Electronic Raman scattering ofCo2+inCdCl2andCsMgCl3

The polarized Raman scattering between the electronic levels of the ${}_{}{}^4{}_{}{}^{}T_{1g}^{}{}_{}{}^{}$ ground term of ${\mathrm{Co}}^{2+}$ in ${\mathrm{CsMgCl}}_3$ has been observed at 2°K. We calculated the fine structure of ${}_{}{}^4{}_{}{}^{}T_{1g}^{}{}_{}{}^{}$ for this system as well as for ${\mathrm{Co}}^{2+}$ in ${\mathrm{CdCl}}_2$ (observed by Lockwood and Christie). Second-order perturbation theory has been employed for a Hamiltonian containing the trigonal crystal field $\Delta$ and spin-orbit interaction $\lambda$. The data are fit satisfactorily with $\frac{\Delta }{\left|\lambda \right|}=+4.4\mathrm{} \mathrm{and} -2.5\mathrm{}$, respectively. Using the crystal-field wave functions we calculated the spectral intensities of the electronic Raman lines as a function of $\frac{\Delta }{\left|\lambda \right|}$, within the framework of Axe's theory. The theory predicts a small asymmetry between $\mathrm{xz}$ and $\mathrm{zx}$ polarizations and a very weak scattering in $\mathrm{zz}$ polarization. These predictions result mainly from the fact that the intermediate configuration $3d^{6}4p$ lies more than 100 000 ${\mathrm{cm}}^{-1\mathrm{}}$ above the $3d^7$ configuration, making the closure assumption an adequate approximation. Good agreement is obtained between observed and calculated spectral intensities for both crystals.