Density, structure, and dynamics of water: The effect of van der Waals interactions
Entity
UAM. Departamento de Física de la Materia CondensadaPublisher
American Institute of PhysicsDate
2011-01-14Citation
10.1063/1.3521268
Journal of Chemical Physics 134.2 (2011): 024516
ISSN
0021-9606 (print); 1089-7690 (online)DOI
10.1063/1.3521268Funded by
The work at Stony Brook University was supported by DOE award numbers DE-FG02-09ER16052, DE-SC0003871 and DE-FG02-08ER46550 and the work in Madrid by MCI Grant No. FIS2009-12712. This research utilized resources at the New York Center for Computational Sciences at Stony Brook University/Brookhaven National Laboratory which is supported by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 and by the State of New York.Editor's Version
http://dx.doi.org/10.1063/1.3521268Subjects
FísicaNote
The following article appeared in Journal of Chemical Physics 134.2 (2011): 024516 and may be found at http://scitation.aip.org/content/aip/journal/jcp/134/2/10.1063/1.3521268Rights
© 2011 American Institute of PhysicsAbstract
It is known that ab initio molecular dynamics (AIMD) simulations of liquid water at ambient conditions, based on the generalized gradient approximation (GGA) to density functional theory (DFT), with commonly used functionals fail to produce structural and diffusive properties in reasonable agreement with experiment. This is true for canonical, constant temperature simulations where the density of the liquid is fixed to the experimental density. The equilibrium density, at ambient conditions, of DFT water has recently been shown by Schmidt et al. [J. Phys. Chem. B, 113, 11959 (2009)] to be underestimated by different GGA functionals for exchange and correlation, and corrected by the addition of interatomic pair potentials to describe van der Waals (vdW) interactions. In this contribution we present a DFT-AIMD study of liquid water using several GGA functionals as well as the van der Waals density functional (vdW-DF) of Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)]. As expected, we find that the density of water is grossly underestimated by GGA functionals. When a vdW-DF is used, the density improves drastically and the experimental diffusivity is reproduced without the need of thermal corrections. We analyze the origin of the density differences between all the functionals. We show that the vdW-DF increases the population of non-H-bonded interstitial sites, at distances between the first and second coordination shells. However, it excessively weakens the H-bond network, collapsing the second coordination shell. This structural problem is partially associated to the choice of GGA exchange in the vdW-DF. We show that a different choice for the exchange functional is enough to achieve an overall improvement both in structure and diffusivity
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Google Scholar:Wang, Jue
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Román Pérez, Guillermo
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Soler Torroja, José María
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Artacho, Emilio
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Fernández-Serra, María Victoria
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