Karel Doclo, David De Corte, Claude Daul and H. U. Güdel
Ground State and Excited State Properties of Hexaamminechromium(III) Ion: A Density Functional Study.
Inorg. Chem. 37, 3842-3847 (1998)                 

Abstract: The electronic structure of the ground and lowest excited states of the hexaamminechromium(III) ion [Cr(NH₃)₆]³⁺ has been investigated through density functional theory. The geometry of the ⁴A_2g ground state and of the ⁴T_2g excited state are optimized. The latter is relaxed along an e_g Jahn-Teller coordinate. The experimentally known geometry distortion, i.e., an axial compression and an equatorial elongation, together with the corresponding energy gain is well reproduced by our calculations. The results for the d-d excitation energies are in reasonable agreement with experiment. The relative performance of local and gradient-corrected functionals is discussed.