α decay calculations with a realistic potential

We have previously used a cluster model, employing a square-well nuclear potential plus a surface-charge Coulomb potential, to satisfactorily describe -decay half-lives for more than 400 nuclei. Here, we investigate a more realistic version of this cluster model, in which the square-well nuclear potential is replaced by a ``cosh'' potential geometry having nonzero diffuseness, and the Coulomb potential by one appropriate to a point charge particle interacting with a uniformly charged spherical core. By varying the adjustable parameters of this more realistic model, we find several potentials which give comparable fits to the -decay data, and select the one which best tallies with information from other areas of nuclear physics. In addition, we find that the -particle preformation probability needed to describe favored transitions in odd-mass nuclei is only 60% of the equivalent quantity required for the ground state to ground state transitions of even-even nuclei.