Classical Scattering Theory

Abstract

The Rutherford model [1.1] of the atom consisting of a positively charged, virtually pointlike nucleus surrounded by a cloud of negative charges was founded on a classical scattering theory. Alpha particles were considered pointlike, moving under the influence of a Coulomb force. Experimental results were completely explained by the angular distribution of scattered particles obtained from their classical trajectories. In 1911, when the classical model came forth, no one knew about wave mechanics or probability amplitudes. Nor did anyone know that there is nothing like a trajectory on the atomic scale. Though the theory was successful— today we know it was good luck, since the classical and quantum mechanical cross sections coincide, by chance, for the Coulomb potential. So, it can be said that a wrong theory, applied onto a correct model, made an early emergence and an early success of atomic physics possible.