Assessment of Tuned Range Separated Exchange Functionals for Spectroscopies and Properties of Uranium Complexes

The Kohn-Sham delocalization error (DE) is quantified in select uranium compounds for various functionals and shown to correlate with the magnitude of dative ligand donation into the 5f shell. Range separated exchange functionals are reparametrized to minimize the DE and analyzed for their spectroscopic predictive capabilities. Valence excitation spectra of occupied 5f systems exhibit noticeable improvement upon reparametrization, e.g. UCl₆^-, UCl₆^2-, and UO₂⁺. Less sensitivity to the reparameterization was observed for closed shell 5f systems and core excitation spectra. A general parametrization is proposed to perform well for valence excitation spectra with small DE.