Why are GGAs so accurate for reaction kinetics on surfaces? Systematic comparison of hybrid vs. nonhybrid DFT for representative reactions

Abstract

"Jacob's Ladder" of approximate exchange-correlation (XC) functionals in Kohn-Sham density functional theory are widely accepted to have systematic errors in reaction barriers. The first-rung local spin-density approximation (LDA) typically predicts barriers below generalized gradient approximations, which in turn predict barriers below experiment and below fourth-rung hybrid functionals incorporating a fraction of exact exchange. We show that several reactions from previous literature reports, as well as new simulations of carbon-carbon coupling in the Fischer-Tropsch process, do not follow this conventional picture. We introduce the AB9 test set of nine abnormal reaction barriers, in which density gradient corrections and exact exchange admixture tend to lower rather than to raise predicted barriers. Comparisons of normal and abnormal reactions rationalize this phenomenon in terms of how density gradient and exact-exchange corrections stabilize transition states relative to reaction intermediates. Multireference diagnostics confirm that this behavior is not merely a consequence of multireference character. Benchmarks of the AB9 set, using the best available ab initio reference values, highlight the role of symmetry breaking and show surprisingly good performance from both the LDA and "Rung 3.5" functionals. This motivates benchmarks of the AB9 set in future XC functional development.

Reaction energetics of hydrogen on Si(100) surface: A periodic many-electron theory study

“…Interestingly, LDA predicts much larger activation energies than GGA, challenging the trend LDA<GGA observed for adsorption barriers of molecular reactions 58 . Similar results, however, have been reported for activation energies of gas-phase reactions 59 . Hybrid functionals mix exact exchange with commonly-used density functionals and partly cancel the spurious self-interaction error.…”

CLB18: A new structural database with unusual carbon–carbon long bonds

“…This is also consistent with the fact that exact exchange is needed to improve the performance on barrier heights. 8,76,[119][120][121][122] Noticeably, we can now add the important information that high percentages of HF exchange are required for describing both energies and geometries of transition states.…”

Assessment of the Accuracy of Density Functionals for Calculating Oxygen Reduction Reaction on Nitrogen Doped Graphene

“…In another recent study, Mahler et al presented results on surface reactions where hybrids fail to improve on GGA functionals which highlights the necessity to re-evaluate the performance of the various DFT rungs for any new material class. 34 The question, therefore, arises how the overpotential for ORR predicted by hybrid functionals for periodic model systems of NG compare with the values previously obtained using GGA functionals, and whether the finite, flake models of NG give similar results as the extended, periodic models. This article reports on a comprehensive study of various DFT functionals for calculating the overpotential for ORR on NG using both periodic as well as finite models.…”