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First-principles energetics of water clusters and ice: A many-body analysis

Gillan, MJ; Alfè, D; Bartók, AP; Csányi, G; (2013) First-principles energetics of water clusters and ice: A many-body analysis. The Journal of Chemical Physics , 139 (24) , Article 244504. 10.1063/1.4852182. Green open access

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Abstract

Standard forms of density-functional theory (DFT) have good predictive power for many materials, but are not yet fully satisfactory for cluster, solid, and liquid forms of water. Recent work has stressed the importance of DFT errors in describing dispersion, but we note that errors in other parts of the energy may also contribute. We obtain information about the nature of DFT errors by using a many-body separation of the total energy into its 1-body, 2-body, and beyond-2-body components to analyze the deficiencies of the popular PBE and BLYP approximations for the energetics of water clusters and ice structures. The errors of these approximations are computed by using accurate benchmark energies from the coupled-cluster technique of molecular quantum chemistry and from quantum Monte Carlo calculations. The systems studied are isomers of the water hexamer cluster, the crystal structures Ih, II, XV, and VIII of ice, and two clusters extracted from ice VIII. For the binding energies of these systems, we use the machine-learning technique of Gaussian Approximation Potentials to correct successively for 1-body and 2-body errors of the DFT approximations. We find that even after correction for these errors, substantial beyond-2-body errors remain. The characteristics of the 2-body and beyond-2-body errors of PBE are completely different from those of BLYP, but the errors of both approximations disfavor the close approach of non-hydrogen-bonded monomers. We note the possible relevance of our findings to the understanding of liquid water.

Type: Article
Title: First-principles energetics of water clusters and ice: A many-body analysis
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1063/1.4852182
Publisher version: http://dx.doi.org/10.1063/1.4852182
Language: English
Additional information: Copyright 2013 AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Gillan, MJ; Alfè, D; Bartók, AP; Csányi, G; (2013) First-principles energetics of water clusters and ice: A many-body analysis. The Journal of Chemical Physics, 139 (24), Article 244504, and may be found at http://dx.doi.org/10.1063/1.4852182.
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/1421830
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