Low-Energy Electron Diffraction: Experiment, Theory and Surface Structure Determination(6 Springer Series in Surface Sciences)

Surface crystallography plays the same fundamental role in surface science which bulk crystallography has played so successfully in solid-state physics and chemistry. The atomic-scale structure is one of the most important aspects in the understanding of the behavior of surfaces in such widely diverse fields as heterogeneous catalysis, microelectronics, adhesion, lubrication, cor­ rosion, coatings, and solid-solid and solid-liquid interfaces. Low-Energy Electron Diffraction or LEED has become the prime tech­ nique used to determine atomic locations at surfaces. On one hand, LEED has yielded the most numerous and complete structural results to date (almost 200 structures), while on the other, LEED has been regarded as the "technique to beat" by a variety of other surface crystallographic methods, such as photoemission, SEXAFS, ion scattering and atomic diffraction. Although these other approaches have had impressive successes, LEED has remained the most productive technique and has shown the most versatility of application: from adsorbed rare gases, to reconstructed surfaces of sem­ iconductors and metals, to molecules adsorbed on metals. However, these statements should not be viewed as excessively dogmatic since all surface­ sensitive techniques retain untapped potentials that will undoubtedly be explored and exploited. Moreover, surface science remains a multi-technique endeavor. In particular, LEED never has been and never will be self­ sufficient. LEED has evolved considerably and, in fact, has reached a watershed.

Table of Contents:
1. The Relevance and Historical Development of LEED.- 1.1 The Relevance of Surface Crystallography.- 1.2 The Historical Development of LEED.- 2. The LEED Experiment.- 2.1 General Features of LEED Experiments.- 2.2 Sample Mounting.- 2.3 Electron Gun and Display System.- 2.4 Methods of Data Acquisition.- 2.5 Instrumental Response Function.- 2.6 Determination of Angle of Incidence.- 2.7 Determination of the Debye Temperature.- 3. Ordered Surfaces: Structure and Diffraction Pattern.- 3.1 Two-Dimensional Periodicity and the LEED Pattern.- 3.2 Superlattices at Surfaces.- 3.3 Stepped and Kinked Surfaces.- 3.4 Symmetries and Domains at Surfaces.- 3.5 Interpretation of LEED Patterns.- 4. Kinematic LEED Theory and Its Limitations.- 4.1 Definition of Kinematic Theory.- 4.2 The Kinematic Structure Factor for Ordered Surfaces.- 4.3 The Scattering Processes in LEED.- 4.4 The Elastic Scattering Potential.- 4.5 Atomic Scattering.- 4.6 The Inner Potential and the Muffin-Tin Constant.- 4.7 Temperature Effects.- 4.8 From Kinematic to Dynamical LEED.- 5. Dynamical LEED Theory.- 5.1 Multiple Scattering.- 5.2 Diffraction in Crystalline Lattices.- 5.3 Multiple Scattering in the Spherical-Wave Representation — Self-Consistent Formalism.- 5.4 Perturbation Expansion of Multiple Scattering in the Spherical-Wave Representation: Reverse-Scattering Perturbation (RSP) Method.- 5.5 Diffraction by a Stack of Layers: Transfer-Matrix and Bloch-Wave Method.- 5.6 Diffraction by a Stack of Layers: Layer-Stacking and Layer-Doubling Method.- 5.7 Diffraction by a Stack of Layers: Renormalized-Forward-Scattering (RFS) Perturbation Method.- 5.8 Efficiency of Computation and the Combined-Space Method.- 5.9 Superlattices and Domains.- 5.10 Symmetries.- 5.11 Thermal Effects.- 5.12 Potential Steps, Surface States,Surface Resonances and LEED Fine Structure.- 5.13 Relativistic and Spin-Dependent Effects in LEED.- 5.14 Some Other Theoretical Techniques.- 5.15 Outstanding Theoretical Problems in LEED.- 5.16 Application of LEED Theory to Other Electron Spectroscopies.- 5.17 Computer Programs.- 6. Methods of Surface Crystallography by LEED.- 6.1 The Kinematic Approach to Surface Crystallography.- 6.2 Averaging Methods.- 6.3 Fourier-Transform Methods.- 6.4 The Dynamical Approach to Surface Crystallography.- 6.5 Reliability Factors (R-Factors).- 6.6 Accuracy and Precision of Structural Determination.- 7. Results of Structural Analyses by LEED.- 7.1 Clean Unreconstructed Surfaces.- 7.2 Reconstructed Surfaces.- 7.3 Adsorbed Atomic Layers.- 7.4 Adsorbed Molecular Layers.- 8. Two Dimensional Order-Disorder Phase Transitions.- 8.1 Introduction to Order-Disorder Phase Transitions at Surfaces...- 8.2 The Interaction of Hydrogen with the (111) Surface of Nickel.- 8.3 The Interaction of Hydrogen with the (100) Surface of Palladium.- 8.4 The Interaction of Hydrogen with the (110) Surface of Iron.- 9. Chemical Reactions at Surfaces and LEED.- 9.1 Monitoring Surface Reactions by LEED.- 9.2 The Adsorption of Oxygen on Rh(111) at 335 K.- 9.3 The Reaction Between Hydrogen and Ordered Oxygen on Rh(111).- 9.4 The Reaction Between Hydrogen and Both Ordered and Disordered Oxygen on Rh(111).- 10. Island Formation of Adspecies and LEED.- 10.1 The Nature of Islands on Surfaces.- 10.2 LEED Beam Profiles for Arrays of Ordered Islands.- 10.3 Island Formation in a Real System: CO on Ru(0001).- 11. The Future of LEED.- 11.1 Experimental Outlook.- 11.2 Theoretical Outlook.- 11.3 Progress in Structural Determination.- 11.4 LEED vs. Other Surface-Sensitive Techniques.- 12. Reference List and Table for Surface Structures.- Appendix A: Acronyms of Techniques Related to Surface Science.- Appendix B: A Computer Program to Determine the Angle of Incidence in LEED.- List of Major Symbols.- References.