Desorption Induced by Electronic Transitions DIET I

The Workshop on Desorption Induced by Electronic Transitions (DIET) took place May 12-14, 1982, in Williamsburg, Virginia. The meeting brought together, for the first time, most of the leading workers in the fields of electron and photon stimulated desorption from surfaces, as well as many workers in related fields, including sputtering, gas-phase photodissociation and solid-state theory. The emphasis of the workshop was on the microscopic mechanism of stimu­ lated desorption. Many possible mechanisms have been proposed, and a few new ones emerged at the meeting. Though no consensus was reached, many views were espoused and criticized, frequently with considerable enthusiasm. The result was an appraisal of our current understanding of DIET, and a focus on the experimental and theoretical efforts most likely to lead to new insights. This volume is an attempt to record the information exchanged in this very successful workshop and, perhaps, convey some of the excitement of the field of DIET. The book is a collection of papers written by participants in the DIET workshop, including in addition a contribution from Dietrich Menzel, who was unable to attend. Thus, this book represents a complete statement of the state of the art of experimental and theoretical studies of DIET and related phenomena. More importantly, it addresses the interesting unsolved problems, and suggests strategies for unraveling them. We acknowledge the assistance given by the other members of the organizing committee, A. E. de Vries, R. Gomer, M. L. Knotek, D. Menzel and D. P.

Contenu

1 Fundamental Excitations.- 1.1 Fundamental Excitations in Solids Pertinent to Desorption Induced by Electronic Transitions..- 1.2 An Analysis of Electronic Desorption.- 1.3 Direct and Indirect Mechanisms of Stimulated Desorption.- 2 Desorption Processes.- 2.1 Mechanisms of Electron-Stimulated Desorption.- 2.2 Mechanisms of Electronically Induced Desorption of Ions and Neutrals..- 2.3 Mechanisms of "Electronic" Desorption..- 2.4 Models for Desorption in Covalent Systems.- 2.5 The Role of the Excited State in DIET Electronic Structure and Evolution in Time..- 3 Desorption Spectroscopy.- 3.1 On the Nature of the ESD Active Species on Metal Surfaces.- 3.2 Photodesorption and Negative Ion ESD..- 3.3 The Determination of Molecular Structure at Surfaces Using Angle Resolved Electron- and Photon-Stimulated Desorption.- 3.4 Stimulated Desorption Spectroscopy.- 3.5 The Electronic Desorption of Excited Alkali Atoms from Alkali Halide Surfaces.- 4 Molecular Dissociation.- 4.1 Dissociation in Small Molecules.- 4.2 The Coulomb Explosion and Recent Methods for Studying Molecular Decomposition.- 5 Ion-Stimulated Desorption.- 5.1 Desorption Stimulated by Ion Impact.- 5.2 F+ Ejection from LiF Surfaces by Ion Bombardment.- 5.3 Similarities in the Relative Populations of Excited States Produced by Sputtering and by Electron Impact.- 5.4 Erosion of Dielectric Solids by High-Energy Ions.- 6 Electronic Erosion.- 6.1 Sputtering of Alkali Halides by Electrons.- 6.2 The Contribution of Electronic Processes in Sputtering.- 6.3 Mechanisms for Defect Creation in Alkali Halides.- 7 Condensed Gas Desorption.- 7.1 The Non-Linear Erosion Yield of Condensed Gas Solids Electronically Excited by Fast Light Ions.- 7.2 Desorption of Condensed Gases and Organic Molecules by Electronic Processes.- 7.3 Photon-Stimulated Ion Desorption from Condensed Molecules: N2, CO, C2H2, CH3OH, N2O, D2O, and NH3.- 7.4 Electron-Stimulated Desorption from Condensed Branched Alkanes.- 7.5 PSD and ESD of Condensed Films: Relevance to the Mechanism of Ion Formation and Desorption.- Index of Contributors.