An atomic nucleus assumes discrete energy levels when added energy excites that nucleus. These energy levels are the nucleus’ unique fingerprint; no two nuclei have identical energy patterns. For exotic nuclei, which have unbalanced numbers of protons and neutrons and often only exist for a fraction of a second, researchers have devised a variety of methods to measure the energies of their excited levels.
Click here for original story, A novel way to get to the excited states of exotic nuclei
Source: Phys.org