The Dynamics Of Gas Surface Interactions Probed By Molecular Beam Scattering From Organized Monolayers Of Organic Amphiphiles

This book gives a representative survey of the state of the art of research on gas-surface interactions. It provides an overview of the current understanding of gas surface dynamics and, in particular, of the reactive and non-reactive processes of atoms and small molecules at surfaces. Leading scientists in the field, both from the theoretical and the experimental sides, write in this book about their most recent advances. Surface science grew as an interdisciplinary research area over the last decades, mostly because of new experimental technologies (ultra-high vacuum, for instance), as well as because of a novel paradigm, the ‘surface science’ approach. The book describes the second transformation which is now taking place pushed by the availability of powerful quantum-mechanical theoretical methods implemented numerically. In the book, experiment and theory progress hand in hand with an unprecedented degree of accuracy and control. The book presents how modern surface science targets the atomic-level understanding of physical and chemical processes at surfaces, with particular emphasis on dynamical aspects. This book is a reference in the field.

Understanding mechanisms at the molecular level is essential for interpreting and predicting the outcome of processes in all fields of chemistry. Insight into gas-surface reaction dynamics can be gained through molecular beam scattering experiments combined with classical trajectory simulations. In particular, energy exchange and thermal accommodation in the initial collision, the first step in most chemical reactions, can be probed with these experimental and computational tools.

Molecular beam scattering techniques have firmly established themselves among the major tools for studying the kinetics and dynamics of gas- surface interactions. They have also proven themselves to be of great use in materials synthesis, most notably being used for the molecular beam epitaxial (MBE) growth of semiconductor substrates and superlattices. During the past few years our research group has been very active in developing new and quite general molecular beam techniques for studying the kinetic mechanisms of surface chemical reactions. We have, in particular, focused much of our attention on extending traditional molecular beam measurements to allow us to routinely explore coverage dependent kinetic mechanisms under essentially linearized conditions. These efforts have been quite successful. Our three molecular beam scattering arrangement is unique in the world, and significantly expands the range and power of modulated beam reactive scattering for studying complex kinetics at surfaces. The experimental methodology we have developed utilizes two continuous, independently adjustable beams to establish a desired steady state surface concentration, while a weaker modulated third beam induces small concentration perturbations around the selected steady state. This linearized approach permits the coupled differential equations which represent the overall surface reaction mechanism to be solved perturbatively, yielding quantitative information about the various kinetic steps which comprise overall reaction mechanisms.