Study of the higher-order corrections to the impact-parameter dependence of energy lossстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:A method is proposed to describe the impact-parameter dependence of energy loss in ion-atom collisions, Delta E(b), which is based on the local plasma frequency (LPF) approach, In this method, a linear response approach is combined with an explicit description of the energy loss to a free electron. This results in a general scheme of calculation where both the Barkas and Bloch corrections are presented. The calculated stopping cross-sections are in satisfactory agreement with the relevant experimental results. However, a serious disagreement was found by comparing the calculations with our recent results for energy losses in a thin gold foil, measured as a function of exit angle. This data reflect the impact-parameter dependence of energy loss in single ion-atom collisions. To explain this disagreement we address the problem of proper conversion of the impact parameter scale to the angle of deflection in single ion-atom collisions, It is argued that, due to specific quantum effects, the deflection angle for a given impact parameter depends significantly on the eventual energy loss. Under the conditions used in the experiment this can lead to an increase by a factor of two of the variation of the energy loss in a foil as a function of exit angle. (C) 2000 Elsevier Science B.V. All rights reserved.