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How van der Waals interactions determine the unique properties of water

Autor(en)
Tobias Morawietz, Andreas Singraber, Christoph Dellago, Joerg Behler
Abstrakt

Whereas the interactions between water molecules are dominated by strongly directional hydrogen bonds (HBs), it was recently proposed that relatively weak, isotropic van der Waals (vdW) forces are essential for understanding the properties of liquid water and ice. This insight was derived from ab initio computer simulations, which provide an unbiased description of water at the atomic level and yield information on the underlying molecular forces. However, the high computational cost of such simulations prevents the systematic investigation of the influence of vdW forces on the thermodynamic anomalies of water. Here, we develop efficient ab initio-quality neural network potentials and use them to demonstrate that vdW interactions are crucial for the formation of water's density maximum and its negative volume of melting. Both phenomena can be explained by the flexibility of the HB network, which is the result of a delicate balance of weak vdW forces, causing, e.g., a pronounced expansion of the second solvation shell upon cooling that induces the density maximum.

Organisation(en)
Computergestützte Physik und Physik der Weichen Materie
Externe Organisation(en)
Ruhr-Universität Bochum (RUB)
Journal
Proceedings of the National Academy of Sciences of the United States of America (PNAS)
Band
113
Seiten
8368-8373
Anzahl der Seiten
6
ISSN
0027-8424
DOI
https://doi.org/10.1073/pnas.1602375113
Publikationsdatum
07-2016
Peer-reviewed
Ja
ÖFOS 2012
103036 Theoretische Physik, 103015 Kondensierte Materie, 103006 Chemische Physik, 103029 Statistische Physik
Schlagwörter
ASJC Scopus Sachgebiete
General
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/83b3d953-50a7-4469-bd7d-847ad6873f77