An extension of the multichannel cluster model (MCCM) is presented to investigate the $\alpha$ decay of odd-mass Bk isotopes from their ground states to more than one rotational band in the daughter Am nuclei. In these cases, the $\alpha$ intensity for the other rotational bands is comparable or dominant with respect to the favored one. Three rotational bands are taken into account for the $\alpha$ decays of ${}^{243,245,247}$Bk from their 3/2${}^{-}$ ground states. The available experimental data concerning fine structure and $\alpha$-decay half-lives are well reproduced within the same framework. Moreover, the ground-state and favored rotational bands are considered for the $\alpha$ decay of ${}^{249}$Bk from its 7/2${}^{+}$ ground state. The calculated results also show good agreement with the latest experimental data [I. Ahmad et al., Phys. Rev. C 87, 054328 (2013)]. This is the first calculation of the $\alpha$ transitions to several rotational bands including favored and unfavored ones within the coupled-channel framework.

• Received 12 June 2013

DOI:https://doi.org/10.1103/PhysRevC.88.014325