Quantum differences between heavy and light water

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 H(2)O is similar to 3% longer than the OD bond length in D(2)O. This is a much larger change than current predictions. Corresponding to this, the hydrogen bond in light water is similar to 4% shorter than in heavy water, while the intermolecular HH distance is similar to 2% longer.