The Strengths, Widths, and Shapes of Lines in the Vibration-Rotation Bands of CO.

Methods described previously were applied to the CO fundamental vibration-rotation band to yield the strengths and widths of the individual lines and some information bearing on their detailed shapes. Less comprehensive data were also obtained for the 2A) and 3-0 bands. The frequencies of several lines of the lA) bands of the isotopic molecules Cl 3016, C110 , C 0 , and C O , as well as lines of the 2-1 band of C13016, were measured relative to the 1-0 band of C13016. These were combined with measurements of the 2-1, 3-2, 4-3, 5-4, and 6-5 bands in emission from flame sources to check the molecular vibrational and rotational constants. The relative line strengths in the lA) band are given fairly well by the rigid rotor approximation, although there is some indication that the vibration-rotation interaction corresponds to the permanent dipole moment and the effective charge on the atoms having opposite signs. The band strength derived for the 1-0 band is S o = 2148 at 300 K. Line widths show a steady decrease with rotational quantum number, ranging from 0085 atm ' at lines R(O) and P(1) to 0.038 at lines R(30) and F(30). At frequency differences from the line center >4 the absorption seems to be falling below that given by the Lorentx formula. The measurements can be fitted by assuming an exponential factor multiplying the Lorentx formula in this frequency range.