Magnetic circular dichroism in real-time time-dependent density functional theory

TL;DR

This paper develops a real-time, real-space computational approach within time-dependent density functional theory to calculate magnetic circular dichroism spectra, demonstrating its effectiveness at higher energies and for spectrum normalization.

Contribution

It introduces a real-time method for MCD calculations in TDDFT, deriving response formulas and sum rules, and applies it to C-60, showing qualitative agreement with experimental signs.

Findings

The method accurately predicts signs of A and B terms for low excitations.

Sum rules are effective for normalization and accuracy assessment.

Qualitative agreement with experimental magnitudes for C-60 spectrum.

Abstract

We apply the adiabatic time-dependent density functional theory to magnetic ci the real-space, real-time computational method. The standard formulas for the MCD response and its A and B terms are derived from the observables in the time-dependent wave function. We find the real time method is well suited for calculating the overall spectrum, particularly at higher excitation energies where individual excited states are numerous and overlapping. The MCD sum rules are derived and interpreted in the real-time formalism; we find that they are very useful for normalization purposes and assessing the accuracy of the theory. The method is applied to MCD spectrum of C-60 using the adiabatic energy functional from the local density approximation. The theory correctly predicts the signs of the A and B terms for the lowest allowed excitations. However, the magnitudes of the terms only show qualitative agreement with experiment.