New approach on molecular ionization by ion impact: the CDW-EIS-SVIM model

Abstract

We have extended the continuum distorted wave eikonal initial state approximation for single ionization of atoms by ion impact to the molecular case where a model potential for the molecular target is introduced. The continuum wavefunctions of the ejected electrons are then calculated in the static-exchange potential field generated by the residual molecular ion. The Schwinger variational iterative method was used in the calculation of these continuum wavefunctions. We apply this model to the single ionization of the hydrogen molecule (H 2 ) by different bare projectiles. Doubly differential cross sections are calculated and compared with available experimental data for intermediate impact energies.

CDW-EIS calculation for ionization and fragmentation of methane impacted by fast protons

“…Orthogonality requirement versus the quality of wavefunctions used in the treatments have been discussed for the case of atomic targets [45,46]. This issue has also been addressed for molecules [20]; however, its clarification needs further efforts, and one of the directions of our future studies is along this line.…”

“…However, the multi-centre or molecular character of collisions has been taken into account mostly for simple diatomic molecules. In [5,7,19], the two effective centre approximations were employed in the exit channel for molecules like H 2 , O 2 or N 2 , while in [20] for describing collision with H 2 , the Swinger variational iterative method was used to obtain the onecentre expanded molecular orbitals for H 2 . For more complex molecules, like CO 2 , H 2 O, CH 4 or the RNA basis uracil, the ionization cross section of a molecular orbital was calculated as a weighted sum of atomic cross sections [3,4,16].…”

Coherent electron emission from simple molecules by impact of energetic charged particles

“…We should note that within the perturbative framework the expressions above obtained are of general validity, being independent of the particular perturbative theoretical model used to calculate the scattering T -matrix element. Just to cite a couple of examples, in [25,26] a continuum distorted wave -eikonal initial state (CDW-EIS) approximation with the MO of the continuum calculated using a Schwinger variational iterative method is employed to study the single ionization of the hydrogen molecule by different bare heavy ions and in [28] triply differential cross sections (TDCS) and doubly differential cross sections (DDCS) for the single ionization of H 2 by proton impact, using the molecular three-body distorted-wave-eikonal initial-state (M3DW-EIS) approach, are presented. In addition, TDCS were calculated with a semiclassical version of the first-order Born approximation by Járai-Szabó et al [27].…”