AVS 45th International Symposium
    Surface Science Division Thursday Sessions
       Session SS-ThP

Paper SS-ThP12
Photoelectron Diffraction Intensity Calculation by Using Tensor LEED Theory

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Surface Science Division Poster Session
Presenter: S. Omori, University of Tokyo, Japan
Authors: S. Omori, University of Tokyo, Japan
Y. Nihei, University of Tokyo, Japan
Correspondent: Click to Email
Low-energy photoelectron diffraction (PED) by using synchrotron radiation (SR) has become more and more important for determining surface structures. In particular, PED has the advantage that surfaces having no two-dimensional translation symmetry such as initial-stage adsorption systems can be analyzed provided that the atomic arrangements around photoelectron emitters are symmetric. Since low-energy PED is extremely sensitive to surface structures, multiple structural parameters are usually to be determined by fitting experiment and theory. However, since multiple-scattering effects are important at low photoelectron energies, the structural analysis might be very time-consuming. In this study, we tried to incorporate the tensor LEED (TLEED) theory, a powerful perturbative approach to LEED intensity calculation,@footnote 1@ into the PED formalism and to develop a high-speed trial-and-error method for the structure determination with PED. Since scattering processes that occur in solid surfaces are almost the same for PED and LEED, the formulation of tensor PED is straight-forward. The change in the transition matrix of an atom brought about by its displacement can be calculated by the same method as in TLEED. Once the quantities related to the reference structure, namely the amplitudes of spherical waves incoming to and outgoing from the displaced atom are calculated in the process of multiple-scattering cluster (MSC) calculation for the reference structure and are stored in a hard disk, it is easy to evaluate the changes in the diffraction wave field for many trial structures. We demonstrate the efficiency and accuracy of this method. @FootnoteText@ @footnote 1@P. J. Rous et al., Phys. Rev. Lett. 57 (1986) 2951.