Generalization of internal Density Functional Theory and Kohn-Sham scheme to multicomponent systems, and link with traditional DFT

TL;DR

This paper extends internal Density Functional Theory and Kohn-Sham schemes to multicomponent systems, explicitly including center-of-mass correlations, and clarifies the approximations in traditional DFT for molecules.

Contribution

It introduces a formalism for multicomponent self-bound systems within internal DFT, incorporating center-of-mass correlations explicitly.

Findings

Formalism applicable to molecules and droplets

Clarifies the role of center-of-mass correlations

Links internal DFT with traditional approaches

Abstract

We generalize the recently developped "internal" Density Functional Theory (DFT) and Kohn-Sham scheme to multicomponent systems. We obtain a general formalism, applicable for the description of multicomponent self-bound systems (as molecules where the nuclei are treated explicitely, atomic nuclei and mix of 3He and 4He droplets), where the fundamental translational symmetry has been treated correctly. The main difference with traditional DFT is the explicit inclusion of center-of-mass correlations in the functional. A large part of the paper is dedicated to the application to molecules, which permits among other to clarify the approximations that underly traditional DFT.