CHD3 dissociation on Pt(111): A comparison of the reaction dynamics based on the PBE functional and on a specific reaction parameter functional

Abstract

We present a comparison of ab initio molecular dynamics calculations for CHD dissociation on Pt(111) using the Perdew, Burke and Ernzerhof (PBE) functional and a specific reaction parameter (SRP) functional. Despite the two functionals predicting approximately the same activation barrier for the reaction, the calculations using the PBE functional consistently overestimate the experimentally determined dissociation probability, whereas the SRP functional reproduces the experimental values within a chemical accuracy (4.2 kJ/mol). We present evidence that suggests that this difference in reactivity can at least in part be attributed to the presence of a van der Waals well in the potential of the SRP functional which is absent from the PBE description. This leads to the CHD molecules being accelerated and spending less time near the surface for the trajectories run with the SRP functional, as well as more energy being transferred to the surface atoms. We suggest that both these factors reduce the reactivity observed in the SRP calculations compared to the PBE calculations.

Dynamical Study of the Dissociative Chemisorption of CHD3 on Pd(111)

“…Another important dynamical aspect of the reaction of methane is the energy transfer from the molecule to the surface. 54 Figure 6 compares for scattered trajectories this energy transfer from CHD 3 to Cu(111), 54 Pt(111), 65 Ni(111), 12 and Pd(111), where the energy transfer E T is defined aswhere V and K are the potential free and kinetic energy of methane at the initial (i) and final (f) steps of the scattered trajectories, respectively. In general, it is observed that the lower the surface atom mass is, the higher the energy transfer is from methane to the surface.…”

Transferability of the SRP32-vdW specific reaction parameter functional to CHD3 dissociation on Pt(110)-(2 × 1)

“…As in a previous study on CHD 3 dissociation on platinum surfaces, 14,23,29,52 we make use of the SRP32-vdW exchange correlation functional, defined as 21…”

“…26 It was suggested that this was due to the functional not including van der Waals correlation, which has been shown to be necessary previously for giving accurate descriptions of dissociation dynamics. 14,27 The transferability of an SRP functional amongst different metals of the same group (group 10) of the periodic table has been demonstrated for methane dissociation, where the same SRP functional gives a chemically accurate description for the reaction of methane on Ni(111), 21,23,28 Pt(111), 23 and Pt(211). 23,29,30 This same SRP functional has recently been used to predict the reactivity of CHD 3 on Cu(111) and Cu(211), 31 and when experimental data become available, this will confirm whether the SRP functional is also transferable to methane dissociation on transition metals in other specific groups of the periodic table.…”

“…11 Whilst this value has not been determined for gas-surface reactions, the activation barriers for dissociation found using typical GGA functionals are not chemically accurate (correct to within 4.2 kJ/mol). 12 As a result of the limited accuracy of GGA-DFT, dynamics calculations 2,4,5,[13][14][15][16] based on models of the molecule-surface interaction employing standard GGA functionals such as the Perdew, Burke and Ernzerhof (PBE) functional 17,18 tend to reproduce sticking probabilities of molecules on metals only semi-quantitatively.…”

HOD on Ni(111): Ab Initio molecular dynamics prediction of molecular beam experiments

“…Therefore, the topology of the potential might be very different, possibly resulting in a different dynamics, similarly to what was observed for CHD 3 on Pt(111). 66 Four angles have been used to characterize the molecular geometry: θ d , θ s , φ, and γ (sketched in Fig. 2).…”