The structure of formate on Cu(100)

Abstract There is some controversy over the question of the correct adsorption site for formate on Cu(100). On the basis of SEXAFS and NEXAFS studies Stohr et al. favour a bridge site with oxygen atoms near fourfold hollows, while Woodruff et al. bring photoelectron diffraction studies to bear argue for a bridge site with the oxygen atoms almost on top of Cu atoms. We calculate the total energies for the two arrangements, optimising the distance of the formate from the Cu surface, using a self-consistent Hartree-Fock scheme with a Gaussian basis. We find the Woodruff structure more stable by some 0.38 eV per formate radical. We calculate the binding energy to be 1.74 eV per formate radical.