Within the one level R-matrix approach several hindrance factors for the radioactive decays in which are emitted ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{20}{}_{}{}^{}\mathrm{O}$ atomic nuclei are calculated. The interior wave functions are supposed to be given by the recently proposed enlarged superfluid model, an extension of the JINR-Dubna’s quasiparticle phonon nuclear model. The spectroscopic factors are expanded in terms of products of cluster overlaps and intrinsic overlap integrals. The cluster overlaps are equivalents of the generalized coefficients of fractional parentage, while for the intrinsic overlap integrals we construct a model, which is an extension of the usual models for simple particle decay such as deuteron, triton, and α decay. The exterior wave functions are calculated from a cluster-nucleus double-folding model potential obtained with the M3Y interaction. As examples of the cluster decay fine structure we analyzed the particular cases of α decay of ${}_{}{}^{255}{}_{}{}^{}\mathrm{Fm}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ decay of ${}_{}{}^{223}{}_{}{}^{}\mathrm{Ra}$ and ${}_{}{}^{20}{}_{}{}^{}\mathrm{O}$ decay of ${}_{}{}^{229}{}_{}{}^{}\mathrm{Th}$ and ${}_{}{}^{255}{}_{}{}^{}\mathrm{Fm}$. A relatively good agreement with the experimental data is obtained especially in the case of the α-decay fine structure.

• Received 7 December 1994

DOI:https://doi.org/10.1103/PhysRevC.51.3264