Diffraction of molecular hydrogen from metal surfaces

Farı́as, Daniel; Miranda, Rodolfo

doi:10.1016/j.progsurf.2011.08.002

Cited by 45 publications

(48 citation statements)

References 171 publications

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“…It is worth emphasizing that the beams quality (concerning angular divergence and energy spread) employed in the sticking experiments is the same usually employed for He and H 2 diffraction measurements using the same apparatus [26]. However, the lowest sticking value which can be detected using the King and Wells method in our setup is ∼ 0.10.…”

Section: Methodsmentioning

confidence: 93%

“…For E i ∼ 0.15 − 0.20 eV and 1% Pd, this value was found to be 6 × 10 −4 , increasing to 7 × 10 −3 for a Pd coverage of 11% [25]. We have recently shown that diffraction of H 2 is a very useful technique to characterize the corresponding PES for hydrogen dissociative chemisorption at metal surfaces [26]. In the case of the Pd-Cu(111) surface, however, since it is not an ordered alloy, this technique cannot be applied to check the quality of the PES reported by the theoretical study.…”

Section: Introductionmentioning

confidence: 99%

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Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Farı́as

Minniti

Taleb

et al. 2013

Zeitschrift Für Physikalische Chemie

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Surface Alloys / Hydrogen Dissociation / ReactivityWe present an experimental study of the initial dissociative sticking probability of H 2 on the PdCu(111) surface alloy at Pd coverages between 1-10%. The measurements have been performed using a supersonic molecular beam with an incident energy range E i = 75-163 meV. In agreement with a recent STM study, our results confirm that small amounts of Pd atoms significantly increase the reactivity of the inert Cu(111) surface, although the measured initial sticking probability values were found to be much lower than the ones estimated from the STM work. For a Pd coverage of 1% and E i ∼ 0.10 eV, the H 2 initial sticking probability was found to be 2 × 10 −3 , increasing to 4 × 10 −3 for a Pd coverage of 10%. This agrees well with a recent molecular dynamics study, in which the initial sticking probability was estimated in 7 × 10 −3 for a Pd coverage of 11% and E i ∼ 0.15-0.20 eV. Essentially the same values were measured in the whole incident energy range investigated. Therefore, our results support the main conclusion of the molecular dynamics calculations about the mechanism leading to the increase of reactivity of the Pd-Cu(111) surface alloy, which combines a lower activation energy barrier for dissociation of ∼ 0.25 eV on top of substitutional Pd atoms with spillover onto the Cu(111) surface.

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Section: Methodsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Farı́as

Minniti

Taleb

et al. 2013

Zeitschrift Für Physikalische Chemie

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“…It is known that surface temperature can lead to a dramatic decrease of the measured diffraction probability due to Debye-Waller (DW) attenuation. 96 To correct for this, the experimental data were extrapolated to T s = 0 K using a DW model. 30 Experiments in the range T s = 500-1000 K were found to obey such a DW model.…”

Section: Scattering and Reaction At Off-normal Incidencementioning

confidence: 99%

The effect of the exchange-correlation functional on H2 dissociation on Ru(0001)

Wijzenbroek¹,

Kroes²

2014

The Journal of Chemical Physics

191

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The specific reaction parameter (SRP) approach to density functional theory (DFT) has enabled a chemically accurate description of reactive scattering experiments for activated H 2 -metal systems (H 2 + Cu(111) and Cu(100)), but its application has not yet resulted in a similarly accurate description of non-activated or weakly activated H 2 -metal systems. In this study, the effect of the choice of the exchange-correlation functional in DFT on the potential energy surface and dynamics of H 2 dissociation on Ru(0001), a weakly activated system, is investigated. In total, full potential energy surfaces were calculated for over 20 different functionals. The functionals investigated include functionals incorporating an approximate description of the van der Waals dispersion in the correlation functional (vdW-DF and vdW-DF2 functionals), as well as the revTPSS meta-GGA. With two of the functionals investigated here, which include vdW-DF and vdW-DF2 correlation, it has been possible to accurately reproduce molecular beam experiments on sticking of H 2 and D 2 , as these functionals yield a reaction probability curve with an appropriate energy width. Diffraction probabilities computed with these two functionals are however too high compared to experimental diffraction probabilities, which are extrapolated from surface temperatures (T s ) ≥ 500 K to 0 K using a Debye-Waller model. Further research is needed to establish whether this constitutes a failure of the two candidate SRP functionals or a failure of the Debye-Waller model, the use of which can perhaps in future be avoided by performing calculations that include the effect of surface atom displacement or motion, and thereby of the experimental T s .

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“…1-4 H 2 diffraction experiments 5 or the possibility of quantum state preparation (detection) of the incident (scattered) molecules [6][7][8][9][10] allows one to explore in more detail the quantum nature of such interactions. Nonetheless, gas-surface experiments cannot monitor step by step the evolution of the molecule (atom) and the surface.…”

Section: Introductionmentioning

confidence: 99%

Influence of the van der Waals interaction in the dissociation dynamics of N2 on W(110) from first principles

Martin-Gondre

Juaristi

Blanco-Rey

et al. 2015

The Journal of Chemical Physics

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Calculation of the structure, potential energy surface, vibrational dynamics, and electric dipole properties for the Xe:HI van der Waals complex J. Chem. Phys. 134, 174302 (2011) ] exchange-correlation functionals were unable to fully describe the dependence of the initial sticking coefficient on the molecular beam incidence conditions as found in experiments. N 2 dissociation on W(110) was shown to be very sensitive not only to short molecule-surface distances but also to large distances where the vdW interaction, not included in semilocal-DFT, should dominate. In this work, we perform a systematic study on the dissociative adsorption using a selection of existing non-local functionals that include the vdW interaction (vdW-functionals). Clearly, the inclusion of the non-local correlation term contributes in all cases to correct the unrealistic energy barriers that were identified in the RPBE at large molecule-surface distances. Among the tested vdW-functionals, the original vdW-DF by Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)] and the ulterior vdW-DF2 give also an adequate description of the N 2 adsorption energy and energy barrier at the transition state, i.e., of the properties that are commonly used to verify the quality of any exchange-correlation functional. However, the results of our AIMD calculations, which are performed at different incidence conditions and hence extensively probe the multi-configurational potential energy surface of the system, do not seem as satisfactory as the preliminary static analysis suggested. When comparing the obtained dissociation probabilities with existing experimental data, none of the used vdW-functionals seems to provide altogether an adequate description of the N 2 /W(110) interaction at short and large distances. C 2015 AIP Publishing LLC.[http://dx

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Diffraction of molecular hydrogen from metal surfaces

Cited by 45 publications

References 171 publications

Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

Initial Sticking Coefficient of H2 on the Pd–Cu(111) Surface Alloy at very Low Coverages

The effect of the exchange-correlation functional on H2 dissociation on Ru(0001)

Influence of the van der Waals interaction in the dissociation dynamics of N2 on W(110) from first principles

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