6533b82cfe1ef96bd128fe95

RESEARCH PRODUCT

Systematics of the α-decay to rotational states

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We analyze \ensuremath{\alpha} decays to rotational states in even-even nuclei by using the stationary coupled channels approach. Collective excitations are described by the rigid rotator model. The \ensuremath{\alpha}-nucleus interaction is given by a double folding procedure using M3Y plus Coulomb nucleon-nucleon forces. We use a harmonic oscillator repulsive potential with one independent parameter, to simulate the Pauli principle. The decaying state is identified with the first resonance inside the resulting pocketlike potential. The energy of the resonant state is adjusted to the experimental Q value by using the depth of the repulsion. We obtained a good agreement with existing experimental data concerning total half-lives and decay widths to $J={2}^{+}$ states by changing the factor multiplying the nucleon-nucleon interaction according to the rule ${v}_{a}=0.668\ensuremath{-}0.004 (A\ensuremath{-}208)$. Concerning the decay widths to $J={4}^{+}$ states we obtained a good agreement for $Z=90$ neutron chain and a satisfactory description for $Z=92,96$, and 98, chains. It is possible to improve the agreement concerning transitions to $J={4}^{+}$ states by considering a constant quenching strength ${v}_{a}=0.6$ and by changing the width of the Gaussian describing the \ensuremath{\alpha}-cluster density according to the rule $b=1.744\ensuremath{-}0.032 (A\ensuremath{-}208)$. We found out that the computed widths to excited states are correlated with the corresponding deformation parameters. We conclude that the \ensuremath{\alpha}-decay fine structure is a sensitive tool to probe fundamental aspects of the effective nuclear interaction and its dependence on the \ensuremath{\alpha} clustering.