Molecular Dynamics Simulation on Thermodynamic Stability of Structure-H Hydrate

摘要

Molecular dynamics simulation of structure-H hydrate has been carried out with 6120 TIP4P water molecules, 900 OPLS-UA methane and 180 large molecular guest substances (LGMS), which is one of the guest molecules under the constant pressure and temperature. LMGS molecules were represented as one-site Lennard-Jones (LJ) model determined by two parameters, σ and ε. We have calculated the free energy difference in LMGS molecules of various molecular sizes and intermolecular interactions between LMGS and water molecules. It has been found that for σ ～ 6.2 A, and larger ε, ΔG is the minimum value and the structure-H hydrate crystal is the most stable in this simulation. All simulations were performed on a special-purpose computer, MDGRAPE-2.