Ionization of N2 in collisions with fast electrons: Evidence of an interference effect

Abstract

<style type="text/css">p { margin-bottom: 2.47mm; line-height: 120%; }</style><p style="margin-bottom: 0mm; line-height: 100%;"><font face="serif"><font size="2" style="font-size: 10pt;">Absolutedouble differential cross sections (DDCS) of electron emission weremeasured for ionization of N<font size="1" style="font-size: 6pt;">2 </font>by fast electrons with energy 7 keV. Measurements wereperformed for different electron emission angles and energies.Evidence of oscillation due to Young-type interference was observedin the DDCS ratios for all angles. The frequency for large backwardangle is found to be larger compared to that for small forward angle.Consequently, the forward-backward asymmetry parameter reveals theoscillatory structure even more clearly. The oscillations observedfor both experimental-to-heoretical DDCS ratios and forward-backwardasymmetry were well explained by the Cohen-Fano model of interferencein a molecular double slit. A periodic deviation of the Cohen-Fanomodel from the asymmetry parameter data reveals the presence of ahigher-frequency</font></font><font face="serif"><font size="2" style="font-size: 10pt;"> component.The first Born model was employed to explain the results of molecularnitrogen for which a complete-neglect-of-differential-overlapapproximation was used along with an effective atomic number.</font></font></p>