Fig. 7. (a) Absorption spectrum obtained from a TD-DFT/B3LYP/6-31G* calculation. To compare the experimental and theoretical spectra, the theoretical absorption curve was scaled such that the absorbance at 396 nm became 0.2. Oscillator strengths for TD-DFT data are shown in an arbitrary unit. The spatial distributions of HOMO (b) and LUMO (c) indicate that the S0–S1 transition is characterized as a LMCT. ΔE(HOMO–LUMO) (=3.21 eV) is much larger than the S0–S1 excitation energy obtained by TDDFT (2.31 eV). The spin density distribution for the T1 state (d) indicates that the spin is localized at the vanadium center.
