Theoretical and experimental(e,2e)study of electron-impact ionization of laser-aligned Mg atoms

Abstract

We have performed calculations of the fully differential cross sections for electron impact ionization of magnesium atoms. Three theoretical approximations, the time dependent close coupling (TDCC), the three body distorted wave (3DW), and the Distorted Wave Born Approximation (DWBA), are compared with experiment in this article. Results will be shown for ionization of the 3s ground state of Mg for both asymmetric and symmetric coplanar geometries. Results will also be shown for ionization of the 3p state which has been excited by a linearly-polarized laser which produces a charge cloud aligned perpendicular to the laser beam direction and parallel to the linear polarization. Theoretical and experimental results will be compared for several different alignment angles, both in the scattering plane as well as in the plane perpendicular to the incident beam direction.

Kinematically complete study of low-energy electron-impact ionization of argon: Internormalized cross sections in three-dimensional kinematics

“…For Ne(2p), unprecedented agreement between experiment and predictions from a B-spline R-matrix (BSR) with pseudostates approach was obtained first for a projectile energy of 100 eV [5] and most recently also for the even lower energy of 65 eV [6]. While other theoretical models pretty much failed, a three-body distorted-wave (3DW) approach [9][10][11][12] also did very well in comparison with experiment for the latter case. This suggested the importance of accounting for the post-collision interaction (PCI) at such low energies of both outgoing electrons.…”

“…Since the details of the 3DW approximation have been outlined before [9][10][11][12], only an overview will be given here. In the 3DW approximation, the direct T matrix is given by…”

“…Much more challenging, however, is the treatment of more complex targets, such as the heavy noble gases Ne−Xe [5][6][7][8][9][10][11][12][13][14][15]. In recent years, we measured the ionization of Ne(2p) [5,6] and Ar(3p) [7,8].…”

Kinematically complete study of low-energy electron-impact ionization of neon: Internormalized cross sections in three-dimensional kinematics

“…The three-body distorted-wave (3DW) approach has been previously discussed in [19,20,27]. Here we present a brief overview with the key features of the theory necessary for the present discussion.…”

“…Theoretical models, which have been frequently used to describe ionization processes in heavy complex targets, are a hybrid distorted-wave Born approximation (DWBA) plus R-matrix (close-coupling) approach [9][10][11][12], the DWBA with inclusion of the post-collision interaction (PCI) by the Gamow factor calculated with the Ward-Macek method [13], the three-body distorted-wave (3DW) approach (see e.g. [14][15][16][17][18][19][20]), and most recently the B-spline R-matrix (BSR) approach [21,22]. Except for BSR, which includes a large number of pseudostates to estimate the effect of the high-lying Rydberg states and the ionization continuum in the ab initio solution of the close-coupling equations, the approaches treat at least some part of the process perturbatively to first or second order.…”