INTRODUCTION TO MODERN VIBRATIONAL SPECTROSCOPY

Transcription

1 INTRODUCTION TO MODERN VIBRATIONAL SPECTROSCOPY MAX DIEM Department of Chemistry City University of New York Hunter College A Wiley-Interscience Publication JOHN WILEY & SONS New York Chichester Brisbane Toronto Singapore

2 CONTENTS Preface 1 Introduction References, 4 2 Results from Quantum Mechanics 2.1 The Concepts of Quantum Mechanics, The Time-Independent Schrödinger Equation, Time-Dependent Description, Transition Moments for Absorption, Particle-in-a-Box: An Example for Stationary State Wavefunctions and Transition Moment, The Vibrational Schrödinger Equation, The Vibrational Transition Moment, Electromagnetic Radiation, Einstein Coefficients of Absorption and Emission, Rotational Energies of Rigid Molecules, Spherical Top Rotors, Linear Molecules, Symmetrie Top Molecules, Rotational Spectra and Selection Rules for Linear Molecules, Rotational Energies and Spectra of Symmetrie Top Rotors, Rotational-Vibrational Spectra, 39

3 vi CONTENTS 2.11 Anharmonicity and Vibrational-Rotational Interaction, 43 References, 44 3 Polyatomic Molecules 3.1 The Separation of Translational and Rotational Coordinates, Classical Vibrations in Mass-Weighted Cartesian Coordinates, Quantum Mechanical Treatment of the Vibrations of Polyatomic Molecules, Accidental Degeneracy and Fermi Resonance, Group Frequencies, Isotopic Substitution and the Teller-Redlich Product Rule, Normal Mode Calculations, Aim of Normal Mode Analysis, Internal Coordinates, Kinetic and Potential Energies in Internal Coordinates, Transformation Between Cartesian, Internal, and Normal Coordinates, Symmetry Coordinates, Force Fields, The Generalized Valence Force Field (GVFF), Urey-Bradley Force Field (UBFF), Ab Initio Force Fields, Example for the Computation of Normal Modes of Vibration, Vibrational Intensities: Absorption, 86 References, 88 4 Symmetry of Molecular Vibrations 4.2 Group Representations, Representations of Molecular Vibrations, Selection Rules tor Normal Modes of Vibration, Symmetry Coordinates, 106 References, Introduction to Raman Spectroscopy 5.1 General Considerations, Classical Description of the Raman Effect, The Polarizability Tensor, Raman Selection Rules, Polarization of Raman Scattering, Raman Scattering Geometries and Depolarization Ratios for Right Angle Scattering, 124

4 CONTENTS Forward and Backscattering, Computation of Raman Scattered Intensities, Resonance Raman Spectroscopy, Time-Resolved Resonance Raman Spectroscopy, Nonlinear Raman Effects, Coherent Anti-Stokes-Raman Scattering (CARS), Stimulated Raman Scattering, Inverse Raman Effect, Raman-Induced Kerr Effects, The Hyper-Raman Effect, Surface Enhanced Raman Scattering (SERS), 142 References, Instrumentation for the Observation of Vibrational Spectra Dispersive Systems, Monochromators, Light Collection Optics for Monochromators, Interferometric Methods, General Aspects of Fourier Transform Infrared Spectroscopy, The Michelson Interferometer, Fourier Series and Fourier Transform, Discrete Fourier Transform and the Fast Fourier Transform Algorithm, Instrumentation for Infrared Spectroscopy, General Experimental Considerations, Dispersive Infrared Instrumentation, Principles of FT Spectrometers, Sampling Techniques in Infrared Spectroscopy, Transmission Spectroscopy, Attenuated Total Reflection and Diffuse Reflectance, Instrumentation for Raman Spectroscopy, Dispersive Single Detector Raman Instrumentation, Multichannel Dispersive Raman Spectrometers, Fourier Transform Raman Instrumentation, Hadamard Transform Spectroscopy, 173 References, Vibrational Spectra of Selected Small Molecules 7.1 Triatomic Molecules, Tetratomic Molecules, Pentatomic Methane Derivatives, Pentatomic Molecules with T d Symmetry, 180

5 viii CONTENTS Pentatomic Molecules with C 3v Symmetry, Pentatomic Molecules with C 2v Symmetry, Pentatomic Low Symmetry Species, Ethane and Ethane Derivatives, Example of an Amino Acid: Alanine, Cyclic Molecules: Benzene, Outlook, 202 References, Biophysical Applications of Vibrational Spectroscopy Peptide Vibrational Spectroscopy, Vibrations of the Peptide Linkage, The Conformational Sensitivity of the Amide I and III Modes, Resonance Raman Spectroscopy of Peptides and Proteins, UV Resonance Raman Studies of the Peptide - Linkage, Resonance Raman Spectroscopy of Prosthetic Groups, Herne Group Resonance Raman Studies, Herne Group Dynamic Studies, Other Prosthetic Groups, Nucleic Acids: DNA and RNA, Phosphodiester Vibrations, Ribose Vibrations, Base Vibrations, Conformational Studies on Model Nucleotides, Lipids, 232 References, Vibrational Optical Activity Infrared (Vibrational) Circular Dichroism, Phenomenological Description and Basic Equations, Observation of VCD, Applications of VCD: Small Molecules, Applications of VCD: Biomolecules, VCD of Peptides and Homo-oligoamino Acids, VCD of Proteins, VCD of Canonical Nucleic Acid Models, VCD Intensity Calculations for d(cg) 5 d(cg) 5, VCD of Small Oligomers, 253

6 CONTENTS ix 9.4 Raman Optical Activity, Phenomenological Description, Observation of ROA, Applications of ROA: Small Molecules, Applications of ROA: Biological Molecules, 260 References, 261 Appendix I Vibrational Frequencies [cm -1 ] for Sorne Common Groups 262 Appendix II Refined Set of Urey Bradley 264 Appendix III Character Tables for Chemically Important Symmetry Groups 266 Index 279