In writing this book I have had in mind the needs of a postgraduate student, or
other researcher of a similar level, starting to work in the area of computational
quantum chemistry. The standard methods of electronic structure
theory are presented, as are the principles necessary for the evaluation of
molecular properties. The output of quantum chemical studies, in the form of
wavefunctions, densities and orbitals, allow connections to be made with
underlying chemical concepts. This can be done in many ways and a number of
methods of analysis are described. An increasingly important area of research
is the quantum chemical treatment of molecules containing heavy elements.
This is the realm of relativistic quantum chemistry and a chapter is devoted to
introducing the background theory to some of the commonly used relativistic
electronic structure methods.