Atomic and molecular adsorption on Ni(111)

Periodic, self-consistent density functional theory (DFT-GGA) calculations are used to study the adsorption properties of atomic species (H, C, N, O, and S), molecular species (CO, HCN, NH3, N-2, and NO), and molecular fragments (CH, CH2, CH3, CN, NH, NH2, HCO, COH, HNO, NOH, and OH) on Ni(111), at a 1/4 monolayer coverage. For each of these species, we calculate the binding energies at all possible sites and determine the optimal binding configuration, calculate the vibrational frequencies and deformation energy at the preferred adsorption site, and estimate the diffusion barrier on Ni(111). Good agreement is found when comparing our calculated results with available literature values determined using various experimental or theoretical methods. Based on the calculated binding energies, thermochemistry potential energy surfaces for adsorption and decomposition of NO, CO, NH3, N-2, and CH4 are developed, showing that the decomposition of all these molecular species is energetically more favorable than their desorption from Ni(111).