Table Of ContentSpringer Series on
35
ATOMIC, OPTICAL, AND PLASMA PHYSICS
Springer-Verlag Berlin Heidelberg GmbH
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Physics and Astronomy
http://www.springer.de/phys/
Springer Series on
ATOMIC, OPTICAL, AND PLASMA PHYSICS
The Springer Series on Atomic, Optical, and Plasma Physics covers in a compre
hensive manner theory and experiment in the entire field of atoms and molecules
and their interaction with electromagnetic radiation. Books in the series provide
a rich source of new ideas and techniques with wide applications in fields such as
chemistry, materials science, astrophysics, surface science, plasma technology, ad
vanced optics, aeronomy, and engineering. Laser physics is a particular connecting
theme that has provided much of the continuing impetus for new developments
in the field. The purpose of the series is to cover the gap between standard under
graduate textbooks and the research literature with emphasis on the fundamental
ideas, methods, techniques, and results in the field.
27 Quantum Squeezing
By P.D. Drumond and Z. Spicek
28 Atom, Molecule, and Cluster Beams I
Basic Theory, Production and Detection of Thermal Energy Beams
ByH. Pauly
29 Polarization, Alignment and Orientation in Atomic Collisions
By N. Andersen and K. Bartschat
30 Physics of Solid-State Laser Physics
By R.C. Powell
(Published in the former Series on Atomic, Molecular, and Optical Physics)
31 Plasma Kinetics in Atmospheric Gases
By M. Capitelli, C.M. Ferreira, B.F. Gordiets, A.1. Osipov
32 Atom, Molecule, and Cluster Beams II
Cluster Beams, Fast and Slow Beams, Accessory Equipment and Applications
ByH. Pauly
33 Atom Optics
By P. Meystre
34 Laser Physics at Relativistic Intensities
By A. V. Borovsky, A.L. Galkin, O.B. Shiryaev, T. Auguste
35 Many-Particle Quantum Dynamics in Atomic and Molecular Fragmentation
Editors: J. Ullrich and v.P. Shevelko
Series homepage - http://www.springer.de/phys/books/ssaop/
Vols. 1-26 of the former Springer Series on Atoms and Plasmas are listed at the end of the book
J. Ullrich v.P. Shevelko (Eds.)
Many-Particle
Quantum Dynamics
in Atomic and Molecular
Fragmentation
With 179 Figures
i
Springer
Professor Dr. Joachim Ullrich
Max-Planck Institut flir Kernphysik
Saupfercheckweg 1, 69117 Heidelberg, Germany
E-mail: [email protected]
Professor Dr. Viatcheslav Shevelko
P.N. Lebedev Physical Institute
Leninskii prospect 53, 119991 Moscow, Russia
E-mail: [email protected]
ISSN 1615-5653
ISBN 978-3-642-0526-0 ISBN 978-3-662-08492-2 (eBook)
DOI 10.1007/978-3-662-08492-2
Library of Congress Cataloging-in-Publication Data
Many-particle quantum dynamics in atomic and molecular fragmentation!). Ullrich, V.P. Shevelko (eds.).
p. cm. - (Springer series on atomic, optical, and plasma physics, ISSN 1615-5653 ; 35)
Includes bibliographical references and index.
1. Collisions (Atomic physics) 2. Atomic and molecular fragmentation. 3. Many-body problem. 4. Quantum
theory. I. Ullrich, ). (Joachim) II. Shevel'ko, V.P. (Viatcheslav Petrovich) III: Series.
QC794·6.C6M342003
539·i57-dc21 2003050419
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Softcover reprint ofthe hardcover I st edition 2003
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Preface
This book aims to give a comprehensive view on the present status of a
tremendously fast-developing field - the quantum dynamics of fragmenting
many-particle Coulomb systems. In striking contrast to the profound theo
retical knowledge, achieved from extremely precise experimental results on
the static atomic and molecular structure, it was only three years ago when
the three-body fundamental dynamical problem of breaking up the hydro
gen atom by electron impact was claimed to be solved in a mathematically
consistent way.
Until now, more "complicated", though still fundamental scenarios, ad
dressing the complete fragmentation of the "simplest" many-electron system,
the helium atom, under the action of a time-dependent external force, have
withstood any consistent theoretical description. Exceptions are the most
"trivial" situations where the breakup is induced by the impact of a single
real photon or of a virtual photon under a perturbation caused by fast, low
charged particle impact. Similarly, the dissociation of the "simplest" molecu
Ht
lar systems like or HD+, fragmentating in collisions with slow electrons,
or the H3 molecule breaking apart into two or three" pieces" as a result of a
single laser-photon excitation, establish a major challenge for state-of-the-art
theoretical approaches.
