Modeling X-ray Photoelectron Spectroscopy of Macromolecules Using GW

TL;DR

This paper introduces a simple additive approach using the GW method to simulate X-ray photoelectron spectra of macromolecules efficiently, enabling analysis of complex materials by combining spectra of smaller components.

Contribution

The paper presents a novel additive scheme combining GW calculations on monomers to accurately simulate the spectra of large macromolecules, reducing computational costs.

Findings

Excellent agreement with experimental spectra for tested polymers.

Method effectively retrieves composition of unknown materials.

Potential to study chemical reactions via spectral comparison.

Abstract

We propose a simple additive approach to simulate X-ray photoelectron spectra (XPS) of macromolecules based on the $GW$ method. Single-shot $GW$ ($G_0W_0$) is a promising technique to compute accurate core-electron binding energies (BEs). However, its application to large molecules is still unfeasible. To circumvent the computational cost of $G_0W_0$, we break the macromolecule into tractable building blocks, such as isolated monomers, and sum up the theoretical spectra of each component, weighted by their molar ratio. In this work, we provide a first proof of concept by applying the method to four test polymers and one copolymer, and show that it leads to an excellent agreement with experiments. The method could be used to retrieve the composition of unknown materials and study chemical reactions, by comparing the simulated spectra with experimental ones.