Correlations of α -decay properties and isospin-asymmetry

The isospin-asymmetry nuclear chains with $N\ensuremath{-}Z$ from 2 to 60 are investigated to find the correlations of $\ensuremath{\alpha}$-decay properties and isospin asymmetry. Both the proton- and neutron-skin thicknesses of $\ensuremath{\alpha}$ emitters belonging to different $N\ensuremath{-}Z$ chains are tightly aligned along straight lines, the slope of which depends on the shell closure. For even-even $\ensuremath{\alpha}$ emitters, the neutron-skin thickness ${\mathrm{\ensuremath{\Delta}}}_{n}$ multiplied by $N\ensuremath{-}Z$ is a parabolic function of the isospin-asymmetry parameter $I=(N\ensuremath{-}Z)/A$. For the nuclei of incomplete neutron shells, the $\ensuremath{\alpha}$-decay half-life ${T}_{\ensuremath{\alpha}}$ exponentially increases with ${\mathrm{\ensuremath{\Delta}}}_{n}$ in the isospin chain. In the nuclei with valence neutrons and/or protons outside the magic core, ${T}_{\ensuremath{\alpha}}$ exponentially decreases with increasing ${\mathrm{\ensuremath{\Delta}}}_{n}$. The values of ${T}_{\ensuremath{\alpha}}$ and ${Q}_{\ensuremath{\alpha}}$ are almost exponential functions of isospin asymmetry.