Peculiarities of the sub-barrier fusion with the quantum diffusion approach

Abstract

With the quantum diffusion approach the unexpected behavior of fusion cross section, angular momentum, and astrophysical S-factor at sub-barrier energies has been revealed. Out of the region of short-range nuclear interaction and action of friction at turning point the decrease rate of the cross section under the barrier becomes smaller. The calculated results for the reactions with spherical nuclei are in a good agreement with the existing experimental data. PACS numbers: 25.70.Ji, 24.10.Eq, 03.65.-w The capture cross section is a sum of partial capture cross sections σ c (E c.m. ) = J σ c (E c.m. , J) = πλ 2 J

Study of fusion of8B +58Ni System in near Barrier Energy Region

“…The quantum diffusion approach is based on the quantum master equation for the reduced density matrix and model the coupling with various channels through the fluctuation and dissipation effects in collisions of heavy ions [14][15][16][17]. Within this approach, the collision of nuclei is treated in terms of two collective variables the relative distance R between the colliding nuclei and the canonically conjugate momentum P [16][17][18][19].The capture cross-section, the sum of partial cross section over possible values of angular momentum at a given centre of mass incident energy E c.m.…”

“…[14]. In the present work we have used this expression for calculating ܲ and hence the fusion excitationfunction for the system considered.…”

Role of neutron transfer and deformation effect in capture process at sub-barrier energies

“…We have to mention that many quantum-mechanical and non-Markovian effects accompanying the passage through the potential barrier are taken into consideration in our formalism [17,19,20]. The details of used formalism are presented in our previous articles [17,18]. All parameters of the model are set as in Ref.…”

“…All calculated results are obtained with the same set of parameters as in Ref. [17]. The absolute values of the quadrupole deformation parameters β 2 of even-even deformed nuclei are taken from Ref.…”

“…In the present paper the quantum diffusion approach [17,18] is applied to study the fusion hindrance and the roles of nuclear deformation and neutron transfer in sub-barrier capture process. Also, we will consider capture reactions with the negative (Q 1n < 0) one-neutron transfer and the positive (Q 2n > 0) two-neutron transfer (before the crossing of the Coulomb barrier), where the one-step neutron pair transfer is expected to prevail.…”