Comparisons are made between potential energy surfaces (PES) for N2 + N and N2 + N2 collisions and between rate coefficients for N2 dissociation that were computed using the quasiclassical trajectory method (QCT) on these PESs. For N2 + N we compare the Laganà's empirical LEPS surface with one from NASA Ames Research Center based on ab initio quantum chemistry calculations. For N2 + N2 we compare two ab initio PESs (from NASA Ames and from the University of Minnesota). These use different methods for computing the ground state electronic energy for N4, but give similar results. Thermal N2 dissociation rate coefficients, for the 10,000K-30,000K temperature range, have been computed using each PES and the results are in excellent agreement. Quasi-stationary state (QSS) rate coefficients using both PESs have been computed at these temperatures using the Direct Molecular Simulation of Schwartzentruber and coworkers. The QSS rate coefficients are up to a factor of 5 lower than the thermal ones and the thermal and QSS values bracket the results of shock-tube experiments. We conclude that the combination of ab initio quantum chemistry PESs and QCT calculations provides an attractive approach for the determination of accurate high-temperature rate coefficients for use in aerothermodynamics modeling.

中文翻译：

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N2 解离的势能面和计算速率系数的比较

对 N2+N 和 N2+N2 碰撞的势能面 (PES) 以及使用准经典轨迹方法 (QCT) 在这些 PES 上计算的 N2 解离率系数之间进行了比较。对于 N2 + N，我们根据从头算量子化学计算将 Laganà 的经验 LEPS 表面与 NASA 艾姆斯研究中心的 LEPS 表面进行比较。对于 N2 + N2，我们比较了两个 ab initio PES（来自 NASA Ames 和来自明尼苏达大学）。它们使用不同的方法来计算 N4 的基态电子能量，但给出了相似的结果。已使用每个 PES 计算了 10,000K-30,000K 温度范围内的热 N2 解离率系数，结果非常一致。使用 Schwartzentruber 和同事的直接分子模拟在这些温度下计算了使用两种 PES 的准稳态 (QSS) 速率系数。QSS 速率系数比热系数低 5 倍，热和 QSS 值包含冲击管实验的结果。我们得出结论，从头算量子化学 PES 和 QCT 计算的组合为确定用于空气热力学建模的准确高温速率系数提供了一种有吸引力的方法。