Infrared spectra of both isomers of CO2-CO in the CO2 ν3 region

Extensive infrared spectra of the weakly-bound CO-CO dimer are observed in the carbon dioxide nu 3 asymmetric stretch region (approximate to 2350 cm) using a tunable infrared OPO laser source to probe a pulsed slit jet supersonic expansion. Both C-bonded and O-bonded isomers are analysed for the normal isotopologue as well as for -CO and O-CO, the latter being the first observation of an asymmetrically substituted form for which all values of K a are allowed. Combination bands involving the lowest in-plane intermolecular bending modes are also studied for both isomers. Weak bands near 2337 cm are assigned to CO hot band transitions , yield-ing the splitting of the degenerate CO bend into in-plane and out-of-plane components due to the presence of the CO. This splitting has rather different values for the C- and O- bonded isomers, 4.57 and 1.59 cm, respectively, with the out-of-plane mode higher in energy than the in-plane for both cases. [GRAPHICS] .

Automated summary

Extensive infrared spectra of the weakly-bound CO-CO dimer were observed in the carbon dioxide nu 3 asymmetric stretch region, analyzing both C-bonded and O-bonded isomers. The splitting of the degenerate CO bend into in-plane and out-of-plane components due to the presence of CO was observed with different values for C- and O-bonded isomers.