Modern Vibrational Spectroscopy and Micro-Spectroscopy: Theory, Instrumentation and Biomedical Applications unites the theory and background of conventional vibrational spectroscopy with the principles of microspectroscopy. It starts with basic theory as it applies to small molecules and then expands it to include the large biomolecules which are the main topic of the book with an emphasis on practical experiments, results analysis and medical and diagnostic applications. This book is unique in that it addresses both the parent spectroscopy and the microspectroscopic aspects in one volume. Part I covers the basic theory, principles and instrumentation of classical vibrational, infrared and Raman spectroscopy. It is aimed at researchers with a background in chemistry and physics, and is presented at the level suitable for first year graduate students. The latter half of Part I is devoted to more novel subjects in vibrational spectroscopy, such as resonance and non-linear Raman effects, vibrational optical activity, time resolved spectroscopy and computational methods. Thus, Part 1 represents a short course into modern vibrational spectroscopy. Part II is devoted in its entirety to applications of vibrational spectroscopic techniques to biophysical and bio-structural research, and the more recent extension of vibrational spectroscopy to microscopic data acquisition. Vibrational microscopy (or microspectroscopy) has opened entirely new avenues toward applications in the biomedical sciences, and has created new research fields collectively referred to as Spectral Cytopathology (SCP) and Spectral Histopathology (SHP). In order to fully exploit the information contained in the micro-spectral datasets, methods of multivariate analysis need to be employed. These methods, along with representative results of both SCP and SHP are presented and discussed in detail in Part II.

Preface xv

Preface to 'Introduction to Modern Vibrational Spectroscopy' (1994) xix

I Modern Vibrational Spectroscopy and Micro-spectroscopy: Theory, Instrumentation and Biomedical Applications 1

I. 1 Historical Perspective of Vibrational Spectroscopy 1

I. 2 Vibrational Spectroscopy within Molecular Spectroscopy 2

References 4

1 Molecular Vibrational Motion 5

1.1 The concept of normal modes of vibration 6

1.2 The separation of vibrational, translational, and rotational coordinates 6

1.3 Classical vibrations in mass-weighted Cartesian displacement coordinates 7

1.4 Quantum mechanical description of molecular vibrations 13

1.4.1 Transition from classical to quantum mechanical description 13

1.4.2 Diatomic molecules: harmonic oscillator 14

1.4.3 Diatomic molecules: anharmonicity 19

1.4.4 Polyatomic molecules 20

1.5 Time-dependent description and the transition moment 22

1.5.1 Time-dependent perturbation of stationary states by electromagnetic radiation 22

1.5.2 The vibrational transition moment for absorption: harmonic diatomic molecules 25

1.5.3 The vibrational transition moment for absorption: anharmonic diatomic molecules 27

1.5.4 The vibrational transition moment for absorption: polyatomic molecules 30

1.5.5 Isotopic effects: diatomic molecules 31

1.6 Basic infrared and Raman spectroscopies 32

1.6.1 Infrared absorption spectroscopy 32

1.6.2 Raman (scattering) spectroscopy 35

1.7 Concluding remarks 38

References 38

2 Symmetry Properties of Molecular Vibrations 39

2.1 Symmetry operations and symmetry groups 40

2.2 Group representations 44

2.3 Symmetry representations of molecular vibrations 50

2.4 Symmetry-based selection rules for absorption processes 54

2.5 Selection rules for Raman scattering 56

2.6 Discussion of selected small molecules 57

2.6.1 Tetrahedral molecules: carbon tetrachloride, CCl₄ , and methane, CH₄ 57

2.6.2 Chloroform and methyl chloride 64

2.6.3 Dichloromethane (methylene chloride), CH₂ Cl₂ 67

2.6.4 Dichloromethane-d₁ (methylene chloride-d₁), CHDCl₂ 68

References 69

3 Infrared Spectroscopy 71

3.1 General aspects of IR spectroscopy 71

3.2 Instrumentation 73

3.2.1 Sources of infrared radiation: black body sources 73

3.2.2 Sources of infrared radiation: quantum-cascade lasers, nonlinear devices 75

3.2.3 Transfer optics 76

3.2.4 Color sorting devices: monochromators 76

3.2.5 Color encoding devices: interferometers 79

3.2.6 Detectors 82

3.2.7 Read-out devices 84

3.3 Methods in interferometric IR spectroscopy 84

3.3.1 General instrumentation 84

3.3.2 Optical resolution 86

3.3.3 Zero filling and fourier smoothing 86

3.3.4 Phase correction 88

3.3.5 Apodization 91

3.4 Sampling strategies 92

3.4.1 Transmission measurement 92

3.4.2 Specular reflection 94

3.4.3 Diffuse reflection 95

3.4.4 Attenuated total reflection 97

3.4.5 Infrared reflection absorption spectroscopy (IRRAS) 99

3.4.6 Fourier transform photoacoustic spectroscopy (FT-PAS) 100

3.4.7 Planar array infrared spectroscopy (PA-IRS) 101

3.4.8 Two-dimensional FTIR 101

3.4.9 Infrared microspectroscopy 102

References 102

4 Raman Spectroscopy 103

4.1 General aspects of Raman spectroscopy 104

4.2 Polarizability 105

4.3 Polarization of Raman scattering 107

4.4 Dependence of depolarization ratios on scattering geometry 111

4.5 A comparison between Raman and fluorescence spectroscopy 114

4.6 Instrumentation for Raman spectroscopy 116

4.6.1 Sources...