That set of books is absolutely indispensable to any serious physicist doing research in molecular spectroscopy. I used these books for two courses in molecular spectroscopy and they are really going deep in the subject. The only "downside" is that the references given are not really up-to-date but they are still classics in the field.

This is the result of a visit of professor Herzberg to Cornell. He built a complet course on the fundamental aspects of molecular spectroscopy using free radicals. Excelent.

Great if this is the topic you are looking for. Spectra of diatomic molecules are hard to interpret if you dont have the right resources. Also very useful in physical chemistry lab classes.

This book is basic to the study of every discipline that depends upon spectroscopy, not so much for the rather good fundamental handling of theory, there are many good books on the subject. My favorite aspect of the book is throughtout its pages and especially its Table 39, rich with experimental results, contains references to seminal works in the field, the starting points of the study of a vast array of subjects in the basic sciences and a singular reference of my work in the study of diatomics.

Updated classic paperback text that covers a broad area from Balmer series to Nuclear Spin. Written without alot of complex mathematics, this is a good introduction to Atomic Spectra for specialists in other fields. I loved the coverage on quantum numbers and alkaline-earth elements.