Desorption Induced by Electronic Transitions DIET V: Proceedings of the Fifth International Workshop, Taos, NM, USA, April 1–4, 1992

343 Pages·1993·21.35 MB·English

by  L. Sanche (auth.)

Springer Series in
Surface Sciences
3l
Editor: Robert Gomer
Springer Series in Surface Sciences
Editors: G. Ertl, R. Gomer and D. L. Mills Managing Editor: H. K. V. Lotsch
Pbysisorption Kinetics 18 Auger Spectroscopy and Electronic Structure
By H. J. Kreuzer, Z. W. Gortel Editors: G. Cubiotti, G. Mondio, K. Wandelt
2 Tbe Structure of Surfaces 19 Desorption Induced by Electronic lransitions
Editors: M. A. Van Hove, S. Y. Tong DIET IV
Editors: G. Betz, P. Varga
3 Dynamical Pbenomena at Surfaces, Interfaces
and Superlattices
Editors: F. Nizzoli, K.-H. Rieder, R. F. Willis 20 Scanning Thnneling Microscopy I
General Principles and Applications to Clean
4 Desorption Induced by Electronic lransitions, and Adsorbate-Covered Surfaces
DIET II Editors: H.-J. Giintherodt, R. Wiesendanger
Editors: W. Brenig, D. Menzel
21 Surface Pbonons
5 Cbemistry and Pbysics of Solid Surfaces VI Editors: W. Kress, F. W. de Welte
Editors: R. Vanselow, R. Howe
22 Cbemistry and Pbysics of Solid Surfaces VIII
6 Low-Energy Electron Diffraction
Editors: R. Vanselow, R. Howe
Experiment, Theory and Surface Structure
Determination
By M. A. Van Hove, W. H. Weinberg, C.-M. Chan 23 Surface Analysis Metbods in Materials Science
Editors: D. J. O'Connor. B. A. Sexton,
7 Electronic Pbenomena in Ads,:,rption and Catalysis R. St. C. Smart
By V. F. Kiselev, O. V. Krylov
24 Tbe Structure of Surfaces III
8 Kinetics of Interface Reactions Editors: S. Y. Tong, M. A. Van Hove,
Editors: M. Grunze, H. J. Kreuzer K. Takayanagi, X. D. Xie
9 Adsorption and Catalysis on lransition Metals and
25 NEXAFS Spectroscopy
Their Oxides
By J. StOhr
By V. F. Kiselev, O. V. Krylov
10 Cbemistry and Pbysics of Solid Surfaces VII 26 Semiconductor Surfaces and Interfaces
Editors: R. Vanselow, R. Howe ByW. Monch
11 Tbe Structure of Surfaces II 27 Helium Atom Scattering from Surfaces
Editors: J. F. van der Veen, M. A. Van Hove Editor: E. Hulpke
12 Diffusion at Interfaces: Microscopic Concepts
28 Scanning Thnneling Microscopy II
Editors: M. Grunze, H. J. Kreuzer, J. J. Weimer
Further Applications and Related Scanning
13 Desorption Induced by Electronic lransitions, Techniques
DIET III Editors: R. Wiesendanger, H.-J. Giintherodt
Editors: R. H. Stulen, M. L. Knotek
29 Scanning Thnneling Microscopy III
14 Solvay Conference on Surface Science Theory of STM and Related Scanning Probe
Editor: F. W. de Welte Methods
Editors: R. Wiesendanger, H.-J. Giintherodt
15 Surfaces and Interfaces of Solids
ByH. Liith
30 Concepts in Surface Pbysics
16 Atomic and Electronic Structure of Surfaces By M. C. Desjonqueres, D. Spanjaard
Theoretical Foundations
By M. Lannoo, P. Friedel 31 Desorption Induced by Electronic lransitions
DIET V
17 Adhesion and Friction Editors: A. R. Burns, E. B. Stechel,
Editors: M. Grunze, H. J. Kreuzer D. R. Jennison
A. R. Burns E. B. Stechel
D. R. Jennison (Eds.)
Desorption Induced.
by Electronic Transitions
DIET V
Proceedings of the Fifth International Workshop,
Taos, NM, USA, April 1-4, 1992
With 173 ,Figures
Springer-Verlag
Berlin Heidelberg New York
London Paris Tokyo
Hong Kong Barcelona
Budapest
Dr. Alan R. Burns
Dr. Ellen B. Stechel
Dr. Dwight R. Jennison
Sandia National Laboratories, Albuquerque, P.O. Box 5800,
Albuquerque, NM 87185, USA
Series Editors
Professor Dr. Gerhard Ertl
Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4--6,
1000 Berlin 33, Germany
Professor Robert Gomer, Ph.D.
