Three-Dimensional Reference Interaction Site ModelSelf-Consistent Field Study of the Electronic Structure of [Cr(H2O)6]3+in Aqueous Solution.

The three-dimensional reference interaction-sitemodel self-consistent-field (3D-RISM-SCF) method was applied to theelectronic structure of hexahydrated chromium trication [Cr(H2O)6]3+in aqueous solution. The 3D distributionaround [Cr(H2O)6]3+showed 12 maximumdensity points arising from hydrogen bonds, as well as eight localmaximum points at the hollow sites, in the second hydration shell.The 3D distribution function also indicated 20 local maximum sitesin the third hydration shell. The low-lying excited states of verticaltransitions were computed using time-dependent density functionaltheory (TD-DFT), including the electric field from the solvent. Theelectronic configurations and excitation energies calculated usingDFT and 3D-RISM-SCF were very similar, although the orbital energiesinvolved in the transition were rather different. The two lowest excitedstates (14T and 24T) were roughly assigned tothe d–d transitions, and the third and fourth excited states(34T and 44T) were assigned to ligand-to-metalcharge-transfer transitions. The computed excited energies were ingood agreement with the experimental values. [ABSTRACT FROM AUTHOR]