Effect of Configuration Mixing and Covalency on the Energy Spectrum of Ruby

Abstract

For the purpose of improving the analysis hitherto done of the optical and microwave spectrum of ruby, a calculation has been performed in the strong cubic field scheme, taking into account the effect of configuration mixing of the higher excited ${t_2}^{2}e$ states into the ${t_2}^3$ states. In the calculation, covalency of the $t_2$ and $e$ electrons is also introduced in a simplified fashion besides the spin-orbit interaction, trigonal field and Zeeman energy. The result shows that configuration mixing and covalency play a very important role in giving zero-field splittings and $g$ values of the ${t_2}^3$ states. It is also found that there is not much difference between the degrees of covalency for the $t_2$ and $e$ electrons, although they are fairly large for both electrons. The best zero-field splitting of the ground state thus obtained is 0.24 ${\mathrm{cm}}^{-1\mathrm{}}$ with the correct sign.