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Construction of a New Forward and Backward Scat-Tering Raman Optical D´epartement de Chimie Universit´ede Fribourg (Suisse) Construction of a New Forward and Backward Scattering Raman Optical Activity Spectrometer and Graphical Analysis of Measured and Calculated Spectra for 2 2 2 (R)-[ H1, H2, H3]-Neopentane these` pr´esent´ee `ala facult´edes Sciences de l’Universit´e de Fribourg (Suisse) pour l’obtention du grade de Doctor rerum naturalium JACQUES HAESLER de Lutschental¨ (BE) Th`ese N° 1509 Imprimerie St-Paul, Fribourg 2006 Accept´ee par la Facult´edes Sciences de l’Universit´ede Fribourg (Suisse) sur la proposition du jury compos´ede MM. Composition du Jury : Prof. Dr. T. A. Jenny, Universit´ede Fribourg, pr´esident du jury, Prof. Dr. W. Hug, Universit´ede Fribourg, D´epartement de Chimie, directeur de th`ese, rapporteur, Prof. Dr. A. Weis, Universit´ede Fribourg, D´epartement de Physique, corapporteur, Prof. Dr. B. Champagne, Facult´es Universitaires Notre-Dame de la Paix, Laboratoire de Chimie Th´eorique Appliqu´ee, Namur (Belgique), corapporteur. Fribourg, le 16 mars 2006. Le Directeur de th`ese Le Doyen Prof. Dr. Werner Hug Prof. Marco Celio A` Marcel, parti trop tˆot. Table of Contents Table of Contents i Acknowledgments v R´esum´e vii Abstract ix I Introduction 1 1 Introduction to Raman Optical Activity 3 1.1 Optical Activity and Chirality ................... 3 1.2 Chirality in Everyday Life ..................... 6 1.3 Raman and ROA in Short ..................... 8 1.3.1 Vibrational Raman Scattering ............... 8 1.3.2 Raman Optical Activity (ROA) .............. 10 1.3.3 Theoretical Aspects ..................... 11 1.3.4 Experimental Aspects ................... 12 1.3.5 Computational Aspects ................... 15 1.4 Scope of Application of ROA ................... 17 1.5 Future of ROA ........................... 18 II Theory 21 2 Vibrational Raman Scattering 23 2.1 Introduction ............................. 23 2.2 Quantum Mechanical Theory ................... 24 2.3 Born-Oppenheimer and Placzek Approximation ......... 25 3 Raman Optical Activity Scattering 29 3.1 Introduction ............................. 29 i 3.2 Born-Oppenheimer and Placzek Approximation ......... 31 4 Raman and ROA Intensities 33 4.1 Illumination-Observation Geometry ................ 33 4.2 Raman and ROA Invariants .................... 35 4.3 Scattering Cross Sections ...................... 37 III Experiment 41 5 Basics of ROA Spectrometers 43 5.1 History ................................ 43 5.2 Practical Limitations of ROA Measurements ........... 44 5.2.1 The Exciting Laser Source ................. 45 5.2.2 The Sample ......................... 45 5.3 The Three Circular Polarisation Schemes ............. 46 5.3.1 Incident Circular Polarisation (ICP) ........... 46 5.3.2 Scattered Circular Polarisation (SCP) ........... 47 5.3.3 Dual Circular Polarisation (DCP) ............. 48 6 Offset Problems in ROA 51 6.1 Elimination of Deterministic Offsets in ROA ........... 51 6.2 Creating the Virtual Enantiomer ................. 52 6.3 The 2- and 4-phase Offset Correction Scheme .......... 54 7 A Novel SCP ROA Spectrometer 57 7.1 Basis of the Spectrometer ..................... 58 7.2 Optical description ......................... 59 7.2.1 Spectrograph and CCD Detector ............. 60 7.2.2 Cross-section Transformer Fiber Optics .......... 62 7.2.3 Light Collection ....................... 65 7.2.4 Circular Polarisation Analyser ............... 67 7.2.5 Correction Scheme Optics ................. 68 7.2.6 Exciting Laser Light .................... 69 7.2.7 Sample Cell and Temperature Control .......... 71 7.3 Data Acquisition System ...................... 72 7.3.1 Basic Acquisition Cycle .................. 74 7.3.2 Timing Units and 8-cycles ................. 75 7.3.3 Complete Acquisition Cycle ................ 76 7.3.4 CCD Readout and Binning ................ 77 7.3.5 The 16 Buffers ....................... 79 ii 8 Instrumental Performances 81 8.1 Backscattering SCP Spectra .................... 81 8.1.1 Degree of Circularity .................... 82 8.1.2 Raman Optical Activity .................. 86 8.2 Forward Scattering SCP Spectra .................. 96 8.2.1 Degree of Circularity .................... 96 8.2.2 Raman Optical Activity .................. 