InitialH2O-induced oxidation of C(001)-(2×1): A study with hybrid density-functional theory

Abstract

Using ab initio molecular-orbital calculations, I have studied the initial ${\mathrm{H}}_2\mathrm{O}$-induced oxidation of a C(001)-(2$\times$1) surface. I have found that the dissociative adsorption of an ${\mathrm{H}}_2\mathrm{O}$ molecule on a C—C dimer is extremely exothermic, being similar to that on a Si—Si dimer. However, on a C—C dimer ${\mathrm{H}}_2\mathrm{O}$ does not form a molecular precursor, and there is an energy barrier from the reactant; in both respects, this is contrary to what occurs on the Si—Si dimer. The transition state geometries, the activation energies, and the intrinsic reaction coordinates were examined for two reactions: dissociative adsorption of a ${\mathrm{H}}_2\mathrm{O}$ molecule on the C—C dimer and the decomposition process of the adsorbed hydroxyl $(-$OH) fragment into a carbonyl (>C=O) group.