Anomalous dissociative capture cross section at the interaction of singly charged ions with molecules of nucleic acid bases

The single electron capture process from adenine molecules by H$^+$, $^3$He$^+$, N$^+$, O$^+$, and Ne$^+$ ions with an energy of 6.3 keV has been studied. It was found that when one electron is captured by He$^+$ and Ne$^+$ ions, the dissociative capture process is dominant, which is fundamentally different from the processes of capture by singly charged ions of atoms with a lower ionization potential and multiply charged ions, as well as from the process of electron impact ionization. This effect is qualitatively explained within the framework of a quasimolecular model.