A1 Refereed original research article in a scientific journal
Cuts through the manifold of molecular H2O potential energy surfaces in liquid water at ambient conditions
Authors: Pietzsch Annette, Niskanen Johannes, Vaz da Cruz Vinicius, Büchner Robby, Eckert Sebastian, Fondell Mattis, Jay Raphael M., Lu Xingye, McNally Daniel, Schmitt Thorsten, Föhlisch Alexander
Publisher: National Academy of Sciences of USA
Publication year: 2022
Journal: Proceedings of the National Academy of Sciences of the United States of America
Journal acronym: PNAS
Article number: e2118101119
Volume: 119
Issue: 28
DOI: https://doi.org/10.1073/pnas.2118101119
Web address : https://www.pnas.org/doi/abs/10.1073/pnas.2118101119
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/175778504
The fluctuating hydrogen bridge bonded network of liquid water at ambient conditions entails a varied ensemble of the underlying constituting H2O molecular moieties.This is mirrored in a manifold of the H2O molecular potentials. Subnatural line width resonant inelastic X-ray scattering allowed us to quantify the manifold of molecular potential energy surfaces along the H2O symmetric normal mode and the local asymmetric O–H bond coordinate up to 1 and 1.5 A, respectively. The comparison of the single ˚ H2O molecular potentials and spectroscopic signatures with the ambient conditions liquid phase H2O molecular potentials is done on various levels. In the gas phase, first principles, Morse potentials, and stepwise harmonic potential reconstruction have been employed and benchmarked. In the liquid phase the determination of the potential energy manifold along the local asymmetric O–H bond coordinate from resonant inelastic X-ray scattering via the bound state oxygen 1s to 4a1 resonance is treated within these frameworks. The potential energy surface manifold along the symmetric stretch from resonant inelastic X-ray scattering via the oxygen 1s to 2b2 resonance is based on stepwise harmonic reconstruction. We find in liquid water at ambient conditions H2O molecular potentials ranging from the weak interaction limit to strongly distorted potentials which are put into perspective to established parameters, i.e., intermolecular O–H, H–H, and O–O correlation lengths from neutron scattering.
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