Fine Structure of the 2.7 Micron Carbon Dioxide Rotation-Vibration Band

The infrared spectrum of CO₂ in the region of 2.7μ has been remeasured. Five rotation‐vibration bands have been identified and analyzed in detail. One of these is due to C¹³O₂. The rotational constants obtained were $$B_{000}\text{=0.3904\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}\hspace{0.17em}\mathrm{and}{\mathrm{\hspace{0.17em}D}}_{000}{\text{=0.25×10}}^{\text{−6}}\hspace{0.17em}{\mathrm{cm}}^{\text{−1}}.$$ In two of the bands l‐type doubling occurs, and the values of the splitting constants q were determined.