Abstract:

Based on statistical thermodynamics and chemical equilibrium theory, citing the spectral data of the atom and molecule, the thermodynamics function(H、C_{p, m}) of diatomic molecule system at thermo-equilibrium is derived in the temperature range from 300K to 20000K. As an example, the dependence of molecular dissociation, atomic ionization and the molar heat capacity for nitrogen plasma system are given. It is shown that the results are in good agreement with those from empirical formula at lower temperature (T<3800K). The results in the higher temperature range are analyzed and discussed, and an analytic expression is given by the least-squares method for the molar heat capacity of nitrogen system.

Key words: Thermal plasma, Statistical thermodynamics, Partition function, Molar heat capacity, Thermo- dynamics function

摘要：

以统计热力学和化学平衡理论为基础，引用原子、分子的光谱数据，计算了在温度300～20000K范围内，双原子分子体系的热平衡等离子体的热力学函数(H、C_{p, m})。给出了氮等离子体体系的分子离解度、电离度和摩尔定压热容随温度变化的关系曲线。所得结果在较低温度范围与经验公式表达的结果良好相符。对较高温度区间的结果作了分析和讨论，并利用最小二乘法给出了氮体系的摩尔热容量的拟合公式。为热等离子体的应用提供了可以参考的数据。

关键词: 热等离子体, 统计热力学, 配分函数, 摩尔定压热容, 热力学函数