Hartmann / Boulet / Robert Collisional Effects on Molecular Spectra

Laboratory Experiments and Models, Consequences for Applications
1. Auflage 2008
ISBN: 978-0-08-056994-9
Verlag: Elsevier Science & Techn.
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 432 Seiten, Web PDF

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

Jean-Michel HARTMANN: born in 1961, « Directeur de Recherche » for the French CNRS (Centre National de la Recherche Scientifique has been carrying research and advising PhD students in the field of the book for about twenty years. He is the director of the French Molecular Spectroscopy Network and the author of more than 100 publications in international journals.

Autoren/Hrsg.

Hartmann, Jean-Michel

Boulet, Christian

Robert, Daniel

Inhaltsverzeichnis

1;Front Cover;1
2;COLLISIONAL EFFECTS ON MOLECULAR SPECTRA: Laboratory Experiments and Models, Consequences for Applications;4
3;Copyright Page;5
4;TABLE OF CONTENTS;8
5;FOREWORD;14
6;ACKNOWLEDGMENTS;16
7;CHAPTER I INTRODUCTION;18
8;CHAPTER II GENERAL EQUATIONS;26
8.1;II.1 INTRODUCTION;26
8.2;II.2 DIPOLE AUTOCORRELATION FUNCTION;27
8.2.1;II.2.1 General formalism;27
8.2.2;II.2.2 The Hamiltonian of the molecular system;30
8.3;II.3 TOWARD "CONVENTIONAL" IMPACT THEORIES;33
8.3.1;II.3.1 General properties of the correlation function;33
8.3.2;II.3.2 The binary collision approximation;34
8.3.3;II.3.3 Initial statistical correlations;36
8.3.4;II.3.4 The impact approximation;37
8.4;II.4 BEYOND THE IMPACT APPROXIMATION;40
8.5;II.5 EFFECTS OF THE RADIATOR TRANSLATIONAL MOTION;42
8.6;II.6 COLLISION-INDUCED SPECTRA;45
8.7;II.7 CONCLUSION;50
8.8;APPENDICES;50
8.8.1;II.A Spectral and time domain profiles in various spectroscopies;50
8.8.1.1;1. Absorption, emission, and dispersion;50
8.8.1.2;2. Rayleigh and spontaneous Raman scatterings;52
8.8.1.3;3. Nonlinear Raman spectroscopies;55
8.8.1.4;4. Time-resolved Raman spectroscopies;59
8.8.2;II.B Some criteria for the approximations;61
8.8.2.1;1. The large number of perturbers;61
8.8.2.2;2. The local thermodynamic equilibrium;62
8.8.2.3;3. The binary collisions;64
8.8.2.4;4. The (full) impact assumption;66
8.8.3;II.C The impact relaxation matrix;67
8.8.3.1;1. Analysis through the time dependence;67
8.8.3.2;2. Analysis through the frequency dependence;71
8.8.4;II.D The Liouville space;72
8.8.5;II.E The resolvent approach;75
8.8.5.1;1. Spectral-shape expression;75
8.8.5.2;2. Rotational invariance;77
8.8.5.3;3. Detailed balance;78
9;CHAPTER III ISOLATED LINES;80
9.1;III.1 INTRODUCTION;80
9.2;III.2 DOPPLER BROADENING AND DICKE NARROWING;90
9.2.1;III.2.1 The Doppler broadening;91
9.2.2;III.2.2 The Dicke narrowing;92
9.3;III.3 BASIC MODELS FOR SPECTRAL LINE SHAPES;94
9.3.1;III.3.1 The Lorentz profile;94
9.3.2;III.3.2 The Dicke profile;95
9.3.3;III.3.3 The Voigt profile;96
9.3.4;III.3.4 The Galatry profile;97
9.3.5;III.3.5 The Nelkin-Ghatak profile;98
9.3.6;III.3.6 Correlated profiles;100
9.3.7;III.3.7 Characteristics of the basic profiles;102
9.4;III.4 SPEED-DEPENDENT LINE-SHAPE MODELS;107
9.4.1;III.4.1 Observation of speed-dependent inhomogeneous profiles;107
9.4.2;III.4.2 Basic speed-dependent profiles;115
9.4.3;III.4.3 The Rautian-Sobelman model;121
9.4.4;III.4.4 The Keilson-Storer memory model;131
9.5;III.5 AB INITIO APPROACHES OF THE LINE SHAPE;143
9.5.1;III.5.1 The Waldmann-Snider kinetic equation;143
9.5.2;III.5.2 The generalized Hess method;145
9.5.3;III.5.3 Collision kernel method;147
9.5.4;III.5.4 Approaches from a simplified Waldmann-Snider equation;150
9.6;III.6 CONCLUSION;156
9.7;APPENDIX;157
9.7.1;III.A Computational aspects;157
9.7.1.1;1. Algorithms for the Voigt and Galatry profiles;157
9.7.1.2;2. Computation of speed-dependent profiles;159
10;CHAPTER IV COLLISIONAL LINE MIXING (WITHIN CLUSTERS OF LINES);164
10.1;IV.1 INTRODUCTION;164
10.2;IV.2 THE SPECTRAL SHAPE;171
10.2.1;IV.2.1 Approximations and general expressions;171
10.2.2;IV.2.2 Asymptotic expansions;175
10.2.3;IV.2.3 Computational aspects and recommendations;186
10.3;IV.3 CONSTRUCTING THE IMPACT RELAXATION MATRIX;190
