December 4, 2020

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Collisional Effects on Molecular Spectra

Collisional Effects on Molecular Spectra
Author : Jean-Michel Hartmann,Christian Boulet,Daniel Robert
Publisher : Elsevier
Release Date : 2008-08-12
Category : Science
Total pages :432
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Gas phase molecular spectroscopy is a powerful tool for obtaining information on the geometry and internal structure of isolated molecules as well as on the interactions that they undergo. It enables the study of fundamental parameters and processes and is also used for the sounding of gas media through optical techniques. It has been facing always renewed challenges, due to the considerable improvement of experimental techniques and the increasing demand for accuracy and scope of remote sensing applications. In practice, the radiating molecule is usually not isolated but diluted in a mixture at significant total pressure. The collisions among the molecules composing the gas can have a large influence on the spectral shape, affecting all wavelength regions through various mechanisms. These must be taken into account for the correct analysis and prediction of the resulting spectra. This book reviews our current experimental and theoretical knowledge and the practical consequences of collisional effects on molecular spectral shapes in neutral gases. General expressions are first given. They are formal of difficult use for practical calculations often but enable discussion of the approximations leading to simplified situations. The first case examined is that of isolated transitions, with the usual pressure broadening and shifting but also refined effects due to speed dependence and collision-induced velocity changes. Collisional line-mixing, which invalidates the notion of isolated transitions and has spectral consequences when lines are closely spaced, is then discussed within the impact approximation. Regions where the contributions of many distant lines overlap, such as troughs between transitions and band wings, are considered next. For a description of these far wings the finite duration of collisions and concomitant breakdown of the impact approximation must be taken into account. Finally, for long paths or elevated pressures, the dipole or polarizability induced by intermolecular interactions can make significant contributions. Specific models for the description of these collision induced absorption and light scattering processes are presented. The above mentioned topics are reviewed and discussed from a threefold point of view: the various models, the available data, and the consequences for applications including heat transfer, remote sensing and optical sounding. The extensive bibliography and discussion of some remaining problems complete the text. State-of-the-art on the subject A bibliography of nearly 1,000 references Tools for practical calculations Consequences for other scientific fields Numerous illustrative examples Fulfilling a need since there is no equivalent monograph on the subject

Recent Advances in Collisional Effects on Spectra of Molecular Gases and Their Practical Consequences

Recent Advances in Collisional Effects on Spectra of Molecular Gases and Their Practical Consequences
Author : Anonim
Publisher : Unknown
Release Date : 2018
Category :
Total pages :129
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Highlights: A review on the progress made in the last decade on pressure effects on absorption shapes. High accuracy measurement techniques. Theories, models and available data for the absorption shapes. Consequences for remote sensing, metrology and heat transfer applications. Over 700 references. Abstract: We review progress, since publication of the book `` Collisional effects on molecular spectra: Laboratory experiments and models, consequences for applications" (Elsevier, Amsterdam, 2008), on measuring, modeling and predicting the influence of pressure ( ie of intermolecular collisions) on the spectra of gas molecules. We first introduce recently developed experimental techniques of high accuracy and sensitivity. We then complement the aforementioned book by presenting the theoretical approaches, results and data proposed (mostly) in the last decade on the topics of isolated line shapes, line-broadening and -shifting, line-mixing, the far wings and associated continua, and collision-induced absorption. Examples of recently demonstrated consequences of the progress in the description of spectral shapes for some practical applications (metrology, probing of gas media, climate predictions) are then given. Remaining issues and directions for future research are finally discussed.

Spectra of Atoms and Molecules

Spectra of Atoms and Molecules
Author : Peter F. Bernath
Publisher : Oxford University Press
Release Date : 2020-04-20
Category : Science
Total pages :488
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This fourth edition of Peter Bernath's successful Spectra of Atoms and Molecules is designed to provide advanced undergraduate and graduate students a working knowledge of the vast field of spectroscopy. Also of interest to chemists, physicists, astronomers, atmospheric scientists, and engineers, this volume emphasizes the fundamental principles of spectroscopy with the primary goal of teaching the interpretation of spectra. Features include a presentation of group theory as needed to understand spectroscopy, detailed worked examples and a large number of excellent problems at the end of each chapter. Bernath provides a large number of diagrams and spectra which have been specifically recorded for this book. Molecular symmetry, matrix representation of groups, quantum mechanics, and group theory are among the topics covered; atomic, rotational, vibrational, electronic and Raman spectra are analyzed as well. Bernath's treatment clears the confusing topic of line strengths as needed for quantitative applications. Responding to student requests, the fourth addition features detailed and worked examples in each chapter. This book has also been updated to include the 2018 CODATA revision of physical constants and a large number of corrections and clarifications. New chapters on atmospheric and astronomical spectroscopy have been added. Spectra of Atoms and Molecules demystifies spectroscopy by showing readers the intermediate steps in a derivation, as well as the final result.

