Macroscopic simulations of dense plasmas rely on detailed microscopic information that can be computationally expensive and is difficult to verify experimentally. In this work, we delineate the accuracy boundary between microscale simulation methods by comparing Kohn–Sham density functional theory molecular dynamics (KS-MD) and radial pair potential molecular dynamics (RPP-MD) for a range of elements, temperature, and density. By extracting the optimal RPP from KS-MD data using force matching, we constrain its functional form and dismiss classes of potentials that assume a constant power law for small interparticle distances. Our results show excellent agreement between RPP-MD and KS-MD for multiple metrics of accuracy at temperatures of only a few electron volts. The use of RPPs offers orders of magnitude decrease in computational cost and indicates that three-body potentials are not required beyond temperatures of a few eV. Due to its efficiency, the validated RPP-MD provides an avenue for reducing errors due to finite-size effects that can be on the order of $\sim 20\%$.

中文翻译：

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径向对电势近似对稠密等离子体分子动力学模拟的功效

密集等离子体的宏观模拟依赖于详细的微观信息，这些信息可能在计算上昂贵并且难以通过实验进行验证。在这项工作中，我们通过比较Kohn–Sham密度泛函理论分子动力学（KS-MD）和径向对位势分子动力学（RPP-MD）在一系列元素，温度和密度下的精确度，来描述微观模拟方法之间的精度界限。通过使用力匹配从KS-MD数据中提取最佳RPP，我们限制了其功能形式并消除了对于小粒子间距离假设恒定幂定律的电位类别。我们的结果表明，RPP-MD和KS-MD在仅几个电子伏特的温度下就多种精度指标达成了极佳的一致性。RPP的使用使计算成本降低了几个数量级，并且表明在几eV的温度范围内不需要三体电势。由于其高效性，经过验证的RPP-MD提供了一种减少误差的途径，该误差是由于有限大小的影响而造成的，其数量级大约为$〜20％$。