Neutron diffraction experiment on -AlOOH and investigation of symmetrization of hydrogen bond

Sano, Asami; Hattori, Takanori

no journal, , 

To investigate the relation between the symmetrization of hydrogen bond and change of physical properties in the hydrous mineral of the -AlOOH, we conducted neutron diffraction experiments at the high-pressure neutron diffractometer PLANET in the J-PARC. We observed the disappearance of 021 reflection at high pressure in -AlOOH which indicates the transition from the structure with asymmetric hydrogen bond () to that with disordered or symmetric hydrogen bond (), in agreement with previous single crystal X-ray diffraction study. On the other hand the transition pressure is higher in -AlOOD, which was determined to be 12 GPa. The detail about the hydrogen distribution around the transition pressure and its relevance to the change of compressibility and anomalies in sound velocities will be discussed.