COMMENTS ON THE CLASSICAL APPROACH TO NON-RUTHERFORD CROSS-SECTION CALCULATIONS

Non-Rutherford cross sections are needed in high energy backscattering spectroscopy. Bozoian et al. have developed a classical model and der ived an analytical expression to calculate the projectile energy E(nr) at which the scattering cross section begins to deviate from its Ruth erford value. We make comments on the model and conclude, through disc ussions and experiments, that (1) it is useful in estimating the energ y value but gives incorrect dependences of E(nr) on the departure fact or F and the scattering angle chi, and (2) these inadequacies originat e from the classical approach, which is an over-simplified and phenome nal description of nature.