Study of 0 states at iThemba LABS

The very strong attractive forces between nucleons in a nucleus cause the protons and neutrons each to pair off into time reversed orbits with magnetic quantum numbers m and -m. Thus the angular momentum of each nucleon is opposite to its pairing partner, giving zero angular momentum for the pair. In nuclei with even numbers of both protons and neutrons (e–e) all the nucleons are paired off and the lowest energy state, the “ground” state, has zero angular momentum and is spherically symmetric. This is written 01 where 1 is for the first state and + is the parity. Odd nuclei, e–e nuclei with an extra proton or neutron, then have the last nucleon in a “single particle” state outside the e–e core. The properties of this state depend critically on the shape of the nucleus.