The newly developed multichannel cluster model (MCCM), based on the coupled-channel Schrödinger equation with outgoing wave boundary conditions, is extended to study the $\alpha$-decay fine structure in heavy odd-odd nuclei. Calculations are performed for the $\alpha$ transitions to favored rotational bands where the unpaired nucleons remain unchanged. The simple WKB barrier penetration formula is also used to evaluate the branching ratios for various daughter states. It is found that the WKB formula seems to overestimate the branching ratios for the second and third members of the favored rotational band, while the MCCM gives a precise description of them without any adjustable parameters. Moreover, the experimental total $\alpha$-decay half-lives are well reproduced within the MCCM.

• Received 1 February 2013

DOI:https://doi.org/10.1103/PhysRevC.87.027602