Development of Novel Kinetic Energy Functional for Orbital-Free Density Functional Theory Applications-II.

Abstract

The development of novel Kinetic Energy (KE) functionals is an important topic in density functional theory (DFT). Here, I present a study of Laplacian-Level kinetic energy functionals
applied to metallic nanosystems. The nanoparticles are modeled using jellium spheres of different sizes, background densities, and number of electrons. The ability of different functionals to reproduce the correct kinetic energy density and potential of various nanoparticles is investigated and analyzed in terms of semilocal descriptors. Most semilocal KE functionals are based on modifications of the second-order gradient expansion GE2 or GE4. After a series of calculations and analyzes on the second and fourth order gradient expansion and respecting the exact constraints, I propose a new functional LAP1 which allows to remove the divergence of the potential of the functional GE4 and to obtain lower errors of both energy and potential.