scholarly journals Molecular Dynamics Simulations of Clathrate Hydrates on Specialised Hardware Platforms

Energies ◽  
2012 ◽  
Vol 5 (9) ◽  
pp. 3526-3533 ◽  
Author(s):  
Nicola Varini ◽  
Niall J. English ◽  
Christian R. Trott
2016 ◽  
Vol 413 ◽  
pp. 229-234 ◽  
Author(s):  
Daniel T. Wilson ◽  
Brian C. Barnes ◽  
David T. Wu ◽  
Amadeu K. Sum

2015 ◽  
Vol 17 (19) ◽  
pp. 12639-12647 ◽  
Author(s):  
Masaki Hiratsuka ◽  
Ryo Ohmura ◽  
Amadeu K. Sum ◽  
Saman Alavi ◽  
Kenji Yasuoka

Molecular dynamics simulations showed the significant impacts of the guest–host hydrogen bonding on the cage stability and vibrational spectra of the clathrate hydrates.


2001 ◽  
Vol 114 (13) ◽  
pp. 5745-5754 ◽  
Author(s):  
E. P. van Klaveren ◽  
J. P. J. Michels ◽  
J. A. Schouten ◽  
D. D. Klug ◽  
J. S. Tse

2015 ◽  
Vol 93 (8) ◽  
pp. 864-873 ◽  
Author(s):  
Hana Dureckova ◽  
Tom K. Woo ◽  
Saman Alavi ◽  
John A. Ripmeester

Clathrate hydrate phases of dihalogen molecules have properties that differ from those of other guest molecules of similar size. The water oxygen–chlorine distances in the structure I (sI) Cl2 hydrate are smaller than the sum of the van der Waals radii of oxygen and chlorine. Bromine hydrate forms a unique clathrate hydrate structure that is not seen in other guest substances. In mixed Cl2/Br2 structure I hydrate, the water oxygen–bromine distances are also smaller than the sum of the oxygen and bromine van der Waals radii. We previously studied the structure of three dihalogen clathrate hydrates using single crystal X-ray diffraction and described these structural features in terms of halogen bonding between the dihalogen and water molecules. In this work, we perform molecular dynamics simulations of cubic sI Cl2, mixed Cl2/Br2, and BrCl clathrate hydrate phases. We perform quantum chemical computations on the dihalogen molecules to determine the nature of σ-hole near the halogen atoms. We fit the electrostatic potential of the molecules to point charge models including dummy atoms that represent σ-holes adjacent to the halogen molecules. Molecular dynamics simulations are used to determine the lattice constants, radial distribution functions, and guest dynamics in these phases. We determine the effect of guest size and difference in halogen bonding on the properties of the clathrate hydrate phase. Simulations for the Cl2, BrCl, and mixed Cl2/Br2 hydrates are performed with small cages of the sI clathrate hydrate phases completely full or filled with experimental occupancies with Cl2 guests.


2003 ◽  
Vol 81 (1-2) ◽  
pp. 493-501 ◽  
Author(s):  
H Itoh ◽  
B Chazallon ◽  
H Schober ◽  
K Kawamura ◽  
W F Kuhs

Low-frequency modes of gas hydrates with Xe, Ar, O2, and N2 atoms/molecules have been studied by inelastic neutron-scattering and molecular dynamics simulations. Type I and type II clathrate hydrates show some small but significant differences of the low-frequency host contribution to the density of states. Both differ markedly from that of ice Ih and depend only weakly on the guest. The vibrational modes associated with Xe atoms were observed at 2.2, 2.9, and 4.0 meV (T = 100 K). They are in good agreement with predictions from molecular dynamics simulations. In the case of N2 hydrate we found a well-defined peak at about 2 meV, which shows a remarkable shift to higher frequency with increasing temperature. This peak and a broad peak that is overlapped with the host lattice modes (6.5 and 10.5 meV) are assigned to the vibration of N2 molecules in the large and small cages, respectively. The calculated vibrational spectra of N2 molecules in doubly occupied large cages show a significant distinct spectral distribution. The anharmonic shift of the guest atoms in large cages is significantly less pronounced in Xe hydrates suggesting that guest-host interactions can vary considerably from one system to another. PACS Nos.: 82.75-z, 78.70N, 71.15Pd, 63


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