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

Gravielle, M. S.; Miraglia, J. E.

doi:10.1103/physreva.92.062709

Cited by 23 publications

(65 citation statements)

References 31 publications

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“…With the goal of checking the quality of the proposed surface potential we use the potential model within the framework of the SIVR approximation in order to evaluate final projectile distributions for swift atoms grazingly impinging on LiF(001) along low-indexed crystallographic channels. The SIVR approach [21,22] is a semiquantum method that provides a clear representation of the main physical mechanisms involved in FAD processes, describing them in terms of classical trajectories through the Feynman path integral formulation of quantum mechanics [47]. It incorporates an adequate description of classically forbidden transitions on the dark side of the rainbow angle, providing reliable FAD patterns along the whole angular range [21,22].…”

Section: Comparison With Grazing Incidence Experimentsmentioning

confidence: 99%

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Reexamination of the interaction of atoms with a LiF(001) surface

Miraglia

Gravielle

2017

Phys. Rev. A

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Pairwise additive potentials for multielectronic atoms interacting with a LiF(001) surface are revisited by including an improved description of the electron density associated with the different lattice sites, as well as non-local electron density contributions. Within this model, the electron distribution around each ionic site of the crystal is described by means of an onion approach that accounts for the influence of the Madelung potential. From such densities, binary interatomic potentials are then derived by using well-known non-local functionals for the kinetic, exchange and correlation terms. Rumpling and long-range contributions due to projectile polarization and van der Waals forces are also included in an analogous fashion. We apply this pairwise additive approximation to evaluate the interaction potential between closed-shell -He, Ne, Ar, Kr, and Xe -and open-shell -N, S, and Cl -atoms and the LiF surface, analyzing the relative importance of the different contributions. The performance of the proposed potentials is assessed by contrasting angular positions of rainbow and supernumerary rainbow maxima produced by fast grazing incidence with available experimental data. The good agreement found for normal energies in the eV-range represents a meaningful evidence of the quality of the present description.

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Section: Comparison With Grazing Incidence Experimentsmentioning

confidence: 99%

“…Similar behavior was also observed in FAD spectra for He projectiles, case investigated with the present pairwise potential model in Refs. [21,22].…”

Section: Comparison With Grazing Incidence Experimentsmentioning

confidence: 99%

Reexamination of the interaction of atoms with a LiF(001) surface

Miraglia

Gravielle

2017

Phys. Rev. A

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“…We describe the elastic scattering of H atoms off the LiF(001) surface within the Surface-Initial Value Repre-sentation (SIVR) approximation [28], which is a semiquantum method that affords a clear representation of the main physical mechanisms in terms of classical trajectories through the Feynman path integral formulation of quantum mechanics [29]. The SIVR method includes an approximate representation of classically forbidden transitions on the dark side of the rainbow angle, providing an appropriate description of GIFAD patterns along the whole angular range [28,30]. Another noteworthy point is that, with a relatively low computational cost, the SIVR approach takes into account the threedimensionality of the PES, without averaging it along the incidence direction.…”

Section: Introductionmentioning

confidence: 99%

van der Waals effects on grazing-incidence fast-atom diffraction for H on LiF(001)

2016

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We theoretically address grazing incidence fast atom diffraction (GIFAD) for H atoms impinging on a LiF(001) surface. Our model combines a description of the H-LiF(001) interaction obtained from Density Functional Theory calculations with a semi-quantum treatment of the dynamics. We analyze simulated diffraction patterns in terms of the incidence channel, the impact energy associated with the motion normal to the surface, and the relevance of Van der Waals (VdW) interactions. We then contrast our simulations with experimental patterns for different incidence conditions. Our most important finding is that, for normal energies lower than 0.5 eV and incidence along the 100 channel, the inclusion of Van der Waals interactions in our potential energy surface yields a greatly improved accord between simulations and experiments. This agreement strongly suggests a non-negligible role of Van der Waals interactions in H/LiF(001) GIFAD in the low-to-intermediate normal energy regime.

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“…Therefore, modifications of the surface can be neglected [13,14]. Among these techniques, especially fast atom diffraction (FAD) [11,[15][16][17][18][19][20][21][22] with de Broglie wavelengths of some 0.001Å gained considerable interest and motivated numerous studies with respect to FADs phenomenological description [23][24][25][26][27][28][29][30][31][32][33][34][35][36] and utilization for epitaxial growth monitoring [37,38] as well as qualitative and quantitative structure determination [19][20][21]33,[39][40][41][42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Quantitative structure determination using grazing scattering of fast atoms: Oxygen-induced missing-row reconstruction of Mo(112)

Seifert

Winter

2016

Phys. Rev. B

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We present an extensive study on the structure of oxygen adsorbates on Mo(112) by means of grazing scattering of fast hydrogen and helium atoms and low-energy electron diffraction. For projectile energies less than 2 keV, fast atom diffraction provides information on the surface unit cell and on adsorption sites for low coverages. In the classical scattering regime, we employed so-called triangulation techniques where for an azimuthal rotation of the target axial surface channels are identified. From comparison with computer simulation positions of surface atoms can be derived. Aside from the detection scheme of projectile-induced electron emission, we present details for a new variant of triangulation based on the detection of angular distributions of scattered particles. The different sensitivity of the methods to the topmost surface layers allows us to efficiently set up structural models for four adsorbate phases for which contradicting models exist in literature. The c(4×2) phase is revealed to be one step in the formation of a missing-row reconstruction with p(1×2) unit cell. Our studies demonstrate the potential of grazing scattering of fast atoms for quantitative structure analysis.

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

Cited by 23 publications

References 31 publications

Reexamination of the interaction of atoms with a LiF(001) surface

Reexamination of the interaction of atoms with a LiF(001) surface

van der Waals effects on grazing-incidence fast-atom diffraction for H on LiF(001)

Quantitative structure determination using grazing scattering of fast atoms: Oxygen-induced missing-row reconstruction of Mo(112)

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