Terahertz time domain spectroscopy on methane hydrate

The methane hydrate still has a mystery about a process of its dissociation. To investigate it, the optical and dielectric properties of methane hydrate in terahertz region are investigated at wide temperature range using terahertz time domain spectroscopy. An abnormal rising of an absorption coefficient was observed at 260 K which is out of stable region for gas hydrate. This fact implies the existence of a liquid state of water molecules during a decomposition of methane hydrate.