Accurate atomic and diatomic partition functions are required to determine the level populations for the calculations of radiative properties in thermodynamic equilibrium and nonequilibrium plasmas produced by various atmospheric re-entries. In this work, a reliable partition functions database was rebuilt for some atomic and diatomic species from 100 K to 50000 K. The atomic partition functions were obtained by a four-level model, while the diatomic partition functions were predicted based upon a more rigorous approach for the computation of the energy levels. Compared with previous publications, the number of diatomic electronic states considered in our work is as large as possible. Estimates are made for the contributions of each electronic state of the diatomic molecule to the partition function. Moreover, the effect of the number of electronic states on the partition function was also evaluated. Finally, we calculated the specific heat based upon the obtained partition functions. All the results were validated by the available data in recent references and the relative errors were systematically analysed.

中文翻译：

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高温大气等离子体中原子和双原子物种的分配函数

需要准确的原子和双原子分配函数来确定能级群，以计算由各种大气再入产生的热力学平衡和非平衡等离子体中的辐射特性。在这项工作中，为一些从 100 K 到 50000 K 的原子和双原子物种重建了一个可靠的分区函数数据库。原子分区函数通过四级模型获得，而双原子分区函数基于更严格的方法进行预测用于计算能级。与以前的出版物相比，我们工作中考虑的双原子电子态的数量尽可能多。估计双原子分子的每个电子态对分配函数的贡献。而且，还评估了电子态数对配分函数的影响。最后，我们根据获得的分配函数计算了比热。所有结果都通过最近参考文献中的可用数据进行了验证，并且系统地分析了相对误差。