of available information. Even more importantly, some authors who have contributed substantially to an area may have been overlooked. For this I apologize. I have, however, not attempted to trace techniques or observa tions historically, so there is no implication (unless specified) that the authors referred to were or were not the originators of a given method or observation. I would like to acknowledge discussions with co-workers at SFU for input relative to their specialties, to acknowledge the help of students who have pointed out errors and difficulties in the earlier presentation, and to acknowledge the infinite patience of my wife Phyllis while I spent my sabbatical and more in libraries and punching computers. S. Roy Morrison 0 1 Contents Notation XV 1. Introduction 1 1. 1. Surface States and Surface Sites . 1 1. 1. 1. The Chemical versus Electronic Representation of the Surface. 1 1. 1. 2. The Surface State on the Band Diagram 4 1. 1. 3. The Fermi Energy in the Surface State Model. 6 1. 1. 4. Need for Both Surface Site and Surface State Models 6 1. 2. Bonding of Foreign Species to the Solid Surface 7 1. 2. 1. Types of Interaction. 7 1. 2. 2. The Chemical Bond . 10 1. 2. 3. Acid and Basic Surface Sites on Solids . 13 1. 2. 4. Adsorbate Bonding on Various Solid Types. 16 1. 2. 5. Movement of Surface Atoms: Relaxation, Reconstruction, and Relocation ."

of available information. Even more importantly, some authors who have contributed substantially to an area may have been overlooked. For this I apologize. I have, however, not attempted to trace techniques or observa tions historically, so there is no implication (unless specified) that the authors referred to were or were not the originators of a given method or observation. I would like to acknowledge discussions with co-workers at SFU for input relative to their specialties, to acknowledge the help of students who have pointed out errors and difficulties in the earlier presentation, and to acknowledge the infinite patience of my wife Phyllis while I spent my sabbatical and more in libraries and punching computers. S. Roy Morrison 0 1 Contents Notation XV 1. Introduction 1 1. 1. Surface States and Surface Sites . 1 1. 1. 1. The Chemical versus Electronic Representation of the Surface. 1 1. 1. 2. The Surface State on the Band Diagram 4 1. 1. 3. The Fermi Energy in the Surface State Model. 6 1. 1. 4. Need for Both Surface Site and Surface State Models 6 1. 2. Bonding of Foreign Species to the Solid Surface 7 1. 2. 1. Types of Interaction. 7 1. 2. 2. The Chemical Bond . 10 1. 2. 3. Acid and Basic Surface Sites on Solids . 13 1. 2. 4. Adsorbate Bonding on Various Solid Types. 16 1. 2. 5. Movement of Surface Atoms: Relaxation, Reconstruction, and Relocation ."

The objective of the present volume is to develop the theory and practice of nonmetal electrochemistry from first principles, emphasizing energy level models, in particular the fluctuating energy level model of Marcus and Gerischer. A single volume emphasizing these models. and the in terpretation of experiments based on these models, has not been available. Yet this area of electrochemical technology, where the use of such models is required, has developed a great deal of interest. This is not only because of the interest in photoelectrochemical solar cells, but also because of the importance of the concepts in corrosion, sensors, coated metal electrodes, and, indeed, to the general theory of electrode reactions. This book is an attempt to fill the void-to develop in a single volume the basic description of electrode reactions on nonmetallic electrodes and oxide-covered metal electrodes. The development of the fluctuating energy level model to describe electrode reactions on nonmetals (as described in Chapters I through 3) has permitted a significant forward step in the understanding of such re actions. The power of the model is illustrated by the simple methods available to determine the energy levels of interest-the conduction and valence bands of the nonmetals (Chapter 5), and their relation to the energy levels of oxidizing or reducing agents in solution. In Chapter 6, we illustrate the ability of the simple models. based on these parameters, to describe successfully electrode reactions at an inert electrode."