GOEPPERT-MAYER, Maria

(b. 28 June 1906 in Kattaivitz, Germany [now Katowice, Poland]; d. 20 February 1972 in San Diego, California), physicist and cowinner of the 1963 Nobel Prize in physics for her discoveries concerning the structure of the atomic nucleus.

Goeppert-Mayer was the only child of Dr. Friedrich Göppert, a pediatrician and university professor, and Maria Wolff Göppert, a piano and French teacher. She entered the University of Göttingen in 1924 at a time when many well-known physicists visited or taught there, including Niels Bohr and Max Born, whose classes ultimately led Goeppert-Mayer to study physics. She learned English during a semester in Cambridge, England, and on 19 January 1930 married Joseph E. Mayer, an American student studying in Göttingen who was a boarder in the family house. They had two children.

After Goeppert-Mayer received her doctorate in physics in 1930 and her husband finished his studies, the couple moved to the United States, where she changed the spelling of her name to the anglicized "Goeppert" and became a U.S. citizen in 1933. As a woman working in a male-dominated field, Goeppert-Mayer was unable to secure a full-time appointment at Johns Hopkins University, where her husband worked. After the beginning of World War II Goeppert-Mayer and her husband went to Columbia University in New York City, where they wrote the book StatisticalMechanics (1940), which became a standard text in the field. As the war progressed Goeppert-Mayer joined a team of researchers working on a nuclear bomb. After the war Goeppert-Mayer became a senior physicist at the Argonne National Laboratory in 1946, where a nuclear reactor was under construction. She also joined the faculty at the University of Chicago, but once again, primarily because of her gender, she first had to work as a volunteer associate professor until she was appointed a full professor in 1959.

In 1960 Goeppert-Mayer and her husband joined the University of California at its new San Diego campus. Two years later she received the 1963 Nobel Prize in physics, only the second woman to be so honored in the category, and the first woman to receive the prize for research into theoretical physics. (Marie Curie had won the prize in 1903 for her research into radiation.) Goeppert-Mayer was honored for her contribution to the understanding of the structure of the atomic nucleus through her work on the nuclear shell model and spin-orbit coupling.

Goeppert-Mayer shared the prize with Eugene Paul Wigner and J. Hans D. Jensen for their collective work concerning theories of atomic nuclei and elementary particles. Goeppert-Mayer's research focused on the nuclear shell model. This theoretical model examines the energy levels of individual protons and neutrons and is used to explain the stability of nuclei. In its simplest form a shell model is a model of a system that is believed to consist of individual particles moving in bound orbits in response to the entire system.

Through her studies of the nuclear shell model, Goeppert-Mayer became the first physicist to provide convincing evidence for the existence of the higher numbers in the so-called "magic numbers." These seven numbers—2, 8, 20, 28, 50, 82, and 126—are the atomic numbers "N" or atomic mass number "Z" of the atomic nucleus that occur again and again in nature. At the time only the first three magic numbers had been explained as corresponding to the shells for light nuclei, but there was no evidence for the existence of such correspondence for the higher numbers. Goeppert-Mayer's work essentially rediscovered the magic numbers, especially the higher numbers, in a more convincing manner, providing evidence for their existence and the existence of closed shells.

Goeppert-Mayer had observed that any element that had any of the magic numbers of protons or neutrons was extremely stable. She believed the existence of magic numbers indicated that protons and neutrons in the nucleus might be arranged in specific energy levels, like those available to electrons in the atom. She theorized that the shell model for the nucleus would be similar to an onion in that layers of protons and neutrons would revolve around each other. The magic numbers represented the points at which the various shells (layers) would be complete. This theory led Goeppert-Mayer to become known as the "Madonna of the Onion." The theory helped to explain why protons and neutrons in a nucleus did not continuously collide with each other.

After this discovery she immediately began to work out the consequences for nuclear properties, such as ground state and angular momenta. Her research suggested that the spin-orbit coupling, which is an interaction between the orbital angular momentum and the spin angular momentum of individual particles, is particularly strong in nuclei. In essence, the particles have different energies as they spin and revolve around the nucleus. Goeppert-Mayer used the analogy of spinning dancers that move clockwise and counterclockwise on their axes as they orbit a central point. In April 1949 Goeppert-Mayer published her hypothesis in Physical Review. With Jensen, one of her Nobel Prize co-winners, who independently had discovered similar findings, she wrote Elementary Theory of Nuclear Shell Structure (1955). The book provided further evidence to the scientific community that their theories were valid.

Although Goeppert-Mayer would later say that conducting the research was more exciting than winning the Nobel Prize, the prize did validate her as an important scientist to the wider scientific community. Such recognition was a just reward after years of working for little or no pay and being treated with much less respect than her male counterparts despite being an accomplished physicist. The American Physical Society annually awards the Maria Goeppert-Mayer Award to an outstanding woman physicist.

Goeppert-Mayer, who smoked throughout her life, suffered a series of health problems throughout the 1960s but continued to teach and conduct research. In 1960 she suffered a stroke that paralyzed one of her arms. She had a pacemaker surgically implanted in 1968. In 1971 she went into a coma after suffering a heart attack, and she died from heart disease the following year.

Goeppert-Mayer's papers, correspondence, photographs, and lecture notes are collected at the Central University Library, University of California, San Diego. A discussion of Goeppert-Mayer's contributions to physics is in Robert G. Sach, "Maria Goeppert-Mayer, A Biographical Memoir," Biographical Memoirs (1979): 302–328. Biographical information is also in Olga S. Opfell, The Lady Laureates: Women Who Have Won the Nobel Prize (1978): 194–208; and Joan Dash, The Triumph of Discovery: Women Scientists Who Won the Nobel Prize (1991). An article on her scientific work is "Maria Goeppert-Mayer," Physics Today (1986). An obituary is in the New York Times (22 Feb. 1972).

David Petechuk