Complete fusion of7Li+16O in the region of the Coulomb threshold

Abstract

Excitation functions of the one-and two-particle evaporation reactions 160(7Li, x~) and 160(7Li, xyT) , x, y=n, p, d, t and c~ have been measured in steps of 100-160 keV for ELi=4-10 MeV. All yield curves were rather smooth and could well be described by statistical model calculations taking into account one-and two-particle decays. No significant deviations of the total fusion cross section from the reaction cross section as given by the optical model were observed. A critical comparison is performed with earlier data of the same reaction taken at slightly higher energies where drastically reduced fusion cross sections were reported.

Fusion cross sections forLi6,7+Ray1, Mukherjee2, Pradhan3 et al. 2008Phys. Rev. C324120View full textAdd to dashboardCite

“…However, as the mass of these target nuclei ( 12 C, 13 C, 16 O) are much less than 24 Mg, 27 Al and 28 [41]. The reduced fusion cross sections for the 6 Li and 7 Li induced reactions are shown in Fig.12 and Fig.13 respectively.…”

“…In contrast to the excitation of 7 25 Mg in the 7 Li + 24 Mg reaction the characteristic γ-ray 1.368MeV of 24 Mg in the 6 Li + 24 Mg reaction is observable at very low bombarding energies ( Fig.3). As the emissions of three particles are expected only at very high bombarding energies which is also corroborated by the CASCADE calculations, such excitation of 24 Mg at low bombarding energies must be due to some other processes like 24 Mg (n,n′γ) and are not considered in the evaluation of channel or fusion cross sections.…”

Light charged particle decay in the reaction7Li+16O

“…exit channel, excitation energies, spins, and parities of the residual states observed are given respective energy ranges covered in [5] and [10] do not overlap, the discrepancy is obvious. The latter data were obtained using the y-ray method: secondary low-energy 7-decays following emission of one or several particles were measured using a Ge(Li) detector.…”

“…Additionally, the contributions of direct reaction modes have to be corrected for properly. For all reasons given in this paragraph, the extraction of fusion cross sections from ),-ray data alone [10] is a highly complex and questionable procedure. Thus the present work can explain the discrepancies between [5] and [10] in favour of [51 .…”

“…VcB, where VcB ~4.6 MeV), the fusion cross section as measured by detecting the heavy residual nuclei [5] amounts only to approximately 50% of the total reaction cross section as obtained from the optical model with parameters from [9]. On the other hand, experimental data taken at energies ranging from below to slightly above the Coulomb barrier [10] do indicate that the fusion cross section is equal to the total reaction cross section. Although the …”