In the recent past, essentially since less than a decade ago, the field was
revolutionized by the invention of advanced, innovative experimental imag
ing and projection techniques such as "Reaction Microscopes" - the "bubble
chambers of atomic and molecular physics" - or similar projection techniques
for fast-moving ion beams. Now these methods enable the measurement of
the vector momenta of several fragments (ions, electrons, molecular ions)
with unprecedented large solid angles, often reaching a hundred per cent of
47r at extreme precision: Energy resolutions below 1 meV are achieved for
slow electrons, while ion momenta are recorded at the /-leV level and below,
corresponding to a temperature of a few mK. Often, even "kinematically
complete" measurements are feasible, where the complete many-particle fi
nal quantum state is mapped and can be visualized, providing the ultimate
benchmark for comparison with theory.
Imaging techniques, on the one hand, essentially rely on advanced meth
ods for precise preparation of the initial quantum state and, thus, are in-
VI Preface
timately "entangled" and immensely boosted by the present explosion-like
advances in the development of cooling techniques: Electron and laser cool
ing in storage rings, cold molecular ion sources in combination with small
linear traps for cold molecular ions, the use of laser cooling to prepare ultra
cold atomic targets or even the Bose-Einstein condensates have just emerged.
On the other hand, these techniques have profited tremendously by the avail
ability of more sophisticated tools to induce the fragmentation process in a
dynamically refined way, to interrogate the breakup time dependence and,
maybe in the near future, to even control fragmentation pathways. Among
the more sophisticated techniques are intense third-generation synchrotron
radiation sources, shorter and shorter, few femto- or even attosecond ("de
signed") pulses, pulse-trains and pump-probe arrangements from table-top
lasers, upcoming femtosecond VUV free-electron lasers (FEL), as well as in
tense beams of highly charged ions providing subattosecond delta pulses to
explore inner atomic or molecular dynamics on an ultrashort timescale.
In parallel, substantial progress has been achieved in the theoretical treat
ment of fragmenting Coulomb systems, driven by conceptual innovations as
well as by the dramatic increase of computational capabilities in recent years.
For example, the exterior complex scaling method along with the excessive
use of massively parallel supercomputers allowed one to solve the fundamental
three-particle Coulomb breakup of atomic hydrogen by slow-electron impact
mentioned above. Convergent close-coupling calculations, as well as hyper
spherical R-matrix methods, the latter combined with semiclassical outgoing
waves, were finally able to reliably predict fully differential fragmentation
patterns for photo double ionization of the simplest correlated two-electron
system, the helium atom. Within the last few years, these methods have
been successfully applied to describe double ionization by charged-particle
impact at high velocities and the first successful attempts have been un
dertaken to implement higher-order contributions at lower velocities. More
over, other sophisticated methods were developed or applied in the recent
past; among them are the S-matrix approaches to describe the interaction of
strong laser fields with atoms, numerical grid methods to directly integrate
the Schrodinger equation, hidden crossing techniques at low collision ener
gies, time-dependent density functional methods to approach "true" many
electron problems, the Green-function theory for N-particle finite systems, as
well as semiclassical and classical Monte Carlo approximations.
While it is certainly impossible to cover all recent achievements in one
single book that, therefore, necessarily has to remain incomplete, we have
tried, at least within our personal subjective perspective, to report and re
view the most basic methods, techniques and advances as well as on the most
significant areas of research by attracting international experts and young
researchers. In this book, after a detailed introduction into basic kinematic
concepts of atomic and molecular fragmentation reactions in Part I, some of
the prominent experimental techniques, underlying concepts, present chal-
Preface VII
lenges and future prospects are discussed in Part II. Various state-of-the-art
theoretical approaches are introduced in Part III followed by different appli
cations in Part IV for fragmentation reactions, induced by time-dependent
perturbations such as single photons, short-pulse lasers or fast as well as
slowly moving electrons and ions.
Care was taken to organize the sequence of chapters and each single con
tribution in such a way that the nonexpert reader or undergraduate stu
dent being familiar with the basic concepts of atomic, molecular and optical
physics could be guided in a comprehensive, pedagogical way from the funda
mental methods to the most recent techniques and then to the cutting edge
of research in the field, experimentally as well as theoretically. At the Uni
versity of Heidelberg, this book serves as accompanying material for a newly
established Graduate School for Atomic, Molecular and Optical Physics.
