(81d) Computational Modeling of Reconstruction Templated Adsorption On the Magnetite(001) Surface

The magnetite(001) surface undergoes a stable reconstruction in which the symmetry of the surface layer is reduced by subsurface charge ordering. This reconstruction causes anti-phase undulations in the surface atoms rows to produce wide and narrow adsorption sites. Recent scanning tunneling microscopy (STM) experiments show H and other adsorbates form stable patterns on the reconstructed magnetite(001) surface, with a clear preference for adsorption at the narrow sites. In this talk, we describe quantum chemistry calculations to elucidate the underlying reasons for adsorbate pattern formation. Because magnetite is a highly correlated material, advanced methods like DFT+U and range-separated hybrid functionals (e.g., HSE06) are required. The magnetic and electronic structure is quantified by computing net atomic charges, atomic spin moments, and effective bond orders. These calculations show reconstruction templated adsorption is strongly coupled to the subsurface charge order. We compare computed geometries, energies, and simulated STM images to the experimental data to explain these complex adsorption processes. We discuss potential catalytic applications of this patterned adsorption.