The electronic structure of the ground and lowest excited states of the hexaamminechromium(III) ion [Cr(NH(3))(6)](3+) has been investigated through density functional theory. The geometry of the (4)A(2g) ground state and of the (4)T(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.

The structures and the conformational energies of nonprotonated, monoprotonated and diprotonated 1,2-ethanediamine have been investigated through density functional theory. The relative performance of local and gradient-corrected functionals is discussed. The existence of hydrogen-bond formation has been determined with electron localisation function calculations. Proton anities for nonprotonated and monoprotonated 1,2-ethanediamine have been calculated and are in agreement with experimental data. The in¯uence of solvation has been accounted for through the selfconsistent isodensity polarisable continuum model. The results for the nonprotonated conformers show that solvation stabilises those conformers which have the lone pair in an antiperiplanar conformation. Solvation of the monoprotonated conformer stabilises signi®cantly the``anti'' conformation, which is unstable in the gas phase. For the di-protonated species, solvation stabilises slightly the gauche conformer, which is unstable in the gas phase.