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