Orbital symmetry, reactivity, and transition metal surface chemistry

The local density of states (DOS), argued here to measure local chemical reactivity, becomes a powerful interpretive tool for surface chemistry when decomposed into components of different orbital symmetry. We compute the symmetry- and layer-resolved DOS for Pd(001) and Rh(001) and use the results to generalize the Harris-Andersson theory of chemisorption, to interpret Feibelman's findings on the interaction of H2 with the Rh(001) surface, and to interpret the preference of atomic H for the fourfold hollow sites of fcc (001) transition metal surfaces.