Radiation chopping techniques have been employed to study infrared fluorescence of pure carbon monoxide in the region of its fundamental. The present study has served to confirm earlier results obtained by R. C. Millikan using quite different techniques. In addition, CO fluorescence emission <i>V</i> = 1 → 0 was observed from samples irradiated in such a manner as to produce only <i>V</i> =0 → 2 initial absorption. The results can be interpreted in terms of resonant collisions, with the selection rule Δ<i>V</i>= ±1, as follows: CO(<i>V</i>=2)+CO(<i>V</i>=0) → CO(<i>V</i>= 1)+CO(<i>V</i>= 1), with fluorescence emission from the molecules in the <i>V</i> = 1 state.
DAVID J. McCAA and DUDLEY WILLIAMS, "Infrared Fluorescence of Carbon Monoxide," J. Opt. Soc. Am. 54, 326-330 (1964)