Alchemical perturbation density functional theory (APDFT)

TL;DR

This paper presents an orbital-free density functional approximation based on alchemical perturbation theory, enabling accurate property predictions for molecules without solving self-consistent equations, at minimal computational cost.

Contribution

It introduces a novel orbital-free functional derived from alchemical perturbation theory that surpasses traditional Kohn-Sham DFT accuracy for molecular properties.

Findings

Accurately predicts covalent bonding potentials.

Efficiently estimates atomic forces and multipole moments.

Requires only perturbed reference densities, no self-consistent field calculations.

Abstract

We introduce an orbital free electron density functional approximation based on alchemical perturbation theory. Given convergent perturbations of a suitable reference system, the accuracy of popular self-consistent Kohn-Sham density functional estimates of properties of new molecules can be systematically surpassed---at negligible cost. The associated energy functional is an approximation to the integrated energy derivative, requiring only perturbed reference electron densities: No self-consistent field equations are necessary to estimate energies and electron densities. Electronic ground state properties considered include covalent bonding potentials, atomic forces, as well as dipole and quadropole moments.