Chemical Physics Letters, Vol.411, No.1-3, 121-127, 2005
Ab initio study of the electronic spectrum of the heptacyanovanadate(III) complex
Extensive ab initio CASSCF/CASPT2 computations have been performed to calculate all ligand field and the lowest charge transfer transitions of the [V(CN)(7)](4-) anion. The electronic structure is analysed in terms of D-5h and C-2v Point group symmetries, i.e., an idealised pentagonal bipyramidal structure and an axially bent structure, respectively. The CASPT2 calculated values for the ligand field transitions reproduce to a fair extent the peak values of the experimental spectra. No significant differences in bonding characteristics between equatorial and axial ligands are found. Spin-orbital coupling induces noticeable splitting of the excited triplet states but only very small singlet-triplet mixings. The lowest calculated charge transfer state is of the ligand-to-metal type and situated at around 40 000 cm(-1) above the ground state. The lowest metal-to-ligand states have been found at least 6000 cm(-1) higher in energy. (c) 2005 Elsevier B.V. All rights reserved.