Lattice-assisted nuclear alpha and beta decay

Nuclear decay rates for nuclei embedded in solids may be affected in principle by atomic-scale interactions, although such effects are usually quite weak. We have recently considered modifications of the alpha and beta decay rates under conditions where the end result of the decay of a single nucleus leads to a significant modification of the structure of phonon mode spectrum. The basic idea is that the production of a vacancy can cause a few phonon modes to jump across a band gap; the associated change in energy of the phonons must be correctly accounted for in the computation of the decay rate. This effect is usually quite small, and it would be unexpected that observable effects would result. However, if the phonon mode that jumps across a band gap is highly excited, then the energy exchange with the lattice ΔE = Nℎδω may be significant. If the mode is strongly driven, or if a phonon laser is operating, then the number of phonons N may be very large and the associated energy transfer significant. We have developed a model suitable for computing reaction rates for such processes; we will present the results of computations for various lattice-assisted alpha and beta decays