Three-cluster states in the spectrum of 8Be (1) Structure and beta-decay of 8B to 16.6 MeV state

We have used a one-dimensional spherical time-dependent Hartree-Fock description at finite temperature, coupled to a restructured aggregation model, to investigate the stability of hot and compressed 208Pb nuclei with respect to multifragmentation. We have found that compression is more efficient to induce multifragmentation than heat. By comparing our results with GSI data, we conclude that about a quarter of the total excitation energy of the system is in the form of compression. We have investigated the problem of spatial anisotropy of multifragmentation and found that the surface of an excited nucleus breaks up before its volume. This leads, in particular, to different crowns in the correlation between the parallel and the perpendicular components of the fragments velocities. Such patterns are observed in emulsion experiments.