Dissociative dynamics of spin-triplet and spin-singlet O2 on Ag(100)

Alducin, M.; Busnengo, H. F.; Muiño, R. Dı́ez

doi:10.1063/1.3012354

Cited by 40 publications

(51 citation statements)

References 74 publications

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“…These results explain the measured low reactivity of this system [5,6]. It is worth to mention that this finding, showing that the Fe(110) inertness to N 2 dissociation is caused by the existence of large energy barriers close to the surface, has been also observed in other low reactive systems as N 2 /Ru(0001) [34], O 2 /Ag(100) [35] and, more recently, on O 2 /Ag(111) [36].…”

Section: Discussionsupporting

confidence: 62%

Dissociative and non-dissociative adsorption dynamics of N2 on Fe(110)

Goikoetxea

Alducin

Muiño

et al. 2012

Phys. Chem. Chem. Phys.

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We study the adsorption dynamics of N 2 on the Fe(110) surface. Classical molecular dynamics calculations are performed on top of a six-dimensional potential energy surface calculated within density functional theory. Our results show that N 2 dissociation on this surface is a highly activated process that takes place along a very narrow reaction path with an energy barrier of around 1.1 eV, what explains the measured low reactivity of this system. By incorporating energy exchange with the lattice in the dynamics, we also study the non-dissociative molecular adsorption process. From the analysis of the potential energy surface, we observe the presence of two distinct N 2 adsorption wells. Our dynamics calculations show that the relative population of these adsorption sites varies with the incident energy of the molecule and the surface temperature. We find an activation energy of around 150 meV that prevents molecular adsorption under thermal and hypothermal N 2 gas exposure of the surface. This finding is also consistent with the available experimental information.

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Section: Discussionsupporting

confidence: 62%

Dissociative and non-dissociative adsorption dynamics of N2 on Fe(110)

Goikoetxea

Alducin

Muiño

et al. 2012

Phys. Chem. Chem. Phys.

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“…Combining this technique with either electron-energy-loss spectroscopy ͑EELS͒, infrared spectroscopy, or thermal desorption spectroscopy ͑TDS͒, it is also possible to extract information on the energetics ruling the elementary gas/surface processes-activation energies, atomic and molecular adsorption energies, and reactive paths. Thanks to these kind of studies we know that O 2 dissociation on flat Ag surfaces is characterized by rather large activation energies 8,9 and, as a consequence only molecular adsorption is possible at crystal temperatures below 150 K. [10][11][12] The chemisorption of O 2 on the Ag͑110͒ surface has been particularly controversial because of the initial disagreement regarding the nature and orientation of the chemisorbed molecule. Density-functional calculations performed by Gravil et al 8 shed light on this controversy showing the existence of two distinct chemisorption states with essentially equal energies.…”

Section: Introductionmentioning

confidence: 99%

Role of molecular electronic structure in inelastic electron tunneling spectroscopy:O2on Ag(110)

2010

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Density-functional theory ͑DFT͒ simulations corrected by the intramolecular Coulomb repulsion U are performed to evaluate the vibrational inelastic electron tunneling spectroscopy ͑IETS͒ of O 2 on Ag͑110͒. In contrast to DFT calculations that predict a spinless adsorbed molecule, the inclusion of the U correction leads to the polarization of the molecule by shifting a spin-polarized molecular orbital toward the Fermi level. Hence, DFT+ U characterizes O 2 on Ag͑110͒ as a mixed-valent system. This has an important implication in IETS because a molecular resonance at the Fermi level can imply a decrease in conductance while in the off-resonance case, an increase in conductance is the expected IETS signal. We use the lowest-order expansion on the electron-vibration coupling in order to evaluate the magnitude and spatial distribution of the inelastic signal. The final IET spectra are evaluated with the help of the self-consistent Born approximation and the effect of temperature and modulation-voltage broadening are explored. Our simulations reproduce the experimental data of O 2 on Ag͑110͒ ͓J. R. Hahn, H. J. Lee, and W. Ho, Phys. Rev. Lett. 85, 1914 ͑2000͔͒ and give extra insight of the electronic and vibrational symmetries at play. This ensemble of results reveals that the IETS of O 2 is more complicated that a simple decrease in conductance and cannot be ascribed to the effect of a single molecular-orbital resonance.

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“…9 and 10) and Ag(100), 11 is an intriguing example for which the adiabatic approximation can fail. Behler et al have been able to reproduce the sticking curve of O 2 on Al(111) by performing state-of-the-art classical dynamics simulations in which O 2 is assumed to remain in an excited spin-triplet state along its approach to the surface.…”

Section: Introductionmentioning

confidence: 99%

Vibrational deexcitation and rotational excitation of H2 and D2 scattered from Cu(111): Adiabatic versus non-adiabatic dynamics

Muzas

Juaristi

Alducin

et al. 2012

The Journal of Chemical Physics

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We have studied survival and rotational excitation probabilities of H 2 (v i = 1, J i = 1) and D 2 (v i = 1, J i = 2) upon scattering from Cu(111) using six-dimensional (6D) adiabatic (quantum and quasi-classical) and non-adiabatic (quasi-classical) dynamics. Non-adiabatic dynamics, based on a friction model, has been used to analyze the role of electron-hole pair excitations. Comparison between adiabatic and non-adiabatic calculations reveals a smaller influence of non-adiabatic effects on the energy dependence of the vibrational deexcitation mechanism than previously suggested by low-dimensional dynamics calculations. Specifically, we show that 6D adiabatic dynamics can account for the increase of vibrational deexcitation as a function of the incidence energy, as well as for the isotope effect observed experimentally in the energy dependence for H 2 (D 2 )/Cu(100). Furthermore, a detailed analysis, based on classical trajectories, reveals that in trajectories leading to vibrational deexcitation, the minimum classical turning point is close to the top site, reflecting the multidimensionally of this mechanism. On this site, the reaction path curvature favors vibrational inelastic scattering. Finally, we show that the probability for a molecule to get close to the top site is higher for H 2 than for D 2 , which explains the isotope effect found experimentally.

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Dissociative dynamics of spin-triplet and spin-singlet O2 on Ag(100)

Cited by 40 publications

References 74 publications

Dissociative and non-dissociative adsorption dynamics of N2 on Fe(110)

Dissociative and non-dissociative adsorption dynamics of N2 on Fe(110)

Role of molecular electronic structure in inelastic electron tunneling spectroscopy:O2on Ag(110)

Vibrational deexcitation and rotational excitation of H2 and D2 scattered from Cu(111): Adiabatic versus non-adiabatic dynamics

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