Density and Potential Functional Embedding: Theory and Practice

Revisiting Understanding of Electrochemical CO2 Reduction on Cu(111): Competing Proton-Coupled Electron Transfer Reaction Mechanisms Revealed by Embedded Correlated Wavefunction Theory

“…Motivated by their success, we began to apply this theory to revisit hypothesized CO 2 reduction mechanisms on Cu. In a recent paper, we reevaluated competing surface *H transfer paths in CO reduction on Cu(111), using embedded complete active space second-order perturbation theory , (emb-CASPT2) with embedding potentials derived from density functional embedding theory (DFET). ,, We confirmed, with this more rigorous theory, that the first step in CO reduction by surface *H transfer on Cu(111) is the formation of *COH instead of *CHO via *CO’s interaction with an adsorbed *H.…”

“…We followed the same steps used to study the mechanisms of CO reduction via surface *H transfer to revisit CO reduction via PCET using ECW theory. We first optimized the embedding potential that represents the interaction between each cluster and its extended environment using DFET ,, at the periodic plane-wave (PW) DFT level. We then conducted constrained optimizations of the reaction pathway structures at the PW DFT level, starting from the ECW-preferred adsorption sites (adsites) for reactants and products determined in previous work .…”

“…In addition, these DFT approximations all suffer from electron self-interaction error and a lack of a derivative discontinuity . This leads to errors in quantities, most notably charge-transfer energetics, critical for simulating heterogeneous electrocatalysis. − By contrast, embedded correlated wavefunction (ECW) theory − provides a regional correction to these XC errors inherent in DFT and represents a suitable method to study heterogeneous (photo)­(electro)­catalysis. − More than a decade ago, Sharifzadeh et al reproduced successfully the experimental CO adsorption site on Cu(111) with ECW theory via an embedded multiconfigurational singles and doubles configuration interaction simulation. Motivated by their success, we began to apply this theory to revisit hypothesized CO 2 reduction mechanisms on Cu.…”

Hot carrier multiplication in plasmonic photocatalysis

“…In ref. 22, high-accuracy embedded correlated wavefunction theory (25)(26)(27)(28) in the form of the embedded complete active space self-consistent field (emb-CASSCF) calculations, followed by a second-order perturbation theory correlation correction (emb-CASPT2) (29,30), was used to calculate groundand excited-state energies along the MEP for this reaction. For the H 2 -D 2 exchange reaction on Cu, the rate-determining step is found to be the associative desorption of H 2 (or equivalently HD) with an emb-CASPT2 activation barrier of 1.10 eV (Fig.…”

Projection-Based Wavefunction-in-DFT Embedding

“…Although we describe the methodological context for projection-based embedding, we also direct the reader to several reviews that provide a more complete description of alternative approaches. 9,10,[34][35][36][37][38] Projection-Based Embedding Quantum embedding methods developed within the framework of DFT offer a formally exact approach to electronic structure calculations in which complex chemical problems are decomposed into the solution of individual smaller subsystems. 19,38 Throughout this review, we shall use the term "exact" to denote that a DFT-in-DFT embedding calculation where both subsystems are treated using the same exchange-correlation (XC) functional yields the same result as a single Kohn-Sham (KS) DFT calculation performed over the full system.…”