Electron–hydrogen-atom ionization collisions at intermediate (5I0–20I0

Abstract

Triple-differential cross sections for ionization of hydrogen atoms by electrons have been calculated both for small-as well as large-momentum-transfer cases at intermediate (5I0 -20I0) and high { & 20I0) energies (I0 being the ionization potential) following a method which uses a final-channel three-particle wave function determined by one of the authors. This wave function resulted from an analysis of the three-particle wave equation in momentum space and is correct to the first order in the interaction potentials. Incidentally, it is also the first-order Faddeev wave function. The wave function has been suitably normalized before it is used. The computed results are generally good. The small-momentumtransfer results are in nice agreement with the experimental data except for a certain angular region which includes the recoil peak. The domain over which the present results agree in trend with the experimental measurements is somewhat larger than that for the distorted-wave-Born-approximation calculation. Large-momentum-transfer results are also in qualitative agreement with experiments. There are indications that quantitatively the present results may be better there. Total-ionization cross-section results are also in excellent agreement with experiment above 200-eV energy. These facts together with the simplicity of the calculation establish that the present method has certain advantages over other existing methods. The present calculation may be the starting point for a more elaborate calculation which will take into account more accurately the correlation and higher-order effects in the final-channel three-particle wave function.PACS number(s): 34.80.0p

Electron Impact Ionisation of Metastable 2s-state Hydrogen Atoms

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AbstractThe triple differential cross section for ionisation of hydrogen atoms in the metastable 2s-state by electrons of 250 eV incidence energy has been calculated following the multiple scattering theory of Das and Seal (1993). The results are compared with the first Born results and with the results of some other theories.

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The First Born Triple Differential Cross-Section for Ionization of H(3P) by Electron Impact in the Asymmetric Coplanar Geometry

“…The multiple scattering theory of ionization of hydrogen atoms by electrons is described in detail [10] [16] [17] [20] and [30]. Here we will describe the method very briefly, for the particular case of hydrogenic 3P-state at intermediate and high energies.…”

“…Presently we have quantum mechanically discussed the TDCS of the metastable 3P-state hydrogen atom by electrons considering at intermediate and high energies due to the multiple scattering theory of Das [9] and Das and Seal [10] which also has important effects on other metastable atomic hydrogen. Though there is the scarcity of any theoretical and experimental results on TDCS for ionization of hydrogen atoms by electrons from metastable 3P-state, the present First Born results for ionization from the 3P-state may also be expected to be good, interesting and significant.…”

Energy Spectrum of Ejected Electrons of H(2P) Ionization by Electrons in Coplanar Asymmetric Geometry

“…Here we have studied the energy spectrum for hydrogenic metastable 2P state at 250eV and 500eV incident energies. Here we also use the earlier method of Das and Seal [21]. This theory [21] has been successfully used in the study of energy spectrum of ejected electrons for ionization of ground state hydrogen atoms [20] and medium-heavy atoms by relativistic electrons [22][23].…”

“…Here we also use the earlier method of Das and Seal [21]. This theory [21] has been successfully used in the study of energy spectrum of ejected electrons for ionization of ground state hydrogen atoms [20] and medium-heavy atoms by relativistic electrons [22][23]. Recently Dhar and Nahar [24][25] calculated triple differential cross sections for ionization of metastable 2P-State hydrogen atoms by electron impact for coplanar asymmetric geometry using the multiple scattering theory of Das and Seal [21].…”