**Meet the editor**

Professor Theophile Theophanides was born in Platamon, Kavala, Greece and is known from his ground-breaking research in the field of Metal Coordination Chemistry and Infrared Spectroscopy. In particular his research focus has been in the areas of life metal ions, bioinorganic chemistry and in his pioneering work in anti-tumor drugs, such as cis-Platinum, commonly

employed in chemotherapy. He has authored over 250 peer-reviewed scientific publications in international journals, penned numerous articles and book chapters and served on the board of many Scientific Associations and Committees. He has been honored many times for his research. He is an Honorary Professor of the University of Montreal and the National Technical University of Athens, Doctor Honoris Causa of the University of Reims and Silver Medalist of the National French Academy of Medicine for his outstanding work on magnesium research. Additionally, he has received medals from Universities, Media and other Associations for his research and communications on Environmental and Public Health issues.

Contents

**Preface XI** 

Chapter Theophile Theophanides

**Section 1 Minerals and Glasses 11** 

Introductory **Introduction to Infrared Spectroscopy 1** 

Chapter 1 **Using Infrared Spectroscopy to Identify New** 

Chapter 2 **Application of Infrared Spectroscopy to** 

Chapter 3 **Structural and Optical Behavior of** 

Chapter 4 **Water in Rocks and Minerals –** 

Chapter 5 **Attenuated Total Reflection –** 

**Infrared Spectroscopy Applied to the Study of Mineral – Aqueous Electrolyte Solution Interfaces:** 

Grégory Lefèvre, Tajana Preočanin and Johannes Lützenkirchen

Chapter 6 **Research of Calcium Phosphates Using** 

**A General Overview and a Case Study 97** 

**Fourier Transform Infrared Spectroscopy 123**  Liga Berzina-Cimdina and Natalija Borodajenko

Jun-ichi Fukuda

Suédina M.L. Silva, Carla R.C. Braga, Marcus V.L. Fook, Claudia M.O. Raposo, Laura H. Carvalho and Eduardo L. Canedo

E. Culea, S. Rada, M. Culea and M. Rada

**Amorphous Phases – A Case Study of Carbonato Complex Formed by Mechanochemical Processing 13** 

**Analysis of Chitosan/Clay Nanocomposites 43** 

**Vanadate-Tellurate Glasses Containing PbO or Sm2O3 63** 

**Species, Distributions, and Temperature Dependences 77** 

Tadej Rojac, Primož Šegedin and Marija Kosec

## Contents

#### **Preface XIII**


**Fourier Transform Infrared Spectroscopy 123**  Liga Berzina-Cimdina and Natalija Borodajenko


Contents VII

Chapter 16 **Infrared Spectroscopy as a** 

**Section 3 Materials Technology 337** 

**Tool to Monitor Radiation Curing 325** 

Simona-Carmen Litescu, Eugenia D. Teodor, Georgiana-Ileana Truica, Andreia Tache

**of Building and Construction Materials 369**  Lucia Fernández-Carrasco, D. Torrens-Martín, L.M. Morales and Sagrario Martínez-Ramírez

Dulce M. A. Melo and Rubens M. Nascimento

**Functionalized Magnetic Nanoparticles 405**  Perla E. García Casillas, Claudia A. Rodriguez Gonzalez

**Gas Phase FTIR Spectroscopy Flow Analysis 421** 

**Characteristics from Infrared Emission Spectra 433**

N. Hamp, J.H. Knoetze, C. Aldrich and C. Marais

**Determination of Pesticide Residue 453**  Yankun Peng, Yongyu Li and Jingjing Chen

**of the Semiconductor Alloys Obtained**

**Using the Synchrotron Radiation as Source 467** 

**Characterization of SOFC Functional Ceramics 383** Daniel A. Macedo, Moisés R. Cesário, Graziele L. Souza, Beatriz Cela, Carlos A. Paskocimas, Antonio E. Martinelli,

Chapter 17 **Characterization of Compositional Gradient** 

Chapter 18 **Fourier Transform Infrared Spectroscopy –** 

Alata Hexig and Bayar Hexig

and Gabriel-Lucian Radu

Chapter 19 **Infrared Spectroscopy in the Analysis**

Chapter 20 **Infrared Spectroscopy Techniques in the** 

and Carlos A. Martínez Pérez

Chapter 22 **Determination of Adsorption Characteristics of Volatile Organic Compounds Using** 

Chapter 21 **Infrared Spectroscopy of** 

Tarik Chafik

Chapter 24 **Optical Technologies for** 

E.M. Sheregii

Chapter 23 **Identification of Rocket Motor** 

Chapter 25 **High Resolution Far Infrared Spectra** 

Marco Sangermano, Patrick Meier and Spiros Tzavalas

**Structure of Polymeric Materials by FTIR Technology 339** 

**Useful Analytical Tool for Non-Destructive Analysis 353**

Chapter 8 **Hydrothermal Treatment of Hokkaido Peat – An Application of FTIR and 13C NMR Spectroscopy on Examining of Artificial Coalification Process and Development 179**  Anggoro Tri Mursito and Tsuyoshi Hirajima

**Section 2 Polymers and Biopolymers 193** 

Chapter 9 **FTIR – An Essential Characterization Technique for Polymeric Materials 195**  Vladimir A. Escobar Barrios, José R. Rangel Méndez, Nancy V. Pérez Aguilar, Guillermo Andrade Espinosa and José L. Dávila Rodríguez


VI Contents

Chapter 7 **FTIR Spectroscopy of**

**Adsorbed Probe Molecules for Analyzing the** 

Roman M. Mironenko, Alexander V. Lavrenov

**Technique for Polymeric Materials 195** Vladimir A. Escobar Barrios, José R. Rangel Méndez, Nancy V. Pérez Aguilar, Guillermo Andrade Espinosa

