Cross sections for positron and electron collisions with an analog of the purine nucleobases: Indole



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Chiari, Luca and Zecca, Antonio and Blanco Ramos, Francisco and García, Gustavo and Brunger, M.J. (2015) Cross sections for positron and electron collisions with an analog of the purine nucleobases: Indole. Physical review A, 91 (1). ISSN 1050-2947

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Quantitative information about positron and electron collisions with nucleobases is required in charged-particle track simulations to accurately model and assess any radiation damage at the subcellular level in biological systems. However, scattering experiments have so far been restricted to the pyrimidine nucleobases. In this paper we report on total-cross-section measurements for positron impact on indole, a parent molecule of the purine nucleobases, at impact energies between 1 and 25 eV. We also present theoretical cross sections for elastic and total scattering, positronium formation, electronic excitations, and direct ionization between 1 and 500 eV, as calculated with the independent-atom model with the screening-corrected additivity rule. Rotational excitation cross sections are additionally calculated within a Born framework over that same energy range. A significant discrepancy is found between the measured and computed total cross sections, which cannot be entirely accounted for by the lack of forward-angle-scattering discrimination in the experiment. The present results are also compared to the available theoretical cross sections for the purine nucleobases. In addition, total cross sections for electron-indole collisions computed within our theoretical formalism are provided.

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©2015 American Physical Society
The experimental work was undertaken under a Memorandum of Understanding between the University of Trento and the Flinders University node of the Australian Research Council Centre of Excellence for Antimatter-Matter Studies. G.G. and F.B. would like to acknowledge the Spanish Ministerio de Economía y Productividad (Project No. FIS2012-31230) and the European Science Foundation (COST Action Grants No. MP1002−Nano-IBCT and No. MC1301-CELINA) for financial support.

Uncontrolled Keywords:Low-energy-electron; RNA bases; Ionization-potentials; Noble-gases; Scattering; DNA; Molecules; Spectroscopy; Pyrimidine; Spectrum
Subjects:Sciences > Physics > Nuclear physics
ID Code:29242
Deposited On:16 Apr 2015 12:13
Last Modified:10 Dec 2018 14:57

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