Electron-atom scattering in a circularly polarized laser field

Abstract

We consider electron-atom scattering in a circularly polarized laser field at sufficiently high electron energies, permitting to describe the scattering process by the first order Born approximation. Assuming the radiation field has sufficiently moderate intensities, the laser-dressing of the hydrogen target atom in its ground state will be treated in second order perturbation theory. Within this approximation scheme, it is shown that the nonlinear differential cross sections of free-free transitions do neither depend on the {\it dynamical phase} $\phi$ of the radiative process nor on the {\it helicity} of the circularly polarized laser light. Relations to the corresponding results for linear laser polarization are established

Inelastic scattering of electrons by metastable hydrogen atoms in a laser field

“…2(a) respectively, occurs because the scalar product ǫ · q vanishes in Eqs. (37) and (40), at the scattering angle given by the relation of θ = arccos(k i /k f ) in the scattering geometry G1. This is the so-called kinematic minimum whose position depends on the polarization geometry and the initial and final energies of the projectile electron, and exists for the photoabsorption (N > 0) scattering processes only, where the projectile electron momenta must satisfy the relation of k f > k i .…”

“…The atomic radial integral J nll ′ is defined as the difference of the two atomic radial integrals Eqs. (25) and (28)…”

“…It is clear from Eqs. (37) and (38) that DCS depends on the projectile electron momenta, photon energy, and has a maxim value in the scattering geometry in which the polarization vector is parallel to the momentum transfer, ǫ q. E. Differential cross section in the limit of negligible field-atom interaction…”

“…originates from the destructive dynamic interference of the electronic and atomic contributions in Eq (37)…”

Elliptic Dichroism in Angular Distributions in Free-Free Transitions in Hydrogen

“…Theseterms were discussed in considerable detail in our precedingwork 8 . The second term, T (1) N , refers to first orderdressing of the atom in which case one of the N photons exchangedbetween the colliding system and the radiation field is interacting with thebound electron, while the third term T (2) N refers to second orderdressing and here two of the N photons exchanged during thescattering interact with the atomic electron.…”