Motion of inclusion gas molecules in clathrate hydrate observed by neutron powder diffraction

Igawa, Naoki   ; Taguchi, Tomitsugu; Fukazawa, Hiroshi; Yamauchi, Hiroki   ; Ishii, Yoshinobu*; Utsumi, Wataru

The structural stabilities of clathrate hydrates are deeply related with the physical properties of inclusion gases. In this study, we carried out neutron powder diffraction measurements of CO and Xe deuterohydrates and the diffraction data were analyzed by the combination of the Rietveld and the maximum entropy method (MEM) to clarify the motion of inclusion gases. The motions of CO and Xe molecules in the small cages show the different manner from those in the large cages. These motions have small temperature dependences, in contrast to the CH hydrate case where the motion of CH molecules in the large cage shows large temperature dependence.