**PVDF/PMMA/Graphene Polymer Blend** 

**Nanocomposites by Using ATR-FTIR Technique 213** 

**Polymers by Means Infrared Spectroscopy 245**

**Process, Phase Separation and Water Uptake 261**

**Self-Healing Functionality of Epoxy Resins 285** Liberata Guadagno and Marialuigia Raimondo

**Layer-By-Layer Polymer Membranes Having**

Weimin Zhou, Huitan Fu and Takaomi Kobayashi

**Characteristics of Heavy Metal Ion Desalination 301**

María González González, Juan Carlos Cabanelas and Juan Baselga

José Luis Rivera-Armenta, Cynthia Graciela Flores-Hernández, Ruth Zurisadai Del Angel-Aldana, Ana María Mendoza-Martínez, Carlos Velasco-Santos and Ana Laura Martínez-Hernández

and Vladimir A. Likholobov

**Section 2 Polymers and Biopolymers 193**

Chapter 9 **FTIR – An Essential Characterization** 

and José L. Dávila Rodríguez

Chapter 10 **Preparation and Characterization of** 

Somayeh Mohamadi

Chapter 11 **Reflectance IR Spectroscopy 233** Zahra Monsef Khoshhesab

Chapter 12 **Evaluation of Graft Copolymerization** 

Chapter 13 **Applications of FTIR on Epoxy Resins –** 

Chapter 14 **Use of FTIR Analysis to Control the** 

Chapter 15 **Infrared Analysis of Electrostatic** 

**of Acrylic Monomers Onto Natural** 

**Identification, Monitoring the Curing** 

Chapter 8 **Hydrothermal Treatment of Hokkaido Peat – An Application of FTIR and 13C NMR Spectroscopy on Examining of Artificial Coalification Process and Development 179** Anggoro Tri Mursito and Tsuyoshi Hirajima

**Surface Properties of Supported Pt (Pd) Catalysts 149**  Olga B. Belskaya, Irina G. Danilova, Maxim O. Kazakov,


XII Contents

Chapter 26 **Effective Reaction Monitoring of Intermediates by ATR-IR Spectroscopy Utilizing Fibre Optic Probes 493**  Daniel Lumpi and Christian Braunshier

Preface

spectroscopy in the materials science.

also been placed on firmer foundations.

This book has been written in response to a need for the edition of a book to support the advances that have been made in Infrared Spectroscopy. It aims to provide a comprehensive review of the most up-to-date knowledge on the advances of infrared

50 years have passed since I have been dealing with the first infrared spectrum when working on my PhD thesis at the University of Toronto. Infrared spectroscopy has developed since into a major field of study with far reaching scientific implications. Topics such as brain activity, chemical research and spectral analyses on cereals, plants and fruits which haven't been discussed 50 years ago, now present major fields in the discipline. More traditional topics such as infrared spectra of gases and materials have

The method of infrared (IR) spectroscopy, discovered in 1835 has so far produced a wealth of information on the architecture of matter in our planet and even in the far away stars. Infrared spectroscopy is a powerful technique that allows us to learn more about the structure of materials and their identification and characterization. This study is based on the interaction of electromagnetic (EM) radiation with matter. The EM radiation has energy states comparable to the vibrational energy states of the molecules. These states are included in the energy region between 14000 cm-1and 100 cm-1 of the Electromagnetic Radiation, which is divided in three sub-regions called 1)

The book contains 3 sections, which regroup the 26 chapters covering Infrared spectroscopy applied in all the above three regions. Section 1: **Minerals and Glasses** contains 8 chapters ,which describe the applications of IR in identifying amorphous phases of materials, glasses, rocks and minerals, catalysts, as well as peat and in reaction processes. Section 2: **Polymers and Biopolymers** deals especially with the characterization and evaluation of polymers and biopolymers using as a tool the IR technique. Finally, the last section 3: **Materials Technology** is concerned with research in FT-IR studies, in particular for characterization purposes and coupled with ATR

The interaction of EM with the vibrational energy states of the molecules gives birth to the IR-spectra in the above three regions. The IR spectra are really the" finger prints"

NEAR-IR, o r NIRS 2) MID-IR or MIRS and 3) FAR-IR. or FIRS:

and fiber optic probes in monitoring reaction intermediates.

## Preface

VIII Contents

Chapter 26 **Effective Reaction** 

**Monitoring of Intermediates by ATR-IR** 

Daniel Lumpi and Christian Braunshier

**Spectroscopy Utilizing Fibre Optic Probes 493** 

This book has been written in response to a need for the edition of a book to support the advances that have been made in Infrared Spectroscopy. It aims to provide a comprehensive review of the most up-to-date knowledge on the advances of infrared spectroscopy in the materials science.

50 years have passed since I have been dealing with the first infrared spectrum when working on my PhD thesis at the University of Toronto. Infrared spectroscopy has developed since into a major field of study with far reaching scientific implications. Topics such as brain activity, chemical research and spectral analyses on cereals, plants and fruits which haven't been discussed 50 years ago, now present major fields in the discipline. More traditional topics such as infrared spectra of gases and materials have also been placed on firmer foundations.

The method of infrared (IR) spectroscopy, discovered in 1835 has so far produced a wealth of information on the architecture of matter in our planet and even in the far away stars. Infrared spectroscopy is a powerful technique that allows us to learn more about the structure of materials and their identification and characterization. This study is based on the interaction of electromagnetic (EM) radiation with matter. The EM radiation has energy states comparable to the vibrational energy states of the molecules. These states are included in the energy region between 14000 cm-1and 100 cm-1 of the Electromagnetic Radiation, which is divided in three sub-regions called 1) NEAR-IR, o r NIRS 2) MID-IR or MIRS and 3) FAR-IR. or FIRS:

The book contains 3 sections, which regroup the 26 chapters covering Infrared spectroscopy applied in all the above three regions. Section 1: **Minerals and Glasses** contains 8 chapters ,which describe the applications of IR in identifying amorphous phases of materials, glasses, rocks and minerals, catalysts, as well as peat and in reaction processes. Section 2: **Polymers and Biopolymers** deals especially with the characterization and evaluation of polymers and biopolymers using as a tool the IR technique. Finally, the last section 3: **Materials Technology** is concerned with research in FT-IR studies, in particular for characterization purposes and coupled with ATR and fiber optic probes in monitoring reaction intermediates.