Chemical Modelling

Chemical Modelling
Author : Royal Society of Chemistry,Barbara Kirchner,Guozhong Wu
Publisher : Royal Society of Chemistry
Release Date : 2012-09-01
Category : Reference
Total pages :217
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Chemical Modelling: Applications and Theory comprises critical literature reviews of all aspects of molecular modelling. Molecular modelling in this context refers to modelliing the structure, properties and reactions of atoms, molecules and materials. Each chapter provides a selective review of recent literature, incorporating sufficient historical perspective for the non-specialist to gain an understanding. With chemical modelling covering such a wide range of subjects, this Specialist Periodical Report serves as the first port of call to any chemist, biochemist, materials scientist or molecular physicist needing to acquaint themselves with major developments in the area.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports
Author : Anonim
Publisher : Unknown
Release Date : 1980
Category : Aeronautics
Total pages :129
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Spectroscopy of the earth's Atmosphere and interstellar Medium

Spectroscopy of the earth's Atmosphere and interstellar Medium
Author : K.N. Rao
Publisher : Academic Press
Release Date : 2012-12-02
Category : Nature
Total pages :538
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Spectroscopy of the Earth's Atmosphere and Interstellar Medium focuses on the characteristics of the electromagnetic spectrum of the Earth's atmosphere in the far-infrared and microwave regions. It discusses the modes of observation in field measurements and reviews the two techniques used in the spectral region. Organized into six chapters, this volume begins with an overview of the effect of water-vapor absorption, followed by a discussion on the two frequently used method for deriving atmospheric parameters from high-resolution infrared atmospheric spectra, namely, the equivalent width (EW) technique and the nonlinear least-square fitting (NLSF). Other chapters consider the mechanisms by which interstellar clouds are formed. In addition, the book explores the composition of interstellar clouds, ion-molecule reactions, and the formation of stars. This book will be useful to anyone involved in, or interested in learning more about the field of atmospheric spectroscopy, including scientists, aeronomers, astronomers, astrophysicists, and students.

Laboratory Astrochemistry

Laboratory Astrochemistry
Author : Stephan Schlemmer,Thomas Giesen,Harald Mutschke
Publisher : John Wiley & Sons
Release Date : 2014-12-08
Category : Science
Total pages :520
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Written by leading scientists in the field and intended for a broader readership, this is an ideal starting point for an overview of current research and developments. As such, the book covers a broad spectrum of laboratory astrophysics and chemistry, describing recent advances in experiments, as well as theoretical work, including fundamental physics and modeling chemical networks. For researchers as well as students and newcomers to the field.

Weakly Interacting Molecular Pairs: Unconventional Absorbers of Radiation in the Atmosphere

Weakly Interacting Molecular Pairs: Unconventional Absorbers of Radiation in the Atmosphere
Author : Claude Camy-Peyret,Andrei A. Vigasin
Publisher : Springer Science & Business Media
Release Date : 2012-12-06
Category : Science
Total pages :287
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The Advanced Research Workshop entitled “Weakly Interacting Molecular Pairs: Unconventional Absorbers of Radiation in the At- sphere” was held in Abbaye de Fontevraud, France, from April 29 to May 3, 2002. The meeting involved 40 researchers from 14 countries. The goal of this meeting was to address a problem that the scienti?c community is aware of for many years. Up now, however, the so- tion for this problem is far from satisfactory. Pair e?ects are called unconventional in the title of this meeting. In speci?c spectral domains and/or geophysical conditions they are recognized to play a dominant role in the absorption/emission properties of the atmosphere. Water vapor continuum absorption is among the most prominent examples. Permanently improving accuracy of both laboratory studies and ?eld observations requires better knowledge of the spectroscopic features - tributable to molecular pairs which may form at equilibrium. The Workshop was targeted both to clarify the pending questions and, as far as feasible, to trace the path to possible answers since the underlying phenomena are yet incompletely understood and since a reliable theory is often not available. On the other hand, the lack of precise laboratory data on bimolecular absorption is often precluding the construction of reliable theoretical models. Ideally, the knowledge accumulated in the course of laboratory studies should correlate with the practical demands from those who are carrying out atmospheric ?eld measurements and space observations.

