Theoretical study of interference effects in single electron ionization of N _2 molecules by proton impact

摘要

Single ionization of diatomic molecules due to the impact of fast proton beams is theoretically studied. The main interest is focussed on the analysis of the possible existence of interference patterns in the corresponding electron spectra due to coherent emission from the vicinities of the molecular centres. The case of N _2 targets is considered. A fully coplanar geometry in which the emitted electron, the incident particle and the molecule are all in the same plane is considered. The dynamics of the reaction is described within the continuum distorted wave-eikonal initial state model, and in the exit channel a two-effective centre approximation is employed. It is shown that fingerprints of coherent electron emission appear in the corresponding angular distributions. Also, double differential cross sections as a function of the energy and of the angle of the ionized electron, obtained by averaging the angular spectra over all molecular orientations, are calculated. Electron emission in opposite phases is found for the two inner 1sσ _g- and 1sσ* _u-orbitals, according with their gerade and ungerade character.