The interaction of EM with the vibrational energy states of the molecules gives birth to the IR-spectra in the above three regions. The IR spectra are really the" finger prints"

#### XIV Preface

of the materials and the absorption or transmission bands are the "signature bands" that characterize such materials (see Introduction to Infrared Spectroscopy). NIRS has been used also extensively in the food and agriculture industry as well as in pharmaceutical industry and medicine for the past 30 years. Recent technological advances have made NIRS an attractive analytical method to use in several other disciplines as well.

This book may be be a useful survey for those who would like to advance their knowledge in the application of FT-IR for the characterization and structural information of materials in materials science and technology.

#### **Theophile Theophanides**

**Introductory Chapter** 

Theophile Theophanides

*Greece*

**Introduction to Infrared Spectroscopy** 

*National Technical University of Athens, Chemical Engineering Department, Radiation Chemistry and Biospectroscopy, Zografou Campus, Zografou, Athens*

Infrared radiation was discovered by Sir William Herschel in 1800 [1]. Herschel was investigating the energy levels associated with the wavelengths of light in the visible spectrum. Sunlight was directed through a prism and showed the well known visible spectrum of the *rainbow colors*, i.e, the visible spectrum from blue to red with the analogous

Spectroscopy is the study of interaction of electromagnetic waves (EM) with matter. The wavelengths of the colors correspond to the energy levels of the rainbow colors. Herschel by slowly moving the thermometer through the visible spectrum from the blue color to the red and measuring the temperatures through the spectrum, he noticed that the temperature increased from blue to red part of the spectrum. Herschel then decided to measure the temperature just below the red portion thinking that the increase of temperature would stop outside the visible spectrum, but to his surprise he found that the temperature was even higher. He called these rays, which were below the red rays "non colorific rays" or invisible rays, which were called later "infrared rays" or IR light. This light is not visible to human eye. A typical human eye will respond to wavelengths from 390 to 750 nm. The IR spectrum starts at 0.75 nm. One nanometer (nm) is 10-9 m The Infrared spectrum is divided into, Near

Infrared (NIRS), Mid Infrared (MIRS) and Far Infrared (FIRS) [4-6].

**1. Introduction** 

**1.1 Short history of the technique**

wavelengths or frequencies [2, 3] (see Fig.1).

Fig. 1. The electromagnetic spectrum.

National Technical University of Athens, Chemical Engineering Department, Radiation Chemistry and Biospectroscopy, Zografou Campus, Zografou, Athens Greece

## **Introductory Chapter**

## **Introduction to Infrared Spectroscopy**

## Theophile Theophanides

*National Technical University of Athens, Chemical Engineering Department, Radiation Chemistry and Biospectroscopy, Zografou Campus, Zografou, Athens Greece* 

#### **1. Introduction**

XII Preface

disciplines as well.

of the materials and the absorption or transmission bands are the "signature bands" that characterize such materials (see Introduction to Infrared Spectroscopy). NIRS has been used also extensively in the food and agriculture industry as well as in pharmaceutical industry and medicine for the past 30 years. Recent technological advances have made NIRS an attractive analytical method to use in several other

This book may be be a useful survey for those who would like to advance their knowledge in the application of FT-IR for the characterization and structural

National Technical University of Athens, Chemical Engineering Department, Radiation Chemistry and Biospectroscopy, Zografou Campus, Zografou, Athens

**Theophile Theophanides** 

Greece

information of materials in materials science and technology.

#### **1.1 Short history of the technique**

Infrared radiation was discovered by Sir William Herschel in 1800 [1]. Herschel was investigating the energy levels associated with the wavelengths of light in the visible spectrum. Sunlight was directed through a prism and showed the well known visible spectrum of the *rainbow colors*, i.e, the visible spectrum from blue to red with the analogous wavelengths or frequencies [2, 3] (see Fig.1).

Fig. 1. The electromagnetic spectrum.

Spectroscopy is the study of interaction of electromagnetic waves (EM) with matter. The wavelengths of the colors correspond to the energy levels of the rainbow colors. Herschel by slowly moving the thermometer through the visible spectrum from the blue color to the red and measuring the temperatures through the spectrum, he noticed that the temperature increased from blue to red part of the spectrum. Herschel then decided to measure the temperature just below the red portion thinking that the increase of temperature would stop outside the visible spectrum, but to his surprise he found that the temperature was even higher. He called these rays, which were below the red rays "non colorific rays" or invisible rays, which were called later "infrared rays" or IR light. This light is not visible to human eye. A typical human eye will respond to wavelengths from 390 to 750 nm. The IR spectrum starts at 0.75 nm. One nanometer (nm) is 10-9 m The Infrared spectrum is divided into, Near Infrared (NIRS), Mid Infrared (MIRS) and Far Infrared (FIRS) [4-6].

