King's College London

Research portal

Efficient excitations and spectra within a perturbative renormalization approach

Research output: Contribution to journalArticle

Original languageEnglish
Article number10.1021/acs.jctc.0c00701
JournalJournal of Chemical Theory and Computation
Accepted/In press4 Sep 2020

Documents

  • main

    main.pdf, 663 KB, application/pdf

    Uploaded date:02 Oct 2020

    Version:Accepted author manuscript

King's Authors

Abstract

We present a self-consistent approach for computing the correlated quasiparticle spectrum of charged exci- tations in iterative O[N5] computational time. This is based on the auxiliary second-order Green’s function approach [O. Backhouse et al., JCTC (2020)], in which a self-consistent effective Hamiltonian is constructed by systematically renormalizing the dynamical effects of the self-energy at second-order perturbation theory. From extensive benchmarking across the W4-11 molecular test set, we show that the iterative renormalization and truncation of the effective dynamical resolution arising from the 2h1p and 1h2p spaces can substantially improve the quality of the resulting ionization potential and electron affinity predictions compared to bench- mark values. The resulting method is shown to be superior in accuracy to similarly scaling quantum chemical methods for charged excitations in EOM-CC2 and ADC(2), across this test set, while the self-consistency also removes the dependence on the underlying mean-field reference. The approach also allows for single-shot computation of the entire quasiparticle spectrum, which is applied to the benzoquinone molecule and demon- strates the reduction in the single-particle gap due to the correlated physics, and gives direct access to the localization of the Dyson orbitals.

View graph of relations

© 2020 King's College London | Strand | London WC2R 2LS | England | United Kingdom | Tel +44 (0)20 7836 5454