In ion irradiation processes, electronic stopping power describes the energy transfer rate from the irradiating ion to the target material's electrons. Due to the scarcity and significant uncertainties in experimental electronic stopping power data for materials beyond simple solids, there has been growing interest in the use of first-principles theory for calculating electronic stopping power. In recent years, advances in high-performance computing have opened the door to fully first-principles nonequilibrium simulations based on real-time time-dependent density functional theory (RT-TDDFT). While it has been demonstrated that the RT-TDDFT approach is capable of predicting electronic stopping power for a wide range of condensed matter systems, there has yet to be an exhaustive examination of the physical and numerical approximations involved and their effects on the calculated stopping power. We discuss the results of such a study for crystalline silicon with protons as irradiating ions. We examine the influences of key approximations in RT-TDDFT nonequilibrium simulations on the calculated electronic stopping power, including approximations related to basis sets, finite size effects, exchange-correlation approximation, pseudopotentials, and more. Finally, we propose a simple and efficient correction scheme to account for the contribution from core-electron excitations to the stopping power, as it was found to be significant for large proton velocities.

中文翻译：

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检查实时时变密度泛函理论非平衡仿真以计算电子制动力

在离子辐照过程中，电子停止功率描述了从辐照离子到目标材料电子的能量转移速率。由于除了简单固体以外的材料的实验性电子止动能力数据的稀缺性和显着不确定性，人们越来越关注使用第一性原理计算电子止动能力。近年来，高性能计算的进步为基于实时时变密度泛函理论（RT-TDDFT）的完全第一性原理的非平衡模拟打开了大门。尽管已经证明RT-TDDFT方法能够预测各种冷凝物系统的电子制动力，尚未对涉及的物理和数值近似及其对计算出的制动力的影响进行详尽的检查。我们讨论了质子作为辐射离子的晶体硅研究的结果。我们研究了RT-TDDFT非平衡模拟中关键近似对计算的电子制动力的影响，包括与基集，有限大小效应，交换相关近似，伪势等相关的近似。最后，我们提出了一种简单有效的校正方案，以解决核心电子激发对停止功率的影响，因为发现它对大质子速度很重要。我们讨论了质子作为辐射离子的晶体硅研究的结果。我们研究了RT-TDDFT非平衡模拟中关键近似对计算的电子制动力的影响，包括与基集，有限大小效应，交换相关近似，伪势等相关的近似。最后，我们提出了一种简单有效的校正方案，以解决核心电子激发对停止功率的影响，因为发现它对大质子速度很重要。我们讨论了质子作为辐射离子的晶体硅研究的结果。我们研究了RT-TDDFT非平衡模拟中关键近似对计算的电子制动力的影响，包括与基集，有限大小效应，交换相关近似，伪势等相关的近似。最后，我们提出了一种简单有效的校正方案，以解决核心电子激发对停止功率的影响，因为发现它对大质子速度很重要。