Gerhard Herzberg

Gerhard Herzberg

Nobel Prize in Chemistry, 1971
Date of Birth: 25.12.1904
Country: Canada

Biography of Gerhard Herzberg

Gerhard Herzberg was a Canadian physicist and Nobel laureate in Chemistry. He was born in Hamburg, Germany, to Albina and Ella Herzberg. After his father's death, his mother emigrated to America, sending money for Gerhard and his brother's education. He completed his bachelor's degree (1927) and doctorate (1928) at the Darmstadt Technical Institute. Although he dreamed of becoming an astronomer, he was not accepted into the Hamburg Observatory.

Herzberg's dissertation, completed while still a student under H. Pay, focused on the interaction of matter with electromagnetic radiation. The following year, he worked under Nobel laureates Max Born (1954) and James Franck (1925) at the University of Göttingen, Germany, and then at the University of Bristol in England. By 1929, he had already published 20 scientific papers and became a lecturer and senior assistant in physics at the Darmstadt Technical Institute. In 1929, while analyzing the spectra of molecular nitrogen, he and his colleague Walter Gehrcke proved that nitrogen nuclei could not consist only of protons and electrons, as previously believed. Shortly after, English physicist and Nobel laureate (1935) James Chadwick discovered that the uncharged particle, neutron, is the primary component of atomic nuclei.

Furthermore, Herzberg discovered the line structure of the diatomic oxygen spectrum, which is now known as Herzberg bands. This discovery was of great significance for the study of the upper atmosphere.

Due to the persecution of Jews by the Nazis, Herzberg emigrated to Canada in 1935, where he became a professor at the University of Saskatchewan. Although there were limited opportunities for experimental work when he arrived, he managed to establish a spectroscopic laboratory. As a foreigner, he did not participate in military research during the Second World War. In 1945, he obtained Canadian citizenship and became a professor at the Yerkes Observatory of the University of Chicago in the United States. With the help of his students, he equipped a renowned laboratory for studying the molecular spectra of stars, comets, and planets. In 1946-1947, he built a special absorption chamber over 20 meters long, which allowed for the study of planetary atmospheric absorption spectra.

Using infrared techniques, Herzberg demonstrated the presence of hydrogen in the atmosphere of certain planets and confirmed the presence of water in comets. He also identified the spectra of molecules such as CO2, CO, NO, C2H2, CH4. Furthermore, he and his colleagues, not only through space observations but also in laboratory conditions, used the flash photolysis method developed by Nobel laureates (Chemistry, 1967) Ronald Norrish and George Porter, in which light or other forms of energy cause chemical dissociation.

They conducted their first successful spectroscopic experiments with the methyl free radical in 1956, and three years later, with the analogous methylene radical. In the same way, free radicals CO, CN, BN, and CH were studied. Three years later, Herzberg returned to Canada as a senior research scientist at the National Research Council's Division of Physics in Ottawa. The following year, he became the director of this division and, in 1955, the director of the Division of Fundamental Physics. In 1969, the Scientific Council of the Institute of Astrophysics recognized him as an outstanding research scientist.

In 1971, he was awarded the Nobel Prize in Chemistry for his contributions to the understanding of electronic structure and molecular structure, especially of free radicals. In his presentation at the Nobel ceremony, Stig Claesson, a member of the Swedish Academy of Sciences, said, "Herzberg's truly elegant experimental studies, together with their theoretical interpretation, made a significant contribution to the development of quantum mechanics, which was decisive for the rapid development of molecular spectroscopy." Claesson noted that around 1950, "molecular spectroscopy advanced so rapidly that it became possible to study much more complex systems, which largely determined the further development of chemistry. This was brilliantly demonstrated in Herzberg's innovative research with free radicals. Knowledge of their properties is of fundamental importance for understanding chemical processes."

In space, radicals are a common state of matter. In interstellar gas and dust clouds, the existence of ordinary molecules is impossible due to the continuous bombardment of atoms by cosmic particles, intense ultraviolet, X-ray, and gamma radiation, causing their excitation. When excited atoms meet, they form new structures that also remain in an excited state and, in turn, exist as free radicals. Many dozens of such radical particles have already been discovered, some of which are carbon chains. This data forms the basis for understanding the evolution of organic matter in space and, in particular, its existence before the formation of the Solar System.

Colleagues described Herzberg as a dynamic scientist, modest, and noble man who enthusiastically lectured to his students. He was constantly in the laboratory, only leaving on Saturdays to summarize experimental data. On Sundays, he enjoyed exploring the surroundings of Ottawa. He was passionate about Italian opera and mountaineering.

Some of his notable works include "Atomic Spectra and Atomic Structure" (1937), "Molecular Spectra and Molecular Structure" (4 vols., 1939-1979) with Klaus-Peter Huber, and "The Spectra and Structures of Simple Free Radicals: An Introduction to Molecular Spectroscopy" (1971).