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Thermal dependence of the hydrated proton and optimal proton transfer
- Publication Year :
- 2023
- Publisher :
- arXiv, 2023.
-
Abstract
- Water is a key ingredient for life and plays a central role as solvent in many biochemical reactions. However, the intrinsically quantum nature of the hydrogen nucleus, revealing itself in a large variety of physical manifestations, including proton transfer, gives rise to unexpected phenomena whose description is still elusive. Here we study, by an unprecedented combination of state-of-the-art quantum Monte Carlo methods and path-integral molecular dynamics, the structure and hydrogen-bond dynamics of the protonated water hexamer, the fundamental unit for the hydrated proton. We report a remarkably low thermal expansion of the hydrogen bond from zero temperature up to 300 K, owing to the presence of short-Zundel configurations, characterised by proton delocalisation and favoured by the synergy of nuclear quantum effects and thermal activation. The hydrogen bond strength progressively weakens above 300 K, when localised Eigen-like configurations become relevant. Our analysis, supported by the instanton statistics of shuttling protons, reveals that the near-room-temperature range from 250 K to 300 K is a ``sweet spot'' for proton transfer, and thus for many phenomena depending on it, including life.<br />Comment: 25 pages, 5 figures, 23 pages of supplementary information, 14 additional figures in the supplementary information
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....69ef98cb888c345f76d3d821f3f92a28
- Full Text :
- https://doi.org/10.48550/arxiv.2301.01825