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At room temperature, the quantum contribution to the kinetic energy of a water molecule exceeds the classical contribution by an order of magnitude. The quantum kinetic energy (QKE) of a water molecule is modulated by its local chemical environment and leads to uneven partitioning of isotopes between different phases in thermal equilibrium, which would not occur if the nuclei behaved classically. In this work, we use ab initio path integral simulations to show that QKEs of the water molecules and the equilibrium isotope fractionation ratios of the oxygen and hydrogen isotopes are sensitive probes of the hydrogen bonding structures in aqueous ionic solutions. In particular, we demonstrate how the QKE of water molecules in path integral simulations can be decomposed into translational, rotational and vibrational degrees of freedom, and use them to determine the impact of solvation on different molecular motions. By analyzing the QKEs and isotope fractionation ratios, we show how the addition of the Na + , Cl − and HPO 4 2− ions perturbs the competition between quantum effects in liquid water and impacts their local solvation structures.
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NQELiq-298: Dataset of nuclear quantum effects and equilibrium isotope effects for 92 chemically diverse molecular liquids
This dataset compiles the results of our study of nuclear quantum effects (NQEs) and equilibrium isotope effects (EIEs) of 92 chemically diverse, organic molecular liquids. It contains the average macroscopic properties (density, molar volume, thermal expansion coefficient, isothermal compressibility, dielectric constant, heat of vaporization) and their associated standard errors computed with four independent classical and path-integral molecular dynamics (PIMD) simulations of each system and their deuterated counterparts. All simulations use the Topology Automated Force-Field Interactions (TAFFI) framework to describe the potential energy surface. In addition, the computed nuclear quantum effects and equilibrium isotope effects resulting from comparison of these simulations are included.
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- Award ID(s):
- 2320649
- PAR ID:
- 10636751
- Publisher / Repository:
- Zenodo
- Date Published:
- Subject(s) / Keyword(s):
- Nuclear Quantum Effects Equilibrium Isotope Effects path-integral molecular dynamics anharmonicity tunneling machine learning
- Format(s):
- Medium: X
- Right(s):
- Creative Commons Attribution 4.0 International
- Sponsoring Org:
- National Science Foundation
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