Thermodynamic Evidence for Water as a Quantum Mechanical Liquid

TL;DR

The paper provides thermodynamic evidence that water's hydrogen nuclei exhibit quantum mechanical behavior, based on differences in phase diagrams between light and heavy water, aligning with scattering data analyses.

Contribution

It demonstrates that hydrogen nuclei motions in water are quantum mechanical, supported by thermodynamic phase diagram differences and scattering data consistency.

Findings

Thermodynamic phase diagrams differ for light and heavy water.

Classical models predict identical phase diagrams, which contradicts experimental data.

Quantum mechanical behavior of hydrogen nuclei explains observed differences.

Abstract

We consider general theoretical models of water and in particular the nature of the motions of the hydrogen nuclei. If the motion of hydrogen nuclei is classical, then the thermodynamic pressure equation of state for heavy water wherein the hydrogen nuclei are deuterons is identical to the pressure equation of state for light water wherein the hydrogen nuclei are protons. Since the experimental thermodynamic phase diagram for light water is clearly measurably different from the experimental thermodynamic phase diagram for heavy water, one may deduce that the motions of hydrogen nuclei are quantum mechanical in nature. This conclusion is in physical agreement with a recent analysis of X-ray, neutron and deep inelastic neutron scattering data.