The dipole moment of supercritical water - local vs. mean-field polarisation contributions
MacPherson, Zoe and Gomes, José R. B. and Jorge, Miguel and Lue, Leo (2024) The dipole moment of supercritical water - local vs. mean-field polarisation contributions. Molecular Physics. pp. 1-13. e2381574. ISSN 0026-8976 (https://doi.org/10.1080/00268976.2024.2381574)
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Abstract
Supercritical water has attracted much attention from both fundamental and technological perspectives, based largely on its ability to solvate other molecules. Predicting and controlling this requires a deeper understanding of water's polarisation behaviour. Using the computationally efficient Self-Consistent Electrostatic Embedding method, we were able to calculate the water dipole moment over an unprecedented range of thermodynamic conditions, covering gas, liquid and supercritical states, with large simulation systems and a high-level quantum mechanical method. We find a discontinuous change in the dipole moment along subcritical isotherms, corresponding to the sharp transition between the vapour and liquid states, with the latter exhibiting induced dipole moments between 0.5 and 0.9 D, depending on the temperature. In contrast, the dipole moment changes continuously from gas-like to liquid-like behaviour in the supercritical regime, allowing the degree of polarisation to be controlled through manipulating temperature and pressure. The dipole moment was found to be linearly related to the average number of hydrogen-bonded neighbours of water, emphasising the key role of local interactions to the polarisation process. Mean-field approaches based on a dielectric continuum representation of the solvent are unable to predict this behaviour due to the neglect of local interactions.
ORCID iDs
MacPherson, Zoe, Gomes, José R. B., Jorge, Miguel ORCID: https://orcid.org/0000-0003-3009-4725 and Lue, Leo ORCID: https://orcid.org/0000-0002-4826-5337;-
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Item type: Article ID code: 89991 Dates: DateEvent25 July 2024Published25 July 2024Published Online7 July 2024Accepted1 May 2024SubmittedSubjects: Technology > Chemical engineering Department: Faculty of Engineering > Chemical and Process Engineering
Strategic Research Themes > Measurement Science and Enabling Technologies
Strategic Research Themes > Energy
Strategic Research Themes > Advanced Manufacturing and Materials
Strategic Research Themes > Society and PolicyDepositing user: Pure Administrator Date deposited: 22 Jul 2024 15:12 Last modified: 25 Sep 2024 15:07 Related URLs: URI: https://strathprints.strath.ac.uk/id/eprint/89991