CORE-LEVEL SPECTRA OF CHROMIUM AND NICKEL ATOMS ON POLYSTYRENE

Nickel and chromium atoms which were vapor deposited on clean surfaces of polystyrene were characterized with x-ray photoemission spectroscopy. For nickel coverages less than 0.01 monolayer the nickel atoms form isolated clusters. As the nickel coverage increases, these islands gradually coalesce into larger islands. The chromium undergoes the same coverage-dependent behavior beginning at about 0.02 monolayer. A comparison of the nickel and chromium data with the corresponding data for copper indicates that the mobility of copper on the polystyrene is less than that of either nickel or chromium. Finally, we did not find a nickel or chromium surface site with an unusually low core-electron binding energy similar to the copper site previously observed.