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

Abstract

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.

Fragmentation mechanisms of cytosine, adenine and guanine ionized bases

“…Sequential HCN loss observed for the adenine cation supports the theory of adenine formation by HCN oligomerization. 31 This work shows the interest of (DFT) calculations for the interpretation of mass spectra of DNA bases through a thorough analysis of the involved fragmentation processes.…”

“…Mainly resulting from the localised interaction of ionizing radiation with the electrons of the molecular system (a few femtosecond time scale) energy deposition induces molecular bond cleavage. Numerous experimental studies investigated this process in the gas phase by photoionization, [6][7][8] electron impact, [9][10][11][12][13][14][15][16][17][18][19][20] photon impact [21][22][23][24][25][26] and ion impact [27][28][29][30][31] followed by mass spectroscopy to record and track fragments. Moreover, proton impact experiments evidence different fragmentation branching ratios for electron-capture induced ionisation and for direct ionisation.…”

Degradation of Adenine on the Martian Surface in the Presence of Perchlorates and Ionizing Radiation: A Reflectron Time-of-flight Mass Spectrometric Study

“…The proposed decomposition mechanism of the irradiated neat adenine (C 5 H 5 N 5 ) is shown in Figure 3. According to earlier decomposition studies (Rice & Dudek 1967;Schwell et al 2006;Chen et al 2011;Minaev et al 2014), the first step of the adenine molecule decomposition is the cleavage of the N(1)-C(6) and C(2)-N(3) bonds resulting in the loss of a hydrogen cyanide (HCN) molecule. This latter species may then take part in a nucleophile substitution on carbon atoms C(2) and/or C(8) of another intact adenine molecule yielding 2-cyano adenine (II, C 6 H 4 N 6 ) and 8-cyano adenine (III, C 6 H 4 N 6 ) or might even lead to the eventual formation of 2, 8-dicyano adenine (IV, C 7 H 3 N 7 , Evans et al 2011).…”

“…It is important to note that II and III are detected precursors in prebiotic adenine formation (Voet & Schwartz 1983;Miller & Cleaves 2007). The other irradiation product of the hydrogen cyanide loss is 1H-5-aminoimidazol-4carbonitrile (I, C 4 H 4 N 4 , formally the tetramer of HCN), which can further lose a carbodiimide (HNCNH) after the breakage of the N(1)-C(5) and N(3)-C(4) bonds to form the radical H 2 C 3 N 2 (Rice & Dudek 1967;Schwell et al 2006;Chen et al 2011;Minaev et al 2014). The carbodiimide can quickly rearrange into its more stable tautomer cyanamide (H 2 N-C≡N, Maier et al 1996) and can be detected via the PI-ReTOF-MS method.…”

Excitation of L-valine molecules by electrons and photons

“…The first one is related to mass spectrometric experiments, in which electrons with an energy of 70-100 eV are used to ionize bioorganic molecules. Among such works on the determination of the mass spectra of molecules that make up amino acids should be mentioned: thymine [15], adenine [16][17][18], cytosine [18], uracil [19], guanine [20], valine [21], and glutamine and glutamic acid [22]. Another line of research is the study of elementary processes of excitation, dissociation and ionization of such molecules under the impact of electrons and photons [22][23][24][25][26].…”