Paramagnetic and Optical Spectra of Divalent Cobalt in Cubic Crystalline Fields

Abstract

The optical and paramagnetic resonance spectra of divalent cobalt in MgO single crystals are reported. The optical spectrum consists of stronger lines which correspond to transitions between Stark levels of the same multiplicities and weak intercombination lines. If the Slater integrals are taken as free parameters then in the intermediate coupling scheme good agreement is obtained between the observed and calculated spectrum with $Dq=960\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$. The Slater integrals are reduced by about 8-10% from those of the free ion. The paramagnetic resonance spectrum shows one electronic isotropic transition consisting of eight hyperfine lines at $g={4.278}_5\pm 0.001$ and $A=({97.7}_9\pm 0.2)\times {10}^{-4\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$. The interpretation of these results shows that the orbital reduction factor $k=0.89-0.85\mathrm{}$. Both the optical and paramagnetic results indicate covalent bonding. The effect of charge transfer is (1) to shield the nuclear charge and (2) to normalize the wave functions. Both these effects results in smaller Coulomb energy, hyperfine structure, and spin-orbit coupling constant.