Density matrix calculation of optical constants from optical to x-ray frequencies

TL;DR

This paper introduces a density matrix-based method for calculating optical constants across a broad frequency spectrum, from infrared to x-ray, applicable to complex aperiodic materials without explicit wave-function computations.

Contribution

The paper develops a novel density matrix approach integrated into the FEFF code, enabling efficient optical property calculations over wide frequency ranges for aperiodic systems.

Findings

Accurate optical constants computed from IR to x-ray frequencies.

Applicable to arbitrary aperiodic systems without explicit wave-function calculations.

Validated with calculations on several materials.

Abstract

We present a theory of linear optical constants based on a single-particle density matrix and implemented in an extension of the real-space multiple scattering code FEFF. This approach avoids the need to compute wave-functions explicitly, and yields efficient calculations for frequencies ranging from the IR to hard x-rays, and applicable to arbitrary aperiodic systems. Our approach is illustrated with calculations of optical properties and applications for several materials.