First-principles investigation on the structural stability of methane and ethane clathrate hydrates

Clathrate hydrates are characterized by their hydrogen-bond linked cavities that can encapsulate guest molecules. First-principles calculations were performed in this study to compare the prototypical structures of methane and ethane hydrates. The relative stability of singly and doubly occupied structures was studied in terms of their structural variations and binding energies. The preferred structures under various gaseous components (methane, ethane, and their mixture) were identified and compared with experimental evidences. The influence of tetrahydrofuran (THF) on the formation of methane and ethane hydrates was rationalized from computations on the methane–ethane–THF-hydrate systems.