Preface

Modern spectroscopy techniques are used for the analysis of materials, such as the elemental, molecular, and chemical compositions, atomic structure, perfection of surfaces of solids, surface layers, and phase boundaries. These techniques employ electromagnetic radiation that is typically classified by the wavelength region of the spectrum. Spectroscopy techniques are used as a tool for studying the structures of atoms and molecules, as a large number of wavelengths emitted by different materials makes it possible to investigate their structures in detail, including the electron configurations of the ground and various excited states.

The book is divided into seven chapters, which are mainly focused on the experimental as well as theoretical aspects. These chapters include an introduction to atomic spectroscopy, vibrational Raman spectroscopy, vibrational zero-point energy of organic compounds, analysis of light absorption phenomenon, and discrimination by infrared spectroscopy. All the authors are experts and active in their fields and therefore this book provides the latest information about these topics. The contents of the book provide fundamental knowledge necessary for the advanced study in the field of modern spectroscopic techniques and applications. Proper references have been provided at the end of each chapter, which can lead the readers to the best sources in the literature and help them read more detail about the topic.

I am indebted to all the authors for helping me to complete this project and also many thanks to the entire IntechOpen publishing team for making this project possible. Furthermore, I am thankful to Ms. Dolores Kuzelj, the Author Service Manager, for her pleasant and cooperative behavior during the publishing process of this book. I hope that this book will help the readers acquire further knowledge about modern spectroscopic techniques and their applications in different areas.

> **Maaz Khan** PINSTECH, Islamabad, Pakistan

**Gustavo Morari do Nascimento** Federal University of ABC, Santo André, Brazil

**Marwa El-Azazy** Department of Chemistry and Earth Sciences, Qatar University, Doha, Qatar

**1**

**Chapter 1**

**Abstract**

*Deniz Sahin*

our analytical problems.

spectroscopy (MS)

**1. Introduction**

spectrometry is used.

according to their mass to charge (m/z) ratio [1].

**2. Atomic spectroscopy: general principles**

Atomic Spectroscopy

Atomic spectroscopy includes a number of analytical techniques used to determine the elemental composition of a sample (it can be gas, liquid, or solid) by observing its electromagnetic spectrum or its mass spectrum. Element concentrations of a millionth (ppm) or one billionth part (ppb) of the sample can be detected.

There are different variations of atomic spectroscopy, emission, absorption, fluorescence, and mass spectroscopy. Determination of an appropriate technique requires a basic understanding of each technique since each has its individual strengths and limitations. This chapter is designed to provide a basic overview to the atomic spectroscopy techniques and how can you select the one that best suits

**Keywords:** atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), atomic fluorescence spectroscopy (AFS), X-ray fluorescence (XRF), mass

Spectroscopy is the study of interactions between matter and different forms of electromagnetic radiation; when practiced to quantitative analysis, the term

Atomic spectroscopy includes the techniques of atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), atomic fluorescence spectroscopy (AFS), X-ray fluorescence (XRF), and inorganic mass spectroscopy (MS). AAS, AES, and AFS exploit interactions between UV-visible light and the valence electrons of free gaseous atoms. In XRF, high-energy charged particles collide with inner-shell electrons of atom, initiating transitions with eventual emission of X-ray photons. For inorganic MS, ionized analyte atoms are separated in a magnetic field

Every element has a characteristic atomic structure, with a small, positively charged nucleus surrounded by a sufficient number of electrons necessary to maintain neutrality. Electrons settle into orbitals within an atom and one of the electrons can also jump from one energy level to the higher level by acquiring the necessitated energy (**Figure 1**). This energy is provided by colliding with other atoms, such as heating-AES, photons derived from light-AAS and AFS, or high-energy electrons-XRF. Possible transitions happen, when the required energy reaches to the difference between two energy states (ΔE). A neutral atom may exist at a low energy shell
