Evidence of line mixing has been observed in the infrared spectra of many gaseous species at high densities or in the low absorbing windows between optical transitions. However, up to this point, no study exists of nitric oxide line mixing at pressures above atmosphere or temperatures several hundred degrees above room temperature. In this paper, the absorption spectrum of nitric oxide’s R-branch broadened by N${}_2$ near 5.2 microns is measured with an external cavity quantum cascade laser in a high-pressure, high-temperature optical static cell over a range of temperatures (294 – 802 K) and pressures (5 – 33 atm). An empirically-based, temperature-dependent line mixing model is built by assembling the impact relaxation matrix from fits (energy gap fitting laws) to pressure broadening coefficients that were measured in a previous study. The resulting line mixing model shows significant improvements over a simple superposition of Lorentzian line shapes when compared to the static cell measurements. To further demonstrate the model’s use, the line mixing model is used to infer temperature in high-pressure (10 – 90 atm) shock tube experiments.

在高密度的许多气体物质的红外光谱中或在光学跃迁之间的低吸收窗中观察到线混合的证据。然而，到目前为止，还没有关于在高于大气压的压力或高于室温数百度的温度下混合一氧化氮管线的研究。在本文中，一氧化氮的 R 分支的吸收光谱被 N 加宽${}_2$近 5.2 微米是在高压、高温光学静态电池中使用外腔量子级联激光器在温度 (294 – 802 K) 和压力 (5 – 33 atm) 范围内测量的。通过将碰撞松弛矩阵从拟合（能隙拟合定律）组装到先前研究中测量的压力展宽系数，构建了一个基于经验的、与温度相关的线混合模型。与静态单元测量相比，生成的线混合模型显示出对洛伦兹线形状的简单叠加的显着改进。为了进一步演示模型的使用，线混合模型用于推断高压 (10 – 90 atm) 激波管实验中的温度。