Critical analysis of the modified Firsov model. II: Sensitivity to the average speed of atomic electrons

Abstract Cheshire's modification to the Firsov model for calculating the low-velocity electronic stopping cross-section ( S e ) is shown to be highly sensitive to the use of an average (〈υ〉) rather than a rms speed (υ rms ) for atomic electrons in the evaluation of S e . Differences of about 40% lower in the predicted values for S e are generally observed when one uses 〈υ〉 instead of υ rms in the the calculations, as prescribed by the original theory. The results of this study are compared with experimental data for amorphous carbon targets as well as for channeling measurements in the 〈110〉 direction for silicon crystals. A brief discussion is presented regarding the importance of the other factors that could affect the outcome of the calculations.