The triple differential cross section for the ionization of hydrogen atoms under electron impact

1984 ◽  
Vol 62 (10) ◽  
pp. 968-972 ◽  
Author(s):  
A. S. Ghosh ◽  
P. S. Mazumdar ◽  
Madhumita Basu
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Reasonable Agreement ◽  
Ionization Cross Section ◽  
Orbital Method ◽  
Distorted Wave ◽  
Hydrogen Atoms ◽  
Ionization Cross ◽  
Triple Differential Cross Section ◽  
Theoretical Predictions

The triple differential ionization cross section (TDCS) in electron–hydrogen scattering has been calculated using a distorted wave polarized orbital method. The present TDCS results at 100 and 113.6 eV are in reasonable agreement with the measured values of Weigold et al. and the theoretical predictions of Smith. Winters, and Bransden.

Positron-impact ionization of hydrogen atoms

1985 ◽  
Vol 63 (5) ◽  
pp. 621-624 ◽  
Author(s):  
A. S. Ghosh ◽  
P. S. Majumdar ◽  
Madhumita Basu
Keyword(s):  
Cross Section ◽  
Ionization Cross Section ◽  
Impact Ionization ◽  
Orbital Method ◽  
Distorted Wave ◽  
Positron Impact ◽  
Hydrogen Atoms ◽  
Ionization Cross ◽  
Channel Wave ◽  
Final Channel

The ionization cross section of hydrogen atoms by positron impact has been calculated by using a distorted-wave polarized-orbital method. We have employed two models depending on the choice of the final-channel wave function, and the two sets of results differ dramatically. We have also found that below 100 eV the total positron-impact ionization cross section including positronium formation is appreciably larger than the corresponding results for electron-impact ionization.

scholarly journals Ionisationsquerschnitt von OV gegenüber Elektronenstoß unter teilweiser Berücksichtigung des Austauschs

1961 ◽  
Vol 16 (6) ◽  
pp. 583-598 ◽  
Author(s):  
F. B. Malik ◽  
E. Trefftz
Keyword(s):  
Angular Momentum ◽  
Kinetic Energy ◽  
Cross Section ◽  
Ionization Energy ◽  
Total Angular Momentum ◽  
Ionization Cross Section ◽  
Wave Method ◽  
Distorted Wave ◽  
Ionization Cross ◽  
Distorted Wave Method

The ionization cross-section of highly ionized oxygen, O4+, is calculated according to the “distorted-wave” method. Exchange between the scattered and the ejected electron is taken into account as far as it is of long range nature. It is shown that contributions of high total angular momentum L are essential, L=0 giving only 3% of the total cross-section. This result should qualitatively be the same for all highly ionized atoms, whereas the following seems to be a special feature of O V ionization: for energies around twice the ionization energy the contributions of the optically allowed transitions of the ejected electron (angular momentum lej=1) are relatively small. The contributions of lej =0, 1, 2 and 3 are about 16%, 18%, 24% and 19% respectively for E=20.13.6 eV=2.39 × Ionization energy. The maximum cross section is 0.112 at. u. = 0.31 ·10-18 cm2 for electrons of 310 eV kinetic energy (2.8 × ionization energy). It is about twice as large as given by the ELWERT formula.

Inner shell (e, 2e) processes

1996 ◽  
Vol 74 (11-12) ◽  
pp. 804-810 ◽  
Author(s):  
Colm T. Whelan ◽  
J. Rasch ◽  
H. R. J. Walters ◽  
S. Keller ◽  
H. Ast ◽  
...  
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Relativistic Effects ◽  
Distorted Wave ◽  
Geometrical Arrangement ◽  
Triple Differential Cross Section ◽  
Large Atom ◽  
Physical Effects ◽  
Coincidence Measurements ◽  
Shell Ionization

The great advantage of coincidence measurements is that by suitable choice of the kinematical and geometrical arrangement one may probe delicate physical effects that would be swamped in less differential experiments. The calculation of the triple-differential cross section for the inner shell ionization of high-Z elements at relativistic energies presents a serious challenge to theory. Relativistic effects enter in both the kinematics and the nature of the target, and the large atom exerts a strong distorting influence. We consider such processes in a range of geometries and kinematics. We report the results of fully relativistic distorted wave calculations. Results are presented for silver, gold, and uranium targets and suggestions for further experimental arrangements proposed where delicate relativistic effects should be readily detectable.

