3,338 research outputs found
Hartree-Fock-Bogoliubov Calculations in Coordinate Space: Neutron-Rich Sulfur, Zirconium, Cerium, and Samarium Isotopes
Using the Hartree-Fock-Bogoliubov (HFB) mean field theory in coordinate
space, we investigate ground state properties of the sulfur isotopes from the
line of stability up to the two-neutron dripline (). In particular,
we calculate two-neutron separation energies, quadrupole moments, and rms-radii
for protons and neutrons. Evidence for shape coexistence is found in the very
neutron-rich sulfur isotopes. We compare our calculations with results from
relativistic mean field theory and with available experimental data. We also
study the properties of neutron-rich zirconium (), cerium
(), and samarium () isotopes which exhibit very large
prolate quadrupole deformations.Comment: 7 pages, 6 figures, 2 tables submitted to Phys. Rev.
TDHF investigations of the U+U quasifission process
The use of actinide collisions have been suggested as a way to produce
neutron rich isotopes of high Z nuclei. The collision dynamics of these
reactions can be studied using unrestricted time-dependent Hartree-Fock (TDHF)
calculations. Here, we report on the recent studies of quasifission for the
U+U system.Comment: Presented at the XXXV Mazurian Lakes Conference on Physics, Piaski,
Poland, September 3-9, 2017
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
Fm. The non-adiabatic 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.Comment: 5 pages, 4 figures. Accepted for publication in Phys. Rev. C - Rapid
Communitatio
Microscopic DC-TDHF study of heavy-ion potentials and fusion cross sections
We study heavy-ion fusion reactions at energies near the Coulomb barrier, in
particular with neutron-rich radioactive ion beams. Dynamic microscopic
calculations are carried out on a three-dimensional lattice using the
Density-Constrained Time-Dependent Hartree-Fock (DC-TDHF) method. New results
are presented for the Sn+Ca system which are compared to
Sn+Ca studied earlier. Our theoretical fusion cross-sections
agree surprisingly well with recent data measured at HRIBF. We also study the
near- and sub-barrier fusion of O on C which is important to
determine the composition and heating of the crust of accreting neutron stars.Comment: Talk given by . Volker E. Oberacker at the 11th International
Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA,
May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of
Physics: Conference Series (JPCS
Time-dependent mean-field investigations of the quasifission process
We demonstrate that the microscopic Time-dependent Hartree-Fock (TDHF) theory
provides an important approach to shed light on the nuclear dynamics leading to
the formation of superheavy elements. In particular, we discuss studying
quasifission dynamics and calculating ingredients for compound nucleus
formation probability calculations. We also discuss possible extensions to TDHF
to address the distribution of observables.Comment: Proceedings of a talk given at FUSION17, Hobart, Tasmania, AU (20-24
February, 2017
Ni+Ni fusion reaction calculated with the density-constrained time-dependent Hartree-Fock formalism
We study fusion reactions of the Ni+Ni system using the
density-constrained time-dependent Hartree-Fock (TDHF) formalism. In this
formalism the fusion barriers are directly obtained from TDHF dynamics. In
addition, we incorporate the entrance channel alignments of the slightly
deformed (oblate) Ni nuclei due to dynamical Coulomb excitation. We show
that alignment leads to a fusion barrier distribution and alters the naive
picture for defining which energies are actually sub-barrier. We also show that
core polarization effects could play a significant role in fusion cross section
calculations.Comment: 7 pages, 6 figure
Time-Dependent Response Calculations of Nuclear Resonances
A new alternate method for evaluating linear response theory is formally
developed, and results are presented. This method involves the time-evolution
of the system using TDHF and is constructed directly on top of a static
Hartree-Fock calculation. By Fourier transforming the time-dependent result the
response function and the total probability amplitude are extracted. This
method allows for a coherent description of static properties of nuclei, such
as binding energies and deformations, while also providing a method for
calculating collective modes and reaction rates. A full 3-D Cartesian
Basis-Spline collocation representation is used with several Skyrme
interactions. Sample results are presented for the giant multipole resonances
of 16O, 40Ca, and 32S and compared to other calculations.Comment: 8 pages, 7 figures, submitted to Phys. Rev.
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