Motivation for this book

Atomic physics is a well-established subject with a distinguished history, and many books are available which cover its traditional applications. However, it is also a rapidly developing research area, and it is perhaps not surprising that most of the classic texts on which undergraduate courses are usually based no longer reflect its evolution. When the early texts on the subject were written, the prime concern was to demonstrate by many beautiful examples how the principles of quantum mechanics find application in atomic physics. Since numerical methods for solving the radial Schrödinger equation were known in principle but were not generally available, the emphasis was on angular momentum algebra and on formal developments involving electron spin, while the radial integrals were treated as parameters.

Such tools are of course essential in the armoury of any practising atomic physicist, but, in the author's view, lengthy developments in angular momentum algebra no longer form the best introduction to the subject. With ready access to fast computers, solving the radial equation is now a straightforward matter, and there exist many excellent codes for this purpose. Thus, a significant change of attitude has occurred amongst researchers: it is no longer sensible to concentrate on the angular part of the central field equation. Indeed, one can argue that the opposite approach is the correct one. The properties of spherical harmonics need only to be determined once, and can then be used to model all central field atoms.