Low-energy (E0=65eV) electron-impact single ionization of Ne (2p) has been investigated to thoroughly test state-of-the-art theoretical approaches. The experimental data were measured using a reaction microscope, which can cover nearly the entire 4π solid angle for the secondary electron emission energies ranging from 2 to 8 eV, and projectile scattering angles ranging from 8.5^∘ to 20.0^∘. The experimental triple-differential cross sections are internormalized across all measured scattering angles and ejected energies. The experimental data are compared to predictions from a hybrid second-order distorted-wave Born plus R-matrix approach, the distorted-wave Born approximation with the inclusion of postcollision interaction (PCI), a three-body distorted-wave approach (3DW), and a B-spline R-matrix (BSR) with pseudostates approach. Excellent agreement is found between the experiment and predictions from the 3DW and BSR models, for both the angular dependence and the relative magnitude of the cross sections in the full three-dimensional parameter space. The importance of PCI effects is clearly visible in this low-energy electron-impact ionization process

Low energy experimental and theoretical triple differential cross sections for the highest occupied molecular orbital of methane (1t(2)) and for the 2p atomic orbital of neon are presented and compared. These targets are iso-electronic, each containing 10 electrons and the chosen orbital within each target has p-electron character. Observation of the differences and similarities of the cross sections for these two species hence gives insight into the different scattering mechanisms occurring for atomic and molecular targets. The experiments used perpendicular, symmetric kinematics with outgoing electron energies between 1.5 eV and 30 eV for CH(4) and 2.5 eV and 25 eV for neon. The experimental data from these targets are compared with theoretical predictions using a distorted-wave Born approximation. Reasonably good agreement is seen between the experiment and theory for neon while mixed results are observed for CH(4). This is most likely due to approximations of the target orientation made within the model.

We report a combined experimental and theoretical study on the electron-impact ionization of water (H 2 O) at the relatively low incident energy of E 0 = 81 eV in which either the 1b 1 or 3a 1 orbitals are ionized leading to the stable H 2 O + cation. The experimental data were measured using a reaction microscope, which can cover nearly the entire 4π solid angle for the secondary electron emission over a range of ejection energies. We present experimental data for the scattering angles of 6 • and 10 • for the faster of the two outgoing electrons as function of the detection angle of the secondary electron with energies of 5 eV and 10 eV. The experimental triple-differential cross sections are internormalized across the measured scattering angles and ejected energies. The experimental data are compared to predictions from two molecular three-body distorted-wave approaches. One applying the orientation-averaged molecular orbital (OAMO) approximation and one using a proper-average (PA) over orientation-dependent cross sections. The PA calculations are in better agreement with the experimental data than the OAMO calculations, for both the angular dependence and the relative magnitude of the observed cross section structures.

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.

Abstract.Ionization triple differential cross sections (TDCS) have been determined experimentally and theoretically for the neutral molecule N 2 over a range of geometries from coplanar to the perpendicular plane. Data were obtained at incident electron energies ~10 eV and ~20 eV above the ionization potential (IP) of the 3σ g , 1π u and 2σ g states, using both equal and non-equal outgoing electron energies. The data were taken with the incident electron beam in the scattering plane (ψ = 0°), at 45° to this plane and orthogonal to the plane (ψ = 90°).The set of nine measured differential cross sections at a given energy were then internormalised to each other. The data are compared to new calculations using various distorted wave methods, and differences between theory and experiment are discussed.