Rethinking CO adsorption on transition-metal surfaces: Effect of density-driven self-interaction errors

Abstract

Adsorption of the molecule CO on metallic surfaces is an important unsolved problem in Kohn-Sham density functional theory (KS-DFT). We present a detailed study of carbon monoxide adsorption on fcc (111) surfaces of 3d, 4d and 5d metals using nonempirical semilocal density functionals for the exchange-correlation energy: the local-density approximation (LDA), two generalized gradient approximations or GGAs (PBE and PBEsol), and a meta-GGA (SCAN). The typical error pattern (as found earlier for free molecules and for free transition metal surfaces), in which results improve from LDA to PBE or PBEsol to SCAN, due to the satisfaction of more exact constraints, is not found here. Instead, for CO adsorption on transition metal surfaces, we find that, while SCAN overbinds much less than LDA, it overbinds slightly more than PBE. Moreover, the tested functionals often predict the wrong adsorption site, as first pointed out for LDA and GGA in the CO/Pt (111) puzzle. This abnormal pattern leads us to suspect that the errors of PBE and SCAN for this problem are density-driven self-interaction errors associated with incorrect charge transfer between molecule and metal surface. We point out that, by the variational principle, overbinding by an approximate functional would be reduced if that functional were applied not to its selfconsistent density for the adsorbed system but to an exact or more correct density for that system. Finally, we show for CO on Pt(111) that the site preference is corrected and the adsorption energy is improved for the PBE functional by using not the selfconsistent PBE density but a PBE+U density. The resulting correction to the PBE total energy is much larger for the adsorbed system than for its desorbed components, showing that the error is in the density of the adsorbed system. This seems to solve the Feibelman 2001 CO/Pt(111) puzzle, in principle if not fully in practice. arXiv:1807.05450v2 [cond-mat.mtrl-sci]

Altering CO binding on gold cluster cations by Pd-doping

“…93 The greater binding strength of CO on Pd, compared to Au, is in line with numerous previous calculations for CO adsorption upon clusters and surfaces. 81,[94][95][96][97] Overall, as seen in Fig. 4, Pd-doping enhances the interaction of CO on the clusters, even in those cases where Au is the adsorption site.…”

Specific Reaction Parameter Density Functional Based on the Meta-Generalized Gradient Approximation: Application to H2 + Cu(111) and H2 + Ag(111)

“…32 Our finding that it performs more poorly than PBE for dissociative chemisorption may seem surprising but it is consistent with studies that find that SCAN overbinds more than PBE for chemisorption on metals. 78,79 The reasons for this are presently not fully understood. Garza et al.…”

“…78 Patra et al have speculated that the SCAN functional should overbind CO on transition metal surfaces primarily due to density driven errors in the self-consistent SCAN energy. 79…”

Toward a First-Principles Evaluation of Transport Mechanisms in Molecular Wires

“…27,28 In particular the accurate first-principles description of molecule-metal interfaces in general is not trivial due to the formation of dipole layers in this region, which is particularly important in case of SAMs. [62][63][64][67][68][69][70][71][72][73][74]…”