Figure 6. Portion of νIII band of the noncyclic (CO2)3 isomer. Some of the main P-branch transitions of the noncyclic trimer are labeled in the model spectrum, and indicated by arrows in the observed spectrum. Also note the strong Q branch marked with an asterisk in the observed spectrum. This corresponds to none of the predicted features, and probably belongs to a cluster larger than the trimer. Conditions: 0.6% CO2 in He, P0=2.1 bar, 2 passes. Model spectrum: Trot=6.5 K, linewidth is 50 MHz. Hybrid character: 0.78 a type, 0.22 c type.