Molecular spectroscopy is the technique for recording the responses of single molecules or molecular ensembles to electromagnetic radiation by means of absorption, emission or scattering processes. Funded on the basics of atomic spectroscopy which was pioneered in the 19th century by the work of Bunsen and Kirchhoff, Gerhard Herzberg figured in the second half of the 20th century as "father of molecular spectroscopy" and received the Nobel Prize in 1971 for "his contributions to the knowledge of electronic structure and geometry of molecules, particularly free radicals". Molecular spectroscopy is a versatile tool, which is widely used in analytical chemistry, but mainly it provides insight into the structure and dynamics of molecules and molecular aggregates in various electronic states. Nowadays, interpretation of molecular spectra is assisted by the use of modern quantum chemical methods, which in turn can be evaluated and calibrated, using the results of molecular spectroscopy.
Gerhard Herzberg was born in Hamburg (Germany) December 25 1904 as son to Albin H. Herzberg and Ella Biber. He received his PhD at the Technical University Darmstadt (Technischen Hochschule Darmstadt) where he was graduated in 1928 as Dr. Ing. Afterwards he worked in Göttingen (1928-1929) with James Franck and Max Born and in Bristol (1929-1930) with John Lennard-Jones, before returning to Damstadt (1930-1935) where he was appointed as lecturer (Privatdozent) in 1930. In 1935 Herzberg was urged to leave Nazi-Germany, since the Ministry of Education suspended his Venia Legendi due to being married with Luise Oettinger, a german physicist who was of jewish decendence. Unlike other famous german physicists (maybe the most famous amongst them was Werner Heisenberg), Herzberg defied the influence of the Nazis and emigrated with Luise to Canada. At the University of Saskatchewan in Saskatoon he was filled a position as guest professor for three months, after which this position was changed to that of a Research Professor.
In 1945 Herzberg received the Canadian citizenship. From 1945 to 1949 he was offered the position as professor of spectroscopy at the Yerkes-Observatory of the University of Chicago. Starting with 1948 he was Director of the Division of Pure Physics at the National Research Council of Canada.
1971 Gerhard Herzberg received the Nobel Prize in Chemistry "for his contributions to the knowledge of electronic structure and geometry of molecules, particularly free radicals".
Gerhard Herzberg shows us by his example, that scientific excellence and social responsibility by no way exclude each other.
Gerhard Herzberg authored four volumes of a famous book on Molecular Spectra and Molecular Structure, which are apart from being classics still are of much use to beginners and professionals in the area of spectroscopy:
- Molecular Spectra and Molecular Structure: I. Spectra of Diatomic Molecules. (Krieger, 1989, ISBN 0894642685)
- Molecular Spectra and Molecular Structure: II. Infrared and Raman Spectra of Polyatomic Molecules. (Krieger, 1989, ISBN 0894642693)
- Molecular Spectra and Molecular Structure: III. Electronic Spectra and Electronic Structure of Polyatomic Molecules. (Krieger, 1989, ISBN 0894642707)
- Molecular Spectra and Molecular Structure: IV. Constants of Diatomic Molecules, K. P. Huber and G. Herzberg, (Van nostrand Reinhold company, New York, 1979, ISBN 0442233949).
Other books on molecular spectroscopy authored by him are:
- Atomic Spectra and Atomic Structure. (Dover Books, New York, 2010, ISBN 0486601153)
- The spectra and structures of simple free radicals: An introduction to molecular spectroscopy. (Dover Books, New York, 1971, ISBN 048665821X)