For cluster model, Li-ZSM-5/CO and Li-FAU/CO
complexes have virtually the same binding energies
(Table 3). We found that the Madelung potential
increases the binding energy by 2.74 kcal/mol in the
Li-ZSM-5 and by about 1 kcal/mol in the Li-FAU
zeolites. With the inclusion of basis-set-superposition-
error correction and the effects of Madelung
potential, we predict that the Li-ZSM-5/CO complex
is more stable by about 1.9 kcal/mol as compared to
the Li-FAU/CO complex. Thus, the Madelung potential
was found to reveal that acidity of zeolite does not
depend only on the acidic site center, but also on the
framework structure where the acidic site is
embedded.