# A Density Functional Extension to Excited State Mean-Field Theory

## TL;DR

This paper introduces a density functional extension to excited state mean-field theory that improves the treatment of charge transfer states by incorporating density functional components, while remaining variational and time-independent.

## Contribution

It presents a novel, variational, time-independent extension of excited state mean-field theory that includes density functional effects to better handle weak electron correlations.

## Key findings

- Improved description of single-component charge transfer states.
- Less reliable for multi-particle-hole transition states.
- Avoids linear response and adiabatic approximation issues.

## Abstract

We investigate an extension of excited state mean-field theory in which the energy expression is augmented with density functional components in an effort to include the effects of weak electron correlations. The approach remains variational and entirely time-independent, allowing it to avoid some of the difficulties associated with linear response and the adiabatic approximation. In particular, all of the electrons' orbitals are relaxed state specifically and there is no reliance on Kohn-Sham orbital energy differences, both of which are important features in the context of charge transfer. Preliminary testing shows clear advantages for single-component charge transfer states, but the method, at least in its current form, is less reliable for states in which multiple particle-hole transitions contribute significantly.