Accurate and Efficient Description of Acidic Zeolites with Plane-Wave Density Functional Theory Using Range-Separated Hybrid Functionals.

Abstract

Brønsted acidic zeolites and their reactivity are routinely studied computationally, mainly with periodic density functional theory (DFT) using the generalized gradient approximation (GGA). In many cases, large errors are observed at the GGA-level of theory, in particular reaction barriers are often underestimated and the stability of carbocations is overestimated. The use of ab initio methods, such as MP2 and CCSD(T), also with local approximations, is mostly limited to nonperiodic cluster models. In this work, for a set of reaction energies and barriers, the random phase approximation and common density functionals are investigated by comparison to DLPNO-CCSD(T) and complete basis set extrapolated MP2 calculations on large cluster models. The most accurate functionals are the range-separated hybrids ωB97M-D4, ωB97M-V, ωB97X-D4, ωB97X-V, and ωB97-D. Compared to our reference calculations, these functionals give mean absolute errors below 8 kJ mol^-1 and also lead to few outliers. ωB97M-D4 performs best, with an MAE of 5.1 kJ mol^-1 and an error that is smaller than that of complete basis set extrapolated MP2. Range-separated functionals are shown to work well in periodic calculations with plane-wave DFT. This allows the efficient calculations of very accurate reaction energies and barriers directly for the periodic system at modest computational cost.