Half or full core-hole in density functional theory X-ray absorption spectrum calculations of water?

TL;DR

This study compares full and half core-hole potentials in density functional theory X-ray absorption spectrum calculations of water, finding the half core-hole approach yields better agreement with experimental data.

Contribution

The paper demonstrates that using a half core-hole potential improves the accuracy of XAS modeling of water compared to the full core-hole approach.

Findings

Half core-hole potential aligns better with experimental spectra.

Full core-hole approach shows poor agreement in intensity and energies.

Half core-hole provides a good compromise between initial and final state effects.

Abstract

We analyze the performance of two different core-hole potentials in the theoretical modeling of XAS of ice, liquid and gas phase water; the use of a full core-hole (FCH) in the calculations, as suggested by Hetenyi et al. [J. Chem. Phys. 120 (18), 8632 (2004)], gives poor agreement with experiment in terms of intensity distribution as well as transition energies, while the half core hole (HCH) potential, in the case of water, provides a better compromise between initial and final state effects, leading to good agreement with the experimental data.