Abstract
The three-dimensional reference interaction-site model
self-consistent-field (3D-RISM-SCF) method was applied to the
electronic structure of hexahydrated chromium trication
[Cr(H2O)6]3+ in aqueous solution. The
3D distribution around [Cr(H2O)6]3+
showed 12 maximum density points arising from hydrogen bonds, as well
as eight local maximum points at the hollow sites, in the second
hydration shell. The 3D distribution function also indicated 20 local
maximum sites in the third hydration shell. The low-lying excited
states of vertical transitions were computed using time-dependent
density functional theory (TD-DFT), including the electric field from
the solvent. The electronic configurations and excitation energies
calculated using DFT and 3D-RISM-SCF were very similar, although the
orbital energies involved in the transition were rather different. The
two lowest excited states (14T and 24T) were
roughly assigned to the d–d transitions, and the third and fourth
excited states (34T and 44T) were assigned to
ligand-to-metal charge-transfer transitions. The computed excited
energies were in good agreement with the experimental values.