A. S. Umar

Ground-state properties of exotic Si, S, Ar and Ca isotopes

Abstract Masses, deformations, radii, two-neutron separation energies and single-particle properties of Si, S, Ar and Ca isotopes are investigated in the framework of the self-consistent mean-field theory. In particular, the role of the N = 28 gap in the neutron-rich isotopes, and differences between proton and neutron deformations are discussed.

Shape coexistence around 1644S28: the deformed N = 28 region 1565

Abstract Masses, deformations, radii, and single-particle properties of the very neutron-rich sulfur isotopes are investigated in the framework of the self-consistent mean-field theory. The stability of the N = 28 magic gap around 44 S is discussed.

Formation and dynamics of fission fragments

Although the overall time scale for nuclear fission is long, suggesting a slow process, rapid shape evolution occurs in its later stages near scission. Theoretical prediction of the fission fragments and their characteristics are often based on the assumption that the internal degrees of freedom are equilibrated along the fission path. However, this adiabatic approximation may break down near scission. This is studied for the symmetric fission of

Basis-Spline collocation method for the lattice solution of boundary value problems

{}^{258,264}

Heavy-ion interaction potential deduced from density-constrained time-dependent Hartree-Fock calculation

Fm. The nonadiabatic evolution is computed using the time-dependent Hartree-Fock method, starting from an adiabatic configuration where the fragments have acquired their identity. It is shown that dynamics has an important effect on the kinetic and excitation energies of the fragments. The vibrational modes of the fragments in the post-scission evolution are also analyzed.

The TDHF code Sky3D

Abstract We study a particular utilization of the basis-spline collocation method (BSCM) for the lattice solution of boundary value problems. We demonstrate the implementation of a general set of boundary conditions. Among the selected problems are the Schrodinger equation in radial coordinates, the Poisson, and the generalized Helmholtz equations in radial and three-dimensional Cartesian coordinates.

Three-dimensional unrestricted time-dependent Hartree-Fock fusion calculations using the full Skyrme interaction

We present a new method for calculating the heavy-ion interaction potential from a density-constrained time-dependent Hartree-Fock calculation.

Axially symmetric Hartree-Fock-Bogoliubov Calculations for Nuclei Near the Drip-Lines

The nuclear mean-field model based on Skyrme forces or related density functionals has found widespread application to the description of nuclear ground states, collective vibrational excitations, and heavy-ion collisions. The code Sky3D solves the static or dynamic equations on a three-dimensional Cartesian mesh with isolated or periodic boundary conditions and no further symmetry assumptions. Pairing can be included in the BCS approximation for the static case. The code is implemented with a view to allow easy modifications for including additional physics or special analysis of the results.

Energy dependence of potential barriers and its effect on fusion cross sections

We present a study of fusion cross sections using a new generation Time-Dependent Hartree-Fock (TDHF) code which contains no approximations regarding collision geometry and uses the full Skyrme interaction, including all of the time-odd terms. In addition, the code uses the Basis-Spline collocation method for improved numerical accuracy. A comparative study of fusion cross sections for

Entrance channel dynamics of hot and cold fusion reactions leading to superheavy elements

^{16}O + ^{16,28}O