Exact non-adiabatic part of the Kohn-Sham potential and its fluidic approximation

TL;DR

This paper introduces a simple fluidic approximation to the non-adiabatic component of the Kohn-Sham potential in time-dependent density functional theory, improving accuracy over traditional adiabatic methods for dynamic systems.

Contribution

The paper proposes a novel geometrical fluidic approximation to the non-adiabatic Kohn-Sham potential, enhancing the accuracy of time-dependent DFT calculations.

Findings

Fluidic approximation significantly reduces errors in non-adiabatic potential calculations.

The method performs well even for systems far from adiabatic evolution.

Exact densities show the approximation captures essential non-adiabatic features.

Abstract

We present a simple geometrical "fluidic" approximation to the non-adiabatic part of the Kohn-Sham potential, $v_{\mathrm{KS}}$, of time-dependent density functional theory. This part of $v_{\mathrm{KS}}$ is often crucial, but most practical functional approximations utilize an adiabatic approach based on ground-state DFT. For a variety of prototype systems, we calculate the exact time-dependent electron density, and find that the fluidic approximation corrects a large part of the error arising from the "exact adiabatic" approach, even when the system is evolving far from adiabatically.