S. Landowne

Calculation of the complete reaction cross section for 16O + 208Pb near the Coulomb barrier

Abstract Coupled-channels calculations are made for 16 O + 208 Pb near the Coulomb barrier. Inelastic and transfer channels are included. An incoming-wave boundary condition is used for fusion; there is no explicit imaginary potential. The elastic angular distributions and the fusion cross sections are well predicted only with a small diffuseness real potential.

Coupled-channels calculations for transfer reactions

Abstract Coupled-channels calculations for one-neutron transfer reactions are carried out for 58 Ni + 64 Ni in order to assess their importance in determining low-energy fusion cross sections. The transfer couplings are specified by an analytic approximation to the microscopic form factors. A rotating frame approximation is used to reduce the number of channels that are explicitly calculated. The fusion process is specified by imposing ingoing-wave boundary conditions. The total reaction cross section and the angular distributions for the transfer reactions are obtained without using imaginary potentials.

Comment on energy dependent barriers for heavy-ion fusion

Abstract It has been suggested that a modulation of the Coulomb barrier in an energy dependent way could be used to describe fusion reactions. Such a procedure fails to give the fusion spin distributions obtained from fully dynamical calculations.

Finite range effects in multi-dimensional barrier penetration problems

Abstract A simple prescription for solving multi-dimensional barrier penetration problems is discussed which allows for finite range effects and contains both the sudden and adiabatic limits as special cases.

Searching for the Berry phase effect with two-particle transfer reactions☆

Abstract Recent structure calculations of two-particle transfer amplitudes between rotating heavy nuclei have predicted strong variations that are related to Berrys topological phase. In this work these amplitudes are incorporated into a new method for calculating the reaction process that allows one to study the consequences of the structure variations on the observable cross sections.

Evidence for the energy dependence of effective heavy-ion interactions

By analyzing the Coulomb-nuclear interference in the excitation of 208 Pb by 16 O at sub-barrier energies, nuclear coupling strength is extracted which twice as large as its value at energies above the barrier.

Pair-transfer with heavy deformed nuclei at high spins☆

Abstract The sudden limit for rotational excitation combined with a macroscopic description of the pair-transfer process allows calculations to be carried out for transfer reactions to high-spin states.

Elastic scattering of 58Ni+64Ni near the Coulomb barrier

Abstract Elastic scattering angular distributions have been measured for 58 Ni+ 64 Ni at three energies around the Coulomb barrier employing a new kinematic coincidence technique. The data are compared with the results of coupled-channels calculations including inelastic excitations as well as one-and two-neutron transfer reactions. The agreement is good and the calculations also agree well with the available transfer and fusion reaction data.

Two-particle transfer reactions with heavy-deformed nuclei

Abstract Detailed calculations of two-particle transfer reactions on heavy, deformed nuclei are carried out within the framework of the macroscopic model for pair transfer and the sudden limit for rotational excitation. The marked structure that appears as a general feature of the angular distributions is explained as an interference of amplitudes that correspond to different orientations of the deformed nucleus. A comparison to recent data supports the existence of this structure.

TRANSFER REACTIONS IN THE SUDDEN LIMIT OF THE PAIRING-ROTOR MODEL

The transfer of multiple pairs of particles in heavy-ion reactions is studied in the sudden limit of the macroscopic pairing-rotor model.