Energy Loss of Charged Relativistic Particles and the Element Periods

Abstract

The stopping power per electron for charged relativistic particles is known to be a function of the electron density of the matter traversed. As the latter is a periodic property of the elements, the stopping power should also be periodic. A calculation shows the energy loss to have maxima at the alkali metals and minima between them. It is suggested that this effect partly caused the periodicity found long ago by Crowther in in the absorption of ${\mathrm{Pa}}^{234}$ beta rays. Differences in stopping power for chemical isomers and element modifications are also discussed.