Seminar Details

Fusion and Quasifission Studies Using Time-Dependent Density Functional Theory

Volker Oberacker, Vanderbilt University
Wednesday, April 23, 4:10 PM - Nuclear Science Seminar
NSCL Lecture Hall

Our research program involves microscopic studies of low-energy nuclear reactions, in particular heavy-ion fusion and quasifission, using time-dependent density functional theory (TDDFT). The dynamic calculations are carried out on a 3-D lattice. There are no adjustable parameters, the only input is an effective nucleon-nucleon interaction. After a brief outline of the TDDFT formalism, I will present various applications: First I will concentrate on fusion reactions involving exotic neutron-rich nuclei which can be studied at Radioactive Ion Beam Facilities. While fusion cross sections at energies above the barrier can be calculated with the standard Time-Dependent Hartree Fock (TDHF) method, calculations at sub-barrier energies require a new approach which we call the Density Constrained TDHF (DC-TDHF) method. This method allows us to calculate microscopically the ion-ion interaction potentials V(R) which determine the fusion cross sections. Some of the effects included in our dynamic approach are: neck formation, deformation of the fragments, average multi-nucleon transfer, and dynamic excitation energies. Specifically, I will show results for fusion reactions of 132Sn + 40,48Ca, and for 40,48Ca + 40,48Ca, with comparison to experimental data. I will briefly discuss a nuclear astrophysics application (very low-energy fusion of stable and neutron-rich C+O and O+O isotopes in the neutron star crust). The final topic will be a study of capture cross sections for 40,48Ca + 238U, leading to superheavy element formation. In this context, I will present some very recent studies of quasifission which is the main competing process.