The interaction of gas-phase molecules with solid surfaces is of importance to heterogeneous catalysis, corrosion, air filtration, pollution control, and chemical deactivation. Our research group has recently obtained some of the first direct measurements of the probability for vibrational deactivation during gas-solid collisions. A pulsed infrared laser is used to excite CO of CO2 vibrationally under conditions where the predominant cause of deactivation is due to the gas-surface collision. The probability of relaxation is then monitored by observing the time-dependent decay of infrared fluorescence from the excited molecules. Results for CO2 (001) show that the deactivation probability is 0.22 for collisions with a stainless steel surface, 0.16 for silver, and 0.20 for nickel.

There is considerable interest, both fundamental and technological, in the way atoms and molecules interact with solid surfaces. Thus the description of heterogeneous catalysis and other surface reactions requires a detailed understand ing of molecule-surface interactions. The primary aim of this volume is to provide fairly broad coverage of atoms and molecules in interaction with a variety of solid surfaces at a level suitable for graduate students and research workers in condensed matter physics, chemical physics, and materials science. The book is intended for experimental workers with interests in basic theory and concepts and had its origins in a Spring College held at the International Centre for Theoretical Physics, Miramare, Trieste. Valuable background reading can be found in the graduate-Ievel introduction to the physics of solid surfaces by ZangwilI(1) and in the earlier works by Garcia Moliner and F1ores(2) and Somorjai.(3) For specifically molecule-surface interac tions, additional background can be found in Rhodin and Ertl(4) and March.(S) V. Bortolani N. H. March M. P. Tosi References 1. A. Zangwill, Physics at Surfaces, Cambridge University Press, Cambridge (1988). 2. F. Garcia-Moliner and F. Flores, Introduction to the Theory of Solid Surfaces, Cambridge University Press, Cambridge (1979). 3. G. A. Somorjai, Chemistry in Two Dimensions: Surfaces, Cornell University Press, Ithaca, New York (1981). 4. T. N. Rhodin and G. Erd, The Nature of the Surface Chemical Bond, North-Holland, Amsterdam (1979). 5. N. H. March, Chemical Bonds outside Metal Surfaces, Plenum Press, New York (1986).

The authors present results from a grant funded under the Department of Energy Office of Basic Energy Sciences. A collaboration between Prof. Alec Wodtke of the Department of Chemistry at UCSB and Daniel J. Auerbach of IBM Almaden Research Labs has allowed new experiments on the dynamics of surface chemical reactivity to be successfully executed. High quality data has been generated which provides an excellent test of theoretical models of surface reactivity, a topic of importance to catalysis. The authors have obtained the first experimental measurements on the influence of reactant velocity on the steric effect in a chemical reaction: the dissociative adsorption of hydrogen on copper. They have also designed and built a molecular beam scattering apparatus for the study of highly vibrationally excited molecules and their interactions with clean and oxidized metal surfaces. With this apparatus they have observed the vibrational energy exchange of highly vibrationally excited NO with an oxidized copper surface. Multi-quantum vibrational relaxation was found ([Delta]v = 1-5). Such remarkably strong and efficient vibrational energy transfer represents a qualitatively new phenomenon and is representative of the exciting new behavior that they had hoped might be observable in this project. Evidence of chemical reactivity of vibrationally excited NO on a clean copper surface was also found.

The present volume is concerned with two of the central questions of chemical dynamics. What do we know about the energies of interaction of atoms and molecules with each other and with solid surfaces? How can such interaction energies be used to understand and make quantitative predictions about dynamical processes like scattering, energy transfer, and chemical reactions? It is becoming clearly recognized that the computer is leading to rapid progress in answering these questions. The computer allows probing dynamical mechanisms in fine detail and often allows us to answer questions that cannot be addressed with current experimental techniques. As we enter the 1980's, not only are more powerful and faster computers being used, but techniques and methods have been honed to a state where exciting and reliable data are being generated on a variety of systems at an unprecedented pace. The present volume presents a collection of work that illustrates the capabilities and some of the successes of this kind of computer-assisted research. In a 1978 Chemical Society Report, Frey and Walsh pointed out that "it is extremely doubtful if a calculated energy of activation for any unimolecular decomposition can replace an experimental deter mination. " However they also recorded that they "believe[d] that some of the elaborate calculations being performed at present do suggest that we may be approaching a time when a choice between reaction mechanisms will be helped by such [computational] work.

This text is the first of a two-volume work on molecule surface interactions addressing topics in chemical physics, surface science, physical chemistry, materials science, and electronics and semiconductor manufacture. As with the other titles in the Advances in Chemical Physics series, the chapters are written by an international group of contributors and cover a wide range of important issues in the field.