Prolate-oblate shape transitions in nuclei

Article By:

Hamilton, Joseph H. Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee.

Luo, Yixiao Lawrence Berkeley National Laboratory, Lawrence, California.

Rasmussen, John O. Lawrence Berkeley National Laboratory, Lawrence, California.

Last reviewed:2014

DOI:https://doi.org/10.1036/1097-8542.YB150615

The shape of an atomic nucleus determines the allowed excited energy levels of a nucleus and other nuclear properties. Current and future developments of more sophisticated nuclear models to explain the behavior of nuclear matter inside a nucleus depend on knowing nuclear shapes. Nuclear shapes can be determined by measuring the properties of the excited states in a nucleus. Most atomic nuclei have either spherical shapes or prolate shapes (like an American or rugby football) for their ground states. In a few regions on the chart of the nuclides, for a given atomic number (Z), nuclei are found to change their ground-state shapes in a complex way from prolate shapes to oblate shapes (like a discus or thick pancake), or vice versa, as their neutron number increases. Both prolate and oblate shapes are axially symmetric, with two axes being equal. Ground-state shape transitions with changing neutron number and coexistence of different shapes in one nucleus provide very sensitive tests to develop and refine microscopic models of the shapes and structure of nuclei.

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