Stopping powers and straggling in neon, argon and krypton

A semi-empirical procedure is used to calculate the mean excitation energies appropriate to stopping powers I and to straggling I 1 in neon, argon and krypton. The results are Ne: I = 150 ev; I 1 = 1200 ev; Ar: I = 220 ev, I 1 = 3200 ev; Kr: I = 360 ev, I 1 = 9600 ev. They are consistent with the experimental data.