Connections Between Molecular Photoionization and Electron-molecule Scattering with Emphasis on Shape Resonances

Connections Between Molecular Photoionization and Electron-molecule Scattering with Emphasis on Shape Resonances PDF Author:
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Category :
Languages : en
Pages :

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Book Description
Most of our detailed information on the spectroscopy and dynamics of the electronic continuum of molecules is based on the complementary probes - photoionization and electron scattering. Though usually studied separately, it is most useful to appreciate the connections between these two processes since our understanding of one is often the key to interpreting or even generating new results in the other. We approach this subject in two steps. First, we very briefly outline the well-established connections, e.g., the Bethe-Born theory and comparisons of isoelectronic systems. Then we focus on a point of contact - the role of shape resonances in molecular photoionization and electron-molecule scattering - for which a substantial amount of new information has become available. Specific topics include mapping of resonances from the neutral (h.nu. + molecule) to the negative ion (e + molecule) system, angular distributions, and interaction with vibration.

Connections Between Molecular Photoionization and Electron-molecule Scattering with Emphasis on Shape Resonances

Connections Between Molecular Photoionization and Electron-molecule Scattering with Emphasis on Shape Resonances PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Most of our detailed information on the spectroscopy and dynamics of the electronic continuum of molecules is based on the complementary probes - photoionization and electron scattering. Though usually studied separately, it is most useful to appreciate the connections between these two processes since our understanding of one is often the key to interpreting or even generating new results in the other. We approach this subject in two steps. First, we very briefly outline the well-established connections, e.g., the Bethe-Born theory and comparisons of isoelectronic systems. Then we focus on a point of contact - the role of shape resonances in molecular photoionization and electron-molecule scattering - for which a substantial amount of new information has become available. Specific topics include mapping of resonances from the neutral (h.nu. + molecule) to the negative ion (e + molecule) system, angular distributions, and interaction with vibration.

Shape Resonances in Molecular Fields

Shape Resonances in Molecular Fields PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
A shape resonance is a quasibound state in which a particle is temporarily trapped by a potential barrier (i.e., the shape of the potential), through which it may eventually tunnel and escape. This simple mechanism plays a prominent role in a variety of excitation processes in molecules, ranging from vibrational excitation by slow electrons to ionization of deep core levels by x-rays. Moreover, their localized nature makes shape resonances a unifying link between otherwise dissimilar circumstances. One example is the close connection between shape resonances in electron-molecule scattering and in molecular photoionization. Another is the frequent persistence of free-molecule shape resonant behavior upon adsorption on a surface or condensation into a molecular solid. The main focus of this article is a discussion of the basic properties of shape resonances in molecular fields, illustrated by the more transparent examples studied over the last ten years. Other aspects to be discussed are vibrational effects of shape resonances, connections between shape resonances in different physical settings, and examples of shape resonant behavior in more complex cases, which form current challenges in this field.

Electron-Molecule Scattering and Photoionization

Electron-Molecule Scattering and Photoionization PDF Author: P.G. Burke
Publisher: Springer Science & Business Media
ISBN: 1461310490
Category : Science
Languages : en
Pages : 275

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Book Description
This volume contains the invited papers and selected contributed papers presented at the International Symposium on 'Electron-Molecule Scattering and Photoionization' held at SERC's Daresbury Laboratory, Cheshire, England from 18th to 19th July, 1987. This Symposium was a Satellite Meeting to the XVth International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC I and follows a tradition of Satellite Meetings i. n related areas of collisions held in association with previous ICPEAC's. In order to make this volume as representative of the Symposium as possible 'Hot Topics' presented orally at the meeting together with a few papers selected by the Programme Committee from the contributed posters are included. The Editors are grateful to the authors for responding rapidly to the invitation to submit their contri butions for inclusion in the volume, as indeed they are grateful to all the authors for the high quality of their contributions. The Symposium brought together over 100 scientists from many countries and from broad interdisciplinary backgrounds to hear about current rapid advances in electron-molecule scatteri. ng and photoioniza tion. These advances have been stimulated on the experimental side by the increasing availability of electron beams with millivolt energy resolution, by synchrotron radiation sources and by intense tunable lasers. On the theoretical side the introduction of new computational methods enables accurate predictions to be made, resulting in a new and deeper understanding of the basic physical processes involved.

