Quantum Differences between Heavy and 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 ${\mathrm{H}}_2\mathrm{O}$ is $\sim 3\%$ longer than the OD bond length in ${\mathrm{D}}_2\mathrm{O}$. This is a much larger change than current predictions. Corresponding to this, the hydrogen bond in light water is $\sim 4\%$ shorter than in heavy water, while the intermolecular HH distance is $\sim 2\%$ longer.