Hey panathinaikos13!
Well I think that the interaction between the carbonyl group and the carbon dioxide molecules is the van Der Waals interaction.
I analise like this:
The carbonyl group is a polar group, in other words, there is a considerable electronegativity difference between carbon and oxigen atoms. But in the case of CO
2, which is a linear molecule, this pole is "canceled" and the carbon dioxide is considerated non polar.
So, I think that can happen a pole induction due to the polar nature of the carbonyl in the CO
2 molecules. The carbonyl electron cloud induct the polarization of the electron cloud of carbon dioxide.
It's that what I think that happens, but I'm not pretty sure of it (sorry about that). I will wait for someone answer better your question. ^^
Bye bye o/