ABSTRACT
This chapter provides the quantum mechanical definition of the multipole moments, and study those of their properties that follow from symmetry considerations. It offers both the power and limitations of symmetry arguments. The interaction between the electromagnetic moments of atoms and nuclei determines the hyperfine structure of the spectrum, and because of this hyperfine spectroscopy is a powerful technique for studying the electromagnetic properties of nuclei. The chapter describes the quantum theory of systems that have a Correspondence Principle limit in classical point mechanics. It explores the detailed connection between the abstract formalism and the wave functions of Schrodinger's theory by computing the x-p transformation function. The chapter offers the symmetry properties of two-nucleon systems. The statistical mechanics of systems obeying the exclusion principle was worked out by Fermi and Dirac and is called Fermi-Dirac statistics; particles that obey this type of statistics are called fermions.
