Low energy positron interactions with uracil—Total scattering, positronium formation, and differential elastic scattering cross sections

Anderson, E. K.; Boadle, Roisin; Machacek, Joshua; Chiari, Luca; Makochekanwa, Casten; Buckman, Stephen; Brunger, M. J.; Garcı́a, Gustavo; Blanco, F.; Ingólfsson, Oddur; Sullivan, James P.

doi:10.1063/1.4887072

Cited by 24 publications

(22 citation statements)

References 27 publications

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“…However, the situation with respect to positron scattering is somewhat poorer, with only a limited number of measurements [20,[25][26][27] and calculations [27][28][29][30] being available. In particular, we note that both the experimental and theoretical effort was largely dedicated to the investigation of the pyrimidine bases, such as pyrimidine itself [20,26,30] and uracil [25,27]. Indeed, there is only one computation for positron impact with the purine bases [29], namely, adenine and guanine, and no measurements to validate that calculation.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2015

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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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Section: Introductionmentioning

confidence: 99%

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

et al. 2015

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“…We did not apply any correction for the angular descrimination to the experimental data and the partial pressure of uracil in the experimental setup is not clear. The agreement is much better between our computed data and the measured data of Anderson et al [22]. A direct comparison has not been done, because both manuscript have been published around the same time.…”

Section: Data Sourcesmentioning

confidence: 55%

“…Below collision energies of 10 eV the agreement is usually within 10 per cent. Cross sections for positron collision with gas-phase uracil have been measured by Surdutovich et al [21] at Detroit and by Anderson et al [22] at ANU. In Franz et al [11] we compare our computed cross section with the experimental data from Surdutovich et al [21].…”

Section: Data Sourcesmentioning

confidence: 99%

The POCOBIO Database for Computed Scattering Cross-Sections for Positron Collisions with Biomolecular Systems

Franz

2017

Acta Phys. Pol. A

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“…However, owing to large uncertainties in the target number density in hot cells (e.g., Ref. [95]) it is likely that only relative cross sections could be measured for the metal targets.…”

Section: Discussionmentioning

confidence: 99%

Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms

Swann¹,

Cassidy

Deller

et al. 2016

Phys. Rev. A

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Predicted twenty years ago, positron binding to neutral atoms has not yet been observed experimentally. A new scheme is proposed to detect positron-atom bound states by colliding Rydberg positronium (Ps) with neutral atoms. Estimates of the charge-transfer reaction cross section are obtained using the first Born approximation for a selection of neutral atom targets and a wide range of incident Ps energies and principal quantum numbers. We also estimate the corresponding Ps ionization cross section. The accuracy of the calculations is tested by comparison with earlier predictions for Ps charge transfer in collisions with hydrogen and antihydrogen. We describe an existing Rydberg Ps beam suitable for producing positron-atom bound states and estimate signal rates based on the calculated cross sections and realistic experimental parameters. We conclude that the proposed methodology is capable of producing such states and of testing theoretical predictions of their binding energies.

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Low energy positron interactions with uracil—Total scattering, positronium formation, and differential elastic scattering cross sections

Cited by 24 publications

References 27 publications

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

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

The POCOBIO Database for Computed Scattering Cross-Sections for Positron Collisions with Biomolecular Systems

Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms

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