Knowledge Bank

Relative line intensities in the 2 $\to$ 0 sequence of bands of carbon monoxide observed in emission from a radio frequency discharge have been measured. An increase in the relative intensities of the R. branch lines and a decrease in the relative intensities of the P branch lines due to vibration-rotation interaction had been observed in agreement with theoretical predictions. The advantages of using emission spectra rather than absorption spectra for this type of study are pointed out. 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.