Neutral and cationic free-space oxygen-silicon clusters SiOn (1 < n <= 6), and possible relevance to crystals of SiO2 under pressure

TL;DR

This study uses quantum-chemical calculations to explore neutral and cationic SiOn and GeOn clusters, revealing structural details and distortions that may relate to SiO2 crystal behavior under pressure.

Contribution

It provides new computational insights into the structures of small SiOn and GeOn clusters, including cationic forms and their distortions, extending understanding of silica chemistry under pressure.

Findings

Structural distortions in cationic clusters.

Bond length data for SiOn and GeOn.

Potential relevance to SiO2 crystal phases.

Abstract

Motivated by the theoretical study of Saito and Ono (2011) on three crystalline forms of SiO2 under pressure, quantum-chemical calculations on various free-space clusters of SiOn and GeOn for 1 < n <= 6 are reported here. Both neutral and cationic clusters have been examined, for both geometry and equilibrium bond lengths. Coupled clusters and correlation-corrected MP2 calculations are presented. For the cations, we emphasize especially the structural distortions occurring in removing degeneracies.