Interaction of halide ions with copper: the DFT approach

The applicability of density functional theory to the adsorbate-adsorbent interaction has been tested with the final goal of defining an appropriate combination of the DFT method with basis sets for metal cluster-halide ions studies. The Cu-X− (X = F, Cl, Br, I) systems have been taken as tests cases to probe the different DFT methods (SVWN, BP86 and B3LYP) together with different combinations of basis sets for systems of this type. For comparison, the standard HF and its MP2 and MP4 corrections have also been calculated. Additionally, the results of a test for the Cu5I− cluster are presented. The good quality of the DFT methods is recorded as they give results comparable to the MP2 and, for some cases, even to the MP4 level of standard calculations. The B3LYP method combined with a fairly inexpensive description of the metal atoms is proposed as an appropriate option for studies of the adsorption of halide ions at noble metal surfaces.