Introduction to Infrared Spectroscopy 3

polarity (dipole moment) in the molecule then the infrared interaction is inactive and the

The forces that hold the atoms in a molecule are the chemical bonds. In a diatomic molecule, such as hydrochloric acid (H-Cl), the chemical bond is between hydrogen (H) and chlorine (Cl). The chemical forces that hold these two atoms together are considered to be similar to those exerted by massless springs. Each mass requires three coordinates, in order to define the molecule's position in space, with coordinate axes x,y,z in a Cartesian coordinate system. Therefore, the molecule has three independent **degrees of freedom** of motion. If there are N atoms in a molecule there will be a total of **3N degrees of freedom** of motion for all the atoms in the molecule. After subtracting the translational and rotational degrees of freedom from the 3N degrees of freedom, we are left with 3N-6 internal motions for a non linear molecule and 3N-5 for a linear molecule, since the rotation in a linear molecule, such as H-Cl the motion around the axis of the bond does not change the energy of the molecule. These internal vibrations are called the normal modes of vibration. Thus, in the example of H-Cl we have one vibration,(3x2)-5=1, i.e. only one vibration along the H-Cl axis or along the chemical bond of the molecule. For a non linear molecule as H2O we have (3x3)-6=3 vibrations, the two vibrations along the chemical bonds O-H symmetrical (*v*s) and antisymmetrical (*v*as) O-H bonds and the bending vibration (δ) of changing the angle H-O-H of the two bonds [3,4]. In this way we can interpret the IR-spectra of small inorganic compounds, such as, SO2, CO2 and NH3 quite reasonably. For the more complicated organic molecules the IR spectrum will give more vibrations as calculated from the 3N-6 vibrations, since the number of atoms in the molecule increases, however the spectrum is interpreted on the basis of characteristic bands.

The interaction of light and molecules forms the basis of IR spectroscopy. Here it will be given a short description of the Electromagnetic Radiation, the energy levels of a molecule and the

The EM radiation is a combination of periodically changing or oscillating electric field (EF) and magnetic field (MF) oscillating at the same frequency, but perpendicular to the electrical

The wavelength is represented by λ [6], which is the wavelength, the distance between two positions in the same phase and frequency (ν) is the number of oscillations per unit time of the EM wave per sec or vibrations/unit time. The wavenumber is the number of waves/unit

where, c is the velocity of light of EM waves, or light waves, which is a constant for a

(1) ߥߣ ൌ ܿ

way the Electromagnetic Radiation interacts with molecules and their structure [5, 6].

molecule does not produce any IR spectrum.

**2.1 Interaction of light waves with molecules** 

length [7]. It can be easily seen [3] that c is given by equation 1:

medium in which the waves are propagating, c=3x 108m/s

**2.2 Electromagnetic radiation** 

field [7] (see Fig.2).

**1.3 Degrees of freedom of vibrations** 

**2. Theory** 

#### **1.2 The three Infra red regions of interest in the electromagnetic spectrum**

In terms of wavelengths the three regions in micrometers (µm) are the following:


In terms of wavenumbers the three regions in cm-1 are:


The first region (NIRS) allows the study of overtones and harmonic or combination vibrations. The MIRS region is to study the fundamental vibrations and the rotation-vibration structure of small molecules, whereas the FIRS region is for the low heavy atom vibrations (metal-ligand or the lattice vibrations).Infrared (IR) light is electromagnetic (EM) radiation with a wavelength longer than that of visible light: ≤0.7µm. One micrometer (µm) is 10-6m.

Experiments continued with the use of these infrared rays in spectroscopy called, Infrared Spectroscopy and the first infrared spectrometer was built in 1835. IR Spectroscopy expanded rapidly in the study of materials and for the chemical characterization of materials that are in our planet as well as beyond the planets and the stars. The renowned spectroscopists, Hertzberg, Coblenz and Angstrom in the years that followed had advanced greatly the cause of Infrared spectroscopy. By 1900 IR spectroscopy became an important tool for identification and characterization of chemical compounds and materials. For example, the carboxylic acids, R-COOH, show two characteristic bands at 1700 cm-1 and near 3500 cm-1, which correspond to the C=O and O-H stretching vibrations of the carboxyl group, -COOH. Ketones, R-CO-R absorb at 1730-40cm-1. Saturated carboxylic acids absorb at 1710 cm-1, whereas saturated/aromatic carboxylic acids absorb at 1680-1690 cm-1 and carboxylic salts or metal carboxylates absorb at 1550-1610 cm-1. By 1950 IR spectroscopy was applied to more complicated molecules such as proteins by Elliot and Ambrose [2]. These later studies showed that IR spectroscopy could also be used to study biological molecules, such as proteins, DNA and membranes and could be used in biosciences, in general [2-8].

Physicochemical techniques, especially infrared spectroscopic methods are non distractive and may be the ones that can extract information concerning molecular structure and characterization of many materials at a variety of levels. Spectroscopic techniques those based upon the interaction of light with matter have for long time been used to study materials both *in vivo* and in *ex vivo* or *in vitro*. Infrared spectroscopy can provide information on isolated materials, biomaterials, such as biopolymers as well as biological materials, connective tissues, single cells and in general biological fluids to give only a few examples. Such varied information may be obtained in a single experiment from very small samples. Clearly then infrared spectroscopy is providing information on the energy levels of the molecules in wavenumbers(cm-1) in the region of electromagnetic spectrum by studying the vibrations of the molecules, which are also given in wavelengths (µm).

Thus, infrared spectroscopy is the study of the interaction of matter with light radiation when waves travel through the medium (matter). The waves are electromagnetic in nature and interact with the polarity of the chemical bonds of the molecules [3]. If there is no

The first region (NIRS) allows the study of overtones and harmonic or combination vibrations. The MIRS region is to study the fundamental vibrations and the rotation-vibration structure of small molecules, whereas the FIRS region is for the low heavy atom vibrations (metal-ligand or the lattice vibrations).Infrared (IR) light is electromagnetic (EM) radiation with a wavelength

