Laser-assisted coplanar symmetric (e, 2e) triple differential cross sections

Abstract

The second Born approximation in laserassisted (e, 2e) collisions in hydrogen I Ajana, A Makhoute, D Khalil et al. AbstractThe modification due to an external linearly polarized monochromatic laser field on the dynamics of the ionization process of an atomic hydrogen by electron-impact is studied theoretically for a coplanar symmetric geometry. The interaction of the laser field with the unbound electrons is treated in a non-perturbative way. The wave functions of the ingoing and outgoing electrons in the laser field are treated as non-relativistic Volkov waves, while the interaction of the bound electron with the laser field is treated by using first-order perturbation theory, assuming that the electric field strength associated with the external laser field is much less than the atomic unit e a 5 10 V cm 2 9 1 =´-. The influence of the laser parameters on the angular distribution is analyzed and several illustrative examples are discussed. Significant changes are noted both in the shape and magnitude of the triple differential cross sections (TDCS) by the application of the laser field. Numerical results show that the TDCS are strongly dependent on the dressing of the projectile by the laser field at low frequency in (e, 2e) spectroscopy region.

Dressing effects in the laser-assisted ( e,2e ) process in fast-electron–hydrogen-atom collisions in an asymmetric coplanar scattering geometry

“…2 and 3 of Ref. [24]. Since the atomic wave function was calculated within the closure approximation [24], our numerical results disagree at larger photon energies ω > 3 eV where the atomic dressing effect is more important, and cannot be accurately described by this approximation.…”

“…[24]. Since the atomic wave function was calculated within the closure approximation [24], our numerical results disagree at larger photon energies ω > 3 eV where the atomic dressing effect is more important, and cannot be accurately described by this approximation. At the resonance photon energy of 10.2 eV, laser intensity of 1.3 × 10 7 W/cm 2 , and polarization ε||k i , in the Ehrhardt asymmetric coplanar geometry, with the incident and ejected electrons kinetic energies E i = 250 eV and E e = 5 eV, and scattering angle θ f = 3 • , the TDCS given by Eq.…”

“…As mentioned before most of these previous theoretical works were focused on scattering geometries involving slow ejected electrons, and only recently it was shown for ejected electrons of high energies that the laser field strongly modifies the (e, 2e) collisions. New theoretical studies for laser-assisted EMS at high impact energy and large momentum transfer were published and it was found that the atomic dressing, calculated in the closure-and low-frequency approximations, substantially influences the laser-assisted TDCSs at low [22,23] and large photon energies [24].…”

Laser-Assisted (e, 2e) Collisions in the Symmetric/Asymmetric Coplanar Geometry

“…This motivated us to attempt many works that study the laser-assisted single ionization of hydrogen and helium atoms in the Ehrhardt asymmetric geometry using a second-order Born calculation [41][42][43][44][45][46]. Our group have also studied the symmetric case by restricting to a first Born treatment [47,48].…”