Angular and charge state distributions of highly charged ions scattered during low energy surface-channeling interactions with Au(110)

Grazing scattering of neutral atoms from insulator surfaces is investigated in the intermediate velocity range, in which interference effects have been recently observed. To describe this process we introduce a distorted-wave method, based on the use of the eikonal wave function, which takes into account the phase of the scattering state along the classical projectile path. The eikonal theory is applied to evaluate the angular distribution of few keV helium atoms after impinging on a LiF(001) surface along low-index crystallographic directions. The interest focuses on the role played by the projectile polarization produced by cations and anions of the crystal surface. For the considered collision system we found a polarization channel, corresponding to the direction <110>, which is affected by this effect, while for incidence in the direction <100> the polarization contribution is nearly negligible. The proposed eikonal approach, including polarization effects, provides angular projectile spectra in good agreement with the experimental data.

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“…by all classically scattered projectiles and consequently, the angular projectile distribution shows the usual banana shape [20].…”

Section: Resultsmentioning

confidence: 99%

Influence of the polarization in grazing scattering of fast helium atoms from LiF(001) surfaces

Gravielle

Miraglia

2008

Phys. Rev. A

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“…Both SIVR distributions reproduce quite well the corresponding experimental ones [1], also displayed in the figures. They present the usual banana shape, characteristic of the axial surface scattering [30], with final dispersion angles lying on a thick annulus, whose mean radius is approximately equal to θ i . From the comparison of Figs.…”

Section: Resultsmentioning

confidence: 99%

Influence of beam collimation on fast-atom diffraction studied via a semiquantum approach

Gravielle

Miraglia

2015

Phys. Rev. A

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The influence of the collimating conditions of the incident beam on diffraction patterns produced by grazing scattering of fast atoms off crystal surfaces is studied within a semi-quantum approach, named Surface Initial Value Representation (SIVR) approximation. In this approach we incorporate a realistic description of the incident particle in terms of the collimating parameters, which determine the surface area that is coherently illuminated. The model is applied to He atoms colliding with a LiF(001) surface after passing through a rectangular aperture. As it was experimentally observed [1], SIVR spectra as a function of the azimuthal angle are very sensitive to the width of the collimating slit. We also found that the length of the collimating aperture affects polar angle distributions, introducing additional interference structures for the longer collimating slits.

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“…We use an Al͑111͒ target, a prototype of the free-electron metal. Compared to a recent experimental study on O Ϫ formation at an Au͑110͒ surface, 19,20 a much larger energy range and a variation over scattering angles are encompassed in our study. Therefore, we are able to observe a ''resonant'' structure for the O Ϫ formation probability as a function of the velocity component parallel to the surface.…”

Section: Introductionmentioning

confidence: 92%

“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Due to the rather small binding energy, the affinity level of the negative ion is primarily in resonance with unoccupied electronic states of the surface above the Fermi level. Then the RT process is dominated by the neutralization of the negative ion via electron loss from the affinity level to the metal surface.…”

Section: Introductionmentioning

confidence: 99%

“…6,[8][9][10][11][12][13][14] Another possibility, present in grazing scattering geometry, is the kinematically induced electrontransfer process, i.e., RT assisted by the collision velocity component parallel to the surface. 7,19,20 Detailed discussions on this so-called ''v ʈ effect'' can be found in Refs. 21-23. Recent developments of nonperturbative methods, treating the properties of negative-ion states in front of metal surfaces, [24][25][26] have provided the quantitative tools to study RT processes.…”

Section: Introductionmentioning

confidence: 99%

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O−formation in grazing scattering from an Al(111) surface

et al. 1998

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We report on the results of a joint experimental and theoretical study on the formation of O Ϫ ions in grazing scattering from an Al͑111͒ surface. The O Ϫ fractions in the scattered beam are studied over a wide range of collision energies. This allows us to observe a resonance structure for the O Ϫ formation probability as a function of the collision velocity component parallel to the surface (v ʈ ). Such a characteristic v ʈ dependence is the signature of a kinematically induced charge-transfer process between the O Ϫ ion and the Al surface. The theoretical treatment of charge transfer is based on the coupled angular mode method. The multistate aspect of the problem originating from the open-shell structure of the O Ϫ ion is taken into account.

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Angular and charge state distributions of highly charged ions scattered during low energy surface-channeling interactions with Au(110)

Cited by 41 publications

References 14 publications

Influence of the polarization in grazing scattering of fast helium atoms from LiF(001) surfaces

Influence of the polarization in grazing scattering of fast helium atoms from LiF(001) surfaces

Influence of beam collimation on fast-atom diffraction studied via a semiquantum approach

O−formation in grazing scattering from an Al(111) surface

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