The Structure of Line Spectra (Classic Reprint)

The years 1922 to 1926 saw great progress in the analysis of spectra. The introduction of the vector model and the formulation of semi-empirical rules governing the interactions of the various vectors led to the systematization and clarification of a great body of spectral data. Since 1926 the quantum mechanics has been shown to provide a justification for the previously developed rules; in fact, it is possible now to discuss spectra by means of the quantum mechanics without the use of the vector model at all. It seems probable, however, on account of its simplicity and ease of visualization, that the vector model will continue to be used as the basis for the treatment of spectra for many years to come. We have attempted to present in this book a description of the vector model of the atom and an account of the interpretation of line spectra in terms of it. We have aimed to write lucidly and intelligibly rather than encyclopedically, having in mind readers entirely unacquainted with the subject as well as those familiar with the empirical side of spectra but not with their interpretation. The book is designed primarily as a textbook for those working in the field of spectroscopy. The recent developments in theoretical physics have, however, caused spectroscopic facts and laws to become of importance for other fields in physics and chemistry, so that we are convinced that many chapters will be of use to workers in these fields also. The book gives the theoretical background of the principles governing the structure of line spectra, but not an account of all observed spectra, experimental data being introduced only as illustrative examples (as in Appendix III). A detailed account of the structure of spectra of different types with mention of all those known in 1927 is given in the excellent book by F. Hund, Linienspektren und periodisches System der Elemente,
(Typographical errors above are due to OCR software and don't occur in the book.)