Title: Repulsive interatomic potentials calculated at three levels of theory Show Chinese title

Title: 排斥性原子间势能的计算在三个理论水平上进行

Abstract: The high-energy repulsive interaction between nuclei at distances much smaller than the equilibrium bond length is the key quantity determining the nuclear stopping power and atom scattering in keV and MeV radiation events. This interaction is traditionally modeled within orbital-free density functional theory with frozen atomic electron densities, following the Ziegler-Biersack-Littmark (ZBL) model. In this work, we calculate atom pair specific repulsive interatomic potentials with the ZBL model, and compare them to two kinds of quantum chemical calculations - second-order M{\o}ller-Plesset perturbation theory in flexible Gaussian basis sets as well as density functional theory with numerical atomic orbital basis sets - which go well beyond the limitations in the ZBL model, allowing the density to relax in the calculations. We show that the repulsive interatomic potentials predicted by the two quantum chemical models agree within $\sim$ 1% for potential energies above 30 eV, while the ZBL pair-specific potentials and universal ZBL potentials differ much more from either of these calculations. We provide new pair-specific fits of the screening functions in terms of 3 exponentials to the calculations for all pairs $Z_1$-$Z_2$ for $1 \leq Z_i \leq 92$, and show that they agree within $\sim 2$% with the raw data. We use the new potentials to simulate ion implantation depth profiles in single crystalline Si and show very good agreement with experiment. However, we also show that under channeling conditions, the attractive part of the potential can affect the depth profiles. The full data sets of all the calculated interatomic potentials as well as analytic fits to the data are shared as open access. Show Chinese abstract

Abstract: 高能排斥相互作用发生在核之间的距离远小于平衡键长时，是决定keV和MeV辐射事件中核停止功率和原子散射的关键量。这种相互作用传统上在无轨道密度泛函理论中用冻结的原子电子密度进行建模，遵循Ziegler-Biersack-Littmark（ZBL）模型。在这项工作中，我们使用ZBL模型计算原子对特定的排斥原子间势能，并将其与两种量子化学计算进行比较——在灵活高斯基组中的二阶M{\o }ller-Plesset微扰理论以及使用数值原子轨道基组的密度泛函理论——这些计算远远超越了ZBL模型的限制，允许在计算中放松密度。我们表明，两种量子化学模型预测的排斥原子间势能在30 eV以上的势能范围内一致，误差在$\sim$ 1%以内，而ZBL原子对特定势能和通用ZBL势能与这些计算相比差异更大。我们提供了所有原子对$Z_1$-$Z_2$对$1 \leq Z_i \leq 92$的计算结果的筛选函数的新原子对特定拟合，使用3个指数项，并显示它们与原始数据的偏差在$\sim 2$%以内。我们使用新的势能模拟单晶硅中的离子注入深度分布，并与实验结果高度吻合。然而，我们也表明，在沟道条件下，势能的吸引部分会影响深度分布。所有计算得到的原子间势能的完整数据集以及对数据的解析拟合均以开放获取的方式共享。