Preface ........................................................ ix
Chapter 1
Introduction to Near-Infrared Spectra ........................... 1
1.1. Molecular Spectra ......................................... 1
1.2. Vibrational Energy Levels ................................. 1
1.3. Spectral Response and Molecular Concentration ............. 1
1.4. Nomenclature of Molecular Vibrations ...................... 3
1.5. Stretching Vibrations ..................................... 3
1.6. Bending ................................................... 5
1.7. Beginning Group Theory for Near-Infrared Spectra .......... 7
1.8. Rotational Axes ........................................... 7
1.9. Reflection Planes ......................................... 7
1.10. Inversion Centers ......................................... 7
1.11. Improper Rotational Axes .................................. 8
1.12. Point Groups .............................................. 8
1.13. Defining a Group Using Matrix Operations .................. 8
1.14. Practical Aspects for Spectral Measurements ............... 8
1.15. Types of Near-Infrared Absorption Bands .................. 10
1.16. Properties of Infrared-Near-Infrared Energy .............. 11
1.17. Normal Mode Theory (The Ideal or Simple Harmonic
Oscillator) .............................................. 12
1.18. The Anharmonic Oscillator ................................ 13
1.19. Illustration of the Simple Harmonic Oscillator or Normal
Mode ..................................................... 16
1.20. The Selection Rule ....................................... 16
1.21. Illustration of the Anharmonic Oscillator ................ 17
1.22. Interpretive Near-Infrared Spectroscopy .................. 17
1.23. Group Frequencies ........................................ 18
1.24. Coupling of Vibrations ................................... 18
1.25. Fermi Resonance (or Second-Order Coupling) ............... 19
1.26. Tools and Techniques for Assigning Band Locations ........ 20
References ..................................................... 21
Chapter 2
Alkanes and Cycloalkanes ....................................... 23
2.1. C-H Functional Groups .................................... 23
2.2. Methyl Groups, CH3 ....................................... 23
2.2.1. First Overtone Region ............................ 23
2.2.2. Higher-Order Overtones ........................... 26
2.2.3. Combination Bands ................................ 26
2.3. Methylene Groups, CH2 .................................... 29
2.3.1. First Overtone Region — Linear Molecules ......... 29
2.3.2. Higher-Order Overtones — Linear Molecules ........ 30
2.3.3. Combination Bands, Linear Molecules .............. 30
2.3.4. First Overtones, Cyclic Molecules ................ 31
2.3.5. Higher-Order Overtones, Cyclic Molecules ......... 31
2.3.6. Combination Bands, Cyclic Molecules .............. 32
2.4. Methine Groups ........................................... 32
2.5. Model Compound Comparisons ............................... 32
References ..................................................... 35
Chapter 3
Alkenes and Alkynes ............................................ 37
3.1. Linear Alkenes, Overtones ................................ 37
3.2. Linear Alkenes, Combinations/Bending Modes ............... 37
3.3. Cyclic Double Bonds ...................................... 39
3.4. Dienes ................................................... 40
3.5. Alkynes and Allenes ...................................... 41
References ..................................................... 41
Chapter 4
Aromatic Compounds ............................................. 43
4.1. Benzene .................................................. 43
4.2. Substituted Aromatics — Alkyl ............................ 43
4.3. Substituted Aromatics — Nonalkyl ......................... 44
4.4. Other Aromatic Compounds ................................. 46
References ..................................................... 49
Chapter 5
Hydroxyl-Containing Compounds .................................. 51
5.1. O-H Functional Groups .................................... 51
5.2. Alcohols ................................................. 51
5.2.1. First Overtone Region ............................ 51
5.2.2. Higher-Order Overtones ........................... 53
5.2.3. Combination Bands ................................ 53
5.3. Phenols .................................................. 55
5.3.1. Overtones ........................................ 55
5.3.2. Phenols Combinations ............................. 55
5.4. Multiple Hydroxyl Compounds .............................. 56
5.5. Hydroperoxides ........................................... 56
5.6. OH in Carboxylic Acids ................................... 58
5.6.1. Overtones ........................................ 58
5.6.2. OH in Carboxylic Acids, Combination Bands ........ 58
