Scalable Molecular GW Calculations: Valence and Core Spectra

Mejı́a-Rodrı́guez, Daniel; Kunitsa, Alexander A.; Aprà, Edoardo; Govind, Niranjan

doi:10.1021/acs.jctc.1c00738

Cited by 29 publications

(66 citation statements)

References 97 publications

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“…8 These energies were then compared with those obtained with the respective completely uncontracted versions, hereafter denoted as un-cc-pVnZ and un-def2-nZVP. The CD-GW approach, recently implemented in the open-source computational chemistry package NWCHEM, 9,31 was used for this task.…”

Section: Computational Detailsmentioning

confidence: 99%

“…The GW approximation (GWA) 5 to the self-energy is a Green's-function-based method that can be used to obtain accurate molecular CLBEs at a reasonable cost. [6][7][8][9] The CLBEs obtained with this approach include some level of orbital relaxation effects, however, the quality of the results might depend strongly on the starting point. For example, it has been known that a large fraction of exact exchange is needed at the one-shot G 0 W 0 level, mainly due to a large self-interaction error (SIE) present when standard "pure" exchange-correlation density functional approximations (DFAs) are adopted.…”

Section: Introductionmentioning

confidence: 99%

“…For example, it has been known that a large fraction of exact exchange is needed at the one-shot G 0 W 0 level, mainly due to a large self-interaction error (SIE) present when standard "pure" exchange-correlation density functional approximations (DFAs) are adopted. 6,7,9 A possible workaround when starting from a pure Kohn-Sham result is to use the more demanding evGW partial self-consistent approach, [7][8][9][10] although some starting-point dependency will remain.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the basis set selection for molecular core-level $GW$ calculations

Mejia-Rodriguez,

Kunitsa,

Aprà

et al. 2022

Preprint

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The GW approximation has been recently gaining popularity among the method for simulating molecular core-level X-ray photoemission spectra. Traditionally, GW core-level binding energies have been computed using either the cc-pVnZ or def2-nZVP basis set families, extrapolating the obtained results to the complete basis set limit, followed by a an elementspecific relativistic correction. Despite of achieving good accuracy, these binding energies are chronically underestimated. By using first-row elements and standard techniques known to offer good cost-accuracy ratio in other theories, we show that the cc-pVnZ and def2-nZVP families show large contraction errors and lead to unreliable complete basis set extrapolations.On the other hand, we demonstrate that uncontracted versions of these basis sets offer vastly improved convergence. Even faster convergence can be obtained using core-rich, propertyoptimized, basis sets families like pcSseg-n, pcJ-n and ccX-nZ. Finally, we also show that the improvement over the core properties does not degrade the calculation of the valence excitations, and thus offer a balanced description of both core and valence regions.

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Section: Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the basis set selection for molecular core-level $GW$ calculations

Mejia-Rodriguez,

Kunitsa,

Aprà

et al. 2022

Preprint

Self Cite

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“…30,[34][35][36] Due to its primary application to solids, GW was traditionally implemented in plane wave codes that typically use pseudo potentials for the deeper states. With the increasing availability of the GW method in localized basis set codes, [37][38][39][40][41][42][43][44] core states moved into focus. Core-level binding energy calculations have emerged as a recent trend in GW .…”

Section: Introductionmentioning

confidence: 99%

“…Core-level binding energy calculations have emerged as a recent trend in GW . 21,23,[43][44][45][46][47][48][49][50][51] By extension to the Bethe-Salpeter equation (BSE@GW ) also K-edge transition energies measured in X-ray absorption spectroscopy can be calculated. 52 These studies focused primarily on molecules.…”

Section: Introductionmentioning

confidence: 99%

Benchmark of $\boldsymbol{GW}$ Methods for Core-Level Binding Energies

Li¹,

Ye²,

Rinke³

et al. 2022

Preprint

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The GW approximation has recently gained increasing attention as a viable method for the computation of deep core-level binding energies as measured by X-ray photoelectron spectroscopy (XPS). We present a comprehensive benchmark study of different GW methodologies (starting-point optimized, partial and full eigenvalue-self-consistent, Hedin shift and renormalized singles) for molecular inner-shell excitations. We demonstrate that all methods yield a unique solution and apply them to the CORE65 benchmark set and ethyl trifluoroacetate. Three GW schemes clearly outperform the other methods for absolute core-level energies with a mean absolute error of 0.3 eV with respect to experiment. These are partial eigenvalue self-consistency, in which the eigenvalues are only updated in the Green's function, single-shot GW calculations based on an optimized hybrid functional starting point and a Hedin shift in the Green's function. While all methods reproduce the experimental relative binding energies well, the eigenvalue self-consistent schemes and the Hedin shift yield with mean errors < 0.2 eV the best results.

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All-Electron BSE@GW Method for K-Edge Core Electron Excitation Energies

Yao

Golze

Rinke

et al. 2022

J. Chem. Theory Comput.

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We present an accurate computational approach to calculate absolute K-edge core electron excitation energies as measured by X-ray absorption spectroscopy. Our approach employs an all-electron Bethe–Salpeter equation (BSE) formalism based on GW quasiparticle energies (BSE@GW) using numeric atom-centered orbitals (NAOs). The BSE@GW method has become an increasingly popular method for the computation of neutral valence excitation energies of molecules. However, it was so far not applied to molecular K-edge excitation energies. We discuss the influence of different numerical approximations on the BSE@GW calculation and employ in our final setup (i) exact numeric algorithms for the frequency integration of the GW self-energy, (ii) G 0 W 0 and BSE starting points with ∼50% of exact exchange, (iii) the Tamm–Dancoff approximation and (iv) relativistic corrections. We study the basis set dependence and convergence with common Gaussian-type orbital and NAO basis sets. We identify the importance of additional spatially confined basis functions as well as of diffuse augmenting basis functions. The accuracy of our BSE@GW method is assessed for a benchmark set of small organic molecules, previously used for benchmarking the equation-of-motion coupled cluster method [Peng et al., J. Chem. Theory Comput., 2015, 11, 4146], as well as the medium-sized dibenzothiophene (DBT) molecule. Our BSE@GW results for absolute excitation energies are in excellent agreement with the experiment, with a mean average error of only 0.63 eV for the benchmark set and with errors <1 eV for the DBT molecule.

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Scalable Molecular GW Calculations: Valence and Core Spectra

Cited by 29 publications

References 97 publications

On the basis set selection for molecular core-level $GW$ calculations

On the basis set selection for molecular core-level $GW$ calculations

Benchmark of $\boldsymbol{GW}$ Methods for Core-Level Binding Energies

All-Electron BSE@GW Method for K-Edge Core Electron Excitation Energies

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