A comparative study of chemisorption by density functional theory, ab initio, and semiempirical methods: carbon monoxide, formate, and acetate on Cu(1 1 0)

We calculate the preferred adsorption sites, molecular structure, infrared spectra, and energies relative to stable gas phase molecules for carbon monoxide, the formate ion, and the acetate ion when adsorbed on the (1 1 0) face of copper. This substrate is modeled using small clusters of (8–46) copper atoms. Our semiempirical calculations compare well with those from ab initio, density functional theory, and with experiments. We offer a method of estimating the adsorption energy.