Water adsorption on a model silicate surface: wollastonite (100)

Fuente: arXiv
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Hauptverfasser: Lezuo, Luca, Conti, Andrea, Hoheneder, Alexander, Vaníčková, Elena, Aloi, Domitilla Alessandra, Abart, Rainer, Mittendorfer, Florian, Schmid, Michael, Diebold, Ulrike, Franceschi, Giada
Format: Preprint
Veröffentlicht: 2026
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author Lezuo, Luca
Conti, Andrea
Hoheneder, Alexander
Vaníčková, Elena
Aloi, Domitilla Alessandra
Abart, Rainer
Mittendorfer, Florian
Schmid, Michael
Diebold, Ulrike
Franceschi, Giada
author_facet Lezuo, Luca
Conti, Andrea
Hoheneder, Alexander
Vaníčková, Elena
Aloi, Domitilla Alessandra
Abart, Rainer
Mittendorfer, Florian
Schmid, Michael
Diebold, Ulrike
Franceschi, Giada
contents Water adsorption on silicate surfaces is a critical yet poorly understood process relevant to, e.g., mineral weathering and cement hydration. This study investigates the structure of water overlayers on a model calcium silicate, the lowest-energy (100) surface of wollastonite (CaSiO3). It combines atomically resolved non-contact atomic force microscopy (nc-AFM), acquired with qPlus sensors and functionalized tips in ultrahigh vacuum (UHV), with density functional theory (DFT) calculations employing the metaGGA r2SCAN+rVV10 functional. Adding incremental doses of water to the sample at cryogenic temperatures produces distinct structures governed by the competition between water-surface and water-water interactions. With two water molecules per surface unit cell, water-surface interactions dominate: In line with previous theoretical predictions, adsorbates follow the surface lattice. As the coverage increases, intermolecular hydrogen bonding competes with bonding to the surface, leading to the emergence of complex, coexisting patterns. While their small energy differences prevent an unambiguous identification of the most stable structure by DFT, the experimentally observed symmetries help constrain plausible structural models. Above a critical density of four water molecules per unit cell, water-water interactions prevail, and water clusters are formed. The results provide an atomic-scale framework for understanding water interactions with calcium silicate surfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2605_07337
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Water adsorption on a model silicate surface: wollastonite (100)
Lezuo, Luca
Conti, Andrea
Hoheneder, Alexander
Vaníčková, Elena
Aloi, Domitilla Alessandra
Abart, Rainer
Mittendorfer, Florian
Schmid, Michael
Diebold, Ulrike
Franceschi, Giada
Materials Science
Chemical Physics
Water adsorption on silicate surfaces is a critical yet poorly understood process relevant to, e.g., mineral weathering and cement hydration. This study investigates the structure of water overlayers on a model calcium silicate, the lowest-energy (100) surface of wollastonite (CaSiO3). It combines atomically resolved non-contact atomic force microscopy (nc-AFM), acquired with qPlus sensors and functionalized tips in ultrahigh vacuum (UHV), with density functional theory (DFT) calculations employing the metaGGA r2SCAN+rVV10 functional. Adding incremental doses of water to the sample at cryogenic temperatures produces distinct structures governed by the competition between water-surface and water-water interactions. With two water molecules per surface unit cell, water-surface interactions dominate: In line with previous theoretical predictions, adsorbates follow the surface lattice. As the coverage increases, intermolecular hydrogen bonding competes with bonding to the surface, leading to the emergence of complex, coexisting patterns. While their small energy differences prevent an unambiguous identification of the most stable structure by DFT, the experimentally observed symmetries help constrain plausible structural models. Above a critical density of four water molecules per unit cell, water-water interactions prevail, and water clusters are formed. The results provide an atomic-scale framework for understanding water interactions with calcium silicate surfaces.
title Water adsorption on a model silicate surface: wollastonite (100)
topic Materials Science
Chemical Physics
url https://arxiv.org/abs/2605.07337