Theory of Elastic Scattering of Alpha Particles by Heavy Nuclei

Abstract

A semiclassical model is used to interpret recent experiments of Farwell and Wegner on the elastic scattering of 13-42 Mev alpha particles by heavy nuclei. In this model the outgoing $l\mathrm{th}$ partial wave is assumed to vanish if the corresponding classical turning point is less than the radius of the nucleus plus that of the alpha particle; otherwise, it has a phase characteristic of pure Coulomb scattering. The theory predicts that the sum of nuclear and alpha-particle radii is approximately equal to the classical apsidal distance evaluated at the energy for which the experimental cross section is one-quarter of the corresponding Rutherford cross section.