ONIOM calculations have been carried out to determine geometries, adsorption energies, and vibrational frequencies of CO on a model for Au-exchanged mordenite catalysts, Au/MOR. The CO-calculated vibrational frequencies (upsilon(CO)) are in good agreement with the reported experimental values. We proposed to interpret the frequency results. CH(3)COCH(3) and CH(3)SH adsorption enthalpy calculations on Au/MOR model show that the Au/MOR catalyst behaves like a soft acid according to Pearson's rule. A higher structural deformation degree of the mordenite was found in the calculations with PM6 than with universal force field approach approach. A new pseudopotential (ACEP-121) was developed to improve the Au-Au distance, and Au ionization potential.

ONIOM and pseudoespectral calculations have been carried out to determine geometries and adsorption energies of NH3 on H-mordenite, H-MOR, with density functional theory. The influence, on the adsorption energy, of a second acid site, close to the one where the adsorption is taking place, was investigated as well as the possibility of adsorbing two NH3 molecules on neighboring sites. The NH3 adsorption energies over MOR with one and two acid sites agree with the temperature-programmed desorption TPD results.

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