Microscopic calculation of deformation energies of nuclei

Abstract

<p>For a given two-body force, we formulate a method for estimating the energy in a constrained Hartree-Fock calculation of a deformed nucleus. This is done by using the information from the first two iterations of the self-consistency cycle. After giving some simple illustrations, the method is applied to obtain the deformation energy curve of some medium heavy nuclei and the fission barrier of ²⁴⁰Pu. The results are compared with the corresponding self-consistent CHF calculations with a standard Vautherin-Brink type Skyrme force to ascertain the accuracy of the method. We investigate further the density dependence of the fission barrier of ²⁴⁰Pu by using five different Skyrme-type forces. The barrier height systematic in relation to the incompressibility and surface energy is investigated. The Kyoto S-MK interaction gives the best results. The energy surfaces of ²³²Th, ²⁵²Fm and ²⁵⁸Fm are also traced with this force. It is found that the Thorium-anomaly persists in our microscopic calculation. Consistent with the usual interpretation of the experimental data, we find a vanishing second barrier for ²⁵⁸Fm.</p>