Axial grazing collisions with insulator surfaces

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

doi:10.1016/j.nimb.2006.12.083

Cited by 4 publications

(5 citation statements)

References 20 publications

(25 reference statements)

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“…It takes into account the energy lost by the atom along the classical trajectory but without including effects of quantum coherence. The influence of quantum interferences in the projectile energy-loss spectrum is expected to be minor because, even for insulator surfaces, where valence electrons are tighter than for metals, coherence quantum effects are completely washed out when partial contributions coming from different initial crystal states are added to obtain the transition probability to a given final state [20].…”

Section: Introductionmentioning

confidence: 99%

Energy-loss contribution to grazing scattering of fast He atoms from a silver surface

et al. 2014

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The energy lost by helium atoms axially scattered from a Ag(110) surface is studied in order to investigate the influence of dissipative processes on fast atom diffraction spectra. In this work inelastic projectile distributions are evaluated within a semiclassical formalism that includes dissipative effects due to electron-hole excitations through a friction force. For incidence along the [112] and [110] directions the model predicts the presence of multiple peaks in the energy-loss spectrum for a given impact energy. But these structures are completely washed out when the experimental dispersion of the incident beam is taken into account, giving rise to a smooth energy-loss distribution. Simulations including the experimental energy spread are in fairly good agreement with available experimental data for the [112] channel. In addition, our results suggest that inelastic processes produce an almost constant background in the transverse momentum distribution, except in the extremes of the momentum range where classical rainbow maxima appear. By adding elastic and inelastic contributions, experimental diffraction patterns are well reproduced.

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Section: Introductionmentioning

confidence: 99%

Energy-loss contribution to grazing scattering of fast He atoms from a silver surface

et al. 2014

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“…The wave functions ϕ i corresponding to the different subshells of the negative fluor ion were represented by Hartree-Fock wave functions for negative ions [37], and no correction was included in ϕ i to take into account the interaction of the target anion with nearest neighbors. The effective hole charge was chosen as z T = n i (−2 (at) i ) 1/2 [31,38], where n i is the principal quantum number of the atomic state ϕ i . The 2s-and 2p-bandwidths of fluor were estimated as 1.6 and 5.0 eV, respectively [39].…”

Section: Resultsmentioning

confidence: 99%

“…(11) it is possible to interpret the process as a collection of individual transitions from different lattice sites R. We assume that when the electron e is ionized from a region close to the R site, the charge of passive electrons fully screens the other ionic centers, but the hole left by the emitted electron is not instantaneously filled up as in metals, remaining in the exit channel [31]. Note that this effect is similar to the one giving rise to the track potential in the case of electron emission by projectile impact [16,32,33].…”

Section: A Csv Transition Amplitudementioning

confidence: 99%

Photoelectron emission from LiF surfaces by ultrashort electromagnetic pulses

Acuna

Gravielle

2011

Phys. Rev. A

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Energy-and angle-resolved electron emission spectra produced by incidence of ultrashort electromagnetic pulses on a LiF(001) surface are studied by employing a distorted-wave method named the crystal surface-Volkov (CSV) approximation. The theory makes use of the Volkov phase to describe the action of the external electric field on the emitted electron, while the electron-surface interaction is represented within the tight-binding model. The CSV approach is applied to investigate the effects introduced by the crystal lattice when the electric field is oriented parallel to the surface plane. These effects are essentially governed by the vector potential of the external field, while the influence of the crystal orientation was found to be negligible.

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“…If we consider that the experimental value of the total electron yield is about 60 [34], taking into account that most of the F − @ excitons might decay producing secondary electrons, these values of the exciton production would represent a considerable contribution to the electron emission probability. In practice, we have to consider that the number of excitons could be larger than the primary one calculated here because additional secondary excitons might be produced by primary ejected electrons colliding with F − @ targets.…”

Section: -9mentioning

confidence: 99%

Production of excitons in grazing collisions of protons with LiF surfaces: An onion model

Miraglia

Gravielle

2011

Phys. Rev. A

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In this work we evaluate the production of excitons of a lithium fluoride crystal induced by proton impact in the intermediate and high energy regime (from 100 keV to 1 MeV). A simple model is proposed to account for the influence of the Coulomb grid of the target by dressing crystal ions to transform them in what we call onions. The excited states of these onions can be interpreted as excitons. Within this model, total cross section and stopping power are calculated by using the first Born and the continuum distorted-wave (CDW) eikonal initial-state (EIS) approximations. We found that between 7 and 30 excitons per incident proton are produced in grazing collisions with LiF surfaces, becoming a relevant mechanism of inelastic transitions.

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Axial grazing collisions with insulator surfaces

Cited by 4 publications

References 20 publications

Energy-loss contribution to grazing scattering of fast He atoms from a silver surface

Energy-loss contribution to grazing scattering of fast He atoms from a silver surface

Photoelectron emission from LiF surfaces by ultrashort electromagnetic pulses

Production of excitons in grazing collisions of protons with LiF surfaces: An onion model

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