Figure 1. show two stationary point were found for the CH3OH-CO2 complex, three for the CH3OH-CO2 one and seven for the CH3OH-CO2-H2O one at the MP2/6-311++G (2d, 2p) level. The optimized structures were confirmed to be a minimum on the potential energy hyper surface by frequency calculations. All dimers was stabilitized by only one interaction, the structure Ico2 and Ih2o are alike, the O atom of water or CO2 bonded with C atom in methanol forming carbon bond O…C-O contact (A1) 1 while the structure IIco2 and IIh2o are similar, the formation with intermolecular contact O…C=O (A2), O-H…O (C1) for which the “lone pairs” of the donating O atom (CH3OH) interact with the accepting C=O (CO2) or O-H (H2O), respectively 2, 3. The stationary point of the IIIb were only found of CH3OH-H2O which is stabilized by O-H…O (C2) interaction with CH3OH donor proton and H2O is accept proton, no correspond structure for the CH3OH-CO2 . There is a difference in geometry between the binary and ternary system for the complexes that is a presence of O-H…O (C3) interaction in CO2-H2O or CO2-CH3OH), C-H…O (E) contact and chacogen bonding O…O (D). The values display in table1 show that all HB bond type O-H…O is the red shift, in which the length of bond and infrared spectroscopy are increase and the frequency is decrease. Particularly, the interaction distance show the difference of each hydrogen bond. Namely, the distance of (C1) and (C2) contacts (in the range of 1.90-1.91, 1.95-1.96 A0, respectively) is much shorter than the (C3) one (range of 2.16-2.23). Furthermore, the AIM analyses provide three properties at each O-H…O bond critical point (BCP), namely, the electron density (), the Laplacian (), and the total energy density () electron density 5, 6. Like the distance, the values of critical bond of (C1) is rather than (C2) and they much stronger than (C3). Particularly the individual hydrogen energy of (C1), (C2), (C3) is range of -27.96- -31.90; -24.32- -26.33 and -11.50- -12.33 kJ.mol-1 show that the most stable in binary and tetrary complexes is the (C1) interaction, where the O of methanol plays electron donor 4 The (C2) is rather lower than C1, but it is much stronger than C3. The result cause proton affinity (PA) and de-proton enthalpy (DPE) values given in table2, in which the PA of CH3OH is stronger than CO2 and H2OThe difference from (A1) and (A2) interactions is presented by each value in table2, in which the electron density and Laplacian of (A1) contact is twice more stability than (A2) one. So that, we suggest the characteristic of A1 and A2 is O-C…O, O=C…O interaction.