Low-Energy Networks of the T-Cage (H₂O)₂₄ Cluster and Their Use in Constructing Periodic Unit Cells of the Structure I (sI) Hydrate Lattice

Hydrate networks are "host" lattices for the storage of "guest" natural gases. To enhance their physical stabilities near ambient conditions, the most stable clathrate hydrates should be identified. Here we report the lowest-energy networks of the tetrakaidecahedral cage (T-cage) (H(2)O)(24) cluster, a constituent of the unit cell of the structure I [denoted (sI)] hydrate. A four-step screening method was employed to search for the lowest-energy T-cage networks, which were eventually optimized at the MP2 level of theory. We further outline a procedure based on the obtained low-energy isomers of the T-cage for constructing periodic unit cells of the (sI) hydrate lattice.