Isomeric states in light francium nuclei:
Francium is the heaviest alkali element. In addition to its simple atomic structure, it also possesses a fairly simple nuclear structure based on what has been observed to be an inert lead core with 5 additional protons. This combination makes francium one of the leading candidates upon which to perform high precision experiments to test both nuclear and atomic theories as well as to perform fundamental tests of the standard model. A precursory experiment to investigate the nuclear structure of very light francium isotopes confirmed for the first time that several isotopes contain long-lived isomeric states. The nuclear structure of these states has been determined via laser spectroscopy, providing invaluable input and tests of both nuclear and atomic theories.