Experiments continued with the use of these infrared rays in spectroscopy called, Infrared Spectroscopy and the first infrared spectrometer was built in 1835. IR Spectroscopy expanded rapidly in the study of materials and for the chemical characterization of materials that are in our planet as well as beyond the planets and the stars. The renowned spectroscopists, Hertzberg, Coblenz and Angstrom in the years that followed had advanced greatly the cause of Infrared spectroscopy. By 1900 IR spectroscopy became an important tool for identification and characterization of chemical compounds and materials. For example, the carboxylic acids, R-COOH, show two characteristic bands at 1700 cm-1 and near 3500 cm-1, which correspond to the C=O and O-H stretching vibrations of the carboxyl group, -COOH. Ketones, R-CO-R absorb at 1730-40cm-1. Saturated carboxylic acids absorb at 1710 cm-1, whereas saturated/aromatic carboxylic acids absorb at 1680-1690 cm-1 and carboxylic salts or metal carboxylates absorb at 1550-1610 cm-1. By 1950 IR spectroscopy was applied to more complicated molecules such as proteins by Elliot and Ambrose [2]. These later studies showed that IR spectroscopy could also be used to study biological molecules, such as proteins, DNA and membranes and could be used in biosciences, in general [2-8]. Physicochemical techniques, especially infrared spectroscopic methods are non distractive and may be the ones that can extract information concerning molecular structure and characterization of many materials at a variety of levels. Spectroscopic techniques those based upon the interaction of light with matter have for long time been used to study materials both *in vivo* and in *ex vivo* or *in vitro*. Infrared spectroscopy can provide information on isolated materials, biomaterials, such as biopolymers as well as biological materials, connective tissues, single cells and in general biological fluids to give only a few examples. Such varied information may be obtained in a single experiment from very small samples. Clearly then infrared spectroscopy is providing information on the energy levels of the molecules in wavenumbers(cm-1) in the region of electromagnetic spectrum by studying

**1.2 The three Infra red regions of interest in the electromagnetic spectrum**  In terms of wavelengths the three regions in micrometers (µm) are the following:

i. NIRS, (0.7 µm to 2,5 µm) ii. MIRS (2,5 µm to 25 µm) iii. FIRS (25 µm to300 µm).

1. (NIRS), 14000-4000 cm-1 2. (MIRS), 4000-400 cm-1 3. (FIRS), 400-10 cm-1

In terms of wavenumbers the three regions in cm-1 are:

longer than that of visible light: ≤0.7µm. One micrometer (µm) is 10-6m.

the vibrations of the molecules, which are also given in wavelengths (µm).

Thus, infrared spectroscopy is the study of the interaction of matter with light radiation when waves travel through the medium (matter). The waves are electromagnetic in nature and interact with the polarity of the chemical bonds of the molecules [3]. If there is no polarity (dipole moment) in the molecule then the infrared interaction is inactive and the molecule does not produce any IR spectrum.

#### **1.3 Degrees of freedom of vibrations**

The forces that hold the atoms in a molecule are the chemical bonds. In a diatomic molecule, such as hydrochloric acid (H-Cl), the chemical bond is between hydrogen (H) and chlorine (Cl). The chemical forces that hold these two atoms together are considered to be similar to those exerted by massless springs. Each mass requires three coordinates, in order to define the molecule's position in space, with coordinate axes x,y,z in a Cartesian coordinate system. Therefore, the molecule has three independent **degrees of freedom** of motion. If there are N atoms in a molecule there will be a total of **3N degrees of freedom** of motion for all the atoms in the molecule. After subtracting the translational and rotational degrees of freedom from the 3N degrees of freedom, we are left with 3N-6 internal motions for a non linear molecule and 3N-5 for a linear molecule, since the rotation in a linear molecule, such as H-Cl the motion around the axis of the bond does not change the energy of the molecule. These internal vibrations are called the normal modes of vibration. Thus, in the example of H-Cl we have one vibration,(3x2)-5=1, i.e. only one vibration along the H-Cl axis or along the chemical bond of the molecule. For a non linear molecule as H2O we have (3x3)-6=3 vibrations, the two vibrations along the chemical bonds O-H symmetrical (*v*s) and antisymmetrical (*v*as) O-H bonds and the bending vibration (δ) of changing the angle H-O-H of the two bonds [3,4]. In this way we can interpret the IR-spectra of small inorganic compounds, such as, SO2, CO2 and NH3 quite reasonably. For the more complicated organic molecules the IR spectrum will give more vibrations as calculated from the 3N-6 vibrations, since the number of atoms in the molecule increases, however the spectrum is interpreted on the basis of characteristic bands.

#### **2. Theory**

#### **2.1 Interaction of light waves with molecules**

The interaction of light and molecules forms the basis of IR spectroscopy. Here it will be given a short description of the Electromagnetic Radiation, the energy levels of a molecule and the way the Electromagnetic Radiation interacts with molecules and their structure [5, 6].

#### **2.2 Electromagnetic radiation**

The EM radiation is a combination of periodically changing or oscillating electric field (EF) and magnetic field (MF) oscillating at the same frequency, but perpendicular to the electrical field [7] (see Fig.2).

The wavelength is represented by λ [6], which is the wavelength, the distance between two positions in the same phase and frequency (ν) is the number of oscillations per unit time of the EM wave per sec or vibrations/unit time. The wavenumber is the number of waves/unit length [7]. It can be easily seen [3] that c is given by equation 1:

$$
\mathcal{L} = \mathcal{X}\nu \tag{1}
$$

where, c is the velocity of light of EM waves, or light waves, which is a constant for a medium in which the waves are propagating, c=3x 108m/s

Introduction to Infrared Spectroscopy 5

The name *atom* was coined by Democritus [9] from the Greek, α-τέµνω, meaning in Greek it cannot be cut any more or it is indivisible. This is the first time that it was postulated that the atom is the smallest particle of matter with its characteristics and it is the building block

Evbr: is the vibrational energy of the molecule, i.e., the sum of the vibrations of the atoms in

Fig. 3. A: Increasing the energy level from E0 to E1 with the wave energy h*v*, which results in the fundamental transition, B: Increasing the energy level from E0 to E2 leads to the first

We have two types of IR spectrophotometers: The classical and the Fourier Transform

The main elements of the standard IR classical instrumentation consist of 4 parts (see Fig.4)

Erot: is the rotational energy of the molecule, which can rotate along the three axes, x,y,z Etra: is the translational energy of the molecule, which is due to the movement of the

EE E E E E ele vib rot tra nuc (6)

of all materials in the universe. Combinations of atoms form molecules.

