PubAg

Main content area

Structural Changes to Supported Water Nanoislands Induced by Kosmotropic Ions

Author:
Weber, Irene, Gerrard, Nikki, Hodgson, Andrew, Morgenstern, Karina
Source:
Journal of physical chemistry 2019 v.123 no.11 pp. 6861-6868
ISSN:
1932-7455
Subject:
desorption, gold, ice, ions, lithium, nanogold, scanning tunneling microscopy, temperature
Abstract:
We report the influence of lithium ions on binding and structure of water nanoislands on Au(111) by temperature-programmed desorption and variable-temperature scanning tunneling microscopy. Water coverages between a fraction and full bilayer and two lithium coverages (<0.15% ML) are explored. Lithium enhances selectively the binding of some of the water molecules on precovered Au(111) as compared to water on pristine Au(111), which is revealed by an increase of the water desorption temperature by approx. 10 K. Surprisingly, the effect of lithium on the structure of water is much more extended than expected from these desorption experiments. A small amount of lithium changes the structure of water nanoislands drastically compared to those on pristine Au(111). On pristine Au(111), water ice grows in the form of crystalline islands that are two or three bilayers high. On Li precovered Au(111), the islands are more corrugated, at a 5 times broader apparent height distribution and much smaller, at a 4 times smaller area distribution. These changes reflect the influence of lithium as a structure maker, or kosmotrope, on water. Our study provides unprecedented real-space information of the influence of a kosmotrope on the water structure at the nanoscale. We utilize its kosmotropic behavior to provide real-space images of desorption.
Agid:
6337133