Surface electron density models for accurate<i>ab initio</i>molecular dynamics with electronic friction

Novko, Dino; Blanco-Rey, M.; Alducin, M.; Juaristi, J. I.

doi:10.1103/physrevb.93.245435

Cited by 63 publications

(112 citation statements)

References 99 publications

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“…For hydrogen atoms and molecules interacting with metallic surfaces at low coverage, for which collisions with pre-adsorbed species are unlikely, the main energy dissipation channel in the picosecond time scale is the excitation of low lying e-h pairs. [45][46][47][48][49][50][51][52] As such an effect depends on the surface electronic structure, its sensitivity to the crystal face is a relevant issue that we address in the present study. To this end, we compare, in the following, the dynamics of H 2 formation by abstraction of pre-adsorbed H atoms upon H atom scattering at finite coverage for the W(100) and W(110) surfaces.…”

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confidence: 99%

“…In the latter, electronic nonadiabaticity is introduced through a dissipative force in the classical equations of motion for the hydrogen atoms. This approach has already been used to investigate non-adiabatic effects in gas-surface elementary processes 46,[48][49][50][51][61][62][63] and allows a good compromise between accuracy and simplicity. 51,64 The friction force, acting independently on each H atom, is approximated as the one corresponding to a homogeneous free electron gas with electronic density equal to that of the bare surface at the atom position.…”

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confidence: 99%

“…51,64 The friction force, acting independently on each H atom, is approximated as the one corresponding to a homogeneous free electron gas with electronic density equal to that of the bare surface at the atom position. This approximation has been recently used to rationalize the adsorption and relaxation of H, N, and N 2 on bare metallic surfaces, 46,48,50 as well as for recombinative H 2 desorption induced by fs-laser pulses. 65,66 Dissipation to surface phonons is neglected here as dissipation to electrons has been recently predicted to largely dominate the relaxation of hydrogen on metals in the sub-picosecond time scale.…”

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Communication: Hot-atom abstraction dynamics of hydrogen from tungsten surfaces: The role of surface structure

Galparsoro

Busnengo

Juaristi

et al. 2017

The Journal of Chemical Physics

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Adiabatic and non-adiabatic quasiclassical molecular dynamics simulations are performed to investigate the role of the crystal face on hot-atom abstraction of H adsorbates by H scattering from covered W(100) and W(110). On both cases, hyperthermal diffusion is strongly affected by the energy dissipated into electron-hole pair excitations. As a result, the hot-atom abstraction is highly reduced in favor of adsorption at low incidence energy and low coverages, i.e., when the mean free path of the hyperthermal H is typically larger. Qualitatively, this reduction is rather similar on both surfaces, despite at such initial conditions, the abstraction process involves more subsurface penetration on W(100) than on W(110).

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Communication: Hot-atom abstraction dynamics of hydrogen from tungsten surfaces: The role of surface structure

Galparsoro

Busnengo

Juaristi

et al. 2017

The Journal of Chemical Physics

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“…This approach thus avoids an explicit propagation of the electron dynamics and concomitant ultrafast time scales by coarse-graining the effects into electronic friction forces linear in nuclear velocities. This enables an efficient combination even with density-functional theory (DFT) based ab initio molecular dynamics (AIMD) simulations on high-dimensional potential energy surfaces as required for surface dynamical studies [15,22,23].Independent of the particular recipe employed to obtain the electronic friction coefficients [12,14,17,20,24,25], however, the downside of the coarse-graining of the electron dynamics is that it precludes a more fundamental understanding of the underlying e-h pair excitations. For instance, recent such calculations for nonadiabatic vibrational lifetimes of several small molecules [17,25,26] still do not elucidate the seemingly nonsystematic trends for different adsorbate-substrate combinations [26][27][28].…”

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Nonadiabatic Vibrational Damping of Molecular Adsorbates: Insights into Electronic Friction and the Role of Electronic Coherence

