Many of the unique properties of water are a result of the hydrogen bonding network between molecules, and the quantum nature of hydrogen nuclei influences how water molecules interact and move. The difference in nuclear quantum effects on hydrogen (H) and its heavier stable isotope, deuterium (D), is substantial. Therefore, by comparing the properties of liquid water (H2O) to those of heavy water (D2O), experiments and computer simulations have attempted to assess nuclear quantum effects on the structure and dynamics of water. Nevertheless, the impact of isotopic substitution on the structure of water remains controversial. We use Coupled Cluster Molecular Dynamics (CCMD), made possible using machine learning, to perform extensive path integral molecular dynamics simulations of H2O and D2O with CCSD(T) quality. We find isotope effects on dynamics in close agreement with experimental benchmarks, and we quantify nuclear quantum effects on the structure of water. We present the atomistic picture that explains the similarities and differences between liquid H2O and D2O, settling long-standing questions about nuclear quantum effects in water.

Biosketch

Dr. Nore Stolte is a postdoctoral research associate in the group of Prof. Dominik Marx at the Ruhr-University Bochum in Germany. Her research covers broad aspects of water and aqueous solutions, and the use of machine learning as a tool in atomistic simulations. Prior to joining the Marx group in 2021, she obtained her Ph.D. In physics from HKUST under the supervision of Prof. Ding Pan, studying aqueous carbon at the extreme pressure-temperature conditions of the deep Earth.
 

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