A DensityBased BasisSet Incompleteness Correction for GW Methods
Abstract
Similar to other electron correlation methods, manybody perturbation theory methods based on Green functions, such as the socalled $GW$ approximation, suffer from the usual slow convergence of energetic properties with respect to the size of the oneelectron basis set. This displeasing feature is due to lack of explicit electronelectron terms modeling the infamous Kato electronelectron cusp and the correlation Coulomb hole around it. Here, we propose a computationally efficient densitybased basis set correction based on shortrange correlation density functionals which significantly speeds up the convergence of energetics towards the complete basis set limit. The performance of this densitybased correction is illustrated by computing the ionization potentials of the twenty smallest atoms and molecules of the GW100 test set at the perturbative $GW$ (or $G_0W_0$) level using increasingly large basis sets. We also compute the ionization potentials of the five canonical nucleobases (adenine, cytosine, thymine, guanine, and uracil) and show that, here again, a significant improvement is obtained.
 Publication:

arXiv eprints
 Pub Date:
 October 2019
 arXiv:
 arXiv:1910.12238
 Bibcode:
 2019arXiv191012238L
 Keywords:

 Physics  Chemical Physics;
 Condensed Matter  Strongly Correlated Electrons;
 Physics  Computational Physics
 EPrint:
 11 pages, 2 figures (supporting information available)