The James Franck Institute, The University of Chicago, 5640 Ellis Avenue,
Chicago, IL 60637, USA
Professor Douglas L. Mills, Ph.D.
Department of Physics, University of California,
Irvine, CA 92717, USA
Managing Editor: Dr. Helmut K. V. Lotsch
Springer-Verlag, Tiergartenstrasse 17,
W-6900 Heidelberg, Germany
ISBN-13: 978-3-642-78082-0 e-ISBN-13: 978-3-642-78080-6
DOT: 10.10071978-3-642-78080-6
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Preface
This volume in the Springer Series on Surface Sciences presents a recent account
of advances in the ever-broadening field of electron- and photon-stimulated sur
face processes. As in previous volumes, these advances are presented as the
proceedings of the International Workshop on Desorption Induced by Electronic
Transitions; the fifth workshop (DIET V) was held in Taos, New Mexico, April
1-4, 1992. It will be abundantly clear to the reader that "DIET" is not restricted
to desorption, but has for several years included photochemistry, non-thermal
surface modification, exciton self-trapping, and many other phenomena that are
induced by electron or photon bombardment. However, most stimulated surface
processes do share a common physics: initial electronic excitation, localization
of the excitation, and conversion of electronic energy into nuclear kinetic energy.
It is the rich variation of this theme which makes the field so interesting and
fruitful.
We have divided the book into eleven parts in order to emphasize the wide
range of materials that are examined and to highlight recent experimental and
theoretical advances. Naturally, there is considerable overlap between sections,
and many papers would be appropriate in more than one part. Part I focuses on
perhaps the most active area in the field today: electron attachment. Here the
detection and characterization of negative ions formed by attachment of elec
trons supplied externally from the vacuum are discussed. In addition, the first
observations of negative ions formed by substrate photoelectrons are presented.
In Part II, the attachment of excited substrate electrons is shown to be involved
in photodesorption and photochemistry. The use of femtosecond laser pulses not
only provides a direct time window on the dynamics, but also has identified mul
tiple excitations in the course of one desorption event. In Part III, laser-induced
ion desorption is studied, which in many cases is relevant for the control and
understanding of plasma ablation.
High-energy processes such as core-excitation-induced dissociation of adsor
bates and gas-phase molecules are discussed in Part IV. This work has provided
new insight into fast fragmentation and specific excitation channels. In addition,
the relative importance of electronic excitation and resonant neutralization versus
momentum transfer in the scattering of high-energy neutrals and ions at surfaces
is discussed. In Part V, current efforts in DIET theory focus on excited-state life
time calculations, Antoniewicz-type dynamics in view of electron attachment pro
cesses, and models for the desorption of physisorbed species. Electron-stimulated
desorption and chemistry of adsorbates on metals is discussed in Part VI. The
v
reader will find much overlap here with Part II, particularly in the importance of
adsorbate internal dynamics in desorption yields.
An exciting new area that promises to expand rapidly is that of spatially
resolved DIET in Part VII. There it is shown that selective bond-breaking and
dissociation of individual molecules can be performed with the tip of a scanning
tunneling microscope. Semiconductor surfaces is the topic of Part VITI. Evidence
for defect-mediated desorption is presented and the important role of mid-gap
surface states is elucidated. Stimulated desorption also continues to be an effective
probe of processes relevant to etching and growth technologies. DIET on oxides,
Part IX, is also of great interest in materials applications, particularly in view of
the large desorption and dissociation cross-sections. In the area of alkali halides,
the subject of Part X, the resolution of some long-standing mysteries is emerging,
such as the origin of excited alkali atoms above the surface. Finally, in Part XI,
low-probability excited states are observed in cryogenic overlayers, where the
excitation can be mobile and self-trap. Desorption from condensed layers on
cooled beam tubes is also a potential problem in future accelerators such as the
proposed Superconducting Super Collider.
For the generous support which allowed both the preparation of these pro
ceedings and the organization of the DIET V workshop, we would like to thank
Dr. Larry Cooper of the Office of Naval Research. We thank Sandia National
Laboratories (operated for the Department of Energy) for administrative support.
