MP2 study of the absorption of CO2 onto the water monomer, dimer and trimer

The nature of the CO 2 -nH 2 O interaction where n=1,2 and 3 is explored to evaluate the energetics of the CO 2 molecule and small water clusters using ab initio MP2 and CCSD(T). We are interested in the absorbance of CO 2 onto the water cluster and not those interactions that significantly alter the original water cluster. Thus, we characterize the interaction energy in terms of CO 2 binding to an intact water cluster. We provide 3 lowest energy isomers of the CO 2 -water trimer not previously reported. We include a description of the bond lengths between the CO 2 and the water and include AIM critical points to identify the hydrogen bond interactions.