Orbital-free density functional theory with atom-centered density matrices*

Orbital-free density functional theory (OFDFT) is one of the most computationally efficient methods for performing electronic structure calculations. OFDFT achieves its speed by treating the electron density as the sole quantity of interest, in contrast to Kohn-Sham density functional theory which incorporates single-particle wave functions. The lack of wave-function manipulations makes OFDFT suitable for the study of millions of atoms, provided it can be made sufficiently accurate.

This presentation will explore recent work that aims to improve the accuracy of OFDFT. The primary modification is the replacement of the density-only description of the system by a hybrid description that includes on-site density matrices. These local density matrices are defined only in spheres immediately surrounding nuclei, and the remainder of the system is described by the electron density alone. The extra information afforded by the hybrid description helps overcome the two primary limitations of conventional OFDFT: that it requires an explicit density functional for the non-interacting kinetic energy, and that it is frequently restricted to calculations involving only pseudopotentials.