Subbarrier fusion ofLi9withZn70

Abstract

The cross section for the fusion of 9 Li with 70 Zn was measured for seven projectile energies spanning the subbarrier and near-barrier region (E c.m. ranging from 9.7 to 13.4 MeV) using the ISAC facility at TRIUMF. γ -ray spectroscopy of the irradiated target foils along with β counting of the chemically separated Ge and As evaporation residues were used to measure the fusion cross sections. Statistical model calculations were used to correct for the yields of any unobserved nuclei. The observed fusion excitation function shows significant subbarrier fusion enhancement with a large deduced value of the fusion radius, R B =12.1±1.0 fm. Coupled-channels calculations do not account for the observed subbarrier enhancement. The implications of this finding for understanding the fusion of 11 Li are discussed.

Fusion at near-barrier energies within the quantum diffusion approach

“…The agreement with the experimental data of Ref. [29] is quite satisfactory. At lowest energies, the calculated cross section is by factor of ∼ 5 less than the experimental value.…”

“…for the reaction 9 Li+ 70 Zn. The experimental data are from Ref [29]6 He+ 68 Zn and 4 He+ 70 Zn, 6 He+ 122 Sn and 4 He+ 124 Sn, 6 He+ 236 U and 4 He+ 238 U, 8 He+ 204 Pb and 4 He+ 208 Pb, 8 Li+ 207 Pb and 7 Li+ 208 Pb, 7 Be+ 207 Pb and 10 Be+ 204 Pb, 9 Be+ 208 Pb and 10 Be+ 207 Pb, 11 Be+ 206 Pb and 10 Be+ 207 Pb, 8 B+ 208 Pb and 10 B+ 206 Pb, 8 B+ 207 Pb and 11 B+ 204 Pb, 9 B+ 208 Pb and 11 B+ 206 Pb, 15 C+ 204 Pb and 12 C+ 207 Pb, 15 C+ 206 Pb and 13 C+ 208 Pb, 15 C+ 207 Pb and 14 C+ 208 Pb, 17 F+ 206 Pb and 19 F+ 208 Pb, leading to the same corresponding compound nuclei, one can analyze the role of the breakup channels in the reactions with the light weakly bound projectiles 6,8 He, 8 Li,7,9,11 Be,8,9 B, 15 C, and 17 F at near and above the barrier energies.…”

Sub-barrier fusion of neutron-rich nuclei and its astrophysical consequences

“…Quite recently the cross section for the fusion of 9 Li with 70 Zn was measured at near and sub-barrier energies [39].…”

“…We performed an analysis of this reaction using the same nucleus-nucleus potential as in Ref. [39] (Woods-Saxon type potential with V 0 = −105 MeV, r 0 = 035809-5 1.12 fm, a = 0.65 fm). One-dimensional barrier penetration model gives the result shown in Fig.…”

Coupled-channels analyses for 9,11Li + 208Pb fusion reactions with multi-neutron transfer couplings

“…Even though the fusion of the 9 Li nucleus is considered to provide reference cross sections in discussing the fusion of the 11 Li nucleus, the standard coupled-channels calculations have faced difficulties in reproducing the experimental data. * e-mail: cheoun@ssu.ac.kr (Corresponding Author) For instance, the fusion cross sections for the 9 Li+ 70 Zn system are largely underestimated at energies below the Coulomb barrier even if the collective excitations in the colliding nuclei as well as the ground-state-to-ground-state two-neutron transfer channel are taken into account [24]. The fusion of the 9 Li+ 208 Pb system also shows a similar difficulty [12,25].…”