On January 19, 1930, Göppert married
Joseph Edward Mayer, an American
Rockefeller fellow who was one of James Franck's assistants. The two had met when Mayer had boarded with the Göppert family. The couple moved to Mayer's home country of the United States, where he had been offered a position as Associate Professor of Chemistry at
Johns Hopkins University in Maryland. They had two children; Maria Ann, who later married
Donat Wentzel, and Peter Conrad. Strict rules against
nepotism prevented Johns Hopkins University from hiring Goeppert Mayer as a faculty member. These rules, created at many universities to prevent patronage, had by this time lost their original purpose and were primarily used to prevent the employment of women married to faculty members. She was given a job as an assistant in the physics department working with German correspondence, for which she received a very small salary, a place to work and access to the facilities. She taught some courses, and published an important paper on
double beta decay in 1935. {{Quote box There was little interest in
quantum mechanics at Johns Hopkins, but Goeppert Mayer worked with
Karl Herzfeld in this area. They collaborated on a number of papers, including a paper with Herzfeld's student A. L. Sklar on the spectrum of
benzene. She also returned to Göttingen in the summers of 1931, 1932 and 1933 to work with her former examiner Born, writing an article with him for the
Handbuch der Physik. This ended when the
Nazi Party came to power in 1933, and many academics, including Born and Franck, lost their jobs. Concerned by the
1933 anti-Jewish laws that ousted professors of Jewish descent, Goeppert-Mayer as well as Herzfeld became involved in refugee relief efforts. Joe Mayer was fired in 1937. He attributed this to the hatred of women on the part of the dean of physical sciences, which he thought was provoked by Goeppert Mayer's presence in the laboratory. Herzfeld agreed and added that, with Goeppert-Mayer, Franck and Herzfeld all at Johns Hopkins, some thought that there were too many German scientists there. There were also complaints from some students that Mayer's chemistry lectures contained too much modern physics. Mayer took up a position at
Columbia University, where the chairman of the physics department,
George B. Pegram, arranged for her to have an office, but she received no salary. She soon made good friends with
Harold Urey and
Enrico Fermi, who arrived at Columbia in 1939, with the three of them and their families living in nearby
Leonia, New Jersey. Fermi asked her to investigate the
valence shell of the undiscovered
transuranic elements. Using the
Thomas–Fermi model, she predicted that they would form a new series similar to the
rare earth elements. This proved to be correct. In 1941, she was elected a Fellow of the
American Physical Society.
Manhattan Project In December 1941, Goeppert Mayer took up her first paid professional position, teaching science part-time at
Sarah Lawrence College in New York. In the spring of 1942, with the United States embroiled in
World War II, she joined the
Manhattan Project. She accepted a part-time research post from Urey with
Columbia University's Substitute Alloy Materials (SAM) Laboratories. The objective of this project was to find a means of separating the
fissile uranium-235 isotope in natural uranium; she researched the chemical and thermodynamic properties of
uranium hexafluoride and investigated the possibility of separating isotopes by photochemical reactions. This method proved impractical at the time, but the development of lasers would later open the possibility of
separation of isotopes by laser excitation. Through her friend
Edward Teller, Goeppert Mayer was given a position at Columbia with the Opacity Project, which researched the properties of matter and radiation at extremely high temperatures with an eye to the development of the
Teller's "Super" bomb, the wartime program for the development of
thermonuclear weapons. In February 1945, Joe was sent to the
Pacific War, and she decided to leave her children in New York and join Teller's group at the
Los Alamos Laboratory. Joe came back from the Pacific earlier than expected, and they returned to New York together in July 1945. In February 1946, Joe became a professor in the chemistry department and the new
Institute for Nuclear Studies at the
University of Chicago, and Goeppert Mayer was able to become a voluntary associate professor of physics at the school. When Teller also accepted a position there, she was able to continue her Opacity work with him. When the nearby
Argonne National Laboratory was founded on July 1, 1946, she was also offered a part-time job there as a senior physicist in the theoretical physics division. She responded, "I don't know anything about nuclear physics." She programmed the
Aberdeen Proving Ground's
ENIAC to solve criticality problems for a
liquid metal cooled reactor using the
Monte Carlo method. While in Chicago, Mayer derived the
Bigeleisen-Mayer equation with
Jacob Bigeleisen. == Nuclear shell model ==