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Title: Ab initio molecular dynamics calculations on scattering of hyperthermal H atoms from Cu(111) and Au(111)

Abstract

Energy loss from the translational motion of an atom or molecule impinging on a metal surface to the surface may determine whether the incident particle can trap on the surface, and whether it has enough energy left to react with another molecule present at the surface. Although this is relevant to heterogeneous catalysis, the relative extent to which energy loss of hot atoms takes place to phonons or electron-hole pair (ehp) excitation, and its dependence on the system's parameters, remain largely unknown. We address these questions for two systems that present an extreme case of the mass ratio of the incident atom to the surface atom, i.e., H + Cu(111) and H + Au(111), by presenting adiabatic ab initio molecular dynamics (AIMD) predictions of the energy loss and angular distributions for an incidence energy of 5 eV. The results are compared to the results of AIMDEFp calculations modeling energy loss to ehp excitation using an electronic friction (“EF”) model applied to the AIMD trajectories, so that the energy loss to the electrons is calculated “post” (“p”) the computation of the AIMD trajectory. The AIMD calculations predict average energy losses of 0.38 eV for Cu(111) and 0.13-0.14 eV for Au(111) formore » H-atoms that scatter from these surfaces without penetrating the surface. These energies closely correspond with energy losses predicted with Baule models, which is suggestive of structure scattering. The predicted adiabatic integral energy loss spectra (integrated over all final scattering angles) all display a lowest energy peak at an energy corresponding to approximately 80% of the average adiabatic energy loss for non-penetrative scattering. In the adiabatic limit, this suggests a way of determining the approximate average energy loss of non-penetratively scattered H-atoms from the integral energy loss spectrum of all scattered H-atoms. The AIMDEFp calculations predict that in each case the lowest energy loss peak should show additional energy loss in the range 0.2-0.3 eV due to ehp excitation, which should be possible to observe. The average non-adiabatic energy losses for non-penetrative scattering exceed the adiabatic losses to phonons by 0.9-1.0 eV. This suggests that for scattering of hyperthermal H-atoms from coinage metals the dominant energy dissipation channel should be to ehp excitation. These predictions can be tested by experiments that combine techniques for generating H-atom beams that are well resolved in translational energy and for detecting the scattered atoms with high energy-resolution.« less

Authors:
;  [1];  [2];  [3];  [4];  [3];  [1];  [5];  [5]
  1. Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands)
  2. Departamento de Física de Materiales, Facultad de Químicas UPV/EHU, Apartado 1072, 20080 Donostia-San Sebastián (Spain)
  3. (Spain)
  4. Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián (Spain)
  5. (Germany)
Publication Date:
OSTI Identifier:
22420002
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ELECTRONS; ENERGY LOSSES; ENERGY-LOSS SPECTROSCOPY; EV RANGE; EXCITATION; MOLECULAR DYNAMICS METHOD; MOLECULES; PEAKS; PHONONS; SCATTERING; SIMULATION

Citation Formats

Kroes, Geert-Jan, E-mail: g.j.kroes@chem.leidenuniv.nl, Pavanello, Michele, Blanco-Rey, María, Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Alducin, Maite, Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Auerbach, Daniel J., Max Planck Institute for Biophysical Chemistry, Göttingen, and Institute for Physical Chemistry, Georg-August University of Göttingen, Göttingen. Ab initio molecular dynamics calculations on scattering of hyperthermal H atoms from Cu(111) and Au(111). United States: N. p., 2014. Web. doi:10.1063/1.4891483.
Kroes, Geert-Jan, E-mail: g.j.kroes@chem.leidenuniv.nl, Pavanello, Michele, Blanco-Rey, María, Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Alducin, Maite, Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Auerbach, Daniel J., Max Planck Institute for Biophysical Chemistry, Göttingen, & Institute for Physical Chemistry, Georg-August University of Göttingen, Göttingen. Ab initio molecular dynamics calculations on scattering of hyperthermal H atoms from Cu(111) and Au(111). United States. doi:10.1063/1.4891483.
Kroes, Geert-Jan, E-mail: g.j.kroes@chem.leidenuniv.nl, Pavanello, Michele, Blanco-Rey, María, Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Alducin, Maite, Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Auerbach, Daniel J., Max Planck Institute for Biophysical Chemistry, Göttingen, and Institute for Physical Chemistry, Georg-August University of Göttingen, Göttingen. Thu . "Ab initio molecular dynamics calculations on scattering of hyperthermal H atoms from Cu(111) and Au(111)". United States. doi:10.1063/1.4891483.
@article{osti_22420002,
title = {Ab initio molecular dynamics calculations on scattering of hyperthermal H atoms from Cu(111) and Au(111)},
author = {Kroes, Geert-Jan, E-mail: g.j.kroes@chem.leidenuniv.nl and Pavanello, Michele and Blanco-Rey, María and Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián and Alducin, Maite and Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastián and Auerbach, Daniel J. and Max Planck Institute for Biophysical Chemistry, Göttingen and Institute for Physical Chemistry, Georg-August University of Göttingen, Göttingen},
abstractNote = {Energy loss from the translational motion of an atom or molecule impinging on a metal surface to the surface may determine whether the incident particle can trap on the surface, and whether it has enough energy left to react with another molecule present at the surface. Although this is relevant to heterogeneous catalysis, the relative extent to which energy loss of hot atoms takes place to phonons or electron-hole pair (ehp) excitation, and its dependence on the system's parameters, remain largely unknown. We address these questions for two systems that present an extreme case of the mass ratio of the incident atom to the surface atom, i.e., H + Cu(111) and H + Au(111), by presenting adiabatic ab initio molecular dynamics (AIMD) predictions of the energy loss and angular distributions for an incidence energy of 5 eV. The results are compared to the results of AIMDEFp calculations modeling energy loss to ehp excitation using an electronic friction (“EF”) model applied to the AIMD trajectories, so that the energy loss to the electrons is calculated “post” (“p”) the computation of the AIMD trajectory. The AIMD calculations predict average energy losses of 0.38 eV for Cu(111) and 0.13-0.14 eV for Au(111) for H-atoms that scatter from these surfaces without penetrating the surface. These energies closely correspond with energy losses predicted with Baule models, which is suggestive of structure scattering. The predicted adiabatic integral energy loss spectra (integrated over all final scattering angles) all display a lowest energy peak at an energy corresponding to approximately 80% of the average adiabatic energy loss for non-penetrative scattering. In the adiabatic limit, this suggests a way of determining the approximate average energy loss of non-penetratively scattered H-atoms from the integral energy loss spectrum of all scattered H-atoms. The AIMDEFp calculations predict that in each case the lowest energy loss peak should show additional energy loss in the range 0.2-0.3 eV due to ehp excitation, which should be possible to observe. The average non-adiabatic energy losses for non-penetrative scattering exceed the adiabatic losses to phonons by 0.9-1.0 eV. This suggests that for scattering of hyperthermal H-atoms from coinage metals the dominant energy dissipation channel should be to ehp excitation. These predictions can be tested by experiments that combine techniques for generating H-atom beams that are well resolved in translational energy and for detecting the scattered atoms with high energy-resolution.},
doi = {10.1063/1.4891483},
journal = {Journal of Chemical Physics},
number = 5,
volume = 141,
place = {United States},
year = {Thu Aug 07 00:00:00 EDT 2014},
month = {Thu Aug 07 00:00:00 EDT 2014}
}