A family of Zn k O k (k = 12, 16) cluster-assembled solid phases with novel structures and properties has been characterized utilizing a bottom-up approach with density functional calculations. Geometries, stabilities, equation of states, phase transitions, and electronic properties of these ZnO polymorphs have been systematically investigated. First-principles molecular dynamics (FPMD) study of the two selected building blocks, Zn 12 O 12 and Zn 16 O 16 , with hollow cage structure and large HOMO−LUMO gap shows that both of them are thermodynamically stable enough to survive up to at least 500 K. Via the coalescence of building blocks, we find that the Zn 12 O 12 cages are able to form eight stable phases by four types of Zn 12 O 12 −Zn 12 O 12 interactions, and the Zn 16 O 16 cages can bind into three phases by the Zn 16 O 16 −Zn 16 O 16 links of H′, C′, and S′. Among these phases, six ones are reported for the first time. This has greatly extended the family of ZnO nanoporous phases. Notably, some of these phases are even more stable than the synthesized metastable rocksalt ZnO polymorph. The hollow cage structure of the corresponding building block Zn k O k is well preserved in all of them, which leads to their low-density nanoporous and high flexibility features. In addition the electronic integrity (wide-energy gap) of the individual Zn k O k is also retained. Our calculation reveals that they are all semiconductor with a large direct or indirect band gap. The insights obtained in this work are likely to be general in II−VI semiconductor compounds and will be helpful for extending the range of properties and applications of ZnO materials.
An all-electron scalar relativistic calculations on Au n CO (n = 1-10) clusters have been performed by using density functional theory with the generalized gradient approximation at the PW91 level. Our results reveal that all Au n CO clusters prefer to keep the planar structures like pure Au n cluster and the Au n structures in all Au n CO clusters are only changed slightly. The carbon monoxide molecule prefers to occupy the on-top and single fold coordination site and small gold cluster would like to bond with carbon. The adsorptions in AuCO, Au 6 CO, Au 9 CO and Au 10 CO clusters are relatively weaker than the adsorptions in other Au n CO clusters. After adsorption of carbon monoxide, the Au-Au interaction is strengthened and the C-O interaction is weakened. The VIPs, HLGs, HOMO and LUMO energy levels for Au n CO clusters have obvious odd-even oscillation. The even-numbered Au n CO cluster is relatively more stable than the adjacent oddnumbered Au n CO cluster electronically and chemically. The odd-even alteration of magnetic moments is observed in Au n CO (n = 1-10) clusters and may be served as the material with tunable code capacity of ''0'' and ''1'' by adsorbing carbon monoxide molecule onto odd or evennumbered gold cluster.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.