The empirical coupled-channel (ECC) model and the universal fusion function (UFF) prescription are used to analyze the data of capture cross sections for reactions ${}^{39}\mathrm{K}+{}^{181}\mathrm{Ta}$ and ${}^{46}\mathrm{K}+{}^{181}\mathrm{Ta}$ reported recently by Wakhle et al.[Phys. Rev. C 97, 021602(R) (2018)]. The results of the ECC model are in good agreement with the data of ${}^{39}\mathrm{K}+{}^{181}\mathrm{Ta}$, while for ${}^{46}\mathrm{K}+{}^{181}\mathrm{Ta}$ the predictions of the ECC model overestimate the above-barrier capture cross sections. Comparing the reduced data of these two reactions, it is found that the above-barrier cross sections of ${}^{39}\mathrm{K}+{}^{181}\mathrm{Ta}$ are consistent with the UFF and are larger than those of ${}^{46}\mathrm{K}+{}^{181}\mathrm{Ta}$. This implies that the capture cross sections of ${}^{46}\mathrm{K}+{}^{181}\mathrm{Ta}$ are suppressed at energies above the Coulomb barrier. Furthermore, at sub-barrier energies, the reduced calculated capture cross sections of ${}^{39}\mathrm{K}+{}^{181}\mathrm{Ta}$ are a little larger than those of ${}^{46}\mathrm{K}+{}^{181}\mathrm{Ta}$, which is owing to the coupling to the positive $Q$-value two-neutron transfer channel.

• Received 8 May 2018

DOI:https://doi.org/10.1103/PhysRevC.98.014615