ИСТИНА

The step of water dissociation under the adsorption on dealuminated mordenites and Y zeolites can be indeed controlled by the Na+ influence but both increase (8R cluster) and decrease (6R+4R) of activation energy was obtained in our model study. Despite a slight variation between relative stabilities of hydrated AlOH2+ and Al(OH)2+ species at the isolated cluster level and using periodic boundary conditions, activation energies remain similar being around 0.3-0.7 eV. This shows relatively easy transformations between the AlOH2+ and Al(OH)2+ species which can vary their AlOX coordination between X = 4 and 5. The inclusion of the inter-conversion between EFAL species can be important for final NMR assignment.