Electron, Positron and Positronium scattering by molecules: Free Electron Gas Approximations

Free Electron Gas (FEG) approximations to the exchange and correlation interactions have long been used in electron scattering by atoms and molecules [1,2]. More recently we developed a FEG model for the exchange and correlation potentials describing the Positronium (Ps)-atom or molecule interaction [3]. This FEG model was applied to Ps-N₂ scattering and successfully reproduced resonant features that were seen experimentally near the Ps-ionization threshold. In this work we apply our FEG model to Ps-O₂ and Ps-CO₂ scattering. For these targets we also see resonance structures in the elastic cross section near the ionization threshold. Lastly, we apply the correlation potential of [2] to positron scattering by the same molecular targets with the purpose of calculation of Ps break-up in the binary-encounter approximation.

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