Molecular Orientation Resolved (e, 2e) Cross Sections for CF4 at 67 eV Impact Energy

Abstract

In this investigation, the fully differential cross sections (FDCS) for ionization of electron impact at low energy (E<sub>0</sub> = 67 eV) were measured for the specific orientations of the molecules and around it axis. In the full perpendicular plane (FPP), the FDCS for CF<sub>4</sub> were experimentally figured out by using reaction microscope (REMI) for different kinematics such as two ejection electron energies of 5 eV and 8 eV, scattering angles of -25° and 30°, and two molecular axis directions of ϕ<sub>Mol</sub> = 0° and 45°, also their relative orientations such as 180° and 225°. The momentum vectors of the two ejected electrons (with energies E<sub>e1</sub>, and E<sub>e2</sub>) and the fragment ions (e, 2e+ ions) were detected by the triple coincidence method. For the duration of dissociation, the time of flight (TOF) of CF<sub>3</sub><sup>+</sup>, CF<sub>2</sub><sup>+</sup>, CF<sup>+</sup>, F<sup>+</sup>, and C<sup>+</sup> are observed in the TOF diagram. During the dissociation of the final fragment of CF<sub>3</sub><sup>+</sup> ion and its electronic ground state neutral F, the momentum vector of CF<sub>3</sub><sup>+</sup> allows us to draw conclusions about the orientation of the molecule in the course of the collision. Finally, it was remarked that concerning molecular orientation, electrons are highly sensitive at low energy and low scattering angle.