Comparison of theoretical models for the electronic stopping power of low-velocity heavy ions

Calculations of the electronic stopping power for low-velocity ($v<\mathrm{}{Z}_1^{\frac{2}{3}}{v}_0, v_0=\frac{e^2}{\hslash }$) heavy ions, based upon three models, are performed for two systems for which experimental data are available: 800-keV ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}_{}^{+}{}_{}{}^{}$ ions incident on amorphous solid targets from carbon to tellurium and 100-keV ${}_{}{}^7{}_{}{}^{}\mathrm{Li}_{}^{+}{}_{}{}^{}$ ions incident on amorphous targets from carbon to selenium. The results of the models are compared with each other and with the experimental data. The models are found to offer qualitatively better fits to the oscillatory experimental data than the smooth curves of the Lindhard-Scharff theory, with a particular modification of the Firsov theory favored for predictive calculations. All the models, as implemented here, required a parameter to be determined by fitting the calculated curves to the experimental points.