2017

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We present a perturbation approach rooted in time-dependent density-functional theory to calculate electron-hole (e-h) pair excitation spectra during the nonadiabatic vibrational damping of adsorbates on metal surfaces. Our analysis for the benchmark systems CO on Cu(100) and Pt(111) elucidates the surprisingly strong influence of rather short electronic coherence times. We demonstrate how in the limit of short electronic coherence times, as implicitly assumed in prevalent quantum nuclear theories for the vibrational lifetimes as well as electronic friction, band structure effects are washed out. Our results suggest that more accurate lifetime or chemicurrentlike experimental measurements could characterize the electronic coherence. DOI: 10.1103/PhysRevLett.119.176808 The tortuous ways in which kinetic and chemical energy is transferred between adsorbates and substrate atoms fundamentally govern the dynamics of surface chemical reactions, for instance, in the context of heterogeneous catalysis or advanced deposition techniques. For metal substrates, the two main energy dissipation mechanisms in this regard are the adsorbate interaction with lattice vibrations, i.e., substrate phonons, and the excitation of electronhole (e-h) pairs. The latter are attributable to the nonadiabatic coupling of nuclear motion to the substrate electronic degrees of freedom (d.o.f.) and seem to be substantial in order to rationalize an increasing number of experimental findings [1,2]. Important steps towards an accurate, yet efficient firstprinciples-based modeling of the energy uptake into phononic d.o.f. have recently been taken [3][4][5][6][7][8][9][10]. In contrast, the explicit description of e-h pair excitations and corresponding nonadiabatic couplings directly from first principles still poses a formidable challenge.In this regard, electronic friction theory (EFT) [11,12] has become a popular workhorse to effectively capture the effects of such nonadiabatic energy loss on the adsorbate dynamics in a computationally convenient way [13][14][15][16][17][18][19]. Inspired by vibrational lifetimes obtained via response theory [20] or Fermi's golden rule in the nuclear system [21], a Langevin equation for the nuclei emerges from a semiclassical picture implying complete electronic decoherence in terms of the Markov approximation [12]. This approach thus avoids an explicit propagation of the electron dynamics and concomitant ultrafast time scales by coarse-graining the effects into electronic friction forces linear in nuclear velocities. This enables an efficient combination even with density-functional theory (DFT) based ab initio molecular dynamics (AIMD) simulations on high-dimensional potential energy surfaces as required for surface dynamical studies [15,22,23].Independent of the particular recipe employed to obtain the electronic friction coefficients [12,14,17,20,24,25], however, the downside of the coarse-graining of the electron dynamics is that it precludes a more fundamental understanding of the underlying e-h pair excit...

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“…It employs Langevin molecular dynamics (MD) to obtain H/D-atom translational energy loss distributions including the effect of electron-hole pair (EHP) excitation; this part of the theory builds on previous work employing a local density friction approximation (LDFA) (17). LDFA combined with ab initio molecular dynamics (AIMD) has also been previously applied to study the associative desorption of diatomics at metal surfaces (18)(19)(20). Here, we extend the LDFA theory to describe the energy spectrum of the excited EHPs produced by the MD trajectories by implementing a forced oscillator model (FOM) (21)(22)(23).…”

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Unified description of H-atom–induced chemicurrents and inelastic scattering

Kandratsenka

Jiang

Dorenkamp

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

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The Born-Oppenheimer approximation (BOA) provides the foundation for virtually all computational studies of chemical binding and reactivity, and it is the justification for the widely used "balls and springs" picture of molecules. The BOA assumes that nuclei effectively stand still on the timescale of electronic motion, due to their large masses relative to electrons. This implies electrons never change their energy quantum state. When molecules react, atoms must move, meaning that electrons may become excited in violation of the BOA. Such electronic excitation is clearly seen for: (i) Schottky diodes where H adsorption at Ag surfaces produces electrical "chemicurrent;" (ii) Au-based metal-insulator-metal (MIM) devices, where chemicurrents arise from H-H surface recombination; and (iii) Inelastic energy transfer, where H collisions with Au surfaces show H-atom translation excites the metal's electrons. As part of this work, we report isotopically selective hydrogen/deuterium (H/D) translational inelasticity measurements in collisions with Ag and Au. Together, these experiments provide an opportunity to test new theories that simultaneously describe both nuclear and electronic motion, a standing challenge to the field. Here, we show results of a recently developed first-principles theory that quantitatively explains both inelastic scattering experiments that probe nuclear motion and chemicurrent experiments that probe electronic excitation. The theory explains the magnitude of chemicurrents on Ag Schottky diodes and resolves an apparent paradox--chemicurrents exhibit a much larger isotope effect than does H/D inelastic scattering. It also explains why, unlike Ag-based Schottky diodes, Au-based MIM devices are insensitive to H adsorption.M ost theoretical studies of atoms and molecules interacting with metal surfaces are based on the Born-Oppenheimer approximation (BOA) (1). However, a growing number of examples have been found where electronic and nuclear degrees of freedom are strongly coupled in violation of the BOA (2-6). H-atom interactions at metals offer a remarkable opportunity to test non-BOA theories against experiment, since H-adsorptioninduced chemicurrent experiments (7-14) offer a direct measure of electronic excitation and H-atom inelastic scattering experiments (15) directly probe nuclear motion. In chemicurrent experiments, exothermic H interactions like adsorption and recombination produce hot electrons that pass over a potential barrier to be collected. Hence, the magnitude of the chemicurrent is dependent on both the reaction-induced production of hot electrons and the likelihood of transmission over the barrier. To reduce uncertainties associated with barrier transmission, the ratio of hydrogen-and deuterium-induced chemicurrent is often measured--H-induced chemicurrents are typically two to five times larger than those from D atoms (7,(11)(12)(13). H-atom surface scattering experiments yield H-atom translational energy loss distributions. The importance of H-atom translation to electronic exc...

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Surface electron density models for accurateab initiomolecular dynamics with electronic friction

Cited by 63 publications

References 99 publications

Communication: Hot-atom abstraction dynamics of hydrogen from tungsten surfaces: The role of surface structure

Communication: Hot-atom abstraction dynamics of hydrogen from tungsten surfaces: The role of surface structure

Nonadiabatic Vibrational Damping of Molecular Adsorbates: Insights into Electronic Friction and the Role of Electronic Coherence

Unified description of H-atom–induced chemicurrents and inelastic scattering

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