Alpha decay and nuclear deformation: the case forfavoured alpha transitions of even-even emitters*

Abstract

Alpha decay half-life for ground-state to ground-statetransitions of 174 even-even alpha emitters has been calculatedfrom a simple, Gamow-like model in which the quadrupoledeformation of the product nucleus (assumed to have anellipsoidal shape) is taken into account. The assumption made isthat before tunnelling through a purely Coulomb potentialbarrier the two-body system oscillates isotropically, thusgiving rise to an equivalent, average polar direction θ0(referred to the symmetry axis of the ellipsoid) for alphaemission. It is shown that the experimental half-life data aremuch better reproduced by the present description than in thespherical shaped approximation for the daughter nucleus.