The energy of a molecule is the sum of 4 types of energies [3]:

Eele: is the electronic energy of all the electrons of the molecule

molecule as a whole along the three cartesian axes, x, y, z .

Energy level electronic transitions (see Figs 3A, 3B):

**2.3 Energy of a molecule** 

the molecule

Enuc: is the nuclear energy

overtone transition or first harmonic.

**3. The techniques of infrared spectroscopy** 

2. A dispersing element, diffraction grating or a prism

spectrophotometers with the interferometer

**3.1 The classical IR spectrometers [3, 4]** 

1. A light source of irradiation

Fig. 2. An Illustration of Electromagnetic Radiation can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This diagram shows a plane linearly polarized wave propagating from left to right. The electric field is in a vertical plane (E) blue and the magnetic field in a horizontal plane (M) red

The wavelength (λ) is inversely proportional to the frequency, 1/ν. The Energy in quantum terms [8]: is given by Planck's equation:

$$\mathbf{E} = h\nu \tag{2}$$

Which was deduced later also by Einstein, where, E is the energy of the photon of frequency ν and h is Max Planck's constant [8], h=6.62606896x 10-34 Js or h =4.13566733x 10-15 ev. Wave number and frequency are related by the equation

$$\mathbf{v} \triangleq \mathbf{\tilde{v}} \tag{3}$$

The EM spectrum can be divided as we have seen into several regions differing in frequency or wavelength. The relationship between the frequency (ν) the wavelength (λ) and the speed of light( c) is given below:

$$\nu = \frac{c}{\lambda} \text{ } \nu = \frac{E}{h} \text{ E} = \frac{\text{hc}}{\lambda} \tag{4}$$

The frequency in wavenumbers is given by the equation:

$$\vec{v} \cdot \vec{v} = \frac{1}{2\pi c} \sqrt{\frac{k}{\mu}} \quad \text{(cm}^{-1}\text{)}\tag{5}$$

Where, k=bond spring constant,µ= reduced mass, c=velocity of light (cm/sec),

µ is the reduced mass of the AB bond system of masses and m= mass of the atoms, mA=mass of A and mB= mass of B. The isotope effect can also be calculated using the reduced mass and substituting the isotopic mass in the equation of the frequency in wavenumbers.

Example, the H-Cl molecule

$$\mu = \frac{\mathbf{m}\_{\rm H} m\_{\rm Cl}}{m\_{\rm H} + m\_{\rm Cl}}$$

mH and mCl are the atomic masses of H and Cl atoms.

#### **2.3 Energy of a molecule**

4 Infrared Spectroscopy – Materials Science, Engineering and Technology

Fig. 2. An Illustration of Electromagnetic Radiation can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This diagram shows a plane linearly polarized wave propagating from left to right. The electric field is in a vertical plane

The wavelength (λ) is inversely proportional to the frequency, 1/ν. The Energy in quantum

Which was deduced later also by Einstein, where, E is the energy of the photon of frequency ν and h is Max Planck's constant [8], h=6.62606896x 10-34 Js or h =4.13566733x 10-15 ev. Wave

The EM spectrum can be divided as we have seen into several regions differing in frequency or wavelength. The relationship between the frequency (ν) the wavelength (λ) and the speed

> � <sup>ℎ</sup> E =

�� <sup>=</sup> <sup>1</sup> ��� �� �

µ is the reduced mass of the AB bond system of masses and m= mass of the atoms, mA=mass of A and mB= mass of B. The isotope effect can also be calculated using the reduced mass

> mH *Cl H Cl m m m*

hc λ

� = � � � =

Where, k=bond spring constant,µ= reduced mass, c=velocity of light (cm/sec),

and substituting the isotopic mass in the equation of the frequency in wavenumbers.

� = ℎ� (2)

ν =cν᷈ (3)

(cm-1) (5)

(4)

(E) blue and the magnetic field in a horizontal plane (M) red

terms [8]: is given by Planck's equation:

of light( c) is given below:

Example, the H-Cl molecule

number and frequency are related by the equation

The frequency in wavenumbers is given by the equation:

mH and mCl are the atomic masses of H and Cl atoms.

The name *atom* was coined by Democritus [9] from the Greek, α-τέµνω, meaning in Greek it cannot be cut any more or it is indivisible. This is the first time that it was postulated that the atom is the smallest particle of matter with its characteristics and it is the building block of all materials in the universe. Combinations of atoms form molecules.

The energy of a molecule is the sum of 4 types of energies [3]:

$$\mathbf{E} = \mathbf{E}\_{\text{ele}} + \mathbf{E}\_{\text{vib}} + \mathbf{E}\_{\text{rot}} + \mathbf{E}\_{\text{tra}} + \mathbf{E}\_{\text{nuc}} \tag{6}$$

Eele: is the electronic energy of all the electrons of the molecule

Evbr: is the vibrational energy of the molecule, i.e., the sum of the vibrations of the atoms in the molecule

Erot: is the rotational energy of the molecule, which can rotate along the three axes, x,y,z Etra: is the translational energy of the molecule, which is due to the movement of the molecule as a whole along the three cartesian axes, x, y, z .

Enuc: is the nuclear energy

Energy level electronic transitions (see Figs 3A, 3B):

Fig. 3. A: Increasing the energy level from E0 to E1 with the wave energy h*v*, which results in the fundamental transition, B: Increasing the energy level from E0 to E2 leads to the first overtone transition or first harmonic.

