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 \footnote{Lehtomaki \textit{et al}., JCP., 141, 234102 (2014).} and we evaluate the performance of a parametrized OF functional for atoms and molecules. We combine the parametrized Thomas-Fermi-Weizs{\" a}cker (TF-W) kinetic model $\lambda$ and $\gamma$ for the fractions of Weizs{\" a}cker and TF functionals, respectively, with LDA for atoms \footnote{Espinosa \textit{et al}., PCCP., (2015).}. We found that one-to-one relation between $\lambda$ and $\gamma$ 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 \footnote{Karpenko \textit{et al}., in preparation.} and we expect will help for further systematic improvement of OF density functionals.