Heidelberg, Joachim Ullrich
May 2003 Viatcheslav Shevelko
Contents
1 Kinematics of Atomic and Molecular
Fragmentation Reactions
V.P. Shevelko and J. Ullrich. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 General Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 Definitions and Parameters .......................... 2
1.1.2 Fragmentation Reactions for Atomic Targets. . . . . . . . . . . 4
1.2 Particle Kinematics: Fragmentation of Atoms . . . . . . . . . . . . . . . . . 6
1.2.1 Momentum and Energy Conservation Equations
in the Nonrelativistic Case. . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2.2 Transverse- and Longitudinal-Momentum Balances. . . . . . 9
1.2.3 Fast Ion-Atom Collisions:
Small Momentum, Energy, and Mass Transfers . . . . . . . .. 10
1.2.4 Fast Ion-Atom Collisions: Recoil-Ion Momenta. . . . . . . .. 12
1.2.5 Relativistic Case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14
1.3 Ion-Atom Collisions: Illustrative Examples ................... 15
1.3.1 Single-Electron Capture. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15
1.3.2 Target Ionization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18
1.4 Photon-Atom Collisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 20
1.4.1 Photoeffect.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 20
1.4.2 Compton Effect .................................... 24
1.5 Particle Kinematics: Fragmentation of Molecules .............. 25
1.5.1 Many-Body Dissociation of Fast Molecular Beams ...... 25
1.5.2 Longitudinal Fragment Velocity Components
in the Approximation Zo = 0 . . . . . . . . . . . . . . . . . . . . . . . .. 28
1.5.3 Transverse Fragment Velocity Components
in the Approximation of Zero-Beam Extension. . . . . . . . .. 28
1.5.4 Transverse Fragment Velocity Components
in the Approximation of Zero-Beam Divergence. . . . . . .. 29
1.5.5 Fragmentation into Two Particles with Equal Masses. . .. 29
References ..................................................... 31
X Contents
2 Recoil-Ion MOlllentulll Spectroscopy
and "Reaction Microscopes"
R. Moshammer, D. Fischer, H. Kollmus. . . . . . . . . . . . . . . . . . . . . . . . . . .. 33
2.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 33
2.2 Imaging Spectrometers for Ions ............................. 33
2.2.1 Time Focusing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37
2.2.2 Reconstruction of Momentum Components. . . . . . . . . . . .. 37
2.2.3 Spectrometers with Position-Focusing. . . . . . . . . . . . . . . .. 39
2.2.4 Electric-Field Distortions and Calibration ............. 40
2.3 Target Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 41
2.3.1 Supersonic Jets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 41
2.3.2 Atomic Traps (MOTRIMS) .... . . . . . . . . . . . . . . . . . . . . .. 44
2.4 Position-Sensitive Detectors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 45
2.4.1 Wedge and Strip Anodes ............................ 45
2.4.2 Delay-Line Anodes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 47
2.4.3 Multiple-Hit Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 48
2.5 Imaging Spectrometers for Electrons. . . . . . . . . . . . . . . . . . . . . . . .. 50
2.5.1 Direct Imaging of Electrons. . . . . . . . . . . . . . . . . . . . . . . . .. 51
2.5.2 Reaction Microscopes: Magnetic Guiding of Electrons ... 52
2.5.3 Reconstruction of Electron Momenta. . . . . . . . . . . . . . . . .. 53
2.6 New Developments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 55
References ..................................................... 57
3 Multiparticle Illlaging
of Fast Molecular Ion Beallls
D. Zajfman, D. Schwalm, A. Wolf. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 59
3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 59
3.2 Basic Concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 59
3.2.1 Distances and Times: Order of Magnitude. . . . . . . . . . . .. 59
3.2.2 Three-Dimensional vs. Two-Dimensional Imaging. . . . . .. 61
3.3 Detector Concepts and Development. . . . . . . . . . . . . . . . . . . . . . . .. 62
3.3.1 Optical Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 63
3.3.2 Electrical Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 64
3.4 Image Reconstruction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 65
3.4.1 Two-Body Fragmentation ........................... 65
3.4.2 Three-Body Channel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67
3.5 Conclusion and Outlook. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 68
References ..................................................... 69
4 Neutral-Atolll Illlaging Techniques
U. Miiller, H. Helm ............................................. 71
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 71
4.2 Fast-Beam Apparatus ..................................... 72
4.3 Detector Requirements and Specifications .................... 73
