Molecular dynamics (MD) simulations are conducted to determine energy and momentum accommodation coefficients at the interface between rarefied gas and solid walls. The MD simulation setup consists of two parallel walls, and of inert gas confined between them. Different mixing rules, as well as existing ab-initio computations combined with interatomic Lennard-Jones potentials were employed in MD simulations to investigate the corresponding effects of gas-surface interaction strength on accommodation coefficients for Argon and Helium gases on a gold surface. Comparing the obtained MD results for accommodation coefficients with empirical and numerical values in the literature revealed that the interaction potential based on ab-initio calculations is the most reliable one for computing accommodation coefficients. Finally, it is shown that gas–gas interactions in the two parallel walls approach led to an enhancement in computed accommodation coefficients compared to the molecular beam approach. The values for the two parallel walls approach are also closer to the experimental values.

中文翻译：

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气-壁和气-气相互作用对稀有气体适应系数的影响：分子动力学研究

进行分子动力学（MD）模拟以确定稀薄气体与固体壁之间的界面处的能量和动量调节系数。MD模拟设置包括两个平行的壁，并在它们之间限制了惰性气体。在MD模拟中，采用了不同的混合规则以及现有的从头计算与原子间Lennard-Jones势相结合的方法，以研究气-面相互作用强度对金表面上氩气和氦气的调节系数的相应影响。将获得的调节系数的MD结果与经验值和数值进行比较，结果表明，基于从头算的相互作用力是计算调节系数最可靠的方法。最后，结果表明，与分子束方法相比，两个平行壁方法中的气体-气体相互作用导致计算的容纳系数的增加。两个平行壁方法的值也更接近实验值。