An attempt is made to describe the observed band shape deformations of a number of CO₂ vibro-rotational absorption bands (1.4, 1.6 and 2.0 pm) making use of the ideas on the associative equilibrium in compressed gas. It is shown that the model of monomer-dimer equilibrium permits representation of the IR absorption band shapes within an experimental accuracy up to 5.0 MPa. The comparison of the found dimeric band shape with the calculated synthetic spectra of P- and T-isomers is also discussed.