Exploring non-adiabatic approximations to the exchange-correlation functional of TDDFT

TL;DR

This paper proposes a new decomposition of the exchange-correlation potential in TDDFT to develop non-adiabatic approximations, tested on simple models to improve accuracy beyond adiabatic methods.

Contribution

It introduces a novel decomposition approach for the exchange-correlation potential in TDDFT, enabling new non-adiabatic approximation strategies.

Findings

Preliminary approximations evaluated against exact conditions.

Performance tested on simple model systems.

Indicates importance of non-adiabatic effects.

Abstract

A decomposition of the exact exchange-correlation potential of time-dependent density functional theory into an interaction component and a kinetic component offers a new starting point for non- adiabatic approximations. The components are expressed in terms of the exchange-correlation hole and the difference between the one-body density matrix of the interacting and Kohn-Sham systems, which must be approximated in terms of quantities accessible from the Kohn-Sham evolution. We explore several preliminary approximations, evaluate their fulfillment of known exact conditions, and test their performance on simple model systems for which available exact solutions indicate the significance of going beyond the adiabatic approximation.