This book explains the theory and methods by which gas molecules can be
polarized by light, a subject of considerable importance for what it
tells us about the electronic structure of molecules and properties of
chemical reactions. Starting with a brief review of molecular angular
momentum, the text goes on to consider resonant absorption,
fluorescence, photodissociation and photoionization, as well as
collisions and static fields. A variety of macroscopic effects are
considered, among them angular distribution and the polarization of
emitted light, ground state depopulation, laser-induced dichroism, the
effect of collisions and external magnetic and electric field effects.
Most examples in the book are for diatomic molecules, but symmetric-top
polyatomic molecules are also included. The book concludes with a short
appendix of essential formulae, tables for vector calculus, spherical
functions, Wigner rotation matrices, Clebsch-Gordan coefficients, and
methods for expansion over irreducible tensors.