This paper presents a method of calculating the valence electron contribution to the stopping and interaction cross sections of swift ions in matter using linear response calculations of the dielectric function in crystals. The ab initio response function is used to calculate excitations at low energy and momentum transfers to account for material-specific effects, while higher energy and momentum transfers use a free electron gas response for increased computational efficiency. The ECPSSR method for computing core cross sections is modified to allow predictions of the core contribution to electronic stopping. The charge distribution by entrained electrons is explicitly modeled to account for the additional screening beyond linear response. We use the methods developed to predict the electronic stopping of protons and $\alpha$ particles in silicon and compare to measured values.

中文翻译：

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硅中质子和α粒子的电子激发计算

本文提出了一种利用晶体中介电函数的线性响应计算来计算价电子对物质中快速离子的终止和相互作用截面的价电子贡献的方法。该从头响应函数用于计算低能量和动量传递时的激发，以解决特定于材料的影响，而较高的能量和动量传递则使用自由电子气响应来提高计算效率。修改了用于计算核心横截面的ECPSSR方法，以允许预测核心对电子停止的贡献。明确模拟了夹带电子的电荷分布，以说明线性响应以外的其他筛选。我们使用开发的方法来预测质子的电子停止和$\alpha$ 硅中的颗粒并与测量值进行比较。