Octahedral monomeric and oligomeric iron oxide clusters represent the basic units in many iron oxide and oxide-hydroxide minerals such as hematite. Doped hematite can be modeled by constructing hybrid clusters. An evaluation of various computational methods has been performed on the experimentally well-known clusters. It is found that all methods provide similar and reliable structures. The ligand-to-metal charge transfer energy is however highly sensitive to the method employed. We also provide interpretations of experimental data in terms of which clusters are present in aqueous conditions. The dimerization process can be regarded as the initial stage to form huge aggregates. The electrostatic repulsion between two charged monomers hinders their close contact and dimerization. A comparison between the calculated structures and experimental results suggests that several dimer species coexist in solution. Multi-reference methods give a detailed analysis of optical properties of these clusters.

Computational modeling of metal oxide clusters resembling pure and doped hematite

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.