(289b) Application of DFT-D and QM/MM Methods in Zeolite-Catalyzed Reactions

Density functional theory (DFT) is currently the method of choice for studying electronic structure in large, extended systems due to its robust nature and balance between computational simplicity and accuracy.  While this method has found wide application for addressing problems in catalysis, recent studies have revealed that accurate representation of reactions occurring in microporous systems, such as zeolites, require large cluster representation and improvements over conventionally used generalized gradient approximation (GGA) and hybrid GGA functionals, e.g., B3LYP, which are unable to describe dispersion interactions.   In this work, we benchmark the performance of modern exchange-correlation functionals for the calculation of heats of adsorption and reaction barriers in zeolite materials.  Comparison with experiment and RI-MP2 in the complete basis set limit give insight into the successes and limitations of current DFT-D and meta-GGA functionals¹.  The application of a QM(DFT-D)/MM method to several acid-catalyzed zeolite reactions² is presented, highlighting the chemical accuracy and computational tractability of this model chemistry.

¹J. Gomes, P.M. Zimmerman, M. Head-Gordon, A.T. Bell, J. Phys. Chem. C 116 (2012), 15406-15414.

²P.M, Zimmerman, D.C. Tranca, J. Gomes, D.S. Lambrecht, M. Head-Gordon, A.T. Bell, J. Amer. Chem. Soc. 134 (2012), 19468-19476.