Publication Date:
2009-10-10
Description:
Despite the industrial implications and worldwide abundance of gas hydrates, the formation mechanism of these compounds remains poorly understood. We report direct molecular dynamics simulations of the spontaneous nucleation and growth of methane hydrate. The multiple-microsecond trajectories offer detailed insight into the process of hydrate nucleation. Cooperative organization is observed to lead to methane adsorption onto planar faces of water and the fluctuating formation and dissociation of early hydrate cages. The early cages are mostly face-sharing partial small cages, favoring structure II; however, larger cages subsequently appear as a result of steric constraints and thermodynamic preference for the structure I phase. The resulting structure after nucleation and growth is a combination of the two dominant types of hydrate crystals (structure I and structure II), which are linked by uncommon 5(12)6(3) cages that facilitate structure coexistence without an energetically unfavorable interface.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Walsh, Matthew R -- Koh, Carolyn A -- Sloan, E Dendy -- Sum, Amadeu K -- Wu, David T -- New York, N.Y. -- Science. 2009 Nov 20;326(5956):1095-8. doi: 10.1126/science.1174010. Epub 2009 Oct 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Hydrate Research, Department of Chemical Engineering, Colorado School of Mines, Golden, CO 80401, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19815725" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink