Effects of target polarization and postcollision interaction on the electron-impact single ionization of Ne(2 p ), Ar(3 p ), and Na(3 s ) atoms

We report the perpendicular plane ionization results of (e, 2e) triple-differential cross sections for the Ne(2p) and Ar(3p) atoms at the incident electron energies ranging from 5 to 50 eV above ionization potential for neon atoms and from 2 to 50 eV above ionization potential for the argon atoms. The present investigation has been done in the modified distorted wave Born approximation and it has been observed that postcollision interaction and polarization of target are important in the perpendicular plane ionization of atoms. We also present the results of triple-differential cross section for the doubly symmetric coplanar ionization of Na(3s) atoms at the incident electron energy ranging from 6 to 60 eV above ionization potential. Thus we are able to see the effects of target polarization and postcollision interaction in coplanar as well as the perpendicular plane geometrical conditions. The results of our calculations for the Ne(2p) and Ar(3p) have been compared with the very recent measurements of Nixon et al. [K. L. Nixon, A. J. Murray, and C. Kaiser, J. Phys. B 43, 085202 (2010)] and the results of coplanar ionization of Na(3s) have been compared with the experimental data of Murray [A. J. Murray, Phys. Rev. A 72, 062711 (2005)]. It is observed that there are certain discrepancies between theoretical and experimental results which indicate that further theoretical efforts are required to understand the cross section trends of neon, argon, and sodium atoms. The cross section in the perpendicular plane ionization exhibits complex variations as a function of incident energy and target.