The quantum dynamics of H2 on Cu(111) at a surface temperature of 925 K: Comparing state-of-the-art theory to state-of-the-art experiments 2

Abstract

State-of-the-art 6D quantum dynamics simulations for the dissociative chemisorption of H2 on a thermally distorted Cu(111) surface, using the static corrugation model, were analysed to produce several (experimentally available) observables. The expected error, especially important for lower reaction probabilities, was quantified using wavepackets on several different grids as well as two different analysis approaches to obtain more accurate results in the region where a slow reaction channel was experimentally shown to be dominant. Lowest reaction barrier sites for different thermally distorted surface slabs are shown to not just be energetically, but also geometrically, different between surface configurations, which can be used to explain several dynamical effects found when including surface temperature effects. Direct comparison of fitted time-of-flight spectra to those obtained from state-of-the-art desorption experiments showed much improved agreement compared to the perfect lattice BOSS approach. Agreement with experimental rotational and vibrational efficacies also somewhat improved when thermally excited surfaces were included in the theoretical model. Finally, we present clear quantum effects in the rotational quadrupole alignment parameters found for the lower rotationally excited states, which underlines the importance of careful quantum dynamical analyses of this system.

Machine Learning Interatomic Potentials for Reactive Hydrogen Dynamics at Metal Surfaces Based on Iterative Refinement of Reaction Probabilities

“…29 In this work, we will use the SRP48 functional due to its prior successful application for various properties beyond sticking probabilities. 27,28,43,91 In this paper, we perform adaptive data generation with uncertainty quantification (UQ) to construct MLIPs based on MPNNs for the simulation of reactive scattering of molecular hydrogen on copper. Because of the impact that the surface termination of the catalyst has on the chemical reactivity, we include multiple copper facets in our model.…”

“…Initially, the works that investigated hydrogen dynamics at Cu surfaces employed generalized gradient approximation functionals such as PW91 or RPBE. ,, However, it was observed that RPBE underestimates and PW91 overestimates reaction probabilities for H 2 dissociation at Cu(111) surfaces . In order to address this issue for hydrogen surface chemistry, the specific reaction parameter (SRP) functional was developed and applied in many studies of dissociation at the Cu(111) surface. ,,,,,, The SRP48 functional employed in most of those studies has additionally been proven to be transferable to other surfaces beyond Cu(111), such as Cu(100) , or Ag(111) . It was also successfully applied to stepped surfaces, including H 2 /Cu­(211) systems. ,,, Another, more recently introduced functional that also shows good agreement with experiments is optPBE-vdW .…”

“…29 In this work, we will use the SRP48 functional due to its prior successful application for various properties beyond sticking probabilities. 27,28,43,91 In this paper, we perform adaptive data generation with uncertainty quantification (UQ) to construct MLIPs based on…”

“…Therefore, to satisfy these requirements, analytical surrogate models of the potential energy surfaces (PESs) are typically employed. Various techniques were used in the past to model the dissociative chemisorption of H 2 at metal surfaces, , such as potentials based on the corrugation-reducing procedure (CRP) , for Cu(111), − ,,, Cu(211), Cu(100), Pd(100), and Ni(111), its extension, dynamic corrugation model (DCM) for Cu(111), , the modified Shepard interpolation , for Cu(111) and Pt(111), , or the permutation invariant polynomials (PIPs) , employing neural networks (PIP-NN) for Cu(111), Ag(111), , and Co(0001). , Besides the PIP-NN, other machine-learning (ML)-based models were employed to study hydrogen chemistry at metal surfaces in the past, such as the embedded atom neural network (EANN), which was also successfully employed for modeling dissociative chemisorption at multiple Cu surfaces . Although these methods have proven to be robust and accurate, most of them have clear limitations.…”

“…The optPBE-vdW functional was also utilized in the unified EANN-based model for H 2 dynamics at multiple facets of copper recently developed by Zhu et al, giving excellent agreement with experiments for all of the modeled surfaces . In this work, we will use the SRP48 functional due to its prior successful application for various properties beyond sticking probabilities. ,,, …”