Low-Order Scaling Quasiparticle Self-Consistent GW for Molecules

Arno Förster*, Lucas Visscher

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Low-order scaling GW implementations for molecules are usually restricted to approximations with diagonal self-energy. Here, we present an all-electron implementation of quasiparticle self-consistent GW for molecular systems. We use an efficient algorithm for the evaluation of the self-energy in imaginary time, from which a static non-local exchange-correlation potential is calculated via analytical continuation. By using a direct inversion of iterative subspace method, fast and stable convergence is achieved for almost all molecules in the GW100 database. Exceptions are systems which are associated with a breakdown of the single quasiparticle picture in the valence region. The implementation is proven to be starting point independent and good agreement of QP energies with other codes is observed. We demonstrate the computational efficiency of the new implementation by calculating the quasiparticle spectrum of a DNA oligomer with 1,220 electrons using a basis of 6,300 atomic orbitals in less than 4 days on a single compute node with 16 cores. We use then our implementation to study the dependence of quasiparticle energies of DNA oligomers consisting of adenine-thymine pairs on the oligomer size. The first ionization potential in vacuum decreases by nearly 1 electron volt and the electron affinity increases by 0.4 eV going from the smallest to the largest considered oligomer. This shows that the DNA environment stabilizes the hole/electron resulting from photoexcitation/photoattachment. Upon inclusion of the aqueous environment via a polarizable continuum model, the differences between the ionization potentials reduce to 130 meV, demonstrating that the solvent effectively compensates for the stabilizing effect of the DNA environment. The electron affinities of the different oligomers are almost identical in the aqueous environment.

Original languageEnglish
Article number736591
Pages (from-to)1-14
Number of pages14
JournalFrontiers in Chemistry
Volume9
Issue numberSeptember
Early online date3 Sept 2021
DOIs
Publication statusPublished - Sept 2021

Bibliographical note

Funding Information:
This research received funding from Netherlands Organisation for Scientific Research (NWO) in the framework of the Innovation Fund for Chemistry and from the Ministry of Economic Affairs in the framework of the TKI/PPS-Toeslagregeling (award number 731.017.417).

Publisher Copyright:
© Copyright © 2021 Förster and Visscher.

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

Keywords

  • analytical continuation
  • convergence acceleration
  • DNA photodamage
  • GW approximation
  • quasiparticle
  • quasiparticle self-consistent GW
  • theoretical spectroscopy

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