Low energy electron diffraction profiles from aluminum (100): Reproducibility and an evaluation of intensity averaged at constant momentum transfer

• Published in: Surface science 1973-02, Vol.34 (3), p.501-521
• Main Authors: Quinto, Dennis T., Robertson, W.D.
• Format: Article
• Language: English
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(73)90022-8

LEED intensity profiles have been obtained from the clean (100) surface of aluminum at small angular and energy intervals for azimuthal angles (0° to 45°) and incident angles (5° to 21°). These data have been compared with the data of Jona, and of Burkstrand and Propst, for reproducibility of independent experiments. The effect of oxygen on intensity, line width and the position of prominent peaks has been evaluated. Averages of intensity over azimuthal rotation, at two angles of incidence, and averages at one azimuth for increments of 2° in angle of incidence have been taken to evaluate the prescription of Lagally, Ngoc and Webb for extracting structural (geometric) information from multiple scattering profiles when applied to aluminum (100), instead of the original evaluations on (111) surfaces of nickel and silver. The principal conclusions are: (1) comparison of data from independent measurements of profiles from clean (oxygen-free) aluminum surfaces indicates that reproducibility of peak position and intensity is comparable with agreement obtained between independent computations of intensity profiles; (2) prominent multiple scattering maxima in profiles from Al (100) are not removed by averaging intensity in the range of incident angle available in most display-type LEED instruments, but a “kinematic-like” average is obtained from the (111) plane of aluminum; (3) comparison of the results of averaging intensity profiles from different metals and different crystal planes shows that additional exploration and a priori justification of the procedure are required to achieve a reliable (approximate) method of extracting surface structure from multiple scattering profiles, in the general case.