Guest molecule dynamics and guest-specific degassing phenomenon of binary gas hydrate investigated by terahertz time-domain spectroscopy

Abstract

The behaviour of clathrate hydrates in the THz region could provide useful information about inclusion compounds. In this study, terahertz time-domain spectroscopy (THz-TDS) revealed the dynamics of gaseous guest molecules inside the water framework of a clathrate hydrate. Distinct footprints of each gaseous molecule (CH4, H-2 and O-2) inside the gas hydrate lattice were analysed. Thermally stimulated gas hydrates give out gas molecules (secondary guests) to remain secure, and each gas has a specific degassing temperature. In this way, they form the stable sII THF hydrate with empty small cages (5(12)) which can survive at temperatures up to 278 K.