Issue 19, 2020

Quantum kinetic energy and isotope fractionation in aqueous ionic solutions

Abstract

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 HPO42− ions perturbs the competition between quantum effects in liquid water and impacts their local solvation structures.

Graphical abstract: Quantum kinetic energy and isotope fractionation in aqueous ionic solutions

Article information

Article type
Paper
Submitted
29 ноем. 2019
Accepted
08 јан. 2020
First published
08 јан. 2020

Phys. Chem. Chem. Phys., 2020,22, 10490-10499

Author version available

Quantum kinetic energy and isotope fractionation in aqueous ionic solutions

L. Wang, M. Ceriotti and T. E. Markland, Phys. Chem. Chem. Phys., 2020, 22, 10490 DOI: 10.1039/C9CP06483D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements