Dramatic differences between the energy landscapes of SiO2 and SiS2 zeotype materials

摘要: Periodic density functional calculations have been carried out on a series of tetrahedral frameworks, which includeknown and hypothetical zeolite topologies. For each framework both SiO2 SiS2 compositions were considered. We demonstrate that the energy landscape sulfides is dramatically different from silica frameworks are too distorted for silica, example, supertetrahedral such as RWY significantly stabilized sulfides. discuss this change in terms increased tolerance distortion more general increase material's flexibility. The latter shown clearly comparison between pseudofrequencies (the frequencies calculated with all atomic masses set to one comparison) two compositions, being noticeably lower case SiS2.