Matthias Brack

Towards a better parametrisation of Skyrme-like effective forces: A critical study of the SkM force☆

Abstract Static nuclear properties associated with a Skyrme-like force in the SkM parametrisation have been extensively studied for both spherical and deformed nuclei through Hartree-Fock plus BCS calculations. These calculations include in particular the determination of the 240 Pu fission barrier up to the second saddle point. The validity of some currently used approximations to the Hartree-Fock approach (self-consistent Strutinsky approach, expectation value method and two-step iterative method) has also been assessed. The results of the microscopic calculations have been systematically compared to the corresponding self-consistent results obtained within the extended Thomas-Fermi framework. Such semiclassical calculations also allow a proper characterisation of the SkM force surface properties (in the liquid drop or droplet model sense). Whereas ground-state radii and multipole moments are found in excellent agreement with experimental data, binding energies are systematically too high and fission barriers are significantly too low. These two defects are shown to be correlated through the too low surface tension of the force. A modified parametrisation is discussed which heals both these defects while keeping intact the good reproduction of other properties. This constitutes a first step in the direction of current efforts to determine a better parametrisation of Skyrme-like forces.

Fragmentation of the photoabsorption strength in neutral and charged metal microclusters

The line shape of the plasma resonance in both neutral and charged small sodium clusters is calculated. The overall properties of the multipeak structure observed in the photoabsorption cross section of spherical

Selfconsistent calculations of highly excited nuclei

{\mathrm{Na}}_{8}

The Strutinsky method and its foundation from the Hartree-Fock-Bogoliubov approximation at finite temperature

and

Pionic disintegration of the deuteron

{\mathrm{Na}}_{20}

Static nuclear properties and the parametrisation of Skyrme forces

neutral clusters can be understood in terms of Landau damping. Quantal configurations are shown to play an important role. In the case of charged

Disappearance of Shell Effects at High Excitation. Self-consistent Calculations at Finite Temperatures

{\mathrm{Na}}_{9}^{+}

On the Extended Thomas-Fermi Approximation to the Kinetic Energy Density

and

On Strutinsky's averaging method

{\mathrm{Na}}_{21}^{+}

Liquid Drop Parameters for Hot Nuclei

clusters a single peak is predicted that carries most of the oscillator strength.