GW and Bethe-Salpeter study of small water clusters

Journal Article · Thu Jan 21 04:00:00 EST 2016 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4940139· OSTI ID:22493659

Blase, Xavier; Boulanger, Paul ^[1]; Bruneval, Fabien ^[2]; Fernandez-Serra, Marivi ^[3]; Duchemin, Ivan ^[4]

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1. CNRS, Institut NEEL, F-38042 Grenoble (France)
2. CEA, DEN, Service de Recherches de Métallurgie Physique, F-91191 Gif-sur-Yvette (France)
3. Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800 (United States)
4. INAC, SP2M/L-Sim, CEA/UJF Cedex 09, 38054 Grenoble (France)

We study within the GW and Bethe-Salpeter many-body perturbation theories the electronic and optical properties of small (H{sub 2}O){sub n} water clusters (n = 1-6). Comparison with high-level CCSD(T) Coupled-Cluster at the Single Double (Triple) levels and ADC(3) Green’s function third order algebraic diagrammatic construction calculations indicates that the standard non-self-consistent G{sub 0}W{sub 0}@PBE or G{sub 0}W{sub 0}@PBE0 approaches significantly underestimate the ionization energy by about 1.1 eV and 0.5 eV, respectively. Consequently, the related Bethe-Salpeter lowest optical excitations are found to be located much too low in energy when building transitions from a non-self-consistent G{sub 0}W{sub 0} description of the quasiparticle spectrum. Simple self-consistent schemes, with update of the eigenvalues only, are shown to provide a weak dependence on the Kohn-Sham starting point and a much better agreement with reference calculations. The present findings rationalize the theory to experiment possible discrepancies observed in previous G{sub 0}W{sub 0} and Bethe-Salpeter studies of bulk water. The increase of the optical gap with increasing cluster size is consistent with the evolution from gas to dense ice or water phases and results from an enhanced screening of the electron-hole interaction.

• OSTI ID: 22493659
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 3 Vol. 144; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BETHE-SALPETER EQUATION
COMPARATIVE EVALUATIONS
EIGENVALUES
ELECTRONIC STRUCTURE
ENERGY GAP
EV RANGE
EXCITATION
GREEN FUNCTION
HOLES
ICE
MANY-BODY PROBLEM
MOLECULAR CLUSTERS
OPTICAL PROPERTIES
PERTURBATION THEORY
WATER