(630d) Establishing the Zeolite SSZ-13 As Test System for Quantum Chemical Methods Conference: AIChE Annual MeetingYear: 2015Proceeding: 2015 AIChE Annual MeetingGroup: Catalysis and Reaction Engineering DivisionSession: Applications of DFT+X in Catalysis II Time: Thursday, November 12, 2015 - 10:10am-10:30am Authors: Göltl, F., UW Madison Sautet, P., University of California Los Angeles Hafner, J., University of Vienna Hermans, I., University of Wisconsin-Madison Understanding the performance of various quantum chemical methods is key in understanding the reliability in applications to realistic systems. The typical approach to address this problem is to investigate test systems, where high-quality experimental data is available or high-quality quantum chemical modeling is possible. In this contribution we describe our efforts in establishing the zeolite SSZ-13 as a test system for quantum chemical modeling. SSZ-13 is a zeolite in the chabazite structure, which has the smallest unit cell. This allows the fully periodic application of various high-level quantum chemical methods, such as the Adiabatic Connection Fluctuation-Dissipation Theorem in its Random Phase Approximation (RPA) and second order Møller-Plesset perturbation theory (MP2) for total energy calculations, or GW and Bethe-Salpeter Equation for spectroscopy. In this work we show our efforts in describing the adsorption of alkanes in SSZ-13. This is a particular challenging problem, since van der Waals interactions represent the largest part of the adsorption strength. We compare the performance of dispersion corrected density functionals (PBE+d(2), PBE-TS, PBE-dDsC) and vdW-DF type functionals (vdW-DF, vdW-optB86b, vdW-DF2, BEEF) to high level quantum chemical methods (RPA, MP2). After a correction for finite temperature effects PBE-d(2) leads to the best agreement with RPA, MP2 and experimental measurements, while all the other methods lead to a significant overestimation of the adsorption strength. We furthermore explain this overestimation as a fundamental flaw in the construction of these functionals, where non-local screening interactions are only included implicitly. The results presented here are highly important to arrive at a solid understanding the performance of different quantum chemical methods in zeolite catalysis and to judge the reliability of computational predictions.