Symmetry and Selection Rules

Abstract

Many laborious calculations in solid-sate physics can be simplified if the symmetry of the system under consideration is properly included. Furthermore, statements about possible transition processes can very often be made just from symmetry considerations, without any calculation. We had plenty of examples in the last chapter. In these symmetry considerations group theory plays a fundamental role. This chapter summarizes the symmetry properties of molecules and crystals, and reviews some elements of group theory. Selection rules for electronic and vibronic transitions will be discussed. An extended summary of group theory, the character tables for the point groups, and more about transformation of coordinates are given in Appendix G.