Quantum Differences between Heavy and Light Water

TLDR

The study investigates the structures of heavy and light water at ambient conditions. The authors employed x‑ray diffraction, neutron diffraction, and computer simulation to probe these structures. The results show that heavy water is more structured than light water, with the OH bond in H₂O about 3 % longer than the OD bond in D₂O—a larger difference than predicted—resulting in a 4 % shorter hydrogen bond and a 2 % longer intermolecular HH distance in light water.

Abstract

The structures of heavy and light water at ambient conditions are investigated with the combined techniques of x-ray diffraction, neutron diffraction, and computer simulation. It is found that heavy water is a more structured liquid than light water. We find the OH bond length in H2O is approximately 3% longer than the OD bond length in D2O. This is a much larger change than current predictions. Corresponding to this, the hydrogen bond in light water is approximately 4% shorter than in heavy water, while the intermolecular HH distance is approximately 2% longer.