Product channel-specific reaction kinetics at low temperature presents a significant challenge for both experiment and theory but provides essential inputs for astrochemical models of cold interstellar environments. Reaction kinetics studies using chirped pulse Fourier transform microwave (CP-FTMW) spectroscopy provide a potential solution but require the use of a buffer gas to thermalize the reactants and products; however, collisions with the buffer gas reduce the length of the detected signal, the free induction decay, through pressure broadening. The effect of this on time domain signals is largely unexplored using CP-FTMW spectrometers. A new E-band (60–90 GHz) spectrometer has been constructed using previously unavailable equipment in order to maximize its performance for detecting molecules in collisional environments. The design of this spectrometer is described in detail. The pressure broadening of OCS in He was used to test the spectrometer under collisional conditions similar to those that are routinely used to perform reaction kinetics measurements. The corresponding pressure broadening coefficients for transitions in this frequency range were determined at room temperature and the performance of the spectrometer was assessed in relation to recently reported chirped pulse in uniform flow experiments.

低温下特定于产物通道的反应动力学对实验和理论都提出了重大挑战，但为冷星际环境的天化学模型提供了必要的输入。使用chi脉冲傅立叶变换微波（CP-FTMW）光谱学进行的反应动力学研究提供了一种潜在的解决方案，但需要使用缓冲气体来加热反应物和产物。但是，与缓冲气体的碰撞会通过加宽压力来减小检测到的信号的长度，自由感应衰减。使用CP-FTMW光谱仪尚未充分探讨这种对时域信号的影响。为了使用其在碰撞环境中检测分子的性能最大化，已使用以前不可用的设备构造了新的E波段（60–90 GHz）光谱仪。详细说明了该光谱仪的设计。OCS中He的压力增宽被用来在类似于常规用于进行反应动力学测量的碰撞条件下测试光谱仪。在室温下确定该频率范围内跃迁的相应压力增宽系数，并在均匀流实验中根据最近报道的chi脉冲来评估光谱仪的性能。