10.3.1;IV.3.1 Simple empirical (classical) approaches;191
10.3.2;IV.3.2 Statistically based energy gap fitting laws;198
10.3.3;IV.3.3 Dynamically based scaling laws;205
10.3.4;IV.3.4 Semi-classical models;216
10.3.5;IV.3.5 Quantum models;228
10.4;IV.4 DETERMINING LINE-MIXING PARAMETERS FROM EXPERIMENTS;235
10.4.1;IV.4.1 Introduction;235
10.4.2;IV.4.2 Relaxation matrix elements;239
10.4.3;IV.4.3 First-order line-coupling coefficients;241
10.4.4;IV.4.4 Mixed theoretical model and measured spectra fitting approaches;244
10.5;IV.5 LITERATURE REVIEW;244
10.5.1;IV.5.1 Available line-mixing data;245
10.5.2;IV.5.2 Comparisons between predictions and laboratory measurements;246
10.5.3;IV.5.3 Comparisons between predictions and atmospheric measurements;249
10.6;IV.6 CONCLUSION;249
10.7;APPENDICES;250
10.7.1;IV.A Vibrational dephasing;250
10.7.2;IV.B Perturbed wave functions;254
10.7.3;IV.C Resonance broadening;255
11;CHAPTER V THE FAR WINGS (BEYOND THE IMPACT APPROXIMATION);258
11.1;V.1 INTRODUCTION;258
11.2;V.2 EMPIRICAL MODELS;260
11.2.1;V.2.1 The . factor approach;260
11.2.2;V.2.2 The tabulated continua;263
11.2.3;V.2.3 Other approaches;265
11.3;V.3 FAR WINGS CALCULATIONS: THE QUASISTATIC APPROACH;265
11.3.1;V.3.1 General expressions;266
11.3.2;V.3.2 Practical implementation and typical results;269
11.3.3;V.3.3 The band average line shape: back to the . factors;272
11.4;V.4 FROM RESONANCE TO THE FAR WING: A PERTURBATIVE TREATMENT;274
11.4.1;V.4.1 General expressions;274
11.4.2;V.4.2 Illustrative results;276
11.5;V.5 FROM RESONANCE TO THE FAR WING: A NON-PERTURBATIVE TREATMENT;278
11.5.1;V.5.1 General expression;278
11.5.2;V.5.2 Illustrative results;280
11.6;V.6 CONCLUSION;282
11.7;APPENDIX;283
11.7.1;V.A The water vapor continuum;283
11.7.1.1;1. Definition, properties and semi-empirical modeling of the H2O continuum;285
11.7.1.2;2. On the origin of the water vapor continua;286
11.7.1.3;3. The self- and N2-broadened continua within the .2 band;288
11.7.1.4;4. Conclusion;289
12;CHAPTER VI COLLISION-INDUCED ABSORPTION AND LIGHT SCATTERING;292
12.1;VI.1 INTRODUCTION;292
12.2;VI.2 COLLISION-INDUCED DIPOLES AND POLARIZABILITIES FOR DIATOMIC MOLECULES;293
12.3;VI.3 COLLISION-INDUCED SPECTRA IN THE ISOTROPIC APPROXIMATION;294
12.3.1;VI.3.1 Two illustrative examples: H2 and N2;294
12.3.2;VI.3.2 Modeling of the line shape;298
12.4;VI.4 EFFECTS OF THE ANISOTROPY OF THE INTERACTION POTENTIAL;301
12.5;VI.5 THE IMPORTANCE OF BOUND AND QUASIBOUND STATES IN CIA SPECTRA;307
12.6;VI.6 INTERFERENCE BETWEEN PERMANENT AND INDUCED DIPOLES (CIA) OR POLARIZABILITIES (CILS);310
12.6.1;VI.6.1 Depolarized light scattering spectra of H2 and N2;311
12.6.2;VI.6.2 The HD problem;313
12.6.3;VI.6.3 Intercollisional dips;317
12.7;VI.7 CONCLUSION;318
13;CHAPTER VII CONSEQUENCES FOR APPLICATIONS;320
13.1;VII.1 INTRODUCTION;320
13.2;VII.2 BASIC EQUATIONS;321
13.2.1;VII.2.1 Radiative heat transfer;321
13.2.2;VII.2.2 Remote sensing;324
13.3;VII.3 ISOLATED LINES;328
13.3.1;VII.3.1 The basic Lorentz and Voigt profiles;328
13.3.2;VII.3.2 More refined isolated line profiles;331
13.4;VII.4 LINE MIXING WITHIN CLUSTERS OF LINES;335
13.5;VII.5 ALLOWED BAND WINGS AND CIA;342
13.5.1;VII.5.1 Allowed band wings;342
13.5.2;VII.5.2 Collision-induced absorption;348
13.6;VII.6 CONCLUSION;350
14;CHAPTER VIII TOWARD FUTURE RESEARCHES;352
14.1;VIII.1 INTRODUCTION;352
14.2;VIII.2 DICKE NARROWING IN SPEED-DEPENDENT LINE-MIXING PROFILES;352
14.2.1;VIII.2.1 Models of profiles in the hard collision frame;352
14.2.2;VIII.2.2 Experimental tests in multiplet spectra;356
14.3;VIII.3 FROM RESONANCES TO THE FAR WINGS;360
14.3.1;VIII.3.1 Semi-classical approach;361
14.3.2;VIII.3.2 Generalized scaling approach;365
14.4;VIII.4 TOMORROW'S SPECTROSCOPIC DATABASES;365
14.4.1;VIII.4.1 Isolated lines;366
14.4.2;VIII.4.2 Line mixing;368
14.4.3;VIII.4.3 Far-wings and collision-induced absorption;369
14.5;VIII.5 CONCLUSION;371
15;APPENDIX;374
15.1;ABBREVIATIONS AND ACRONYMS;374
15.2;SYMBOLS;377
15.3;UNITS AND CONVERSIONS;379
16;REFERENCES;382
17;SUBJECT INDEX;426