Gorfinkiel, JimenaLimão-Vieira, PauloLoupas, Alexandra Cristina Rodrigues2020-02-262020-02-2620192019http://hdl.handle.net/10362/93349This thesis is focused on the application of the R-matrix method, as implemented in the UKRmol and UKRmol+ suites, to study low-energy electron collisions with three medium-sized molecules of biological relevance: para-benzoquinone, thiophene and alanine. Our goals for all the targets are mainly three: (i) to identify and characterize respective resonances; (ii) to calculate elastic and inelastic integral and elastic differential cross sections; and (iii) compare our results with the literature. To do so, we use several scattering models, choosing the most suitable on the basis of the characteristics being investigated: Static Exchange, Static Exchange plus Polarization and/or Close-Coupling approximation. Specially at higher energies, we find an unexpectedly large number of resonances for the three targets, most of them of core-excited and core-excited shape character. We compare our results with other calculations and/or experiments in the literature, but the absence of detailed experimental results for many targets at these energies precludes a meaningful comparison. Nonetheless, three scenarios are then obtained: in the first one, for para-benzoquinone, the agreement with previous results is satisfactory; in the second, for thiophene, is excellent; and finally, for alanine, there is not much prior information on the literature to make decisive conclusions. This work was all published in peer-reviewed journals.engLow-energy electron-collisionselastic and inelastic scatteringR-matrix methodorganic moleculesdoctoral thesis101654421