Measuring the kernel of time-dependent density functional theory with X-ray absorption spectroscopy of 3d transition metals

TL;DR

This paper uses TDDFT to analyze the 2p-3d core hole interactions in X-ray absorption spectra of 3d transition metals, providing insights into spectral deviations and extracting exchange-correlation kernel information.

Contribution

It introduces a simple three-level model within TDDFT to explain spectral deviations and directly derive exchange-correlation kernel matrix elements from experimental data.

Findings

Explains deviations from one-particle branching ratios in spectra.

Provides a method to extract XC kernel matrix elements from experiments.

Offers a theoretical framework for interpreting X-ray absorption spectra.

Abstract

The 2p-3d core hole interaction in the L2,3 absorption spectra of the 3d transition metals is treated within time-dependent density functional theory (TDDFT). A simple three-level model explains the origin of the strong deviations from the one-particle branching ratio and yields matrix elements of the unknown exchange-correlation (XC) kernel directly from experiment.