Parameters in Some Oxide Lattices

Abstract

Numerical perturbation methods are used to express trigonal stress splittings in terms of two phenomenological parameters, $v_s$ and $v_s^{}{}_{}{}^{\prime }$, for many levels of ${\mathrm{Cr}}^{3+}$, ${\mathrm{V}}^{2+}$, ${\mathrm{Ni}}^{2+}$ in MgO, and ${\mathrm{Cr}}^{3+}$ in ruby and emerald. Values of $v_s$ and $v_s^{}{}_{}{}^{\prime }$ for ruby and for ${\mathrm{Cr}}^{3+}$ and ${\mathrm{V}}^{2+}$ in MgO have been determined from published data. Point-charge calculations using Hartree-Fock free-ion radial wave functions give useful estimates of the stress-induced crystal-field parameters.