Nuclei beyond the drip line

The picture above shows some predicted energies (the y-axis) of the oxygen isotopes as a function of the number of nucleons (the x-axis). The black lines are nuclear states that cannot decay by emitting neutrons. The nucleus 24O is the nucleus with the largest number of nucleons whose lowest energy state (the ground state) cannot neutron decay. 24O has 16 neutrons and 8 protons for a total of 24 nucleons. The nuclei with more neutrons than 24O are said to lie beyond the "neutron drip line" because neutrons are emmitted (drip off) in their ground states.

In order to understand the properties of states that can neutron decay (the colored lines in the picture) Alexander Volya and Vladimir Zelevinsky have developed a new version of the "Continuum Shell Model". This model simultaneously describes the energies and neutron decay lifetimes for all states shown in the figure.

This model and results for the helium and oxygen nuclei are presented in
Physical Review Letters 94, (2005) page 052501.