High resolution slit-jet infrared spectroscopy of ethynyl radical: 2?-2S+ vibronic bands with sub-Doppler resolution.
Sharp-Williams EN, Roberts MA, Nesbitt DJ. High resolution slit-jet infrared spectroscopy of ethynyl radical: 2?-2S+ vibronic bands with sub-Doppler resolution. J Chem Phys. 2011 Feb 14; 134(6):064314.