Broken symmetry in deuterium

The solid hydrogen compounds (H₂, D₂, HD) are quantum molecular solids. They change structure when submitted to very high pressures. As an example, the “broken symmetry” phase – stable above 25 GPa at 4 K – was studied by a combination of X-ray and neutron single-crystal diffraction. A local ordering and an incommensurate structure were revealed, at odds with most theoretical predictions.

Very high pressures can be obtained inside a diamond anvil cell.

Further information:

• First Data on the Structure of Phase III of Hydrogen Above 150 GPa
  
• The Broken Symmetry Phase of Solid Deuterium
  
• Ref.: I. Goncharenko and P. Loubeyre, Nature 435, 1206 (2005).