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Title: The individual and collective effects of exact exchange and dispersion interactions on the ab initio structure of liquid water

In this work, we report the results of a series of density functional theory (DFT) based ab initio molecular dynamics (AIMD) simulations of ambient liquid water using a hierarchy of exchange-correlation (XC) functionals to investigate the individual and collective effects of exact exchange (Exx), via the PBE0 hybrid functional, non-local van der Waals/dispersion (vdW) interactions, via a fully self-consistent density-dependent dispersion correction, and an approximate treatment of nuclear quantum effects, via a 30 K increase in the simulation temperature, on the microscopic structure of liquid water. Based on these AIMD simulations, we found that the collective inclusion of Exx and vdW as resulting from a large-scale AIMD simulation of (H{sub 2}O){sub 128} significantly softens the structure of ambient liquid water and yields an oxygen-oxygen structure factor, S{sub OO}(Q), and corresponding oxygen-oxygen radial distribution function, g{sub OO}(r), that are now in quantitative agreement with the best available experimental data. This level of agreement between simulation and experiment demonstrated herein originates from an increase in the relative population of water molecules in the interstitial region between the first and second coordination shells, a collective reorganization in the liquid phase which is facilitated by a weakening of the hydrogen bond strength by themore » use of a hybrid XC functional, coupled with a relative stabilization of the resultant disordered liquid water configurations by the inclusion of non-local vdW/dispersion interactions. This increasingly more accurate description of the underlying hydrogen bond network in liquid water also yields higher-order correlation functions, such as the oxygen-oxygen-oxygen triplet angular distribution, P{sub OOO}(θ), and therefore the degree of local tetrahedrality, as well as electrostatic properties, such as the effective molecular dipole moment, that are in much better agreement with experiment.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [4] ;  [4]
  1. Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)
  2. Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States)
  3. Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)
  4. (United States)
Publication Date:
OSTI Identifier:
22419829
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CORRELATION FUNCTIONS; DENSITY FUNCTIONAL METHOD; DIPOLE MOMENTS; DISPERSIONS; HYBRIDIZATION; HYDROGEN; INCLUSIONS; INTERACTIONS; LIQUIDS; MOLECULAR DYNAMICS METHOD; MOLECULES; OXYGEN; SIMULATION; TRIPLETS; VAN DER WAALS FORCES; WATER