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Updated: Jul 6, 2026

Methane Hydrate Crystallization on Sessile Water Droplets
Published on: May 26, 2021
Application of the independent molecule model to elucidate the dynamics of structure I methane hydrate: a second
1Yatsushiro National College of Technology, Yatsushiro 866-8501, Japan. yoshioki@as.yatsushiro-nct.ac.jp
Abstract:
Two model systems of methane hydrate are constructed. One has a small cage surrounded by 12 large cages. The other has a large cage surrounded by four small cages and ten large cages. Three different H-bonding network patterns between waters are formed, and three random configurations of methane in each cage are chosen. A new method called the surface water fixed model is presented in which the energy minimum conformations for both model systems are preserved close to the X-ray crystallized structure. With normal mode analysis, we calculated frequencies of 2916.6 cm(-1) for a small cage at a centre, 2915.9 cm(-1) not at a centre, and 2911.7 cm(-1) for a large cage at a centre, and 2911.3 cm(-1) not at a centre. These frequencies are in moderate agreement with the corresponding Raman spectra, though not adequate. With our new method, however, it should be possible to improve agreement with the Raman spectra, if a model system vastly larger than the present model systems were constructed.
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The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.

