Assessment methods for embedding schemes – Ceria as an example

The purpose of this paper is to present tests that are suitable to perform as an assessment of the quality of embedded-cluster models for ionic surfaces. Bulk and surface clusters of CeO2 were constructed and the embedding quality was evaluated as a function of cluster size and stoichiometry. Out of the properties evaluated, it is found that the difference electron density (between the embedded cluster model and an equivalent periodic slab model), as well as the electrostatic potential above the surface are very sensitive to the embedding quality and can successfully be used as selection tools in the quality assessment. This was confirmed by subsequent CO2 physisorption calculations for a number of embedded CeO2(1 1 1) clusters.