Effect of oxygen content and charge on the structure, stability and optoelectronic properties of yttrium oxide clusters

• The electronic and geometrical structures of neutral and charged YOn (n=2–12) clusters have been investigated using DFT.
• The oxygen atom in YOn has been found to be in oxo, peroxo and in superoxo forms.
• Yttrium showed higher coordination number than scandium.
• YO10+ and YO12+ were found to be highly exothermic to release one and two oxygen molecules.
• Computed absorption spectra of small clusters are mainly contributed by yttrium metal d and s valence orbitals.

The electronic and geometrical structures of neutral and charged YOn (n=2–12) clusters have been investigated using density functional theory (DFT) with generalized gradient approximation. The oxygen atom in YOn has been found to be in oxo, peroxo and in superoxo forms. The geometrical structures and topologies of small size anionic clusters resemble that of neutral clusters. Yttrium showed higher coordination number than scandium. Computed results reveal the existence of YO10 cluster to have a penta-peroxo oxygen with a homoleptic Y(η2 –O2)5 geometrical configuration. The HOMO–LUMO gaps decrease with increasing n due to the increase in 2p orbital population of oxygen atoms. It has been shown that in these clusters bonding are predominantly ionic in nature and anions are thermodynamically more stable, due to the charge delocalization between the metal atom and oxygen ligands. YO10+ and YO12+ were found to be highly exothermic to release one and two oxygen molecules, while YO11+ dissociates though the ozonide dissociation channel. Computed absorption spectra of small clusters are mainly contributed by yttrium metal d and s valence orbitals. The absorbance spectra, shifts towards lower energy with cluster size increase, while charge has no substantial effect on the absorption spectrum.