The second Born approximation in electron-atom collisions in the presence of a laser field

Makhoute, A.; Khalil, Diaa; Zitane, Mohamed; Bouzidi, M.

doi:10.1088/0953-4075/35/4/319

Cited by 12 publications

(7 citation statements)

References 30 publications

(47 reference statements)

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“…[15]). More recently an experiment was performed at higher laser frequencies [16] and theory was developed beyond a perturbative treatment [17][18][19].…”

mentioning

confidence: 99%

Electron Impact Ionization in the Presence of a Laser Field: A Kinematically Complete(nγe,2e)Experiment

et al. 2005

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Single ionization of He by 1 keV electron impact in the presence of an intense (I=4×10 12 W/cm 2 ) laser field (λ=1064 nm) has been explored in a kinematically complete experiment using a "Reaction Microscope". Distinct differences in the singly to fully differential cross sections compared to the field-free situation are observed which cannot be explained by a first-order quantum calculation.Major features, such as the number of photons exchanged and the modification of the energy spectrum of emitted electrons can be qualitatively understood within a simple classical picture.

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“…[15]). More recently an experiment was performed at higher laser frequencies [16] and theory was developed beyond a perturbative treatment [17][18][19].…”

mentioning

confidence: 99%

Electron Impact Ionization in the Presence of a Laser Field: A Kinematically Complete(nγe,2e)Experiment

et al. 2005

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“…We present here a short description of our theoretical approach to deal with the electron's impact excitation of the helium atom in the presence of a laser field. A detailed description can be found in our previous works [32][33][34]. The scenario we considered here can be simplified into the following form:…”

Section: Theoretical Descriptionmentioning

confidence: 99%

“…The wave functions ψ i , ψ f , and ψ n are the stationary states associated with the eigenenergies E i , E f , and E n of the helium target, respectively. These states were evaluated using the Sturmian approach (see [26,34,36]).…”

Section: Theoretical Descriptionmentioning

confidence: 99%

Simultaneous Excitation of Helium by Means of an Electron and a Photon: A Joined Experimental and Theoretical Study

Ajana

Nehari

Khalil

et al. 2021

Atoms

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We report on a joined experimental and theoretical study of differential cross-sections resulting from inelastic scattering of a monoenergetic electron by helium atoms in the presence of an intense carbon dioxide laser. In particular, we measured the signals of the scattered electrons during the simultaneous electron–photon excitation of He 21P state for the first three microseconds of the laser pulse. The signals were measured for an incident electron energy of 45 eV and showed a structure that emerged at small scattering angles. The latter was found to be sensitive to the nature of the transferred photons, as well as the intensity of the laser field. The experimental findings were supported by quantum calculations based on the second-order Born approximation in which the correlated electron–electron interactions were taken into account.

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“…In the region of high intensity, theoretical calculations using Floquet R-Matrix theory cannot reproduce experimental results [50] and for some electron energies in question the contribution from the second-Born approximation will also be negligible [51]. Since both laser-target effects [50], as well as second-Born contributions [51] do not readily explain experimental data, it seems reasonable, also in view of the more recent experimental results, to re-evaluate some of the other aspects of the scattering process, drawing on recent knowledge from other parts of strong-field physics. To this end, we note that multiple studies on strong-field ionisation (see, e.g., references [52][53][54][55][56][57][58]) have reported that a breakdown of the D approximation for infrared fields appeared at intensities comparable to the highest intensity used in LAES-experiments.…”

Section: Introductionmentioning

confidence: 99%

“…Laser-assisted scattering therefore remains a research area with open questions, and with the introduction of femtosecond lasers, new applications as well as new challenges occur [8,9]. In the region of high intensity, theoretical calculations using Floquet R-Matrix theory cannot reproduce experimental results [50] and for some electron energies in question the contribution from the second-Born approximation will also be negligible [51]. Since both laser-target effects [50], as well as second-Born contributions [51] do not readily explain experimental data, it seems reasonable, also in view of the more recent experimental results, to re-evaluate some of the other aspects of the scattering process, drawing on recent knowledge from other parts of strong-field physics.…”

Section: Introductionmentioning

confidence: 99%

Nondipole effects in laser-assisted electron scattering

Jensen

Madsen

2020

J. Phys. B: At. Mol. Opt. Phys.

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Laser-assisted electron scattering is often described using the electric dipole approximation for the interaction between the electron and the assisting electromagnetic field. Within the dipole approximation, theory predicts a vanishing scattering cross section for processes involving exchange of photons in critical geometries, where the electron momentum transfer vector is perpendicular to the linear polarisation of the external field. In a nonrelativistic spin-free treatment, we consider modifications of the scattering cross section by nondipole contributions to the first order in 1/c in the interaction between the laser field and the electron using the nondipole strong-field-approximation Hamiltonian [Jensen et al. Phys. Rev. A. 101, 043408 (2020)]. The approach allows for an analytical solution for the wave function of a free electron in the laser field with a nondipole contribution.This wave function leads to an analytical formula for the laser-assisted scattering cross section including nondipole effects. The nondipole corrections depend on the propagation direction of the field relative to the electron momentum transfer vector. The approach gives a finite cross section in scattering geometries, where the dipole approach predicts a vanishing cross section. The theory is illustrated by application to scattering geometries similar to those considered in experiments where large deviations between experimental data and predictions based on the dipole approximation have been reported. In these scattering geometries, the nondipole strong-field-approximation approach suggests an increase in the cross section by orders of magnitude compared to results obtained within the dipole approximation.

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The second Born approximation in electron-atom collisions in the presence of a laser field

Cited by 12 publications

References 30 publications

Electron Impact Ionization in the Presence of a Laser Field: A Kinematically Complete(nγe,2e)Experiment

Electron Impact Ionization in the Presence of a Laser Field: A Kinematically Complete(nγe,2e)Experiment

Simultaneous Excitation of Helium by Means of an Electron and a Photon: A Joined Experimental and Theoretical Study

Nondipole effects in laser-assisted electron scattering

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