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

We investigate Ge 3 n +1 O -/0 ( n = 1-3) clusters using anion photoelectron spectroscopy and theoretical calculations. The results show that the lowest energy structure of Ge 4 O - is a bent C s symmetric trigonal bipyramidal structure, while Ge 4 O has a C 3v symmetric trigonal bipyramidal structure. Ge 7 O - has two coexisting low-lying isomers, the first one can be viewed as a Ge 2 O 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 Ge 7 O 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 Ge 10 O - and Ge 10 O can be obtained by adding an O atom to different binding sites of a C 3v symmetric Ge 10 . Chemical bonding analyses of Ge 3 n +1 O ( n = 1-3) reveal that the O atom interacts with its neighboring three Ge atoms forming one 4c-2e σ bond and two 4c-2e π bonds in the top Ge 3 O trigonal pyramid, while the terminal Ge atom forms one 4c-2e σ bond in the bottom Ge 4 trigonal pyramid. The large HOMO-LUMO gaps of Ge 3 n +1 O ( n = 1-3) indicate that they have good stabilities. Ab initio molecular dynamics simulations suggest that both Ge 7 O and Ge 10 O 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 Ge 3 n +1 O.