Herzberg, Gerhard (1904-1999) was a German-born Canadian physicist. He won the 1971 Nobel Prize in chemistry for his research in the electronic structure of molecules, particularly for his work on molecular fragments called free radicals. His studies contributed greatly to such specialized fields of science as physical chemistry, astrophysics, and quantum mechanics. He was the first Canadian citizen to win a Nobel Prize in either chemistry or physics.

Herzberg was born on Dec. 25, 1904, in Hamburg, Germany. He received a doctorate in engineering physics from the Darmstadt Institute of Technology in 1928. From 1929 to 1930, he did postdoctoral studies at the University of Göttingen, where he studied under physicists Max Born and James Franck, and at the University of Bristol in England. From 1930 to 1935, Herzberg was lecturer and senior assistant in physics at the Darmstadt Institute of Technology. During this period, he used the spectroscope, a scientific instrument that spreads out light into a spectrum and displays it as a series of lines or bands for analysis. The atoms or molecules of all substances give off light when heated to high temperatures, but the pattern of light given off is different for every substance. Thus, Herzberg could identify a substance or determine its chemical composition by analyzing its spectrum. The field of chemical analysis using the spectroscope is called spectroscopy.

In 1935, after Adolf Hitler and the Nazi government of Germany rose to power, the Herzbergs fled Germany and moved to Canada. From 1935 to 1945. Herzberg was a professor at the University of Saskatchewan in Saskatoon. He became a Canadian citizen in 1945.

Herzberg continued his research in spectroscopy at the University of Saskatchewan and began to write books explaining his work. He summarized his earliest findings in the book Atomic Spectra and Atomic Structure (1937). He published a more comprehensive work under the title Molecular Spectra and Molecular Structure, in four volumes: Spectra of Diatomic Molecules (1939), Infrared and Raman Spectra of Polyatomic Molecules (1945), Electronic Spectra and Electronic Structure of Polyatomic Molecules (1966), and Constants of Diatomic Molecules (1979). Polyatomic molecules each have three or more atoms in each molecule, and diatomic molecules have two atoms in each molecule.

From 1945 to 1948, Herzberg was professor of spectroscopy at the Yerkes Observatory of the University of Chicago. His techniques allowed astronomers to study the atmosphere of planets in the solar system.

Herzberg returned to Canada in 1948 and spent the rest of his career working for the National Research Council (NRC) in Ottawa, Canada. From 1949 to 1955, he was director of the council's Division of Physics. From 1955 to 1969, he was director of the Division of Pure Physics. From 1969 to 1994, he held the title of distinguished research scientist of the Division of Physics. In 1975, the National Research Council established the Herzberg Institute of Astrophysics.

During his time at the National Research Council, Herzberg expanded his research in spectroscopy. He determined the structures of many diatomic and polyatomic molecules, including the structures of many free radicals. Free radicals are unstable molecules produced by a chemical reaction in which a substance loses electrons, often while combining with oxygen. They exist only for millionths of a second before taking electrons from other molecules and rearranging into new molecular structures.

In addition to the Nobel Prize, Herzberg won the Henry Marshall Tory Medal of the Royal Society of Canada in 1953, the Gold Medal of the Canadian Association of Physicists in 1957, the Willard Gibbs Medal of the American Chemical Society in 1969, and the Royal Medal of the Royal Society of London in 1971.

Herzberg remained active in research until the end of his life. He died on March 3, 1999, at his home in Ottawa.