Core-Level Spectra for Disordered Systems from<i> GW</i>

We apply our recently developed GW core-level method to predict highly accurate X-ray photoelectron spectra (XPS) of disordered carbon-based materials, which require model sizes of more than 100 atoms. GW has become the method of choice for the computation of valence excitations [1]. We recently showed that GW can be also used for core excitations, even though it requires computationally more accurate techniques for the frequency integration of the self-energy than for valence states [2]. In addition, partial self-consistent schemes and relativistic corrections are crucial. For a benchmark set of small molecules, we find that GW-computed absolute and relative core-level binding energies deviate only 0.3 and 0.2 eV from experiment, respectively. Core-level spectroscopy is one of the few techniques that can be used to characterize disordered materials, such as functionalized amorphous carbon, which shows potential as coating and electrode material. However, the experimental spectra are difficult to interpret. We show that our method provides reliable computational references to support the peak assignment in experimental XPS spectra of amorphous carbon.

[1] D. Golze et. al. Front. Chem, 2019, 7, 377
[2] D. Golze et. al. JCTC, 2018, 14, 4856