Unrestricted open-shell Kohn–Sham scheme with local hybrid exchange-correlation potentials: improved calculation of electronic g-tensors for transition-metal complexes

The localized Hartree–Fock approximation is applied to convert `traditionalʹ non-local and non-multiplicative hybrid exchange-correlation potentials into local and multiplicative Kohn–Sham potentials for the open-shell case, within the spin-unrestricted formalism. The method has been evaluated in calculations of g-tensors for nine first-row transition-metal compounds. Local potentials allow one to improve the results by increasing the exact exchange admixture to a certain limit, whereas this is more difficult for non-local potentials. Exact-exchange admixture of ca. 0.5 provides the best agreement with the experimental g-tensors which is consistent with previous local hybrid potential results for nuclear shielding constants of closed-shell main-group molecules.