α-decay spectroscopy of deformed nuclei reexamined

Abstract

We perform an extensive analysis of $\ensuremath{\alpha}$-decays to ${2}^{+}$ and ${4}^{+}$ states in deformed even-even nuclei by using the stationary coupled channels approach. Collective excitations are described within the rigid rotor model. The $\ensuremath{\alpha}$-nucleus interaction is given by a double folding procedure with M3Y plus Coulomb nucleon-nucleon forces. We use a repulsive potential with one independent parameter in order to localize the $\ensuremath{\alpha}$-particle on the nuclear surface and to fit the experimental $Q$-value. The decaying state is identified with the first resonance inside the resulting pocket-like potential, as suggested by microscopic calculations. We obtain a good agreement with existing experimental data concerning decay widths to $J={2}^{+},{4}^{+}$ states. The total $\ensuremath{\alpha}$-decay half-lives agrees very well with experimental values by fitting the spectroscopic factor in terms of charge and neutron numbers separately for $Z<82$ and $Z>82$. We give predictions for intensities and hindrance factors for 52 even-even $\ensuremath{\alpha}$-emitters with ${\ensuremath{\beta}}_{2}>0.15$ and ${E}_{{2}^{+}}<200 \mathrm{kev}$. Comparison between the phenomenological and microscopic spectroscopic factors revealed large $\ensuremath{\alpha}$-clustering components for nuclei close and above $N=82,Z=82,N=126$ magic numbers.