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Electronic structure calculations are widely used to complement experimental studies in surface science. However, in the case of ceria, the standard approximations (GGA/LDA) to density functional theory (DFT) are inadequate. The two major shortcomings of GGA/LDA in the case of ceria surface chemistry are the delocalization of f-electrons, erroneously predicting partially
reduced ceria to be metallic, and the inability to describe dispersive interactions in e.g. molecular physisorption. Since both partial reduction and molecule-surface interactions are imperative for the functionality of ceria in e.g. three-way catalysts, methods that do not rely on the GGA or LDA are needed.
We have adopted an embedded-cluster approach to investigate the surface chemistry of ceria, using explicitly correlated wave function based techniques from molecular quantum chemistry. We have applied this approach to studies of molecular adsorption (CO,N2O) and partial reduction at low index surfaces of ceria. |