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In this work, we report theoretical electron capture cross sections for single-electron removal from molecules of biological interest and noble gases by bare ion (H + and H e 2+) impact at energies ranging from 25 to 10,000 keV/amu. We use a distorted wave (DW) method where the intermediate continuum state of the active electron with the target ion has been taken into account. This method is developed within the framework of the independent electron model taking particular care of the representation of the bound continuum target states. Two different approximations have been considered for molecular targets: molecular representation of the bound-state target wavefunction and Bragg's additivity rule. The molecular orbital for targets are described within the framework of the complete neglect of differential overlap (CNDO) method based on the linear combination of atomic orbital (LCAO) approximation. Using the DW method, we have also calculated the K-, Land M-shell electron capture in collisions of bare ions with three noble gases He, Ne, and Ar respectively. Contributions from different molecular orbitals and different shells to the total cross sections (TCS) are studied. The preference of electron capture occurs in accordance as the binding energy of the active electron in molecular orbital and atomic shell. The maximum contributions to TCS for SC comes from the less bound electrons in repetitive orbitals, whereas the tightly bound electrons dominate the TCS at higher projectile energy regime. Variation of TCS with impact energy are compared with the available experimental observation and other theoretical findings. We find that the present theoretical method is satisfactory in both intermediate and high-energy region for molecules as well as noble gas targets to give reliable outcomes compared to other theoretical methods.

Synopsis Distorted wave model has been used to predict total cross sections (TCSs) of single electron capture process for several ion-biological molecule collisional systems in the intermediate and high energy regime. TCSs are calculated in the Independent Electron Model (IEM) In this work, we studied with water, nitrogen, oxygen, methane, adenine or cytosine targets impacted by protons and α-particles with kinetic energy ranging from 25 keV/amu to 10,000 keV/amu. It is observed that the present investigation produces results which are in good agreement with experimental observations for all cases.

We present triple differential cross sections (TDCS) for single ionization of atoms by proton and highly charged bare ions impact by means of the three-body formalism of the fi rst Born, two-Coulomb wave and three-Coulomb wave methods, respectively. The TDCS has been calculated both in the scattering and perpendicular planes. The purpose of this work is to investigate the validity of different methods as well as the role of interaction between projectile and residual target-ion in the fi nal state for weak perturbation strength with low electron emission energy at several momentum transfers. By comparing our calculations with experimental data, overall, the 3CW predicts better agreement with experiments than other calculations in the scattering plane. In the perpendicular plane, all calculations deviate from experimental data with increasing transverse momentum transfer for p - He collision. At low momentum transfer, the location of binary peak obtained by the FBA calculation is well established with the experiment for proton impact. On the other hand, the 3CW model is in much better agreement with experiments, both in absolute values and peak position for highly charged impact. Finally, the strong influence of the inter nuclear Coulomb distortion on TDCS has been observed at low and intermediate momentum transfer.

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