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Nuclear Quantum Effects in Liquid Water Are Marginal for Its Average Structure but Significant for Dynamics
Nore Stolte1, János Daru1,2, Harald Forbert3
1Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany.
The Journal of Physical Chemistry Letters
|November 28, 2024
Summary
Nuclear quantum effects significantly impact water
Area of Science:
- Physical Chemistry
- Computational Chemistry
- Materials Science
Background:
- Nuclear quantum effects (NQEs) influence material properties.
- The role of NQEs on liquid water structure is debated.
- Experimental comparisons of H2O and D2O probe NQEs.
Purpose of the Study:
- To definitively assess NQEs on liquid water structure and dynamics.
- To resolve controversy regarding NQEs in water experiments.
- To compare simulation results with experimental findings.
Main Methods:
- Utilized machine-learned high-dimensional neural network potentials.
- Performed converged path integral simulations at coupled cluster quality.
- Simulated both H2O and D2O at ambient conditions.
Main Results:
- Observed significant H/D quantum effects on water's rotational and translational dynamics.
- Found minimal impact of H/D quantum effects on average intramolecular and H-bonding structures (approx. 1/1000 Å).
- Demonstrated that NQEs increase fluctuations, making H2O more "liquid" than D2O.
Conclusions:
- NQEs substantially alter water dynamics but minimally affect its average structure.
- The "liquidness" of water is enhanced by NQEs, with H2O exhibiting greater liquidity than D2O.
- Simulation results align well with experimental observations on water dynamics.
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