Hyperthermal Ar atom scattering from a C(0001) surface

Gibson, K. D.; Sibener, S. J.; Upadhyaya, Hari P.; Brunsvold, Amy L.; Zhang, Jianming; Minton, Timothy K.; Troya, Diego

doi:10.1063/1.2924126

Cited by 36 publications

(39 citation statements)

References 19 publications

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“…The scattering of rare gas atoms by metal surfaces continues to be of both theoretical 1,2 and experimental interest. 3 Recent reviews may be found in Refs. 4-6.…”

Section: Introductionmentioning

confidence: 99%

Classical theory for the in-plane scattering of atoms from corrugated surfaces: Application to the Ar–Ag(111) system

Pollak

Miret‐Artés

2009

The Journal of Chemical Physics

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A classical Wigner in-plane atom surface scattering perturbation theory within the generalized Langevin equation formalism is proposed and discussed with applications to the Ar-Ag(111) system. The theory generalizes the well-known formula of Brako as well as the "washboard model." Explicit expressions are derived for the joint angular and final momentum distributions, joint final energy, and angular distributions as well as average energy losses to the surface. The theory provides insight into the intertwining between the energy loss and angular dependence of the scattering. At low energies the energy loss in the horizontal direction is expected to be large, leading to a shift of the maximum of the angular distribution to subspecular angles, while at high energies the energy loss in the vertical direction dominates, leading to a superspecular maximum in the angular distribution. The same effect underlies the negative slope of the average final (relative) energy versus scattering angle at low energies which becomes positive at high energies. The theory also predicts that the full width at half maximum of the angular distribution varies as the square root of the temperature. We show how the theory provides insight into the experimental results for scattering of Ar from the Ag(111) surface.

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“…The scattering of rare gas atoms by metal surfaces continues to be of both theoretical 1,2 and experimental interest. 3 Recent reviews may be found in Refs. 4-6.…”

Section: Introductionmentioning

confidence: 99%

Classical theory for the in-plane scattering of atoms from corrugated surfaces: Application to the Ar–Ag(111) system

Pollak

Miret‐Artés

2009

The Journal of Chemical Physics

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“…While increased thermal roughening apparently does not result in full thermalization of hyperthermal Ar atoms, both angular distributions are somewhat broad, with a full width at half-maximum of about 45°, indicating that the surface is rough in comparison to HOPG, which was shown to have a sharply peaked angular distribution beyond the specular direction. 50 In addition, the TOF distributions in Figure 6 show a slight broadening with increasing temperature, indicative of a larger range of energy transfers at the surface, albeit for IS and not TD processes. Although effects of thermal roughening can be observed in the scattering dynamics of hyperthermal Ar, there is no evidence that physical changes in the surface associated with temperature lead to significant energy loss and enhanced thermal desorption.…”

Section: Results and Analysismentioning

confidence: 95%

Inelastic and Reactive Scattering Dynamics of Hyperthermal O and O₂ on Hot Vitreous Carbon Surfaces

