The Analysis of the Vibration-Rotation Bandω3forC12O162andC13O162

The vibration-rotation band ${\omega }_3$ for normal and isotopic C${\mathrm{O}}_2$ has been completely remeasured with a 7200 line-per-inch grating and the rotation lines of both bands are completely resolved. Identification of the rotation lines up to $J=90\mathrm{}$ in the $P$ branch and $J=56\mathrm{}$ in the $R$ branch for the band in normal C${\mathrm{O}}_2$ was made, while for the isotopic band they are identified to $J=94\mathrm{}$ in the $R$ branch and to $J=44\mathrm{}$ in the $P$ branch. The combination principle was applied to the new data and new values of the band centers and the rotational constants $B_{000}$, $B_{001}$, and ${\alpha }_3$ have been determined. These new values are compared with those obtained from the earlier data.