Fusion barrier distributions inLi6,7+Bi209reactions from quasi-elastic and fusion excitation function measurements

Abstract

Fusion barrier distributions have been obtained from the measurement of the quasi-elastic scattering excitation functions at a backward angle in the reactions of $^{6,7}\mathrm{Li}$ with $^{209}\mathrm{Bi}$. Comparisons have been carried out among barrier distributions, obtained from quasi-elastic scattering by considering elastic + inelastic and elastic + inelastic + [breakup(BU) and/or transfer] and also from fusion excitation function measurements. It has been observed that representations of barrier distributions obtained from elastic + inelastic + [breakup(BU) and/or transfer] and from fusion excitation functions are in good agreement showing the importance of the inclusion breakup channels for the correct fusion barrier representations in the $^{6,7}\mathrm{Li}+^{209}\mathrm{Bi}$ reactions. The observed discrepancy in the resultant barrier distributions with and without including breakup and/or transfer has been interpreted in terms of the capture barrier distribution. The results obtained from the continuum discretized coupled channels calculations also follow the fusion barrier distributions which have been obtained from the fusion excitation functions measurements. It has been observed that the inclusion of direct breakup $\ensuremath{\alpha}$ with the elastic and inelastic channels in quasi-elastic scattering play an important role in explaining consistently the fusion barrier distributions for both the $^{6,7}\mathrm{Li}+^{209}\mathrm{Bi}$ systems.