This book offers a concise introduction to the angular momentum, one of the most fundamental quantities in all of quantum mechanics. Beginning with the quantization of angular momentum, spin angular momentum, and the orbital angular momentum, the author goes on to discuss the Clebsch-Gordan coefficients for a two-component system. After developing the necessary mathematics, specifically spherical tensors and tensor operators, the author then investigates the 3-j, 6-j, and 9-j symbols. Throughout, the author provides practical applications to atomic, molecular, and nuclear physics. These include partial-wave expansions, the emission and absorption of particles, the proton and electron quadrupole moment, matrix element calculation in practice, and the properties of the symmetrical top molecule.

A course in angular momentum techniques is essential for quantitative study of problems in atomic physics, molecular physics, nuclear physics and solid state physics. This book has grown out of such a course given to the students of the M. Sc. and M. Phil. degree courses at the University of Madras. An elementary knowledge of quantum mechanics is an essential pre-requisite to undertake this course but no knowledge of group theory is assumed on the part of the readers. Although the subject matter has group-theoretic origin, special efforts have been made to avoid the gro- theoretical language but place emphasis on the algebraic formalism dev- oped by Racah (1942a, 1942b, 1943, 1951). How far I am successful in this project is left to the discerning reader to judge. After the publication of the two classic books, one by Rose and the other by Edmonds on this subject in the year 1957, the application of angular momentum techniques to solve physical problems has become so common that it is found desirable to organize a separate course on this subject to the students of physics. It is to cater to the needs of such students and research workers that this book is written. A large number of questions and problems given at the end of each chapter will enable the reader to have a clearer understanding of the subject.

This 1985 text develops the theory of angular momentum from the viewpoint of a fundamental symmetry in nature and shows how this concept relates to applied areas of research in modern quantum physics.

Designed as a learning tool for those with limited background in quantum mechanics, this book provides comprehensive coverage of angular momentum in quantum mechanics and its applications to chemistry and physics. Based on class-tested material, this presentation offers clear explanations of theory while giving equal attention to solving real problems. Theoretical considerations are made concrete and accessible through extensive examples and applications at the end of each chapter. Problem sets, designed as both individual and group exercises, are treated as an integral part of the text in order to stimulate student interest and clarify the abstract principles discussed. Examples are drawn primarily from atomic and molecular phenomena, and include many intermediate steps (often left out of other texts) to ensure complete mastery of the material, and to lay the groundwork for understanding photon and particle collision phenomena, and more advanced studies.

The first comprehensive and authoritative coverage of the angular momentum of light, illustrating both its theoretical and applied aspects.

Ch. 1. Elements of vector and tensor theory -- ch. 2. Angular momentum operators -- ch. 3. Irreducible tensors -- ch. 4. Wigner D-functions -- ch. 5. Spherical harmonics -- ch. 6. Spin functions -- ch. 7. Tensor spherical harmonics -- ch. 8. Clebsch-Gordan coefficients and 3jm symbols -- ch. 9. 6j symbols and the Racah coefficients -- ch. 10. 9j and 12j symbols -- ch. 11. The graphical method in angular momentum theory -- ch. 12. Sums involving vector addition and recoupling coefficients -- ch. 13. matrix elements of irreducible tensor operators