Interaction of mordenite with an aromatic hydrocarbon: An embedded ONIOM study

Abstract

The structure of mordenite (MOR) and its interaction with benzene has been investigated within the framework of our-own-N-layered integrated molecular orbital + molecular mechanics (ONIOM) approach utilizing the two-layer ONIOM scheme (B3LYP/6-31G(d,p):UFF). The effect of the long range interactions is also included via optimized point charges added to the ONIOM2(B3LYP/6-31G(d,p):UFF), embedded ONIOM. Inclusion of the extended zeolitic framework covering the nanocavity has an effect on the adsorption properties. The adsorption energies estimated from 3T and 12T quantum clusters of -6.0 and -6.9 kcal/mol, respectively, are significantly lower than that obtained from the 120T ONIOM2 scheme of -16.6 kcal/mol. The completed adsorption model obtained at the embedded ONIOM2(MP2/6-31G(d,p):UFF) method predicts the adsorption energy of -23.4 kcal/mol, which is comparable to the van der Waals-corrected periodic calculation adsorption energy of -21.5 kcal/mol. © 2006 Elsevier B.V. All rights reserved.