Heterocyclic Molecules’ Fragmentation Due to the Capture of a Single Electron by Doubly Charged Ions

The fragmentation processes of adenine (Ade, C₅H₅N₅) and cyclodiglycine (DKP, C₄H₆N₂O₂) ions formed in capturing a single electron during the interaction of molecules in the gas phase with C²⁺ and O²⁺ ions with an energy of 12 keV are studied by time-of-flight mass spectrometry. The experimentally observed dependence of the relative fragmentation cross section of molecular ions on the type of projectile is qualitatively explained within the framework of the quasi-molecular model. Using the multiconfiguration method of a self-consistent field in a complete active space (CASSCF), the fragmentation reaction paths of Ade⁺ and DKP⁺ ions are calculated. The calculated energy values of the appearance of fragments are in close agreement with the available experimental data.