ABSTRACT
This recently discovered mode of radioactive decay, like a-decay and spontaneous fission, involves quantum-mechanical tunneling through the deformation-energy barrier between a very heavy nucleus and two separated fragments, the sum of whose masses is less than the mass of the parent nucleus. All nuclides with Z > 40 are metastable with respect to heavy ion emission, but only in favorable cases where the difference between the barrier height and the Q-value is not too great does the decay proceed at a detectable rate.
