Electron-capture Process Induced by Bare Ion Impact on Biological Targets

Abstract

Within the framework of independent electron approach, the prior form of boundary corrected continuum intermediate state (BCCIS) approximation is employed to calculate the cross sections for total single electron capture in collision of bare ions (H + , He 2+ and Li 3+ ) with biological molecules in the intermediate to high energy regimes. With a suitable choice of the distorting potential, the boundary condition is satisfied with a proper account of the intermediate continuum states. The cross sections have been calculated from 25 keV/amu to 10 MeV/amu. We have approximated the cross sections for molecular targets by the linear combination of atomic cross sections weighted by the effective occupation electron number. Furthermore, the multi-electronic problem is reduced to a mono-electronic one using a version of the independent electron approximation. A detailed analysis on the contributions from different molecular orbitals to total cross sections is reported. In the present investigation, we observe clearly the importance of the core contribution in the change of slope of the TCS curves. Moreover, analysis has been made on the cross section per target electron resulting in achievement of a 'universal' cross section. However, some negligible discrepancies are observed for the case of the CH 4 molecule. The present computed results in prior from of BCCIS method have been compared with the available theoretical and experimental results. We found that our computed results are in good agreement with the experimental findings.

Net Electron Capture in Collisions of Multiply Charged Projectiles with Biologically Relevant Molecules

“…At energies above 100 keV where both our IAM calculations merge they fall in-between the CDW and CDW-EIS results of Champion et al [39]. The distorted-wave CNDO calculations of Purkait et al [40,41] cross the CDW results, while being lower below 100 keV and higher above the transition point in energy where the IAM-AR and IAM-PCM results merge. At low energies the IAM-PCM results are clearly the lowest by about a factor of three.…”

“…At low energies the IAM-PCM results are clearly the lowest by about a factor of three. The experimental data are from Reference [38], the other theoretical data are from References [39][40][41]. A lower bound for the experimental uncertainties (not shown) can be estimated from the electron capture branching ratio (shown in Figure 1 of Reference [38]) to be on the order of 20% at the lowest energy and a few percent at the highest energies.…”