Vibrational Frequencies of Halogen Atoms Adsorbed on Silver Metal Surfaces

摘要

The vibrational frequencies of halogens adsorbed on Ag(100) are calculated. The frequency of a single adsorbed atom vibration perpendicular to the surface is obtained from AgX (X = F, Cl, Br, I) crystal frequencies. Interaction between dipoles consisting of the effective charge on the adsorbed atom and its induced image charge produces a coverage dependent frequency. The effective charge on the adsorbed atom is assumed to be 1.0 e, while the electronic polarizability of the real-plus-image atom system is assumed to be twice the electronic polarizability of X-. At full coverage, the calculated frequencies for the k = O modes are 437, 241, 150, and 113/cm respectively for X = F, C, Br, I, which compare well with experimental values, and these frequencies are assigned to external vibrational modes of halogen atoms adsorbed on silver. (Author)