ADSORPTION OF CESIUM ATOMS AT STRUCTURAL DEFECTS ON SAPPHIRE SURFACES

Results are presented from an experimental study of the adsorption of cesium atoms on sapphire surfaces and their photostimulated desorption . The adsorbed atoms are found to form chains on the surface which are localized near one-dimensional structural defects of the surface. One -dimensional adsorption is analyzed theoretically with different assum ptions regarding the mobility of adsorbed atoms along a chain. A compa rison of the theories with experimental data favors localized adsorpti on described in terms of a one-dimensional lattice gas model. The ener gy of adsorption for an isolated atom on a linear surface structural d efect is 0.58 eV, while the energy of attraction between neighboring a toms in the chain is 26 meV. (C) 1997 American Institute of Physics.