Electron-impact ionization of the metastable Mg(...2p63s3p3P0,2) atoms

Abstract

Electron-impact ionization of Mg atoms from metastable states was investigated. The method and technique of crossed atomic and electron beam studies are described. The value of the total ionization cross section from the 3s3p P metastable states for 4 2 21 eV incident electron energy was determined. It was found that ionization cross sections from the metastable and ground states differ considerably. This is mainly due to the different mechanisms of ion formation from the metastable and ground states. The results obtained are compared with those calculated in the classical mechanics binary approximation.

Electron-impact ionization cross section for metastable Ca (3p64s4p3P0,2) atoms

“…The ground-state and metastable-state concentrations in the region of interaction of the atoms with the electron beam were determined by an absorption method. We shall not describe in detail the experimental technique since it was similar to that discussed elsewhere [1] except for certain modifications. These are as follows.…”

“…0953-4075/00/050905+06$30.00 © 2000 IOP Publishing Ltd (b) The method of production of the metastable Ca atom beam was modified in such a way that, contrary to [1], one did not require the introduction of an additional Na atom beam into chamber 2 (figure 1) in order to provide stable discharge (as was done in [1]). The ion detection and data processing systems were the same as in [1].…”

“…In our previous paper [1], we presented experimental results on electron-impact ionization studies of metastable Mg atoms. In order to elucidate the general regularities one requires to extend the ionization studies to other alkaline-earth metastable atoms, we discuss in this paper results on Ca atom ionization from the triplet metastable 3 P 0,2 states.…”

Diffusion superélastique des électrons sur les états métastables nsnp 3P0,2 des atomes de magnésium et de strontium

“…Pendant cette étude, les paramètres du faisceau d'atomes dans la région de son interaction avec le faisceau d'électrons étaient les suivants : les concentrations d'atome de Mg et de Sr en états métasta-bles nsnp correspondaient à 4 Â 10 9 cm -3 et à 5 Â 10 9 cm -3 , la divergence angulaire était égale à 8,7 Â 10 -2 rad (1 rad = 10 mGy). Les méthodes de l'obtention d'un faisceau d'atomes de Mg et de Sr en états métastables ainsi que la détermination de leurs concentrations sont décrites d'une manière plus détaillée dans les ouvrages [10,11].…”

“…La valeur de k pendant ces expériences changeait dans les limites entre 0,7 et 0,8. Les données pour la valeur s m i pour le magnésium et le strontium ont été tirées des travaux[10,11].…”