Applications of Surface Science 22/23 (1985) 3547 North-Holland, Amsterdam 35 zyxwvutsrqpo SURFACE BARRIER STUDIES WITH LEED FINE STRUCTURE ANALYSIS P.J. JENNINGS School of Mathematical and Physical Sciences, Murdoch University, Murdoch, WA 6150, Australia and R.O. JONES Institut fiir Festkiirperforschung der Kemforschungsanlage Jiilich, Postfach 1913, D-51 70 Jiilich, Fed. Rep. of Germany Received 27 August 1984; accepted for publication 31 October 1984 The application of LEED fine structure analysis to the study of the surface potential energy barrier is reviewed. Analysis of data for W(OO1) and W(110) using a saturated image barrier model demonstrates the adequacy of the model and provides further details of the barrier structure. The computational model and the results of the analysis are compared with recent theories of the metal-vacuum interface. The present evidence suggests that jellium calculations provide a qualitatively correct picture of the barrier on transition metal surfaces. LEED fine structure analysis also appears to be a promising direct method for further studies of surface barriers. 1. The surface barrier A knowledge of the structure of the potential energy barrier at the metal-vacuum interface is important for a full description of many surface processes, including thermionic and field emission, photoemission and low energy electron diffraction (LEED). The analysis of some of these processes, particularly LEED fine structure, requires reliable models of the surface barrier. In the past a variety of simplified models has been used to study these problems [l]. Tractable analytic forms such as the simple step barrier and the exponential barrier were popular but often gave unrealistic results. The image barrier from classical electrostatics has the form (Rydberg atomic units) 0378-5963/85/$03.30 @ Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)