Inelastic H and D atom scattering from Au(111) as benchmark for theory

Jiang, Hongyan; Dorenkamp, Yvonne; Krüger, Kerstin; Bünermann, Oliver

doi:10.1063/1.5094693

Cited by 12 publications

(21 citation statements)

References 26 publications

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“…We could observe no influence of the azimuthal angle of the crystal on the inelastic scattering and find a uniformly small isotope effect. 136 All of these observations could be reproduced by our molecular dynamics models.…”

Section: Inelastic Scattering Of H-atoms From Metal Surfacessupporting

confidence: 57%

“…To experimentally resolve the phononic and electronic contributions from one another, measurements were performed with H and D at the same incidence speed. 136 Here, the electronic coupling should be equal for H and D, but the phononic excitation is not. With this simple approach, we found from experiment that 89% of the incidence energy is transferred to electron–hole pair excitation in case of H and 68% in case of D, close to the values predicted by the theoretical simulation.…”

Section: Inelastic Scattering Of H-atoms From Metal Surfacesmentioning

confidence: 99%

“…With this simple approach, we found from experiment that 89% of the incidence energy is transferred to electron–hole pair excitation in case of H and 68% in case of D, close to the values predicted by the theoretical simulation. 136 …”

Section: Inelastic Scattering Of H-atoms From Metal Surfacesmentioning

confidence: 99%

“…We also performed a detailed study of the influence of the experimental incidence conditions for H scattering from Au(111). 136 We explored a large range of kinetic energies, incidence angles from 15° to 60°, and scattering angles from −10° to +75°. Furthermore, the influence of the azimuthal surface orientation was studied.…”

Section: Inelastic Scattering Of H-atoms From Metal Surfacesmentioning

confidence: 99%

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Inelastic Scattering of H Atoms from Surfaces

2021

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We have developed an instrument that uses photolysis of hydrogen halides to produce nearly monoenergetic hydrogen atom beams and Rydberg atom tagging to obtain accurate angle-resolved time-of-flight distributions of atoms scattered from surfaces. The surfaces are prepared under strict ultrahigh vacuum conditions. Data from these experiments can provide excellent benchmarks for theory, from which it is possible to obtain an atomic scale understanding of the underlying dynamical processes governing H atom adsorption. In this way, the mechanism of adsorption on metals is revealed, showing a penetration–resurfacing mechanism that relies on electronic excitation of the metal by the H atom to succeed. Contrasting this, when H atoms collide at graphene surfaces, the dynamics of bond formation involving at least four carbon atoms govern adsorption. Future perspectives of H atom scattering from surfaces are also outlined.

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Section: Inelastic Scattering Of H-atoms From Metal Surfacessupporting

confidence: 57%

Section: Inelastic Scattering Of H-atoms From Metal Surfacesmentioning

confidence: 99%

Section: Inelastic Scattering Of H-atoms From Metal Surfacesmentioning

confidence: 99%

Section: Inelastic Scattering Of H-atoms From Metal Surfacesmentioning

confidence: 99%

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Inelastic Scattering of H Atoms from Surfaces

2021

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“…Inelastic H-atom scattering from metal surfaces 24 , 25 , 37 , 38 provides a direct probe of electronically nonadiabatic forces in a system that can be treated classically in full dimensions, including surface atom motion. 39 , 40 Experimental and theoretical energy-loss distributions can be compared to test models of electronic friction.…”

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confidence: 99%

Random Force in Molecular Dynamics with Electronic Friction

et al. 2021

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Originally conceived to describe thermal diffusion, the Langevin equation includes both a frictional drag and a random force, the latter representing thermal fluctuations first seen as Brownian motion. The random force is crucial for the diffusion problem as it explains why friction does not simply bring the system to a standstill. When using the Langevin equation to describe ballistic motion, the importance of the random force is less obvious and it is often omitted, for example, in theoretical treatments of hot ions and atoms interacting with metals. Here, friction results from electronic nonadiabaticity (electronic friction), and the random force arises from thermal electron–hole pairs. We show the consequences of omitting the random force in the dynamics of H-atom scattering from metals. We compare molecular dynamics simulations based on the Langevin equation to experimentally derived energy loss distributions. Despite the fact that the incidence energy is much larger than the thermal energy and the scattering time is only about 25 fs, the energy loss distribution fails to reproduce the experiment if the random force is neglected. Neglecting the random force is an even more severe approximation than freezing the positions of the metal atoms or modelling the lattice vibrations as a generalized Langevin oscillator. This behavior can be understood by considering analytic solutions to the Ornstein–Uhlenbeck process, where a ballistic particle experiencing friction decelerates under the influence of thermal fluctuations.

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Isotope effect suggests site‐specific nonadiabaticity on Ge(111)c(2×8)

Krüger,

Wang,

Zhu

et al. 2023

Natural Sciences

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Energy transferred in atom‐surface collisions typically depends strongly on projectile mass, an effect that can be experimentally detected by isotopic substitution. In this work, we present measurements of inelastic H and D atom scattering from a semiconducting Ge(111)c(2×8) surface exhibiting two scattering channels. The first channel shows the expected isotope effect and is quantitatively reproduced by electronically adiabatic molecular dynamics simulations. The second channel involves electronic excitations of the solid and, surprisingly, exhibits almost no isotope effect. We attribute these observations to scattering dynamics, wherein the likelihood of electronic excitation varies with the impact site engaged in the interaction.Key Points Previous work revealed that H atoms with sufficient translational energy can excite electrons over the band gap of a semiconductor in a surface collision. We studied the isotope effect of the energy transfer by H/D substitution and performed band structure calculations to elucidate the underlying excitation mechanism. Our results suggest a site‐specific mechanism that requires the atom to hit a specific surface site to excite an electron‐hole pair.

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Inelastic H and D atom scattering from Au(111) as benchmark for theory

Cited by 12 publications

References 26 publications

Inelastic Scattering of H Atoms from Surfaces

Inelastic Scattering of H Atoms from Surfaces

Random Force in Molecular Dynamics with Electronic Friction

Isotope effect suggests site‐specific nonadiabaticity on Ge(111)c(2×8)

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