After more than a century of study, the hydrogen atom still presents challenges and opportunities to theoretical as well as to experimental physicists. The discovery of the Lamb shift in the late nineteen forties, followed by the development of QED and the introduction of powerful new experimental techniques in the nineteen sixties and seventies, have preserved for hydrogen its central place in atomic physics. Part I of this book, a reprint of the work published in 1957, covers the period from the earliest days up to the late nineteen fifties. Part II, a collection of progress reports written by well-known specialists on hydrogen and hydrogen-like systems, presents the advances in theory and experiment that have occurred since that time.

After more than a century of study, the hydrogen atom still presents challenges and opportunities to theoretical as well as to experimental physicists. The discovery of the Lamb shift in the late nineteen forties, followed by the development of QED and the introduction of powerful new experimental techniques in the nineteen sixties and seventies, have preserved for hydrogen its central place in atomic physics. Part I of this book, a reprint of the work published in 1957, covers the period from the earliest days up to the late nineteen fifties. Part II, a collection of progress reports written by well-known specialists on hydrogen and hydrogen-like systems, presents the advances in theory and experiment that have occurred since that time.

For more than a century, studies of atomic hydrogen have been a rich source of scientific discoveries. These began with the Balmer series in 1885 and the early quantum theories of the atom, and later included the development of QED and the first successful gauge field theory. Today, hydrogen and its relatives continue to provide new fundamental information, as witnessed by the contributions to this book. The printed volume contains invited reviews on the spectroscopy of hydrogen, muonium, positronium, few-electron ions and exotic atoms, together with related topics such as frequency metrology and the determination of fundamental constants. The accompanying CD contains, in addition to these reviews, a further 40 contributed papers also presented at the conference "Hydrogen Atom 2" held in summer 2000. Finally, to facilitate a historical comparison, the CD also contains the proceedings of the first "Hydrogen Atom" conference of 1988. The book includes a foreword by Norman F. Ramsey.

For beginners and specialists in other fields: the Nobel Laureate's introduction to atomic spectra and their relationship to atomic structures, stressing basics in a physical, rather than mathematical, treatment. 80 illustrations.

Introduction to the Theory of Atomic Spectra is a systematic presentation of the theory of atomic spectra based on the modern system of the theory of angular momentum. Many questions which are of interest from the point of view of using spectroscopic methods for investigating various physical phenomena, including continuous spectrum radiation, excitation of atoms, and spectral line broadening, are discussed. This volume consists of 11 chapters organized into three sections. After a summary of elementary information on atomic spectra, including the hydrogen spectrum and the spectra of multi-electron atoms, the reader is methodically introduced to angular momentum, systematics of the levels of multi-electron atoms, and hyperfine structure of spectral lines. Relativistic corrections are also given consideration, with particular reference to the use of the Dirac equation to determine the stationary states of an electron in an arbitrary electromagnetic field. In addition, the book explores the Stark effect and the Zeeman effect, the interaction between atoms and an electromagnetic field, and broadening of spectral lines. The final chapter is devoted to the problem of atomic excitation by collisions. This book is intended for advanced-course university students, postgraduate students and scientists working on spectroscopy and spectral analysis, and also in the field of theoretical physics.