Founder of molecular spectroscopy

PATHS OF INNOVATORS: Gerhard Herzberg (1904-1999)

GERHARD HERZBERG was born on December 24, 1904 in Hamburg, Germany. He was ten years old when his father died, but scholarships made it possible for him to attend local schools.

As a twelve-year old boy, Herzberg and his friend made a home- made telescope. On clear nights, they used to set it up in the city park at Hamburg to look at the moon and planets.

Naturally he chose astronomy as his profession and applied for a job to the city observatory. The application was returned with the remark, ``there is no point in thinking of a career in astronomy, unless one has private means of support.''

The support came from his widowed mother who took up a housekeeper's job to send small amounts to her son. The young Herzberg endured these lean and lonely years by turning to the study of mathematics, physics and chemistry.

Herzberg came under the spell of a superb physics teacher in the high school; the latter, Mr. Hillers, introduced him to the work of Niels Bohr (1885-1962) which more than compensated the discouraging response of the Observatory. His teacher advised him to join the newly-started course in engineering physics at the Technical University of Darmstadt. His education was supported by a local industrialist.

In 1928, he earned his doctorate degree. He published 12 papers in atomic and molecular physics, which earned him a postdoctoral fellowship at the University of Goettingen. Here he worked under Max Born (1885-1970) and James Franck (1882-1964) who were applying the newly developed quantum mechanics to the mysteries of atomic and molecular structures. Herzberg made an important contribution to molecular-orbital structure with his theory of bonding and anti-bonding electrons. This innovation resulted in an invitation for working at the University of Bristol (1929).

Back home in 1930, he became ``privat dozent'' (unsalaried lecturer) at Darmstadt Institute of Technology. He earned a small salary, in return for managing undergraduate laboratory. During the next five years, he worked on spectroscopy; he published a major paper on vibrational structures of electronic transitions in polyatomic molecules.

Migrating to Canada

With the Nazis coming to power, he had to flee Germany. Opportunities in America were scarce because of the Great Depression. Dr. Walter Murray. President of the University of Saskatchewan, came to his help and created for him a position, supported for two years by the Carnegie Foundation Herzberg arrived in Canada, with $2.50 in his pocket (September 1935). Later he was research professor of physics until 1945. From 1945 to 1948, he was on the faculty of the Yerkes Observatory, University of Chicago. To one who had never forgotten his early ambition to be an astronomer, the stay at Yerkes was rewarding; he quickly established a laboratory for investigating planetary spectra by pioneering methods that became standard worldwide.

In 1948, when the National Research Council for Canada (NRCC) invited Herzberg to establish a laboratory for fundamental research in spectroscopy he accepted. He was made Director of the Physics Division, a position he held until 1969. He remained at the NRCC in Ottawa until 1994, when he attained the age of 90. He died at his home on March, 1999.

Development of spectroscopy

Herzberg's main contributions are in atomic and molecular spectroscopy. He discovered the spectra of certain ``free radicals'' that are intermediate stages in numerous chemical reactions. For example, the molecule CH2 or methylene is a free radical, namely it has an extra pair of electrons that it tries to share with another molecule. As their lifetime is short, (millionth of a second) Herzberg pioneered pulsed, spectroscopic techniques to determine their structures. This understanding is fundamental to scientists' ability to understand how chemical reactions proceed. Herzberg was the first to identify the spectra of certain radicals in the stellar gas. He obtained much spectrographic information on the atmosphere of outer planets and stars.

Herzberg received many awards, Gibbs Medal (1969), Faraday Medal (1970), Pauling Medal (1971) and many honorary degrees. He won the Nobel Prize in 1971; it was mentioned in the citation how a physicist came to receive the Nobel Prize in Chemistry. In recognition of his work, the Herzberg Institute of Astrophysics was created in 1974.``Herzberg proved himself to be an outstanding and caring lecturer - well organized and with a knack for choosing the right amount of detail in his presentation.''

His books Atomic Spectra and Atomic Structure (still in print after six decades) and the four-volume Molecular Spectra and Molecular Structure (1939-79) have become the bible for researchers in the field of spectroscopy. (Physics Today August 1999).

R. Parthasarathy

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