Search

A time-dependent microscopic approach of the fission process based on the constrained HFB approach with the Gogny force and the Hill and Wheeler configuration mixing method is described. Recent results concerning fragment distributions (mass, kinetic and deformation energies) and other fragment observables in 238U obtained with such an approach are presented and discussed. [ABSTRACT FROM AUTHOR]

Theoretical results for giant resonances in the three doubly magic exotic nuclei 78Ni, 100Sn and 132Sn are obtained from Hartree-Fock (HF) plus Random Phase Approximation (RPA) calculations using the D1S parameterization of the Gogny two-body effective interaction. Special attention is paid to full consistency between the HF field and the RPA particle-hole residual interaction. The results for the exotic nuclei, on average, appear similar to those of stable ones, especially for quadrupole and octupole states. More exotic systems have to be studied in order to confirm such a trend. The low energy of the monopole resonance in 78Ni suggests that the compression modulus in this neutron-rich nucleus is lower than the one of stable ones. [ABSTRACT FROM AUTHOR]

A microscopic theory for the decay of a compound nucleus is presented which is formulated in the spirit of transport theories. Its basic physical assumption is the existence of two time scales, a rapid one concerning the creation of intrinsic excitations and a slow one controlling the change of the nuclear shape. This fact is used in the derivation of an equation of motion for the reduced density by applying the so-called Markov approximation. A canonical distribution of the system with regard to the intrinsic excitations at a given shape is assumed as an approximation and a temperature T(q, t) depending on the nuclear shapes and time t is defined so as to render the canonical distribution as realistic as possible. [ABSTRACT FROM AUTHOR]

Two-dimensional Hartree-Fock-Bogoliubov (HFB) calculations have been performed from spherical shapes to large deformations with constraints on axial quadrupole and octupole deformations in 238U, 256–260Fm and 226Th actinides. Scission configurations have then been identified in this subspace of collective coordinates and many nuclear properties of the nascent fragments have been derived, such as deformation, deformation energy or prompt neutron multiplicity. The HFB states have then served as basis states for time-dependent collective calculations based on the Time-Dependent Generator Coordinate Method and the Gaussian Overlap Approximation to derive fission fragment yields. [ABSTRACT FROM AUTHOR]