Gerhard Herzberg (1904–99) to Have a Major Role in Identifying Hydrogen Both in Interstellar Space and in Patriarch of Modern Planetary and Stellar Atmospheres

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Obituary spectrum of molecular hydrogen, destined Gerhard Herzberg (1904–99) to have a major role in identifying hydrogen both in interstellar space and in Patriarch of modern planetary and stellar atmospheres. In 1948 A he returned to Canada to join the National AD molecular spectroscopy Research Council laboratory (NRC) in Gerhard Herzberg, who died on 3 March, Ottawa, in which he served as director of was one of the world’s foremost molecular physics for 20 years. During his era, the

spectroscopists. The myriad wavelengths NRC became the foremost laboratory for CH COUNCIL CAN of light emitted or absorbed by molecules molecular spectroscopy in the world, by offer a vast lode of knowledge about the virtue of his own fruitful work, and the arrangement of atoms within molecules, enterprising spirit and creative freedom he AL RESEAR TION

the properties of the chemical bonds fostered in the research staff. A N linking atoms, and the electronic Herzberg was a mentor to legions of interactions governing those bonds. scientists by means of his definitive series Moreover, insight into how bonds can be of books on atomic and molecular made or broken in chemical reactions is spectroscopy, published in five volumes crucial for understanding phenomena in between 1936 and 1979. Extraordinary in physics and astrophysics, chemistry, scope, yet readable by the neophyte, his materials science, biology and medicine. books have been translated into several Developing the means to observe and languages. Researchers find them essential decipher molecular spectral patterns has guides, with their comprehensive tables of been a mighty task, in which Herzberg had At the invitation of J. E. Lennard-Jones, molecular parameters and abundant a leading role for 60 years. who was also working on molecular illustrations of characteristic spectra and Herzberg was born on Christmas day orbital theory, Herzberg continued his diagrams explaining theoretical concepts. in 1904 in Hamburg, Germany. When he studies of spectra at the University of Herzberg’s unpretentious, forthright was a young student, inspiring teachers Bristol, and diligently practised his manner, integrity and devotion to science encouraged his interest in science. English. He submitted his work on were greatly admired by colleagues and However, after the director of the molecular orbitals as a habilitation thesis students. His voice was a powerful Hamburg Observatory dissuaded him to Darmstadt and in 1930 was appointed baritone, enhanced by singing lessons from pursuing advanced study in Privatdozent there. This meant he did not with which he rewarded himself after astronomy, he entered the Technische receive a salary, but was able to earn a completing his first book. Also relished Hochschule in Darmstadt, where he modest income by supervising were his ready humour and storytelling. completed a doctorate in engineering laboratories and research students. He A revealing tale stemmed from a visit to physics in 1928. The period of his doctoral pursued research vigorously, and the Soviet Union in 1959. His books had work coincided with the advent of collaborated with Edward Teller in been reprinted for Soviet scientists, and at quantum mechanics, the essential working out selection rules for the his request the royalties were delivered: a theoretical foundation for molecular vibrational structure of electronic shoebox full of roubles that could only be spectroscopy. Herzberg liked to say “this transitions of polyatomic molecules. spent within the Soviet Union. Cheerfully, fortunate accident made it possible for me When deuterium was discovered by he applied a strategy akin to that he had to learn the subject while it was being Harold Urey in 1932, Herzberg recognized used when leaving Nazi Germany over 25 developed”. how this isotope of hydrogen might years before. With the roubles he At Göttingen, then one of the prime benefit studies of molecular structure. He purchased several round-the-world centres for quantum mechanics, Herzberg demonstrated this by synthesizing several aeroplane tickets, which he later worked both in the experimental institute deuterium-labelled compounds and exchanged for cash. headed by James Franck and the analysing the spectral shifts induced by Herzberg received many honours, theoretical institute led by Max Born. replacing hydrogen with deuterium. including the 1971 Nobel Prize in During that time, Herzberg made his first After Hitler came to power in 1933, Chemistry. Particularly cited were his measurements of electronic transitions in anyone with a Jewish wife was not allowed intrepid studies of free radicals, extremely polyatomic molecules. He also did to teach at a German university, and reactive chemical species that are transient important theoretical work. In particular, Herzberg looked for a position in another intermediates in many reaction processes. in collaboration with Walter Heitler, country. In 1935, the Herzbergs relocated In 1975 the NRC Herzberg Institute of Herzberg made use of a theorem, proven to the University of Saskatchewan in Astrophysics was created in his honour, by Eugene Wigner a few months before, to Saskatoon, Canada. This haven came about and he continued active research until the show that intensity variations seen in because of the efforts of a young physical age of 90. His legacy will long endure, and rotational lines of the spectrum of the chemist, J. W. T. Spinks, who had worked continue to grow, as methods he developed diatomic nitrogen molecule were in with Herzberg on deuterated molecules. or elucidated enable new generations of conflict with the prevailing view of nuclear Here Herzberg began some of his most scientists to read intriguing messages structure. This was a striking result, not seminal work, including experiments in encoded in molecular spectra. cleared up until three years later, when which he identified molecules in Dudley Herschbach James Chadwick discovered the neutron. interstellar space by replicating their Dudley Herschbach is in the Department of Herzberg also began work on molecular spectra in the laboratory. Chemistry and Chemical Biology, Harvard orbital theory as a systematic approach to In 1945 Herzberg went to the Yerkes University, 12 Oxford Street, Cambridge, describing the electronic configurations of Observatory of the University of Chicago, Massachusetts 02138, USA. molecules and their spectral transitions. where he discovered the quadrupole e-mail: [email protected]