Semilocal Pauli kinetic potential for orbital-free density functional theory, with an application to jellium clusters

The kinetic energy (KE) functional development has been a well-established research field for several decades, but there are only a few studies that considered the KE Pauli potential as the main quantity and developed approximations for it. In this work, we follow this unconventional path and construct the Direct Semilocal-Laplacian Potential (DSLP) Pauli potential approximation that satisfies important exact conditions, such as an accurate linear response of the uniform electron gas at small wave vectors and a realistic asymptotic decay outside of the jellium spheres in the vacuum. We performed orbital-free density functional theory (OFDFT) calculations for jellium clusters, which are accurate models for real metal clusters. We also investigated the response to external, time-independent perturbations. In general, the DSLP Pauli potential significantly enhances the accuracy of OFDFT calculations compared to the popular second-order KE gradient expansion and the Thomas-Fermi-Weizsäcker functional. Thus, the DSLP Pauli potential can be further applied to real applications of metal nanoparticles.