Time-Dependent Quasiparticle Current Density Functional Theory of X-Ray Nonlinear Response Functions

TL;DR

This paper develops a real-space TDCDFT framework to compute nonlinear x-ray response functions of many-electron systems, enabling advanced spectroscopic analysis.

Contribution

It introduces closed-form expressions for linear, quadratic, and third-order response functions within the adiabatic TDCDFT approach.

Findings

Derived explicit formulas for nonlinear response functions

Applicable to x-ray spectroscopy and magnetic susceptibility studies

Provides a foundation for future computational implementations

Abstract

A real-space representation of the current response of many-electron systems with possible applications to x-ray nonlinear spectroscopy and magnetic susceptibilities is developed. Closed expressions for the linear, quadratic and third-order response functions are derived by solving the adiabatic Time Dependent Current Density Functional (TDCDFT) equations for the single-electron density matrix in Liouville space.