Electron emission in ionization of He and Ne by fast dressed oxygen ions and projectile-charge-state dependence

Abstract

The double-differential cross sections (DDCS) of low-energy electrons emitted at forward, backward, and perpendicular directions are reported for collisions of 3.75 MeV/u O q+ (q = 5, 6, 7, 8) projectiles with He and Ne targets. The measured DDCS are found to be deviating from the q 2 dependence throughout the entire energy region. The effect of projectile electrons, for the dressed ions, as a function of the impact parameter is clearly noticeable for large as well as low-impact parameter collisions. We also present a theoretical calculation based on the prior form of the continuum distorted wave-eikonal initial state approximation, in which the projectile-active electron interaction is modeled with the Green-Sellin-Zachor potential. This particular representation of the potential has been proven to give good qualitative results for projectiles with residual electrons. In addition to the total DDCS, the individual contributions from target ionization, projectile electron loss, and simultaneous ionization processes are also calculated. The total DDCS obtained from these calculations are shown to be in excellent agreement with the experimental observations.

Differential electron emission from polycyclic aromatic hydrocarbon molecules under fast ion impact

“…In the present experiment, electron DDCS measurements for coronene and fluorene molecules were carried out with 3.75 MeV/u O 8+ ions. The use of bare highly charged ions ensures to work in a strong perturbation regime as well as get rid of other complicated interactions 44 , 45 . The effusive vapour jets of coronene and fluorene molecules (99% pure, Sigma-Aldrich) were prepared by heating these at around 200 °C and 50 °C, respectively.…”

Triple differential cross sections for single ionization of an atom by bare ion impact

“…three-body problem in which involved charged particles interact via long-range Coulomb potentials. In this context, a lot of theoretical [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and experimental [18,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] investigations have been carried out for this collision process. For example, the first Born approximation (FBA) [6,20], the threebody distorted-wave (3DW) [37,38], the 3DW eikonal-initialstate (3DW-EIS) [27,39], the continuum distorted-wave EIS (CDW-EIS) [40,41], the nonperturbative impact-parameter coupled-pseudo state [42,43] approximations.…”

Electron emission from fluorene (C13H10) upon 3.5 MeV/u Si8+ ion impact: double differential distributions

“…Moreover, the double differential cross section of electron emission from atoms and molecules upon ion impact provides a stringent test to the various theoretical models in addition to the information about underlying processes. Although the multi-electronic, multi-particle description of the molecule poses a difficult challenge to the theory, various theoretical models have been successful to a great extent in modeling the electron emission from atoms and small molecules in such collisions [25][26][27][28][29][30][31][32]. Significant progress has also been made for large bio-molecules e.g.…”