Molecular Spectroscopy

Molecular Spectroscopy
Author : R. F. Barrow,Derek Albert Long
Publisher : Royal Society of Chemistry
Release Date : 1976
Category : Reference
Total pages :320
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Specialist Periodical Reports provide systematic and detailed review coverage of progress in the major areas of chemical research. Written by experts in their specialist fields the series creates a unique service for the active research chemist, supplying regular critical in-depth accounts of progress in particular areas of chemistry. For over 80 years the Royal Society of Chemistry and its predecessor, the Chemical Society, have been publishing reports charting developments in chemistry, which originally took the form of Annual Reports. However, by 1967 the whole spectrum of chemistry could no longer be contained within one volume and the series Specialist Periodical Reports was born. The Annual Reports themselves still existed but were divided into two, and subsequently three, volumes covering Inorganic, Organic and Physical Chemistry. For more general coverage of the highlights in chemistry they remain a 'must'. Since that time the SPR series has altered according to the fluctuating degree of activity in various fields of chemistry. Some titles have remained unchanged, while others have altered their emphasis along with their titles; some have been combined under a new name whereas others have had to be discontinued. The current list of Specialist Periodical Reports can be seen on the inside flap of this volume.

Molecular Spectroscopy: Spectroscopy of the Earth's atmosphere and interstellar medium

Molecular Spectroscopy: Spectroscopy of the Earth's atmosphere and interstellar medium
Author : K. Narahari Rao,C. Weldon Mathews
Publisher : Unknown
Release Date : 1972
Category : Molecular spectra
Total pages :129
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Molecular and Laser Spectroscopy

Molecular and Laser Spectroscopy
Author : Zu-Geng Wang,Hui-Rong Xia
Publisher : Springer Science & Business Media
Release Date : 2012-12-06
Category : Science
Total pages :281
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The spectra of molecules containing more than one atom are necessarily of single atoms. They are correspondingly much more complex than those richer, not only in the number of spectral lines, but also in qualitatively different phenomena which do not have any counterpart in single atoms. Historically, molecular spectra have revealed much fundamental phy sics, such as the connection between nuclear spin statistics. They have pro vided models of physical systems which have been useful in quite different areas, such as particle physics. Most especially, molecular spectra are of fundamental importance in understanding chemical bonding. They reveal not only bond lengths but also the strength of the bonding potential between atoms. Moreover, these measurements are obtained for electronic excited states, as well as for the ground state, and for unstable short-lived molecules. In recent years, tunable lasers have provided powerful tools for the measurement and analysis of molecular spectra. Even before that, molecules were being used in lasers, most notably in the carbon dioxide laser, which finds many industrial applications.

Molecular Spectroscopy: Modern Research

Molecular Spectroscopy: Modern Research
Author : K. Narahari Rao,C. Weldon Mathews
Publisher : Unknown
Release Date : 1972
Category : Technology & Engineering
Total pages :452
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Molecular Spectroscopy: Modern Research, Volume III is a collection of papers presented at the 40th Annual Molecular Spectroscopy Symposium, held at the Ohio State University. The contributors of this seven-chapter text cover the significant advances in molecular spectroscopic research and their application in chemistry. Chapters 1 and 2 discuss first the higher-order vibration-rotation interactions in molecules and then present formulas and an insight into the direction being taken in theoretical pursuits. Chapter 3 provides an extensive compilation of published intensity and collision broade ...

Spectral Line Shapes

Spectral Line Shapes
Author : Marco Antonio Gigosos,Manuel A. Gonzalez,Manuel Angel Gonzalez
Publisher : American Institute of Physics
Release Date : 2008-11-04
Category : Science
Total pages :390
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This biennial conference is the main international forum for both fundamental and applied works dealing with processes related to the formation of the spectral line profiles and with their use for diagnostic purposes. On the fundamental side, the study of the line profiles reveals the underlying atomic and molecular interactions. On the practical side, the line profiles are employed as powerful diagnostic tools for various media, such as neutral gases, technological gas discharges, magnetically-confined plasmas for fusion, laser- and Z-pinch-produced plasmas, astrophysical plasmas, and planetary atmospheres.

Semiclassical Methods in Molecular Scattering and Spectroscopy

Semiclassical Methods in Molecular Scattering and Spectroscopy
Author : NATO Advanced Study Institute Staff,NATO advanced study institute
Publisher : Springer Science & Business Media
Release Date : 1980
Category : Science
Total pages :332
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Proceedings of the NATO Advanced Study Institute, Cambridge, England, September 1979

Collision-induced Absorption in Gases

Collision-induced Absorption in Gases
Author : Lothar Frommhold
Publisher : Cambridge University Press
Release Date : 2006-05-18
Category : Science
Total pages :452
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This book reviews the theory and experiment of collision-induced absorption of infrared radiation in dense gases. Throughout the book, the emphasis is on absorption by binary molecular complexes, but the onset of many-body effects, such as ternary spectral components and intercollisional processes, are also considered in detail.