Electron-Molecule and Photon-Molecule Collisions

Electron-Molecule and Photon-Molecule Collisions PDF Author: T.N. Rescigno
Publisher: Springer Science & Business Media
ISBN: 1468469886
Category : Technology & Engineering
Languages : en
Pages : 350

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Book Description
The First Asilomar Conference on Electron- and Photon-Molecule Collisions was held August 1-4, 1978 in Pacific Grove, California. This meeting brought together forty scientists who are actively involved in theoretical studies of electron scattering by, and photoionization of, small molecules. In this volume, are collected the contributions of the invited speakers, as well as the roundtable and evening discussions condensed from taped recordings of the entire proceedings. The subject matter reflects current activity in the field and describes many of the techniques that are being developed and applied to molecular collision problems. We would like to thank the Air Force Office of Scientific Research (AFOSR) and the Office of Naval Research (ONR) for providing the financial support that made this conference possible. Special thanks are due to Dr. Robert Junker of ONR and Dr. Ralph Kelley of AFOSR for the interest and encouragement they provided in all phases of this meeting. We also thank all the participants whose efforts and contributions made this conference a success. Finally, we thank Ms. Charlotte MacNaughton and Ms. Sara Jackson for the many hours they spent transcribing tapes and preparing this volume for publication.

Shape-resonance-enhanced Nuclear Motion Effects in Electron-molecule Scattering and Molecular Photoionization. [Review].

Shape-resonance-enhanced Nuclear Motion Effects in Electron-molecule Scattering and Molecular Photoionization. [Review]. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Shape resonances in the electronic continuum of molecules induce strong coupling between vibrational and electronic motion over a spectral range much broader than the resonance half width. In photoionization, this coupling causes large deviations from Franck-Condon intensity distributions and strong dependence of photoelectron angular distributions on the vibrational state of the residual ion. In electron scattering, it enhances vibrational excitation. Recent work is reviewed in which new, observable manifestations of this coupling were predicted theoretically and then verified experimentally. 67 references.

Low-Energy Electron Scattering from Molecules, Biomolecules and Surfaces

Low-Energy Electron Scattering from Molecules, Biomolecules and Surfaces PDF Author: Petr Carsky
Publisher: CRC Press
ISBN: 1439839115
Category : Science
Languages : en
Pages : 311

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Book Description
Since the turn of the 21st century, the field of electron molecule collisions has undergone a renaissance. The importance of such collisions in applications from radiation chemistry to astrochemistry has flowered, and their role in industrial processes such as plasma technology and lighting are vital to the advancement of next generation devices. F

Shape Resonances in Molecular Photoionization

Shape Resonances in Molecular Photoionization PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 55

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Book Description
Full text: Shape resonances have begun to play a central role in the study of spectroscopy and dynamics of molecular photoionization. They manifest themselves as bands of enhanced absorption in the spectra of most (nonhydride) molecules and often stand out prominently against a nonresonant background. These resonances arise from centrifugal barriers in the molecular potential experienced by the escaping photoelectron, and their gross features can be described in terms of simple barrier-penetration concepts. Using both experimental data and recent theoretical calculations, we survey the properties (e.g., symmetry, spatial distribution, and dominant partial waves) of several molecular shape resonances and show how this information relates to the analysis of wavelength-dependent photoelectron spectra, photoelectron angular distributions, and photoabsorption spectra of molecules in different physical states. Special emphasis will be given to the correspondence between resonances in molecular photoionization and electron-molecule scattering.

Energy Research Abstracts

Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 852

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Book Description


Resonances in Electron-molecule Scattering, Van Der Waals Complexes, and Reactive Chemical Dynamics

Resonances in Electron-molecule Scattering, Van Der Waals Complexes, and Reactive Chemical Dynamics PDF Author: Donald G. Truhlar
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 544

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Book Description


Electron-Molecule Collisions

Electron-Molecule Collisions PDF Author: Isao Shimamura
Publisher: Springer Science & Business Media
ISBN: 1461323576
Category : Science
Languages : en
Pages : 578

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Book Description
Scattering phenomena play an important role in modern physics. Many significant discoveries have been made through collision experiments. Amongst diverse kinds of collision systems, this book sheds light on the collision of an electron with a molecule. The electron-molecule collision provides a basic scattering problem. It is scattering by a nonspherical, multicentered composite particle with its centers having degrees of freedom of motion. The molecule can even disintegrate, Le., dissociate or ionize into fragments, some or all of which may also be molecules. Although it is a difficult problem, the recent theoretical, experimental, and computational progress has been so significant as to warrant publication of a book that specializes in this field. The progress owes partly to technical develop ments in measurements and computations. No less important has been the great and continuing stimulus from such fields of application as astrophysics, the physics of the earth's upper atmosphere, laser physics, radiation physics, the physics of gas discharges, magnetohydrodynamic power generation, and so on. This book aims at introducing the reader to the problem of electron molecule collisions, elucidating the physics behind the phenomena, and review ing, to some extent, up-to-date important results. This book should be appropri ate for graduate reading in physics and chemistry. We also believe that investi gators in atomic and molecular physics will benefit much from this book.