Hydrogen bond topology reveals layering of LDL-like and HDL-like water at its liquid/vapor interface

Author(s)

Pal Jedlovszky, Christoph Dellago, Marcello Sega

Abstract

The discovery of high-density liquid (HDL) and low-density liquid (LDL) water has been a major success of molecular simulations, yet extending this analysis to interfacial water is challenging due to conventional order parameters assuming local homogeneity. This limitation previously prevented resolving the composition of the surface layer of the liquid/vapor interface. Here, we apply a recently introduced topological order parameter [R. Foffi and F. Sciortino, J. Phys. Chem. B 127, 378-386 (2022)] to analyze the composition of the water/vapor interface across a broad temperature range. Our results reveal that LDL-like water dominates the outermost region at all temperatures, while HDL-like water accumulates beneath it, presenting a clear layering roughly below the temperature of maximum density. This structured stratification, previously inaccessible, highlights the power of the topological order parameter in resolving interfacial molecular heterogeneity and provides new insights into the structural properties of water at interfaces.

Organisation(s)

Computational and Soft Matter Physics, Research Platform Accelerating Photoreaction Discovery

External organisation(s)

Eszterházy Károly University of Applied Sciences, University College London

Journal

Journal of Chemical Physics

Volume

163

No. of pages

7

ISSN

0021-9606

DOI

https://doi.org/10.48550/arXiv.2505.12953

Publication date

07-2025

Peer reviewed

Yes

Austrian Fields of Science 2012

103015 Condensed matter, 103006 Chemical physics

ASJC Scopus subject areas

General Physics and Astronomy, Physical and Theoretical Chemistry

Portal url

https://ucrisportal.univie.ac.at/en/publications/ede57d4d-377c-4ed2-b7e1-9379250711df