et al. 2015

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We have undertaken a series of experiments to learn the mechanisms of carbon oxidation over a wide range of temperatures that extend to the conditions encountered during atmospheric re-entry, with a particular interest in understanding how these mechanisms change with temperature. We report here the hyperthermal scattering dynamics of ground-state atomic oxygen, O( 3 P), and molecular oxygen, O 2 ( 3 Σ g − ), on vitreous carbon surfaces at temperatures from 600 to 2100 K. A molecular beam containing neutral O and O 2 in a mole ratio of 0.93:0.07 was prepared with a nominal velocity of 7760 m s −1 , corresponding to a translational energy of 481 kJ mol −1 for atomic oxygen. This beam was directed at a vitreous carbon surface, and angular and translational energy distributions were obtained for inelastically and reactively scattered products with the use of a rotatable mass spectrometer detector. Unreacted oxygen atoms exited the surface through both impulsive scattering and thermal desorption. The preferred scattering process changed from impulsive scattering to thermal desorption as the surface temperature increased. O 2 scattered mainly impulsively from the surface, and its scattering dynamics were essentially unaffected by surface temperature. The predominant reactive product was carbon monoxide (CO). Carbon dioxide (CO 2 ) was also formed at lower surface temperatures. The flux of the CO product rose with temperature to a maximum at approximately 1500−1900 K, depending on heating rate, and then decreased with increasing surface temperature. The CO 2 flux dropped dramatically with increasing surface temperature and was below detectable limits above 1100 K. A minor reactive pathway was identified that produced O 2 , presumably through a direct Eley−Rideal reaction of an incident oxygen atom with an O atom residing on the surface. Decreased oxygen surface coverage at higher temperatures was found to limit the reactivity of the surface by inhibiting the production of CO and CO 2 at very high surface temperatures. The observed inelastic and reactive scattering behavior reveals a complex interplay between reactivity and surface temperature.

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“…To date, extensive studies involving noble gas atoms with hyperthermal energies scattering from metal, 1,7,8,[10][11][12][13][14][15] semiconductor, 11,16 and graphite 17 surfaces have been performed. The Ar/Ru(0001) system has been investigated using supersonic molecular beam techniques for incident particle energies ranging from 0.08 to 2.32 eV.…”

Section: Introductionmentioning

confidence: 99%

Scattering of hyperthermal argon atoms from clean and D-covered Ru(0001) surfaces

Ueta

Gleeson

Kleyn

2011

The Journal of Chemical Physics

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Hyperthermal Ar atoms were scattered from a Ru(0001) surface held at temperatures of 180, 400 and 600 K, and from a Ru(0001)-(1×1)D surface held at 114 and 180 K. The resultant angular intensity and energy distributions are complex. The in-plane angular distributions have narrow (FWHM ≤ 10°) near-specular peaks and additional off-specular features. The energy distributions show an oscillatory behavior as a function of outgoing angle. In comparison, scattered Ar atoms from a Ag(111) surface exhibit a broad angular intensity distribution and an energy distribution that qualitatively tracks the binary collision model. The features observed for Ru, which are most evident when scattering from the clean surface at 180 K and from the Ru(0001)-(1×1)D surface, are consistent with rainbow scattering. The measured TOF profiles cannot be adequately described with a single shifted Maxwell-Boltzmann distribution. They can be fitted by two components that exhibit complex variations as a function of outgoing angle. This suggests at least two significantly different site and∕or trajectory dependent energy loss processes at the surface. The results are interpreted in terms of the stiffness of the surface and highlight the anomalous nature of the apparently simple hcp(0001) ruthenium surface.

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Hyperthermal Ar atom scattering from a C(0001) surface

Cited by 36 publications

References 19 publications

Classical theory for the in-plane scattering of atoms from corrugated surfaces: Application to the Ar–Ag(111) system

Classical theory for the in-plane scattering of atoms from corrugated surfaces: Application to the Ar–Ag(111) system

Inelastic and Reactive Scattering Dynamics of Hyperthermal O and O₂ on Hot Vitreous Carbon Surfaces

Scattering of hyperthermal argon atoms from clean and D-covered Ru(0001) surfaces

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Hyperthermal Ar atom scattering from a C(0001) surface

Cited by 36 publications

References 19 publications

Classical theory for the in-plane scattering of atoms from corrugated surfaces: Application to the Ar–Ag(111) system

Classical theory for the in-plane scattering of atoms from corrugated surfaces: Application to the Ar–Ag(111) system

Inelastic and Reactive Scattering Dynamics of Hyperthermal O and O2 on Hot Vitreous Carbon Surfaces

Scattering of hyperthermal argon atoms from clean and D-covered Ru(0001) surfaces

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Inelastic and Reactive Scattering Dynamics of Hyperthermal O and O₂ on Hot Vitreous Carbon Surfaces