A photoelectron diffraction method to evaluate in-plane atomic distances at surfaces: the two atoms approximation

We propose a procedure based on the photoelectron diffraction technique to evaluate in-plane atomic distances for adsorbate systems and overlayers. A comparison between the experimentally determined angular position of the fi rst order interference maxima in photoelectron diffraction azimuthal scans at the grazing angle and the same quantity calculated by a simplified singl e scattering cluster calculation provides approximate in-plane distances be tween atoms which can be used as a starting point for more complex calculat ions. In this paper we test this approach to evaluate the geometrical atomi c structure of two prototypical cases, the O-(2 x 1)/Cu(110) and the Si-c(2 x 2)/Cu(110) systems. The applicability and limitations of the method are thoroughly discussed in the text. (C) 1999 Elsevier Science B.V. All rights reserved.