Theoretical investigations of CH4, C2H6, CO2 and N2 guest molecules into a dodecahedron water cluster cavities

The properties of the regular and irregular dodecahedron water clusters (H2O)20, with and without the presence of guest molecules such as N2, CO2, CH4, and C2H6 are calculated at the Hartree-Fock (HF) level of theory with 6-31G(d) basis set. Although the dodecahedron in its regular arrangement is more favourable than the irregular one, embedding a guest molecule in the cavity of the cage structure leads to a different behaviour as far as the calculated data between these two different conformations are concerned. The computed stabilisation energy for each system increases with the presence of the guest molecules in the cavity. The Morokuma's decomposition of the total interaction energy performed on three dimensional clusters leads to a better understanding of the cluster formation with a strong charge transfer energy component from the host to the guest.