This course on “Introduction to Atomic and Molecular Physics” is focused to develop a base for understanding modern science. Since the constituents of materials are atoms and molecules, the overall picture about these constituents is necessary. Keeping this in mind, a chronological development of the concept of the matter in microscopic level namely atoms and molecules and their interactions with light is systematically presented in this course.  Although the concept of quantization of the light as well as atomic energy levels is developed, but the mathematical formalisms of the quantum mechanics are not derived here. While developing this course, it is assumed that the basics of the quantum mechanics are known. Thus, the quantum mechanical formalisms are used to show that how these help to understand the experimental observations of atomic and molecular spectra.

There are several text books and also lectures /websites available in the internet related to Atomic and Molecular physics. These have been the valuable references in organizing many concepts of the course and are listed in the reference section.

The organization of this course is as follows:

Module-I: Initially, the importance of the atomic and molecular physics in current science is presented. The direct applications in day to day life are also presented in lecture-1. A historical journey of this field from the ancient days given in lecture-2 to lecture-4 will provide an idea about the conceptual development in this area of research. Finally the basic background needed for understanding this course is presented in lecture-5 and lecture-6.

Module-II: This module mainly deals with the development of atomic physics and their energy level structures. The understanding of quantum mechanical derivations for one electron atom is presented in the beginning. Slowly, the modifications of the theory for multi-electron atoms on the basis of the experimental observations are elaborated sequentially. The outcome of these theoretical concepts exploited to develop different applications oriented experiments is emphasized.

Module-III: This module mainly deals with the development of molecular physics and their energy level structures, mainly diatomic molecules. The electronic, vibrational and rotational spectra are also analyzed with the help of the developed theory.

• The Atomic and Molecular Physics is the world of Atoms, Molecules, Ions, Clusters and Photons.
• It is the one of the most fundamental and important field in development of knowledge in Physical and Chemical sciences.
• It is the oldest branch of Quantum Physics. The field contributed so much to the development of quantum mechanics that until thirties of last century, atomic and molecular physics was inseparable from quantum physics.
• It remains one of the most important subjects for the testing grounds of the quantum theory
• In spite of being the oldest field, it has retained its freshness all along and is continuing to contribute to the understanding of the fundamental laws of nature and also to the development of new technologies.