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Water Diffusion Proceeds via a Hydrogen-Bond Jump Exchange Mechanism.

Axel GomezZeke A PiskulichWard H ThompsonDamien Laage
Published in: The journal of physical chemistry letters (2022)
The self-diffusion of water molecules plays a key part in a broad range of essential processes in biochemistry, medical imaging, material science, and engineering. However, its molecular mechanism and the role played by the water hydrogen-bond network rearrangements are not known. Here we combine molecular dynamics simulations and analytic modeling to determine the molecular mechanism of water diffusion. We establish a quantitative connection between the water diffusion coefficient and hydrogen-bond jump exchanges, and identify the features that determine the underlying energetic barrier. We thus provide a unified framework to understand the coupling between translational, rotational, and hydrogen-bond dynamics in liquid water. It explains why these different dynamics do not necessarily exhibit identical temperature dependences although they all result from the same hydrogen-bond exchange events. The consequences for the understanding of water diffusion in supercooled conditions and for water transport in complex aqueous systems, including ionic, biological, and confined solutions, are discussed.
Keyphrases
  • molecular dynamics simulations
  • high resolution
  • healthcare
  • public health
  • ionic liquid
  • magnetic resonance imaging
  • photodynamic therapy
  • room temperature