5.7. Silanols ................................................. 59
5.8. Enols and Enolates ....................................... 60
References ..................................................... 61
Chapter 6
Water .......................................................... 63
6.1. Water .................................................... 63
6.2. Liquid Water, Ice, and Water Vapor ....................... 63
6.3. Deuterium Oxide (D20) .................................... 65
6.4. Water in Various Solvents ................................ 66
6.5. Water in Other Matrices, including Glasses ............... 67
6.6. Ionic Species in Water ................................... 67
References ..................................................... 69
Chapter 7
Carbonyls ...................................................... 71
7.1. Organic Carbonyl Compounds, Overtones 71
7.2. Organic Carbonyl Compounds, Combination Bands ............ 72
7.3. Carbonate ................................................ 74
7.4. Isocyanates .............................................. 74
References ..................................................... 75
Chapter 8
Amines and Amides .............................................. 77
8.1. N-H Functional Groups .................................... 77
8.2. Amines, Aliphatic ........................................ 77
8.2.1. Overtones ........................................ 77
8.2.2. Combinations ..................................... 77
8.3. Amines, Aromatic ......................................... 78
8.3.1. Overtones ........................................ 78
8.3.2. Combinations ..................................... 80
8.4. Ammonia .................................................. 81
8.5. Amides, Aliphatic and Aromatic ........................... 81
8.5.1. Overtones ........................................ 81
8.5.2. Amides, Combinations ............................. 82
8.6. Amides, Cyclic (lactams) ................................. 84
References ..................................................... 85
Chapter 9
P-H and S-H .................................................... 87
9.1. P-H ...................................................... 87
9.2. S-H ...................................................... 87
References ..................................................... 88
Chapter 10
Carbohydrates .................................................. 89
10.1. Introduction ............................................. 89
10.2. Cellulose and Cellulosic Compounds ....................... 89
References ..................................................... 92
Chapter 11
Amino Acids, Peptides, and Proteins ............................ 93
11.1. Proteins ................................................. 93
11.2. Protein Structure ........................................ 93
References ..................................................... 95
Chapter 12
Synthetic Polymers and Rubbers ................................. 97
12.1. Introduction ............................................. 97
12.2. Interpretive Spectroscopy of Organic Compound Spectra
for Polymers and Rubbers in the NIR Region ............... 97
12.3. Polymers ................................................. 97
12.4. Rubbers .................................................. 99
References .................................................... 105
Chapter 13
History of Near-Infrared (NIR) Applications ................... 107
13.1. History of NIR for Industrial Chemicals ................. 107
13.2. History of NIR for Food and Agriculture ................. 108
13.3. History of NIR for Pharmaceuticals ...................... 109
References .................................................... 109
Appendix 1
NIR Absorption Band Charts—An Overview ........................ 113
Appendix 2a
Spectra-Structure Correlations—Labeled Spectra from
10,500 cm-1 to 6300 cm-1 (952 nm to 1587 nm) .................. 117
Appendix 2b
Spectra-Structure Correlations—Labeled Spectra from
7200 cm-1 to 3800 cm-1 (1389 nm to 2632 nm) ................... 165
Appendix 3
Detailed Spectra-Structure Correlations—Overlapping Spectra
from 10,500 cm-1 to 3800 cm-1 (952 nm to 2632 nm) ............. 207
Appendix 4a
Spectra-Structure Correlations for Near Infrared
(in Ascending Wavelength and Descending Wavenumber Order) ..... 239
Appendix 4b
Spectra-Structure Correlations for Near-Infrared
(in Ascending Alphabetical Functional Group Order) ............ 265
Appendix 5
Spectra Index by Functional Group or Comparison Series
Group ......................................................... 289
Appendix 6
Spectra Index by Alphanumerical Order of Compound Name ........ 299
Appendix 7
Spectra Index by Molecular Formula (Carbon Number) ............ 309
Index ......................................................... 319
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