# Development of a Practical Multicomponent Density Functional for Electron-Proton Correlation to Produce Accurate Proton Densities

## TL;DR

This paper introduces epc17, a new electron-proton correlation functional for multicomponent DFT, which accurately predicts proton densities and is efficiently implemented within the NEO framework for diverse applications.

## Contribution

A novel electron-proton correlation functional, epc17, derived from Colle-Salvetti formalism, enhancing proton density accuracy in multicomponent DFT.

## Key findings

- epc17 produces accurate proton densities
- Efficient implementation within NEO-DFT framework
- Promising for diverse quantum chemical applications

## Abstract

Multicomponent density functional theory (DFT) enables the consistent quantum mechanical treatment of both electrons and protons. A major challenge has been the design of electron-proton correlation functionals that produce even qualitatively accurate proton densities. Herein an electron-proton correlation functional, epc17, is derived analogously to the Colle-Salvetti formalism for electron correlation and is implemented within the nuclear-electronic orbital (NEO) framework. The NEO-DFT/epc17 method produces accurate proton densities efficiently and is promising for diverse applications.