Anion Photoelectron Spectroscopy and Theoretical Studies of Ge3n+1O (n=1-3) Clusters with the C-3v Symmetric Ge-3 Structural Unit

We investigate Ge3n+1O-/0 (n = 1-3) clusters using anion photoelectron spectroscopy and theoretical calculations. The results show that the lowest energy structure of Ge4O- is a bent Cs symmetric trigonal bipyramidal structure, while Ge4O has a C3v symmetric trigonal bipyramidal structure. Ge7O- has two coexisting low-lying isomers, the first one can be viewed as a Ge2O unit interacting with a Ge-5 trigonal bipyramid, the second one can be regarded as an O atom interacting with a Ge-7 pentagonal bipyramid; whereas Ge7O has a C-3v symmetric structure with a Ge atom and an O atom capping a Ge(6 )trigonal antiprism from the bottom and top, respectively. The structures of Ge10O- and Ge10O can be obtained by adding an O atom to different binding sites of a C-3v symmetric Ge-10. Chemical bonding analyses of Ge3n+1O (n = 1-3) reveal that the O atom interacts with its neighboring three Ge atoms forming one 4c-2e s bond and two 4c-2e p bonds in the top Ge3O trigonal pyramid, while the terminal Ge atom forms one 4c-2e s bond in the bottom Ge4 trigonal pyramid. The large HOMO-LUMO gaps of Ge3n+1O (n = 1-3) indicate that they have good stabilities. Ab initio molecular dynamics simulations suggest that both Ge7O and Ge10O are dynamically stable in general at 300 and 500 K. The current work suggests that the C(3v )symmetric Ge-3 units and the insertion growth pattern may be viable for constructing 1D germanium oxide nanostructures with the chemical formula of Ge3n+1O.

Automated summary

In this study, Ge3n+1O-/0 (n = 1-3) clusters were investigated using anion photoelectron spectroscopy and theoretical calculations. The lowest energy structures of Ge4O- and Ge4O were found to be a bent Cs symmetric trigonal bipyramidal structure and a C3v symmetric trigonal bipyramidal structure, respectively. Ge7O- showed two coexisting low-lying isomers, while Ge7O had a C-3v symmetric structure. The structures of Ge10O- and Ge10O were obtained by adding an O atom to different binding sites on a C-3v symmetric Ge-10. The chemical bonding analyses revealed the interactions between the O atom and nearby Ge atoms, forming various bonds in different geometries. The large HOMO-LUMO gaps of Ge3n+1O (n = 1-3) indicated their high stability. Molecular dynamics simulations showed that both Ge7O and Ge10O were dynamically stable at 300 and 500 K. This work suggests that the C(3v) symmetric Ge-3 units and the insertion growth pattern may be applicable for constructing 1D germanium oxide nanostructures with the chemical formula of Ge3n+1O.