Theoretical Alpha-Decay Rates for the Actinide Region

Alpha-Particle Angular Distributions of At and Rn Isotopes and Their Relation to Nuclear Structure

“…They adopted the same approach as in older calculations [5,6] but employed a much larger shell model configuration space to compute the formation probabilities. Their calculations indicated that deformation should be the most important factor in modeling the anisotropic a decay and that the angular distribution pattern should reflect the intrinsic shape of the nucleus.…”

“…Thus anisotropic a emission from an oriented ensemble of deformed nuclei should be observed. Later, a firmer theoretical framework was built [5][6][7], using the shell modelincluding BCS pairing [8]-to compute the formation probability of the a particle at the nuclear surface and using the WKB approximation [9] to calculate tunneling through the (deformed) Coulomb barrier. The first experimental tests of this theory were performed on prolate deformed actinide nuclei [10].…”

Angular Distributions ofαParticles Emitted by Deformed Oriented Nuclei

“…Hill and Wheeler [2] argued that in a nucleus with a deformed Coulomb barrier the tunneling probability becomes direction dependent, resulting in anisotropic a emission from an ensemble of oriented nuclei (i.e., nuclei with a preferential spin direction in space). A firmer theoretical framework was built later [3][4][5][6], in which the shell model-including Bardeen-Cooper-Schriefer pairing [7]-was used to compute the formation amplitude of the a particle at the nuclear surface while employing the Wentzel-Kramers-Brillouin approximation [8] to calculate tunneling through the (deformed) Coulomb barrier.Based on the works mentioned above, the observation of anisotropic a emission from heavy nuclei has often been attributed to the tunneling of the a particles through a deformed barrier, thus relating a anisotropies to nuclear deformation [9]. This relationship, however, has not been firmly established experimentally.…”

“…[19][20][21], by Stewart et al [22], and by Berggren [23]. In their "tunneling" model, the former have adopted the same approach as in older work [3][4][5] but employed a much larger shell model configuration space to compute the formation probabilities and also included possible octupole deformation in the determination of the tunneling factors. In these calculations nuclear deformation is the most important factor in modeling anisotropic a decay, and it was found the angular distribution should reflect the shape of the nucleus.…”

Coupled channel alpha decay theory for even- and odd-mass light and heavy nuclei

“…The scattering amplitude n t is related with phase shift 0t as = (52) and is determined by smoothly joining the interior wave function at the matching radius to its asymptotic form of the wave function. If we join the interior wave function to the outgoing wave only, the energy £L becomes complex (discrete) and the integration in Eq.…”