Microcanonical molecular simulations of methane hydrate nucleation and growth: evidence that direct nucleation to sI hydrate is among the multiple nucleation pathways

摘要: The results of six high-precision constant energy molecular dynamics (MD) simulations initiated from methane–water systems equilibrated at 80 MPa and 250 K indicate that methane hydrates can nucleate via multiple pathways. Five trajectories to an amorphous solid. One trajectory nucleates a structure-I hydrate template with long-range order which spans the simulation box across periodic boundaries despite presence several defects. While experimental data for nucleation different time- length-scales suggest there may exist pathways nucleation, including metastable intermediates direct formation globally-stable phase, this work provides most compelling evidence globally stable crystalline phase is one available nucleation.