#### **3. The techniques of infrared spectroscopy**

We have two types of IR spectrophotometers: The classical and the Fourier Transform spectrophotometers with the interferometer

#### **3.1 The classical IR spectrometers [3, 4]**

The main elements of the standard IR classical instrumentation consist of 4 parts (see Fig.4)


Introduction to Infrared Spectroscopy 7

Fig. 5A. Michelson FT-IR Spectrometer has the following main parts:

Fig. 5B. Schematic illustration of a modern FTIR Spectrophotometer.

Infrared spectroscopy underwent tremendous advances after the second world war and after 1950 with improvements in instrumentation and electronics, which put the technique at the center of chemical research and later in the 80's in the biosciences in general with new sample handling techniques, the attenuated total reflection method (ATR) and of course the interferometer [13]. The Fourier Transform.IR spectrophotometry is now widely used in both research and industry as a routine method and as a reliable technique for quality control,

1. Light source

4. Detector

3. Translating mirror

2. Beam splitter (half silvered mirror)

5. Optical System (fixed mirror)

#### 3. A detector

4. Optical system of mirrors

Schematics of a two-beam absorption spectrometer are shown in. Fig. 4.

Fig. 4. A schematic diagram of the classical dispersive IR spectrophotometer.

The infrared radiation from the source by reflecting to a flat mirror passes through the sample and reference monochromator then through the sample. The beams are reflected on a rotating mirror, which alternates passing the sample and reference beams to the dispersing element and finally to detector to give the spectrum (see Fig 4). As the beams alternate the mirror rotates slowly and different frequencies of infrared radiation pass to detector.

### **3.2 Fourier Transform IR spectrometers**

The modern spectrometers [7] came with the development of the high performance Fourier Transform Infrared Spectroscopy (FT-IR) with the application of a Michelson Interferometer [10]. Both IR spectrometers classical and modern give the same information the main difference is the use of Michelson interferometer, which allows all the frequencies to reach the detector at once and not one at the time/

In the 1870's A.A. Michelson [11] was measuring light and its speed with great precision(3) and reported the speed of light with the greatest precision to be 299,940 km/s and for this he was awarded the Nobel Prize in 1907. However, even though the experiments in interferometry by Michelson and Morley [12] were performed in 1887 the interferograms obtained with this spectrometer were very complex and could not be analyzed at that time because the mathematical formulae of Jean Baptiste Fourier series in 1882 could not be solved [13]. We had to wait until the invention of Lasers and the high performance of electronic computers in order to solve the mathematical formulae of Fourier to transform a number of points into waves and finally into the spectra [14]

The addition, of the lasers to the Michelson interferometer provided an accurate method (see Figs. 5A & 5B) of monitoring displacements of a moving mirror in the interferometer with a high performance computer, which allowed the complex interferogram to be analyzed and to be converted *via* Fourier transform to give spectra.

Schematics of a two-beam absorption spectrometer are shown in. Fig. 4.

Fig. 4. A schematic diagram of the classical dispersive IR spectrophotometer.

The infrared radiation from the source by reflecting to a flat mirror passes through the sample and reference monochromator then through the sample. The beams are reflected on a rotating mirror, which alternates passing the sample and reference beams to the dispersing element and finally to detector to give the spectrum (see Fig 4). As the beams alternate the

The modern spectrometers [7] came with the development of the high performance Fourier Transform Infrared Spectroscopy (FT-IR) with the application of a Michelson Interferometer [10]. Both IR spectrometers classical and modern give the same information the main difference is the use of Michelson interferometer, which allows all the frequencies to reach

In the 1870's A.A. Michelson [11] was measuring light and its speed with great precision(3) and reported the speed of light with the greatest precision to be 299,940 km/s and for this he was awarded the Nobel Prize in 1907. However, even though the experiments in interferometry by Michelson and Morley [12] were performed in 1887 the interferograms obtained with this spectrometer were very complex and could not be analyzed at that time because the mathematical formulae of Jean Baptiste Fourier series in 1882 could not be solved [13]. We had to wait until the invention of Lasers and the high performance of electronic computers in order to solve the mathematical formulae of Fourier to transform a

The addition, of the lasers to the Michelson interferometer provided an accurate method (see Figs. 5A & 5B) of monitoring displacements of a moving mirror in the interferometer with a high performance computer, which allowed the complex interferogram to be

mirror rotates slowly and different frequencies of infrared radiation pass to detector.

3. A detector

4. Optical system of mirrors

**3.2 Fourier Transform IR spectrometers** 

the detector at once and not one at the time/

number of points into waves and finally into the spectra [14]

analyzed and to be converted *via* Fourier transform to give spectra.

Fig. 5A. Michelson FT-IR Spectrometer has the following main parts:


Fig. 5B. Schematic illustration of a modern FTIR Spectrophotometer.

Infrared spectroscopy underwent tremendous advances after the second world war and after 1950 with improvements in instrumentation and electronics, which put the technique at the center of chemical research and later in the 80's in the biosciences in general with new sample handling techniques, the attenuated total reflection method (ATR) and of course the interferometer [13]. The Fourier Transform.IR spectrophotometry is now widely used in both research and industry as a routine method and as a reliable technique for quality control,

Introduction to Infrared Spectroscopy 9

Fig. 7. Breast tissue: a 3-axis diagram and the mean spectral components are shown [25].

medical sciences.

