Single ionization of Ar(2p) by electron and antiproton impact

Complete text of publication follows. One interesting and fundamental part of the collision physics is the understanding of the ionization process in ion-atom collisions. Study of the energy and angular distribution of the ejected electrons and scattered projectiles gives a basic information about the collision dynamics. Moreover, it is a sensitive test of various theories when the calculated cross sections are compared with each other. In recent decades both classical and quantum-mechanical theories have been extensively used to calculate the ionization cross sections of atoms and molecules for various projectiles. The main difficulty of calculations is that long-range character of Coulomb interactions have to be taken into account for accurate description of the cross sections. The classical trajectory Monte Carlo (CTMC) method has been quite successful in dealing with ionization processes in ion-atom collisions. The CTMC simulation is a non-perturbative method. One of its main advantages is that many-body interactions are exactly taken into account during the collision. Recently, the continuum-distorted-with-eikonal-initial-state (CDW-EIS) model has also successfully been applied to study the ionization process by proton impact. In the present work CTMC theory is used to calculate ionization cross sections in electron and argon(2p) atom collisions. The energies of the projectile electrons investigated were 300 eV, 500 eV and 2 KeV. Model calculations using a CTMC and CDW-EIS approximation have also been made for the collisions between antiproton and argon(2p) atoms at impact energy having equivalent velocity to 2 keV electron. It is shown that the calculated cross sections are in relatively good agreement. The best agreement can be found at 90 degree