Revisiting the role of exact exchange in DFT spin-state energetics of transition metal complexes.

摘要: The effect of the exact exchange on spin-state energetics transition metal complexes is revisited with an attempt to clarify its origin and regard performance DFT methods. Typically, by increasing amount in exchange-correlation functional, higher spin states are strongly stabilized respect lower states. But this not always case, as revealed from presented studies heme non-heme complexes, cations surrounded point charges. It argued that sensitivity admixture rooted description metal-ligand bonding rather than metal-centered interactions. In typical where a state involves electron promotion nonbonding antibonding orbital, has more delocalized charge distribution contains larger nondynamical correlation energy state. However, methods have problems describing these two effects accurately. This interpretation allows us explain why much smaller transitions involve only d orbitals.