• Lee, H.
• Yeon, S.-H.
• N., Choi Y.

Abstract

The guest dynamics and thermal behavior occurring in the cages of clathrate hydrates appear to be too complex to be clearly understood through various structural and spectroscopic approaches, even for the well-known structures of si, sil, and sH. Neutron diffraction studies have recently been carried out to clarify the special role of guests in expanding the host water lattices and have contributed to revealing the influence factors on thermal expansivity. Through this letter we attempt to address three noteworthy features occurring in guest inclusion: (1) the effect of guest dimension on host water lattice expansion; (2) the effect of thermal history on host water lattice expansion; and (3) the effect of coherent/incoherent scattering cross sections on guest thermal patterns. The diatomic guests of H2, D2, N2, and O2 have been selected for study, and their size and mass dependence on the degree of lattice expansion have been examined, and four sil clathrate hydrates with tetrahydrofuran (THF) have been synthesized in order to determine their neutron powder diffraction patterns. After thermal cycling, the THF + H2 clathrate hydrate is observed to exhibit an irreversible plastic deformationlike pattern, implying that the expanded lattices fail to recover the original state by contraction. The host-water cage dime

Topics

• impedance spectroscopy
• polymer
• inclusion
• neutron diffraction