# Exchange Correlation Potentials from Full Configuration Interaction in a Slater Orbital Basis

## TL;DR

This paper develops and tests the Ryabinkin-Kohut-Staroverov (RKS) method with Slater atomic orbitals, enabling accurate exchange-correlation potentials from full configuration interaction calculations, crucial for density functional theory.

## Contribution

The work introduces the first implementation of the RKS method with Slater orbitals, demonstrating its efficiency and importance of cusp conditions for accurate potentials.

## Key findings

- RKS method produces artifact-free exchange-correlation potentials.
- Enforcing nuclear cusp conditions is essential for success.
- Applicable to both weakly and strongly correlated systems.

## Abstract

Ryabinkin-Kohut-Staroverov (RKS) theory builds a bridge between wave function theory and density functional theory by using quantities from the former to produce accurate exchange-correlation potentials needed by the latter. In this work, the RKS method is developed and tested alongside Slater atomic orbital basis functions for the first time. To evaluate this approach, Full Configuration Interaction computations in the Slater orbitals are employed to give quality input to RKS method, allowing full correlation to be present along with correct nuclei cusps and asymptotic decay of the wavefunction. The RKS method will be shown to be an efficient algorithm to arrive at exchange correlation potentials without unphysical artifacts in moderately-sized basis sets. Furthermore, enforcement of the nuclear cusp conditions will be shown to be vital for the success of the Slater-basis RKS method. Examples of weakly and strongly correlated molecular systems will demonstrate the main features of Slater RKS.