Abstract
Low frequency Raman profiles of type II clathrate hydrate (CH) of various guest molecules have been studied and their common feature, the sharp peak at 60 cm−1, was identified as the most dominant low frequency Raman characteristics of those system. The broad peak at 20 cm−1 was found to have strong dependence on the guest molecules. The spectral features around 210 cm−1 of the CH were similar to that of ice Ih shifted slightly toward lower frequency side. Using these low frequency Raman profile of type II CH, the phase diagram of tetrahydrofuran–water system was constructed and compared to the phase diagram constructed with other method to test the usability of those Raman profiles.
