Nuclear spin of odd-odd α emitters based on the behavior of α-particle preformation probability.

The preformation probabilities of an cluster inside radioactive parent nuclei for both odd-even and odd-odd nuclei are investigated. The calculations cover the isotopic chains from Ir to Ac in the mass regions 1666AA215 and 777ZZ89. The calculations are employed in the framework of the density-dependent cluster model. A realistic density-dependent nucleon-nucleon (NN) interaction with a finite-range exchange part is used to calculate the microscopic -nucleus potential in the well-established double-folding model. The main effect of antisymmetrization under exchange of nucleons between the and daughter nuclei has been included in the folding model through the finite-range exchange part of the NN interaction. The calculated potential is then implemented to find both the assault frequency and the penetration probability of the particle by means of the Wentzel-Kramers-Brillouin approximation in combination with the Bohr-Sommerfeld quantization condition. The correlation of the -particle preformation probability and the neutron and proton level sequences of the parent nucleus as obtained in our previous work is extended to odd-even and odd-odd nuclei to determine the nuclear spin and parities. Two spin coupling rules are used, namely, strong and weak rules to determine the nuclear spin for odd-odd isotopes. This work can be a useful reference for theoretical calculation of undetermined nuclear spin of odd-odd nuclei in the future. [ABSTRACT FROM AUTHOR]