Hong Qizhen, Sun Quanhua, Bartolomei Massimiliano, Pirani Fernando, Coletti Cecilia
State Key Laboratory of High Temperature Gas Dynamics, Institute of Mechanics, Chinese Academy of Sciences, 100190 Beijing, China.
Phys Chem Chem Phys. 2020 May 7;22(17):9375-9387. doi: 10.1039/d0cp00364f. Epub 2020 Apr 20.
A modification in the potential energy surface (PES) for N-N interactions, reported in the literature [D. Cappelletti et al., Phys. Chem. Chem. Phys., 2008, 10, 4281], has been presented to improve its description of, particularly, the short range behavior for specific configurations, with the aim of producing a large database of vibration to vibration (V-V) and vibration to translation/rotation (V-T/R) energy transfer rate coefficients, with an increased accuracy extended to large temperature ranges relevant to the modeling of hypersonic gas flows. The modifications were introduced in a physically meaningful fashion and they are shown to improve the performance of the PES in a wide temperature range, not only for calculating rate coefficients, but also for determining a variety of physical properties. This new PES was then used to calculate V-V and V-T/R rate coefficients for inelastic N-N collisions through a mixed quantum-classical method, based on the quantum treatment of molecular vibrations, for vibrationally excited states up to v = 40. Such a large V-T/R coefficient database is quite unprecedented, and the comparison of the efficiency of the related processes with the corresponding V-V coefficients shows that vibrational relaxation plays a very relevant role in high temperature regimes.
文献[D. 卡佩莱蒂等人，《物理化学化学物理》，2008年，第10卷，4281页]报道了对N - N相互作用势能面（PES）的一种修正，其目的是改进对特定构型短程行为的描述，以便生成一个关于振动 - 振动（V - V）和振动 - 平动/转动（V - T/R）能量转移速率系数的大型数据库，并将提高后的精度扩展到与高超声速气流建模相关的大温度范围。这些修正以一种具有物理意义的方式引入，结果表明它们不仅在计算速率系数方面，而且在确定各种物理性质方面，都能在很宽的温度范围内提高PES的性能。然后，基于分子振动的量子处理，通过一种混合量子 - 经典方法，利用这个新的PES计算了高达v = 40的振动激发态下非弹性N - N碰撞的V - V和V - T/R速率系数。如此庞大的V - T/R系数数据库是相当前所未有的，相关过程效率与相应V - V系数的比较表明，振动弛豫在高温区域起着非常重要的作用。
