Place: United States of America, Germany
Subject: biography, physics
German-born US physicist who shared the 1963 Nobel Prize for discovering the shell model of nuclear structure.
Maria Goeppert was born on 28 June 1906 in Kattowitz, Upper Silesia (now Katowice in Poland). When Maria was four years old her father was appointed professor of paediatrics at the University of Göttingen and the family moved there. High inflation rates in Germany in the 1920s meant that the only school capable of preparing girls for the abitur exam was closed, so Maria's education had to be continued in private. She passed the exam in Hanover in 1924. Maria Goeppert entered Göttingen University as a mathematics student but was excited by quantum mechanics - Max Born was on the staff in Göttingen - and quickly changed to physics. She obtained her doctorate in theoretical physics in 1930 and married Joseph Edward Mayer, a US physicist working in Göttingen with James Franck. The couple moved to Johns Hopkins University in Baltimore, USA, where Maria worked on chemical physics and the colour of organic molecules, and to Columbia University in 1939, where she worked on isotope separation. In 1946 Maria was appointed a professor in the physics department at Chicago and given a post at the nearby Argonne National Laboratory. Such an appointment came as a relief as Maria had not been paid at Johns Hopkins and felt she had been kept on the sidelines at Columbia.
In 1945 Goeppert-Mayer had developed a ‘little bang’ theory of cosmic origin with Edward Teller to explain element and isotope abundances in the universe and so became interested in the stability of nuclei. The ‘liquid drop’ model of the nucleus explained some properties but nuclei with certain numbers of neutrons (or protons) were known to be exceptionally stable. The stability of some of the light elements - helium (two neutrons and two protons), oxygen (eight each), calcium (20 each) - could be explained, but what about nuclei with 28, 50, 82 and 126 neutrons? The stability of nuclei with these so-called magic numbers of neutrons or protons had been demonstrated in experiments but could not be explained. Goeppert-Mayer and Hans Jensen independently proposed a shell model in which the nucleons (protons and neutrons) moved in orbits (or shells) around the centre of the nucleus. This gave the neutrons orbital angular momentum, which then coupled to their spin (inbuilt angular momentum). A combination of the shell model and this spin-orbit coupling correctly predicted which nuclei were the most stable. Goeppert-Mayer and Jensen shared half of the 1963 Nobel Prize - the other half went to Eugene Wigner (1902-1995) - and in 1955 they wrote a book Elementary Theory of Nuclear Shell Structure. In 1960 Goeppert-Mayer and her husband moved again, to take up professorships in physics and chemistry respectively at the University of California, La Jolla. She died in San Diego on 20 February 1972.
Maria Goeppert succeeded in making major contributions to science despite many obstacles. She first studied...