If one plots the stopping power of one substance for various ions at constant, sufficiently low, velocity versus the atomic number of the ion, Z1, one obtains Z1-oscillations which correspond to the different atomic structures of the various ions. Similarly, graphs of the stopping power of one ion versus the atomic number of the target atom, Z2, show Z2-oscillations. Some examples are shown below.
The optical oscillator strengths listed here for Al, Cu,and Au are due to J.M. Fernández-Varea, R. Mayol, D. Liljequist and F. Salvat, J. Phys.: Condens. Matter 5 (1993) 3593-3610. They are shown graphically in Fig. 1 of that paper.
The optical oscillator strengths for Si are due to D.Y. Smith et al., see H. Paul, P.L.Grande, D.Y.Smith, "Optical Oscillator Strengths, Mean Excitation Energy, Shell Corrections and experimental values for Stopping Power" Nucl. Instrum. Methods B 267 (2009) 2471.
