Electronic structure calculations based on density functional theory provide valuable information about geometries, stabilities, and reactivities of the catalytic systems, whose reliabilities and usefulness, in turn, depend critically on the approximations made in the exchange-correlation functionals. Aiming for a better accuracy, we have proposed a new class of doubly hybrid functionals, namely xDHs,[1,2] that not only mixes in some exact exchange, but also introduces certain portion of the second-order perturbation term, on top of Kohn-Sham orbitals from conventional functionals (e.g. B3LYP or PBE). For an efficient modeling of the catalytic systems, our effort has been devoted to the development of an embedded cluster model, leading to the extended ONIOM (XO) model.[3] XO allows flexible ways of doing partition and combining various levels of theory to diminish the boundary effects. The xDH functionals, in particular, when combined with the XO models, are shown to provide more accurate geometries and energetics,[1,2,4,5] in a more efficient way.[3,6,7] Challenges and our future plans will be discussed. References [1] Y. Zhang, X. Xu, W. A. Goddard III, Proc. Nat. Acad. Sci, USA, 106 (2009) 4963. [2] I. Y. Zhang, X. Xu, Y. Jung, W. A. Goddard III, Proc. Nat. Acad. Sci, USA, 108 (2011) 19896. [3] W. Guo, A. Wu, X. Xu, Chem. Phys. Lett., 498 (2010) 203. [4] N. Q. Su, I. Y. Zhang, X. Xu, J. Comput. Chem., 34 (2013) 1759. [5] N. Q. Su, W. Yang, P. Mori-Sánchez, X. Xu, J. Phys. Chem. A, 118 (2014) 9201. [6] Z. Chu, G. Fu, W. Guo, X. Xu, J. Phys. Chem. C 115 (2011) 14754. [7] W. Guo, C. Michel, R. Schwiedernoch, R. Wischert, X. Xu, P. Sautet, Organometallics 33, (2014) 6369.

Towards the accurate and efficient theoretical modelling of catalysis

251st National Meeting (2016)

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