HIGH-RESOLUTION ELECTRON-ENERGY LOSS SPECTROSCOPIC CHARACTERIZATION OF ORDERED ATOMIC OVERLAYERS ON FE(100)

Several ordered atomic overlayers, c(2 × 2)-C, c(2 × 2)-N, p(1 × 1)-O, c(2 × 2)-C,O, and c(2 × 2)-S on the Fe(100) surface, have been prepared and studied by High Resolution Electron Energy Loss Spectroscopy (HREELS). The following vibrational peaks were observed: a peak at 520 cm-1 for c(2 × 2)-C, a peak at 490 cm-1 for c(2 × 2)-N, two peaks at 280 cm-1 and 430 cm-1 for p(1 × 1)-O, two peaks at 395 cm-1 and 515 cm-1 for c(2 × 2)-C,O and a peak at 270 cm-1 for c(2 × 2)-S. The metal-atom stretching frequencies are ordered as ṽFe-C > ṽFe-N > ṽFe-O on the Fe(100) surface. Differences between these observations and previous measurements on the Fe(111) surface are discussed. © 1990 Elsevier Science Publishers B.V. (North-Holland).