Fragmentation of singly charged adenine induced by neutral fluorine beam impact at 3 keV.

The fragmentation scheme of singly charged adenine molecule (H(5)C(5)N(5)(+)) has been studied via neutral fluorine impact at 3 keV. By analyzing in correlation the kinetic energy loss of the scattered projectile F(-) produced in single charge transfer process and the mass of the charged fragments, the excitation energy distribution of the parent adenine molecular ions has been determined for each of the main dissociation channels. Several fragmentation pathways unrevealed in standard mass spectra or in appearance energy measurements are investigated. Regarding the well-known hydrogen cyanide (HCN) loss sequence, we demonstrate that although the loss of a HCN is the dominant decay channel for the parent H(5)C(5)N(5)(+) (m = 135), the decay of the first daughter ion H(4)C(4)N(4)(+) (m = 108) involves not only the HNC (m = 27) loss but also the symmetric breakdown into two dimers of HCN.