Study of adsorbed gas films by electron diffraction

Electron Diffraction in Surface Chemistry

“…In these early experiments, adsorbed gas, believed to be CO, caused to appear in the diffraction pattern new weak diffraction beams that Davisson and Germer attributed to a regular two-dimensional gas lattice on the surface with spacings different from the nickel substrate. These observations were strongly supported 33 years later, in 1960, by the experiments of Germer, Scheibner, and Hartman (67), who used the new display-type apparatus. The earliest paper of 1927 contained observations, overlooked by many for decades, of first importance for surface science.…”

“…Schematic drawing of diffraction apparatus. An exterior photograph of apparatus is on page 67 The wavelength X is fixed at an electron voltage V by the deBroglie relationship. Angstroms (2) Here h = Planck's constant and p is the nonrelativistic electron momentum.…”

Local structure determination for low-coverage CO on Ni(111)

“…On the other hand, despite the large number of previous investigations of the Ni(111)/CO surface interaction, there are no really exhaustive studies of the range of coverage and temperature corresponding to the different ordered phases. Most of the earlier studies [28][29][30] (and indeed many of the later ones [32,6,7,33]), which do report the ordered LEED patterns seen, were conducted only close to room temperature. In some cases, higher coverages were achieved at room temperature by investigating the LEED pattern while the surface was held in a partial pressure of CO, and there was evidence for electron beam damage effects [29,30].…”

Surface-potential study of the chemisorption of hydrogen and carbon monoxide on evaporated copper and gold films

“…Evidence already quoted for the importance of double-spaced arrays of oxygen and carbon monoxide on copper is reinforced by the work of Germer et a2. 18 on the adsorption of carbon monoxide on the (1 11) face of a nickel single crystal using slow electron diffraction. Double-spaced lattices have been observed for oxygen on the (1 10) face 19 and (100) face 20~21 of nickel.…”