**5. References** 

press, 1969, 472 p

Ltd. 105p

applications of IR spectroscopy are the following:

[1] W. Herschel, Phil. Trans.R.Soc.London, 90, 284 (1800)

as biological molecules proteins, DNA and membranes. In the last decade infrared spectroscopy started to be used to characterize healthy and non healthy human tissues in

IR spectroscopy is used in both research and industry for measurement and quality control. The instruments are now small and portable to be transported, even for use in field trials. Samples in solution can also be measured accurately. The spectra of substances can be compared with a store of thousands of reference spectra [18]. Some samples of specific

IR spectroscopy has been highly successful in measuring the degree of polymerization in polymer manufacture [18]. IR spectroscopy is useful for identifying and characterizing substances and confirming their identity since the IR spectrum is the "fingerprint" of a substance. Therefore, IR also has a forensic purpose and IR spectroscopy is used to analyze substances, such as, alcohol, drugs, fibers, blood and paints [19-28]. In the several sections that are given in the book the reader will find numerous examples of such applications.

[2] Elliot and E. Ambrose, Nature, Structure of Synthetic Polypeptides 165, 921 (1950);

[4] J. Anastasopoulou and Th. Theophanides, Chemistry and Symmetry", In Greek National

[5] G.Herzberg, Atomic spectra and atomic structure, Dover Books, New York,Academic

[6] Maas, J.H. van der (1972) *Basic Infrared Spectroscopy*.2nd edition. London: Heyden & Son

[7] Colthup, N.B., Daly, L.H., and Wiberley, S.E.(1990).*Introduction to Infrared and Raman* 

*Spectroscopy*.Third Edition. London: Academic press Ltd, 547 p.

Related Biological Substances, Current Research, Vol. 12, , 1950 , 516p [3] T. Theophanides, In Greek, National Technical University of Athens, Chapter in

"Properties of Materials", NTUA, Athens (1990); 67p

Technical University of Athens, NTUA, (1997), 94p

D.L.Woernley, Infrared Absorption Curves for Normal and Neoplastic Tissues and

molecular structure determination and kinetics [14-16] in biosciences(see Fig. 6). Here the spectrum of a very complex matter , such as an atheromatic plaque is given and interpreted.

In practice today modern techniques are used and these are the FT-methods. The non- FT methods are the classical IR techniques of dispersion of light with a prism or a diffraction grading. The FT-technique determines the absorption spectra more precisely. A Michelson interferometer should be used today to obtain the IR spectra [17]. The advantage of FTmethod is that it detects a broad band of radiation all the time (the multiplex or Fellget advantage) and the greater proportion of the source radiation passes through the instrument because of the circular aperture (Jacquinot advantage) rather than the narrow slit used for prisms or diffraction gratings in the classical instrument.

Fig. 6. FT-IR spectrum of a coronary atheromatic plaque is shown with the characteristic absorption bands of proteins, amide bands, O-P-O of DNA or phospholipids, disulfide groups, etc.

#### **3.3 Micro-FT-IR spectrometers**

The addition of a reflecting microscope to the IR spectrometer permits to obtain IR spectra of small molecules, crystals and tissues cells, thus we can apply the IR spectroscopy to biological systems, such as connective tissues, blood samples and bones, in pathology in medicine [15, 26-27]. In Fig. 7 is shown the microscope imaging of cancerous breast tissues and its spectrum.

#### **4. Applications**

Infrared spectroscopy is used in chemistry and industry for identification and characterization of molecules. Since an IR spectrum is the "fingerprint" of each molecule IR is used to characterize substances [16, 17]. Infrared spectroscopy is a non destructive method and as such it is useful to study the secondary structure of more complicated systems such

molecular structure determination and kinetics [14-16] in biosciences(see Fig. 6). Here the spectrum of a very complex matter , such as an atheromatic plaque is given and interpreted. In practice today modern techniques are used and these are the FT-methods. The non- FT methods are the classical IR techniques of dispersion of light with a prism or a diffraction grading. The FT-technique determines the absorption spectra more precisely. A Michelson interferometer should be used today to obtain the IR spectra [17]. The advantage of FTmethod is that it detects a broad band of radiation all the time (the multiplex or Fellget advantage) and the greater proportion of the source radiation passes through the instrument because of the circular aperture (Jacquinot advantage) rather than the narrow slit used for

Fig. 6. FT-IR spectrum of a coronary atheromatic plaque is shown with the characteristic absorption bands of proteins, amide bands, O-P-O of DNA or phospholipids, disulfide

The addition of a reflecting microscope to the IR spectrometer permits to obtain IR spectra of small molecules, crystals and tissues cells, thus we can apply the IR spectroscopy to biological systems, such as connective tissues, blood samples and bones, in pathology in medicine [15, 26-27]. In Fig. 7 is shown the microscope imaging of cancerous breast tissues

Infrared spectroscopy is used in chemistry and industry for identification and characterization of molecules. Since an IR spectrum is the "fingerprint" of each molecule IR is used to characterize substances [16, 17]. Infrared spectroscopy is a non destructive method and as such it is useful to study the secondary structure of more complicated systems such

prisms or diffraction gratings in the classical instrument.

groups, etc.

and its spectrum.

**4. Applications** 

**3.3 Micro-FT-IR spectrometers** 

Fig. 7. Breast tissue: a 3-axis diagram and the mean spectral components are shown [25].

as biological molecules proteins, DNA and membranes. In the last decade infrared spectroscopy started to be used to characterize healthy and non healthy human tissues in medical sciences.

IR spectroscopy is used in both research and industry for measurement and quality control. The instruments are now small and portable to be transported, even for use in field trials. Samples in solution can also be measured accurately. The spectra of substances can be compared with a store of thousands of reference spectra [18]. Some samples of specific applications of IR spectroscopy are the following:

IR spectroscopy has been highly successful in measuring the degree of polymerization in polymer manufacture [18]. IR spectroscopy is useful for identifying and characterizing substances and confirming their identity since the IR spectrum is the "fingerprint" of a substance. Therefore, IR also has a forensic purpose and IR spectroscopy is used to analyze substances, such as, alcohol, drugs, fibers, blood and paints [19-28]. In the several sections that are given in the book the reader will find numerous examples of such applications.

#### **5. References**


**Section 1** 

**Minerals and Glasses** 

