Monte Carlo Simulations and DFT Studies of the Structural Properties of Silicon Oxide Clusters Reacting with a Water Molecule

In this study, the H2O reaction with SiO clusters was investigated using ab initio Monte Carlo simulations and density functional theory calculations. Three chemistry models, PBE1/DGDZVP (Model 1), PBE1/DGDZVP (Si atom), and aug-cc-pVDZ (O and H atoms), (Model 2) and PBE1/aug-cc-pVDZ (Model 3), were used. The average bond lengths, as well as the relative and reaction energies, were calculated using Models 1, 2, and 3. The average bond lengths of Si-O and O-H are 1.67-1.75 Å and 0.96-0.97 Å, respectively, using Models 1, 2, and 3. The most stable structures were formed by the H transfer from an H2O molecule except for Si3O3-H2O-1 cluster. The Si3O3 cluster with H2O exhibited the lowest reaction energy. In addition, the Bader charge distributions of the SinOn and (SiO)n-H2O clusters with n = 1-7 were calculated using Model 1. We determined that the reaction sites between H2O and the SiO clusters possessed the highest fraction of electrons.