96 IV Computation 119 9 Computational Approach 121 9.1 Raman Optical Activity ......................121 9.1.1 Harmonic Force Field ....................122 9.1.2 Gradient of Electronic Tensors ...............123 10 VOAView: a Graphical User Interface 125 10.1 Installing and Launching VOAView ................126 10.2 Main Features of VOAView ....................127 10.2.1 Input File ..........................128 10.2.2 Vibrational Analysis ....................129 10.2.3 Molecular Structure .....................129 10.2.4 Vibrational Normal Modes .................130 10.2.5 Scattering Cross Sections ..................133 10.2.6 Group Coupling Matrices (GCM) .............134 10.2.7 Atomic Contribution Patterns (ACP) ...........135 10.2.8 Further Options .......................138 10.2.9 Output File .........................140 10.3 Main Features of VOAPlot .....................140 10.4 Simulating a Voigt Profile .....................141 10.5 IR and VCD .............................149 10.5.1 Expressions for VOAView .................149 10.5.2 Expressions for VOAPlot ..................150 V Applications 151 11 Neopentane and Neopentane-d12 153 11.1 Geometry and Conformation ....................154 11.2 Vibrational Frequencies .......................155 11.3 Raman Spectra ...........................162 11.3.1 Assignment for Neopentane ................162 iii 11.3.2 Assignment for Neopentane-d12. ..............168 2 2 2 12 (R)-[ H1, H2, H3]-Neopentane 177 12.1 Publication in Int. J. Quantum Chem. ..............177 2 2 2 12.2 Geometry and Conformations of (R)-[ H1, H2, H3]-neopentane 199 12.3 Vibrational frequencies .......................200 12.4 Simulation of Raman and ROA Spectra ..............200 VI Appendices 211 A ROA Spectrometer .........................213 B Additional Spectra .........................217 C VOAView ..............................223 D Computations ............................231 E DALTON vs. Gaussian03 .....................235 Conclusion and Outlook 237 References 239 List of Abbreviations 250 Curriculum Vitae 251 iv Remerciements Je tiens tout d’abord `aremercier mon directeur de th`ese, le professeur Werner Hug, de l’Universit´ede Fribourg (Suisse). Sa passion et son d´evouement sans ´egal pour la spectroscopie d’activit´eoptique vibrationnelle Raman (ROA) m’ont ´et´etransmis avec conviction, et je lui en suis particuli`erement recon- naissant. Je remercie le professeur Benoˆıt Champagne des Facult´es Universitaires Notre-Dame de la Paix de Namur (Belgique) ainsi que le professeur Antoine Weis de l’Universit´ede Fribourg pour avoir accept´eet accompli leur rˆole de corapporteur. Je remercie ´egalement le Prof. Titus A. Jenny pour avoir pr´esid´e le jury ainsi que le Prof. Thomas Bally pour ses corrections linguistiques. Je tiens `aremercier tout particuli`erement Markus Racheter et Olivier Graber, pour leur participation active `ala r´ealisation de notre spectrom`etre, mais ´egale- ment pour les bons moments pass´es ensemble. Un grand mercia ` Alphonse Crottet et Oswald Raetzo des diff´erents ateliers m´ecaniques. L’accomplissement de cette th`ese dois beaucoup `amon pr´ed´ecesseur, le docteur G´erard Zuber, que je remercie du fond du cœur pour sa disponibilit´e ainsi que pour tous ces conseils. Je remercie le professeur Benoˆıt Champagne, le docteur Olivier Quinet et Vincent Li´egeois pour notre ´etroite collaboration et pour les bons moments partag´es. Je remercie chaleureusement Marion Heckenroth, L´aszl´oMercs, Aur´elie Poulain et Claudio Gandolfi, l’´equipe du caf´edu matin, Oliver Graber, Verena v Schwalm, Anne Schuwey et Freddy Nydegger, ainsi que les diff´erents adeptes de la course `apied de notre d´epartement. Mes remerciements s’adressent ´egalement aux diff´erents personnes ayant contribu´es de pr`es ou de loin `ala r´ealisation de cette th`ese: Prof. Christian Bochet, Dr. Emmanuel Riguet, Ivan Schindelholz, Dmytro Dudenko, Maxim Fedorovsky, Elena Hasanova, Dr. Christine Deillon, Dr. Svetlana Zˇivanov, Dr. Krzysztof Piech, Dr. Pavel Bednarek, Olivier Aebischer, Rafa¨el Nussbaum, Pio B¨attig, Jo¨el Kuhni,¨ Frederic Birbaum, Claire-Lise Ciana, Emerith Brugger,¨ Hubert Favre, Xavier Hanselmann, Lucienne Rouiller, No¨el Chassot, Michel Piccand, Inge Muller¨ ainsi que tous ceux que j’aurais omis de citer. Une pens´ee toute particuli`ere est r´eserv´ee `amon amie Val´erie, pour m’avoir support´eet accompagn´edurant ces 4 ans. Ma maman ainsi que son ami Jean, mon fr`ere C´edric, sa femme Florence et leurs enfants Hugo et Mathieu, toute ma famille ainsi que tous mes proches sont ´egalement chaleureusement remerci´es. Finalement, je tiens `aremercier le Fond National Suisse de la Recherche Scientifique ainsi que le Canton de Fribourg pour leur financement. vi R´esum´e La construction d’un instrument unique au monde pour la d´etermination de la configuration absolue de compos´es chiraux, par spectroscopie d’activit´eoptique vibrationnelle Raman (AOVR), constitue la majeure partie du travail r´ealis´e durant cette th`ese. Le d´eveloppement d’un programme informatique muni d’une interface graphique, ainsi que son utilisation dans l’analyse comparative de r´esultats exp´erimentaux et computationnels, pr´esentent les capacit´es de cette m´ethode encore trop peu connue. Le Professeur Hug poss`ede un spectrom`etre d’AOVR, issu de son pro- pre d´eveloppement, situ´e`al’Universit´ede
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