On the deformation of the α-band

Recently, a new positive-parity rotational band was observed in even-even actinide and rare earth nuclei, having a moment of inertia slightly larger than those of the ground, β, γ, as well as negative-parity bands. This may be understood by a vibron model together with octupole vibration. Using a simple geometrical picture, the polarization of the core is estimated for cases where an α-cluster is found in the surface region. The same polarization effect may also be observed in the angular distribution of α-decays