Bootstrap approximation for the exchange-correlation kernel of time-dependent density functional theory

TL;DR

This paper introduces a new parameter-free exchange-correlation kernel for time-dependent density functional theory, enabling accurate optical spectra calculations across diverse materials without empirical parameters.

Contribution

The paper presents a self-consistent, parameter-free approximation for the exchange-correlation kernel in TDDFT, improving spectral predictions for various insulators.

Findings

Accurately predicts optical spectra for small and large bandgap materials.

Works well for magnetic insulators like NiO.

Universal applicability demonstrated across diverse materials.

Abstract

A new parameter-free approximation for the exchange-correlation kernel $f_{\rm xc}$ of time-dependent density functional theory is proposed. This kernel is expressed as an algorithm in which the exact Dyson equation for the response as well as a further approximate condition are solved together self-consistently leading to a simple parameter-free kernel. We apply this to the calculation of optical spectra for various small bandgap (Ge, Si, GaAs, AlN, TiO$_2$, SiC), large bandgap (C, LiF, Ar, Ne) and magnetic (NiO) insulators. The calculated spectra are in very good agreement with experiment for this diverse set of materials, highlighting the universal applicability of the new kernel.