Undergraduate Lecture Notes in Physics

This book is based on a set of course notes developed for a fourth- year undergraduate course in Atomic and Molecular Physics. It assumes some quantum mechanics as background and presents material central to an understanding of structure for both atoms and molecules, developed with a thoroughness comparable to the classics texts of John C. Slater. It makes no attempt to cover scattering or the many topics related to trapping, cooling, or condensation. Unlike other texts on atomic physics, it treats complex atoms in detail, using the two-electron atom as the simplest example and then turning to carbon without needing to develop additional equations. Again unlike most texts at this level, spontaneous emission from an atom or molecule in an excited state is developed using time-dependent perturbation theory. Advanced texts can start with Fermi's golden rule while quantum mechanics texts often end there. Asking why does an excited atom decay at all, can stimulate the student to learn quantum electrodynamics. The electronic structure of diatomic molecules is not as accessible as the ro-vibrational interactions, so most books will start with the latter. But the treatment in this text of electronic structure of atoms provides an excellent foundation for the electronic structure of the simplest molecule, H2+. We use prolate spheroidal coordinates which are natural to the problem; the student can perform all of the needed integrals. We then look at H2 which becomes the molecular analogue of progressing from the hydrogen atom to the multi-electron system. One cannot overstate the usefulness for understanding molecular bonding of solving the quantum mechanics of the hydrogen molecular ion and molecule.