A measurement of the electron impact ionization cross section of atomic hydrogen in the metastable 2S state

1975 ◽  
Vol 343 (1634) ◽  
pp. 333-349 ◽  
Keyword(s):  
Electric Field ◽  
Electron Energy ◽  
Cross Section ◽  
Cross Sections ◽  
Ionization Cross Section ◽  
Impact Ionization ◽  
Weak Field ◽  
Weak Electric Field ◽  
Hydrogen Atoms ◽  
Ionization Cross

The total ionization cross section for electrons colliding with metastable 2S atoms has been measured up to 500 eV electron energy by a crossed beam technique. A beam of fast hydrogen atoms, containing about 25% in the 2S state and the rest in the IS ground state, is formed by charge capture onto protons that are passed through a caesium vapour target. Protons emerging from the target are removed from the beam by deflexion in a weak electric field. Atoms formed by capture into long-lived, high quantum states are first ionized in a topographically suitable field and then removed by deflexion in the weak field. The signal arising from electron ionization of the 2S atoms is identified by quenching them in a pulsed electric field. Contributions from other sources of extraneous ionization are eliminated by modulated beam techniques. The cross sections are determined from absolute measurements of the beam fluxes, the geometry of the interaction region and the rate at which 2S atoms are ionized. The results show that as the electron energy is raised, the ionization cross section for 2S atoms rises to a maximum at about 4 times the ionization energy of the 2S state. This maximum, about 10 -15 cm 2 , is 13 times larger than th at of the IS atoms. Comparison with various theoretical determinations indicates th at best agreement is obtained with the Born approximation which includes exchange, but below 100eV the classical Monte Carlo approximation agrees equally well with observations.

scholarly journals The convergence of electron collisional ionization cross-section computations for atoms and ions in distorted-wave approximation

2018 ◽  
pp. 1-24
Author(s):  
Boris Nikolaevich Chetverushkin ◽  
Vladimir Anontol’evich Gasilov ◽  
Mikhail Evgenievich Zhukovsky ◽  
Vasily Sergeevich Zakharov ◽  
Mikhail Borisovich Markov
Keyword(s):  
Cross Section ◽  
Ionization Cross Section ◽  
Distorted Wave ◽  
Ionization Cross ◽  
Wave Approximation ◽  
Collisional Ionization

scholarly journals Schwinger Variational Calculation for Ionisation of Hydrogen Atoms by Electrons

1994 ◽  
Vol 47 (6) ◽  
pp. 751 ◽  
Author(s):  
JN Das ◽  
A Dey ◽  
K Chakrabarti
Keyword(s):  
Variational Principle ◽  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Variational Calculation ◽  
Hydrogen Atoms ◽  
Triple Differential Cross Section ◽  
High Energies ◽  
Schwinger Variational Principle

The Schwinger variational principle has been used to calculate the triple differential cross section for ionisation of hydrogen atoms by electrons at intermediate and high energies for Ehrhardt-type asymmetric geometry. The results are somewhat better in the recoil peak regions compared with those of the second Born and other similarly successful calcula

scholarly journals Investigating Inner Shell Ionisation via the (e, 2e) Technique

1998 ◽  
Vol 51 (4) ◽  
pp. 679 ◽  
Author(s):  
Birgit Lohmann ◽  
S. J. Cavanagh ◽  
M. A. Haynes ◽  
I. Taouil ◽  
A. Duguet ◽  
...  
Keyword(s):  
Binding Energy ◽  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Valence Shell ◽  
Distorted Wave ◽  
Triple Differential Cross Section

The (e, 2e) technique has been applied successfully to valence shell ionisation of many targets, but studies of inner shell ionisation by this technique have been limited. The triple differential cross section for the latter process exhibits behaviour which is very different to that observed for valence shell ionisation, particularly when the energy of the slow ejected electron is decreased below the binding energy of the inner shell orbital. Our recent results for inner shell ionisation of argon and krypton will be discussed, and comparisons made with distorted wave calculations.

scholarly journals Distortion of the Ionization Cross Section of He by the Coherence Properties of a C6+ Beam

Atoms ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 31 ◽  
Author(s):  
Francisco Navarrete ◽  
Raúl Barrachina ◽  
Marcelo Ciappina
Keyword(s):  
Cross Section ◽  
Born Approximation ◽  
Qualitative Agreement ◽  
Ionization Cross Section ◽  
Distorted Wave ◽  
Initial State ◽  
Ionization Cross ◽  
Final State ◽  
Refined Method ◽  
Rigorous Procedure

We analyze the influence of the coherence of the projectile’s beam in scattering phenomena. We focus our study in the ionization of He by C 6 + projectiles at 100 MeV/amu. We assess the influence of this effect by performing a Born initial state and continuum distorted wave final state (CDW-B1) calculation together with a rigorous procedure to account for the initial coherence properties of the projectile’s beam. These calculations, which had been previously performed for only the scattering and perpendicular collision planes and within the First Born approximation (FBA), were repeated for an ampler set of collision planes. Additionally, a more refined method to describe the applicability of the aforementioned procedure, is used. We achieve a better qualitative agreement with the experimental results.

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