The NH radical is an extremely important specie in nitrogen chemical reaction networks, in the interstellar medium and atmospheric chemistry. Time resolved Fourier transform spectroscopy technique in the frequency range 10–13 µm has been applied for the measurement of a pure rotational spectrum of the NH free radical (NH) in the ground X³Σ⁻ electronic state. Twelve high N (26–29) triplet-resolved pure rotation lines of NH were experimentally observed in the laboratory and compared with satellite ACE (Atmospheric Chemistry Experiment) solar data. In addition, discharge-generated vibration-rotation NH radical bands in the spectral range 1923–3571 cm⁻¹ have been measured with a microsecond time resolution and spectral resolution of 0.02 cm⁻¹. The spectra of the NH radical have been studied in two experimental arrangements. Firstly, in a pulsed positive column discharge of pure hydrogen-nitrogen mixture and secondly, in a discharge of nitrogen-ammonia mixture in the presence of argon buffer gas. Both production methods are described and compared. The population analysis of the experimental spectra was performed via modelling using the accurate MoLLIST line lists for NH. It was shown that laboratory data can be well reproduced by use of a mixture of the local-thermal-equilibrium (LTE) and non-LTE models corresponding to high temperatures (up to 8000 K and up to 6000 K rotational).

NH自由基是氮化学反应网络、星际介质和大气化学中极其重要的一种。频率范围为 10–13 µm 的时间分辨傅里叶变换光谱技术已应用于测量基态 X ³ Σ ^-电子态中的 NH 自由基 (NH) 的纯旋转光谱。在实验室中实验观察到了12 条高N（26-29）三重态分辨纯旋转线，并与卫星 ACE（大气化学实验）太阳数据进行了比较。此外，在 1923-3571 cm ^{-1光谱范围内放电产生的振动旋转 NH 自由基带}已经以微秒时间分辨率和0.02 cm ^-1的光谱分辨率测量。NH 自由基的光谱已经在两个实验装置中进行了研究。首先，在纯氢-氮混合物的脉冲正极柱放电中，其次，在氩缓冲气体的存在下，在氮-氨混合物的放电中。两种生产方法都进行了描述和比较。实验光谱的总体分析是通过使用 NH 的准确 MoLLIST 线列表建模进行的。结果表明，通过使用与高温（高达 8000 K 和高达 6000 K 旋转）相对应的局部热平衡 (LTE) 和非 LTE 模型的混合，可以很好地再现实验室数据。