One-neutron stripping process in the ²⁰⁹Bi(⁶Li, ⁵Li)²¹⁰Bi* reaction reaction

One-neutron stripping process between \(^{6}\) ${}^6$ Li and \(^{209}\) ${}^{209}$ Bi was studied at 28, 30, and 34 MeV using the in-beam \(\gamma \) $\gamma$ -ray spectroscopy method. The \(\gamma \) $\gamma$ – \(\gamma \) $\gamma$ coincident analysis clearly identified two \(\gamma \) $\gamma$ -rays feeding the ground and long-lived isomeric states, which were employed to determine the cross section. The one-neutron stripping cross sections were similar to the cross sections of complete fusion in the \(^6\) ${}^6$ Li+ \(^{209}\) ${}^{209}$ Bi system, but the one-neutron stripping cross sections decreased more gradually at the sub-barrier region. A coupled-reaction-channel calculation was performed to study the detailed reaction mechanism of the one-neutron stripping process in \(^6\) ${}^6$ Li. The calculations indicated that the first excited state of \(^5\) ${}^5$ Li is critical in the actual one-neutron transfer mechanism, and the valence proton of \(^{209}\textrm{Bi}\) ${}^{209}\text{Bi}$ can be excited to the low-lying excited state in ( \(^{6}\textrm{Li}\) ${}^6\text{Li}$ , \(^{5}\textrm{Li}\) ${}^5\text{Li}$ ) reaction, unlike in the (d,p) reaction.