We are indebted to Dr. Fred Vook (Sandia) for making it possible to pursue these
efforts. Finally, we thank Sharon Voccio (Sandia) for her considerable secretarial
help before and during the workshop.
Albuquerque, NM A.R. Burns
September 1992 E.B. Stechel
D.R. Jennison
VI
Contents
Part I Electron Attachment
Surface Reactions and Desorption by Electron Attachment
By L. Sanche (With 8 Figures) ........................ . . . . . 3
Desorption of H-, 0- and OH- Ions
During Impact of Very Low Energy Electrons on Surfaces
By M. Bernheim and T.-D. Wu (With 4 Figures) ................ 15
Electron and Photon Stimulated Desorption of Negative Ions
from Oriented Physisorbed Molecules
By R.J. Guest, R.A. Bennett, L.A. Silva, R.G. Sharpe, J.e. Barnard,
R.E. Palmer, and M.A. MacDonald (With 4 Figures) .............. 21
Resonance Electron Scattering by 02 Monolayers on Graphite:
Reinterpreted
By H. Sambe and D.E. Ramaker . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29
Non-Adiabatic Curve Crossings
in Dissociative Electron Attachment of Condensed O
2
By H. Sambe and D.E. Ramaker (With 1 Figure) ................ 33
Charge-Transfer Photodissociation and Photoreaction in Adsorbates
at a Metal Surface
By St.J. Dixon-Warren, E.T. Jensen, and J.e. Polanyi
(With 3 Figures) ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 38
Part IT Photodesorption and Photochemistry
Desorption Induced by Femtosecond Laser Pulses:
Surface Dynamics at High Electronic Temperatures
By T.F. Heinz, J.A. Misewich, M.M.T. Loy, D.M. Newns,
and H. Zacharias (With 3 Figures) .......................... 47
A New Way to Characterize the Excitation Mechanism
in Surface Photochemistry
By M. Wolf, X.-Y. Zhu, and J.M. White (With 1 Figure) 53
VII
Photodesorption Dynamics and Structural Infonnation
for Oz Adsorbed on Pd(I11)
By A. de Meijere, H. Hirayama, F. Weik, and E. Hasselbrink
(With 2 Figures) ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 57
Dynamics of Ammonia Photodesorption from GaAs(100):
A Vibration-Mediated Mechanism
By X.-Y. Zhu, M. Wolf, T. Huett, and J.M. White (With 2 Figures) 63
Molecular Photochemistry on Surfaces:
Role of Adsorbate-Substrate Structure
By J.M. White (With 4 Figures) ............................ 67
Part ill Laser-Induced Ion Desorption
Desorption of Ions and Neutrals with >6 eV Laser Light
By Y. Murata, K. Fukutani, A. Peremans, and K. Mase
(With 4 Figures) ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 75
Laser-Induced Desorption of Positive Ions
from Wide Band Gap Insulators
By O. Kreitschitz, W. Husinsky, G. Betz, and N.H. Tolk
(With 6 Figures) ....................................... 81
Laser-Induced Desorption from Sapphire Surfaces
By M.A Schildbach and AV. Hamza (With 2 Figures) ............ 91
UV Pulsed Laser Desorption from Ag/Al/Sapphire Films: Changes in the
Ion Desorption Process for Excitations near the Ag d-Band Threshold
By H.-S. Kim, L. Wiedeman, and H. Helvajian (With 3 Figures) ...... 95
Part IV High Energy Processes
Core-Induced Photodissociation of Surface Molecules
Investigated by Ionic Desorption and Correlated Electronic Spectra
By D. Menzel (With 3 Figures) ............................ 101
The Relevance of Gas-Phase Core-Electron Excitation and Decay
Phenomena to Molecular Adsorbate Structure and Desorption
By D.M. Hanson (With 4 Figures) .......................... 110
Dissociation in Fast Molecule-Surface Collisions
By AW. Kleyn (With 5 Figures) ........................... 116
Orientation Effects in the Scattering of Hz and H2 from Cu(I11)
By R. Harder, G. Herrmann, J.-H. Rechtien, and K.J. Snowdon
(With 2 Figures) ....................................... 125
VIII
Desorption from LiF(lOO)
by Singly- and Doubly-Charged Hyperthermal He Ions
By T. Neidhart, M. Schmid, and P. Varga (With I Figure) 129
