On the transferability of a parametrized kinetic functional for orbital-free density functional theory calculations

Because of issues with accuracy and transferability of existing orbital-free (OF) density functionals, OF functional development remains an active research area. Due to numerical difficulties, all-electron self-consistent assessment of OF functionals is limited. Using the projector augmented wave method we compute OFDFT all-electron values and we evaluate the performance of a parametrized OF functional for atoms and molecules. We combine the parametrized Thomas-Fermi-Weizsäcker (TF-W) kinetic model λ and γ for the fractions of Weizsäcker and TF functionals, respectively, with LDA for atoms. We found that one-to-one relation between λ and γ values defines a region in parameter space that allows the atomic energies and eigenvalues to be approximated with a small average error with respect to the Kohn-Sham values. The optimum values is however different for every property and for every atom. Recently, these results have been combined to test parameter transferability from atoms to molecules and we expect will help for further systematic improvement of OF density functionals.