Maria Mayer And Her Shell Model

Till date, 51 women have won the prestigious Nobel Prize in distinguished fields. Maria Goeppert Mayer is one of these genius women, rather, the first women ever to have earned this honour in the field of theoretical Nuclear Physics. However, many people believe that Marie Curie was the first women to win it in this field. No doubt, that Marie Curie was the first women ever to have won this award in 1903. But, the lady won it for her work on Radioactivity, not Nuclear Physics. The field of nuclear physics stemmed with the discovery of atomic nucleus in the second decade of 1900. This article aims to learn about the lesser known life of Maria Mayer and what lead her way to the Nobel Prize.

Maria Mayer
Maria Goeppert Mayer
Image : Science Photo Library
Early life and Education :

Maria Goeppert was born on June 28, 1906 in Kattowitz, which was part of Germany at that time. In 1910, her family moved to Göttingen, where her father was a professor of pediatrics. Her father always encouraged her to grow up to be more than a housewife. After attending public school and a college preparatory academy for girls, in 1924 she entered the University of Göttingen. At first, she intended to study mathematics. But after attending Max Born’s quantum mechanics seminar, she switched her focus to physics. Consequently, she completed her Ph.D. in 1930, with a thesis on double photon reactions.

Marriage and the struggle for recognition:

After completing her Ph.D, she married the American chemical physicist Joseph E. Mayer.Together they moved to the United States, Baltimore. For years after moving to the United States, Nepotism played its part. Despite being highly deserving, Maria was still only getting offered jobs with no pay or unofficial jobs in University laboratories. But the lady never gave up!

Maria Mayer
Maria and Joseph E. Mayer
Image: Photo Science Library

Over the next nine years she was associated with Johns Hopkins as a volunteer associate. During that time she collaborated with Karl Herzfeld and her husband in the study of organic molecules. She became a U.S. citizen in 1933. In 1939 she and her husband both received appointments in chemistry at Columbia University, where Maria Mayer worked on the separation of uranium isotopes for the atomic bomb project. The Mayers published Statistical Mechanics in 1940. The couple remained at Columbia throughout World War II.

Also Read: 8 mind blowing facts about nuclear physics

The Ground breaking discovery and the Nobel Prize :

However, after World War II, Maria shifted her focus to nuclear physics, unknowingly setting herself on a path to the most ground breaking discovery of her life. During that time, studying the nuclear structure and magic numbers was one of the hottest topic of research. In 1937, Neil's Bohr and F. kalcar proposed the Liquid drop model of nucleus, where the atomic nucleus was compared to a liquid drop. Though this model is of utmost importance to understand some of the basics of binding energies. But, it could not explain why some nuclei having protons or neutrons or both as 2, 8, 20, 28, 50, 82, 126 (magic numbers) have higher binding energies, making them more stable than others. This lead scientists to find a better model for enhanced explanations. This is where Maria Mayer's shell model came into picture.

No doubt, the shell model was first proposed by Dmitry Ivanenko in 1932. But, to understand the ambiguity about magic numbers, it was further developed independently by Maria Goeppert-Mayer along with some other physicists in 1949. The nuclear shell model is partly analogous to the atomic shell model which describes the arrangement of electrons in an atom, in that a filled shell resulting in greater stability. This model proved instrumental in explaining the existence of magic numbers and the stability and high binding energy on the basis of closed shells. It also provided explanation for the ground state spins and the magnetic dipole moment of nuclei. This enhancement of the shell model helped Maria Mayer to step up to the podium in Stockholm, Sweden to accept the Nobel Prize in Physics in 1963.

Also Read: 5 Great Indian Physicists Who Did Not Win The Nobel Prize

Other notable works :

Most of Maria's other works, which are not as well known, demonstrate Mayer’s unusual physical intuition. Much of this work has remained unchanged since the 1930’s and provides theoretical bases for several important developments in laser physics, laser isotope separation, double-beta decay, and molecular orbital calculation. During World War II, she contributed significantly as a member of the Manhattan Project team. She also worked as a lecturer in some distinguished institutes. This includes accepting an appointment at the University of California at San Diego in 1960.

Maria Mayer
Maria Mayer - Revisiting Science at Sarah Lawrence College
Image: Sarah Lawrence College Archives

Goeppert-Mayer died due to a heart failure in San Diego, California, on February 20, 1972, aged 65. Maria's life is nothing short of an inspiration. Though she faced some problems in the beginning of her career, but her perseverance helped her pave her way through all the obstacles, consequently winning the highest honour in field of Science.
Happy Birthday Maria!

Also Read: Basics of Astrophysics Series

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