Ion-Induced Electron Excitation at Magnetic Surfaces
By C. Rau, N.J. Zheng, M. RosIer, and M. Lu (With 3 Figures) 133
Part V Theory
Excited States Lifetimes Near Surfaces
By P. Nordlander (With 3 Figures) .......................... 139
ESD from Physisorbed Layers on Metal Surfaces:
Theoretical Investigation of Two Desorption Scenarios
By Z.W. Gortel (With 3 Figures) ........................... 145
Computer Simulation of DIET Processes:
Molecular Dynamics with Electronic Transitions
By J.e. Tully and M. Head-Gordon (With 2 Figures) 150
Some Current Theoretical Insights on DIET
By J.W. Gadzuk (With 2 Figures) ........................... 158
Part VI Electron Stimulated Desorption
and Chemistry of Adsorbates on Metals
Isotope Effect in Electron Stimulated Desorption - The Role of Internal
Degrees of Freedom in CO Desorption from Pt(lll)
By A. Szab6 and J.T. Yates, Jr. (With 3 Figures) ................ 167
Quantum-Resolved Angular Distributions of Neutral Products
in Electron-Stimulated Surface Processes
By A.R. Bums, E.B. Stechel, and D.R. Jennison (With 3 Figures) 173
Electron Stimulated Desorption of the Metallic Substrate at Monolayer
Coverage: Sensitive Detection via 193 nm Laser Photoionization
of Neutral Aluminum Desorbed from CH30/AI(lII)
By C.E. Young, J.E. Whitten, M.J. Pellin, D.M. Gruen, and P.L. Jones
(With 4 Figures) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 178
Structure and Kinetics of Electron Beam Damage
in a Chemisorbed Monolayer: PF3 on Ru(OOOI)
By T.E. Madey, H.-S. Tao, L. Nair, U. Diebold, S.M. Shivaprasad,
A.L. Johnson, A. Poradzisz, N.D. Shinn, J.A. Yarmoff, V. Chakarian,
and D. Shuh (With 6 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 182
Electron-Induced Decomposition of Metal Carbonyls on Ag(lll)
By R.D. Ramsier, M.A. Henderson, and J.T. Yates, Jr. (With 2 Figures). 189
IX
Quantum-Resolved Stimulated Surface Reactions
By T.M. Orlando, A.R. Burns, E.B. Stechel, and D.R. Jennison
(With 3 Figures) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 194
Part VII Spatially Resolved DIET
Atomic Scale Desorption and Fragmentation with the STM
By Ph. Avouris (With 7 Figures) ........................... 201
Atomic Force Microscopy of Surface Defects on NaCI(100)
By R.T. Williams, R.M. Wilson, and G.P. Williams, Jr.
(With 2 Figures) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 212
Electron Microscopy of Electron-Stimulated Processes at Oxide Surfaces
By D.J. Smith, M.R. McCartney, and M. Gajdardziska-Josifovska
(With 4 Figures) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 218
Part vm Semiconductors
State-Resolved Studies of the Laser-Induced Desorption of NO
from Si(111): The Importance of Localized Excitations
By L.J. Richter, S.A. Buntin, D.S. King, and R.R. Cavanagh
(With 1 Figure) ....................................... 227
Laser-Induced Electronic Processes on Semiconductor Surfaces
By N. Itoh, Y. Nakai, K. Hattori, A. Okano, and J. Kanasaki
(With 2 Figures) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 233
Mechanisms of Metastable Atom Quenching on GaAs(100)
By A. Ludviksson and R.M. Martin (With 2 Figures) .. . . . . . . . . . . .. 238
The Synchrotron Radiation Induced Chemistry
of the Adamantane/Si(111)-7x7 Surface
By J.K. Simons, S.P. Frigo, and R.A. Rosenberg (With 2 Figures) 244
Photolysis Enhancement by Excitation of Si(2p) Core Level Electrons
in SiF4/Ge(100)
By S.P. Frigo, J.K. Simons, and R.A. Rosenberg (With 2 Figures) ..... 248
Photon Stimulated Desorption of Fluorine from Semiconductor Surfaces
By J.A. Yarmoff, D.K. Shuh, V. Chakarian, T.D. Durbin, K.A.H. German,
and C.W. Lo (With 3 Figures) ............................. 253
ESDIAD Studies of Chlorine Adsorption at Silicon(100)
By S.L. Bennett, C.L. Greenwood, and E.M. Williams
(With 2 Figures) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 259
x