Abstract
Relative line intensities in the 2 → 0 sequence of bands of carbon monoxide observed in emission from a radio-frequency discharge have been measured. An enhancement of the R branch lines and a diminution of the P branch lines due to vibration–rotation interaction has been observed in agreement with theoretical predictions. Vibrational and rotational temperatures have been calculated and when allowance is made for the vibration–rotation interaction these prove to be equal within experimental error indicating the existence of thermal equilibrium in the discharge.