Elastic positron-uracil scattering cross sections

Abstract

We report elastic integral and differential cross sections for positron collisions with uracil (${\mathrm{C}}_{4}{\mathrm{H}}_{4}{\mathrm{N}}_{2}{\mathrm{O}}_{2}$) for impact energies up to 10 eV. The cross sections were calculated employing the Schwinger multichannel (SMC) method in the static plus polarization approximation. The Born-closure procedure was applied to account for the long-range potential due to the permanent dipole moment of uracil. The present results are compared with experimental and theoretical data available in the literature, showing an overall good agreement with previously reported results. We also applied our differential cross sections to provide a correction to the total cross-section measurements by Anderson et al. [J. Chem. Phys. 141, 034306 (2014)] in order to account for the lack of angular resolution in the apparatus used by these authors. Besides, we applied a simple model employed by Franz and Gianturco [Phys. Rev. A 88, 042711 (2013)] to estimate the temperature effects on the uracil cross section. In particular, the level of agreement of the SMC differential cross sections as compared with the experimental findings is encouraging.