Understanding Isotope Substitution Effects in Water Using the Potential Energy Landscape Formalism for Quantum Liquids
Abstract
Isotope substitution effects are known to alter the thermodynamic, dynamic, and structural properties of water, particularly, at low temperatures. In this work, we perform path-integral (PI) computer simulations of H2O, HDO, D2O, and T2O, and provide a rigorous description of the H ↔ D ↔ T isotope substitution effects in water based on the potential energy landscape (PEL) formalism for quantum liquids. Our PI computer simulations at 200 ≤ T ≤ 400 K and v = 18.0 cm3/mol (corresponding to a density for H2O of ρ = 1.00 g/cm3) indicate that the same potential energy minima (inherent structures, IS) are present in the PEL of quantum water and its isotopes (sampled in PI computer simulations). These IS are also isomorphic to (and can be obtained from) the IS of classical water (sampled in classical computer simulations). Isotope substitutions in water (H ↔ D ↔ T) have the only effect of altering the curvature (and shape) of water’s PEL basins about the corresponding IS. Specifically, the PEL basins become wider along the sequence H2O → HDO → D2O → T2O, as the atoms delocalization become less pronounced. From a thermodynamic point of view, we find that water and its isotopes at a given temperature, sample different IS of the corresponding PEL, with different curvatures, explaining the subtle variations in the properties of H2O, HDO, D2O, and T2O. It is also shown that the Adam–Gibbs relation remains valid for water and its isotopes implying that, in all these cases, the topography…
Read the paper
Related studies
- Chaos and quantum thermalization
- The Dalton quantum chemistry program system
- Cord Blood Leptin and Adiponectin as Predictors of Adiposity in Children at 3 Years of Age: A Prospective Cohort Study
- Quantitative metabolomics by H-NMR and LC-MS/MS confirms altered metabolic pathways in diabetes
- Stable adiabatic quantum batteries
- A novel self-lipid antigen targets human T cells against CD1c(+) leukemias
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.