Gerhard Herzberg (1904â1999)
David DeVorkin
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Bulletin of the AAS
Gerhard Herzberg, 1971 Nobel laureate in Chemistry, passed away on 3/4 March 1999. He was a world expert on ions and radicals, Rydberg states, laboratory astrophysics, metal compounds, as well as a recognized teacher and leader in the theory and technique of atomic and molecular spectroscopy.

Herzberg was born in Hamburg, Germany, on 25 December 1904 and received his early formal training in that city, being very lucky to come under the wing of a gifted science teacher who was very excited by the revolutions in physics then underway. Herzberg overcame a very difficult childhood after his father Albin H. Herzberg died in 1914 and his mother Ella (Biber) struggled to keep her two sons alive by working as a housekeeper. Although interested in astronomy, Herzberg chose engineering physics because of its quicker financial promise. He obtained the Dr. Ing. degree from Darmstadt Institute of Technology in 1928, working under H. Rau and then went on for postdoctoral work at Gottingen under James Franck and then Max Born. In 1930 he was appointed "Privatdozent" or lecturer in physics at Darmstadt. He married a Jewish woman, Luise Oettinger, in 1929 and they had two children.

Unlike other prominent physicists, like Erich Regener, who had married Jews but had established considerable political influence in the fatherland, Herzberg chose to leave Germany because under the circumstances, he could not hold a job. He and his wife came as refugees to Canada in August 1935, where, through the good offices of a Canadian colleague, he was able to obtain a senior post at the University of Saskatchewan (Saskatoon), supported by the Carnegie Corporation. He soon was made a regular member of the faculty and stayed there until 1945. One of his early achievements at Saskatchewan was finding CH+ in interstellar clouds. As a result he came to the attention of Gerard Kuiper and Otto Struve and was offered the chance to found a major astrophysical laboratory at the Yerkes Observatory of the University of Chicago. As professor of physics and spectroscopy, Herzberg attracted much attention by his studies of infrared molecular spectra using long absorption tubes, applying his work largely to planetary atmospheres, a major Kuiper interest. But partly due to the volatile professional climate at Yerkes, and his personal loyalties to Canada, he and his wife returned in 1948 when he was invited to become principal research officer and then director of the Division of Physics of the National Research Council.

Herzberg's contributions at the NRC began when he established a vital group of young spectroscopic experimentalists who explored the microwave, infrared, visible and vacuum ultraviolet regions of the electromagnetic spectrum. After he was appointed division director, he created new teams in solid state and theoretical physics, all devoted to the systematic study of major spectroscopic problems. Throughout his tenure as division director, which, after a reorganization of the division in 1955, was limited to pure physics, his interests remained in the astrophysical aspects of spectroscopy, concentrating on understanding of the physics of interstellar clouds. In an interview he regarded himself as "25 percent astronomer, 30 percent chemist, 40 percent physicist" though he is best known for his three monographs. including his seminal textbook Atomic Spectra and Atomic Structure, which he completed in 1936 in German and then translated the next year, updating it many times in the following decades.

Much of his work was directed towards detecting and understanding free radicals. Free radicals are difficult to understand due partly to their very short lifetimes (millionths of a second). To be able to capture their signatures, Herzberg developed high intensity pulsed spectroscopic techniques to precisely determine the structures and properties of dozens of free radicals. In 1969, Herzberg was designated Distinguished Research Scientist when the physics divisions of the NRC recombined into one unit. Three years later he won the Nobel Prize and continued to make seminal contributions such as the discovery of triatomic hydrogen (H3) for which he was awarded a Prize by the APS. H3 was one of his most surprising results, as he recalled: "We were actually looking for positively charged H3 + at the time but found neutral H3 instead."

Among his many long-term efforts, he spent over 18 years looking for CH2 (methylene) which, though simple to produce in the laboratory, was difficult to understand in nature. He managed to do so by examining changes in laboratory spectra as he removed hydrogen atoms, and was able to deduce the structure of the molecule. He feels this work led to his Nobel Prize as much as anything else, though the citation acknowledges his wide contributions to knowledge of the structure of molecules, particularly free radicals.

Herzberg had two children, Paul and Agnes, by his first wife, and one, Luise, with his second wife, Monika Tenthoff, whom he married after his first wife died in 1971.

Material for this obituary was collected from various commemorative Websites including those maintained by the National Research Council of Canada. Most of the Web essays depended upon the biographical work of a Herzberg colleague, Boris Stoicheff, who prepared an appreciation for a special edition of Physics in Canada (Volume 28, April 1972) celebrating Herzberg'S Nobel Prize.

Photo courtesy of the National Research Council of Canada