Introduction

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book has a general review of atomic theory. It deals with different aspects of an atomic structure computation. According to quantum mechanics, a stationary state of an N-electron atom is described by a wave functionψ. The wave function is assumed to be continuous with respect to the space variables and is a solution to the wave equation. The Hamiltonian is valid under the assumptions that relativistic effects are neglected and that the atomic nucleus are treated as a point charge of infinite mass. Relativistic and finite nuclear mass effects are treated by methods appropnate for small effects that are included in the Hamiltonian of a configuration interaction problem. The book determines the optimum set of radial functions for spin-orbitals used in defining the configuration state functions and with efficient expansions that results in reliable estimates of atomic state functions.