Fragmentation of the adenine and guanine molecules induced by electron collisions

Journal Article · Wed May 07 04:00:00 EDT 2014 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4871881· OSTI ID:22252959

Shafranyosh, M. I.; Svida, Yu. Yu; Sukhoviya, M. I.; Shafranyosh, I. I. ^[1]; Baryshnikov, G. V.; Minaeva, V. A. ^[2]

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1. Uzhgorod National University, 88000 Uzhgorod (Ukraine)
2. Bohdan Khmelnitsky National University, 18031 Cherkasy (Ukraine)

Secondary electron emission is the most important stage in the mechanism of radiation damage to DNA biopolymers induced by primary ionizing radiation. These secondary electrons ejected by the primary electron impacts can produce further ionizations, initiating an avalanche effect, leading to genome damage through the energy transfer from the primary objects to sensitive biomolecular targets, such as nitrogenous bases, saccharides, and other DNA and peptide components. In this work, the formation of positive and negative ions of purine bases of nucleic acids (adenine and guanine molecules) under the impact of slow electrons (from 0.1 till 200 eV) is studied by the crossed electron and molecular beams technique. The method used makes it possible to measure the molecular beam intensity and determine the total cross-sections for the formation of positive and negative ions of the studied molecules, their energy dependences, and absolute values. It is found that the maximum cross section for formation of the adenine and guanine positive ions is reached at about 90 eV energy of the electron beam and their absolute values are equal to 2.8 × 10{sup −15} and 3.2 × 10{sup −15} cm{sup 2}, respectively. The total cross section for formation of the negative ions is 6.1 × 10{sup −18} and 7.6 × 10{sup −18} cm{sup 2} at the energy of 1.1 eV for adenine and guanine, respectively. The absolute cross-section values for the molecular ions are measured and the cross-sections of dissociative ionization are determined. Quantum chemical calculations are performed for the studied molecules, ions and fragments for interpretation of the crossed beams experiments.

• OSTI ID: 22252959
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 17 Vol. 140; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ADENINES
ANIONS
CATIONS
DNA
ELECTRON BEAMS
ELECTRON COLLISIONS
ELECTRON EMISSION
ENERGY DEPENDENCE
ENERGY TRANSFER
FRAGMENTATION
GUANINE
IONIZATION
MOLECULAR BEAMS
MOLECULAR IONS
PEPTIDES
RADIATION EFFECTS
SACCHARIDES
TOTAL CROSS SECTIONS