Physics of unstable nuclei: from structure to sequential decays

In this presentation we discuss features of nuclear structure and properties of nuclear decays that result from coupling to the reaction states with one and two nucleons in the continuum. Physics of the one-body decays is reviewed, and perturbations due to the virtual excitations into the continuum of reaction states are examined. The two-body decays are explored using the sequential decay mechanism. The two-neutron s-wave breakups are of particular interest, here the two-body nature of the process appears to suppress the decay rate as compared to the kinematically equivalent one-body s-wave decay. The effective phase space scaling and the resulting from it decay width as a function of the available energy are examined for identical and non-identical particles assuming different values of the scattering length.