On the Calculations of Electron Impact Ionization Cross-Sections for Selected Nucleosides and Deoxyribose Molecules

Total cross-sections for the single electron impact ionization of deoxyribose (C5H10O4), Uridine (C9H12N2O6), Thymidine (C10H14N2O5), Cytidine (C9H13N3O5), Adenosine (C10H13N4O4), and Guanosine (C10H13N5O5) have been calculated using the binary-encounter-Bethe model from the first ionization threshold up to 4 keV. Electronic structure calculations of the studied targets have been performed at the Hartree–Fock (H-F) level using quantum chemical methods, including the outer valence Green function (OVGF) method, in order to obtain all the necessary physical input parameters for the BEB method. The possibility and feasibility of estimating the ionization cross-sections of larger DNA building blocks, such as nucleosides, based on the sum of the ionization cross-sections of DNA bases and simple sugar analogs, such as α-tetrahydrofurfuryl alcohol or deoxyribose, are also discussed.