J. Peresse

Triple differential cross sections for low energy electron impact ionisation of helium

Abstract Measurements are reported of the triple differential cross sections for the ionisation of helium by electron impact. Data are presented for incident energies of 100 and 80.5 eV at several scattering angles and compared with previous measurements and theoretical calculations.

Triple differential cross section for autoionisation of helium by electron impact at 100 eV

Abstract Cross sections for autoionisation of helium by electron impact have been measured by an electron-electron coincidence technique at an incident electron energy of 100 eV and a scattering angle of 15°. The variation of the direct ionisation cross section and the resonance parameters for the (2 s 2 p ) 1 P autoionising level, as functions of ejected electron angle, are compared with the results of recent theoretical calculations.

Etude de l'energie des electrons ejectes au cours de l'ionisation penning de l'hydrogene moleculaire par les etats metastables 21S et 23S de l'helium

Abstract The authors report experiments on the Penning ionization of molecular hydrogen by metastable helium (21S and 23S states). The vibrational structure of the H2+ ion in the state X2Σg+ is resolved. The relative population of the three first vibrational levels is obtained. The authors also show that a continuum is superposed on the Penning ionization due to the autoionization process.

Etude de l'ionisation penning de l'hydrogene moleculaire mise en evidence d'une reaction secondaire

Abstract In this paper we try to elucidate the origin of the electron continuum background observed in Penning ionization of molecular hydrogen by helium metastables states 21S and 23S. Using mass-spectrometry studies we verify that this anomaly is not due to the presence of water in our apparatus. However, we found an H+3 ion which we believe is produced by the reaction: H ∗ 2 + H 2 → H + 3 + H + e leading to electronic emission.

Nouveaux processus d'ionisation du xenon par impacts d'electrons

Abstract Because of the large separation between the 2 P 3 2 and 2 P 1 2 levels of Xe + , we have observed several autoionisation processes between these two levels. We can emphasize that in the threshold region a great number of ions are created through autoionisation processes.

Mise en evidence de phenomenes d'autoionisation dans L'etude experimentale de l'ionisation du krypton par impacts d'electrons monoenergetiques

The authors report the ionization curve of krypton near threshold, obtained by monoenergetic electron bombardment. Autoionization processes between the 2P32 and 2P12 states of Kr+ are well displayed by that curve. New Processes have been obtained at 2.97, 4.50 and 7.92 eV above threshold. Although no excited state of Kr is spectroscopically known in the energy region, these processes might be due to auto-ionization of forbidden states.