OPTICAL ABSORPTION SPECTRA OF DIVALENT MANGANESE SALTS.

Author Institution: Institute for the Study of Metals, University of ChicagoOptical absorption studies using polarized light and temperatures down to $4.2^{\circ}K$ have been made on single crystals of a number of divalent manganese salts, including $MnCO_{2}, MnCl_{2}-2H_{2}O, MnCl_{2}-4H_{2}O, MnSO_{4}-4H_{2}O, CdF_{2}(Mn)$, and ZnS(Mn). The energies, intensities, polarizations, and fine structure of these spectra, plus similar data from the literature on other manganese salts, have been analyzed in terms of ligand field theory. Anomalously strong intensities in some systems have suggested a cooperative mechanism involving more than one cation. Zeeman splittings obtained for several salts with a pulsed magnetic field have provided additional data such as excited state splitting factors. Semi-emperical molecular orbital calculations of the extended-Huckel type have been used to estimate excited-state distortions, electric-dipole intensities in the non-centro-symmetric complexes, anisotropic second-order spin-orbit effects, and the changes in the electron-repulsion interactions produced by low-symmetry distortions