Formation of ground and excited hydrogen atoms in proton–caesium inelastic scattering

2015 ◽  
Vol 93 (11) ◽  
pp. 1283-1291 ◽  
Author(s):  
S.A. Elkilany
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Transition Matrix ◽  
Reasonable Agreement ◽  
Total Angular Momentum ◽  
Computer Code ◽  
Hydrogen Atoms ◽  
Static Approximation ◽  
Total Cross Sections ◽  
First Time

The inelastic scattering of a proton with a caesium atom is treated for the first time as a three-channel problem within the framework of the improved coupled static approximation with the assumption that the ground (1s state) and excited (2s state) hydrogen formation channels are open for seven values of the total angular momentum, [Formula: see text] at energies between 50 and 500 keV. The Green’s function iterative numerical method is used to obtain the computer code to calculate iterative partial cross sections. This can be done through calculating the reactance matrix at different values of considered energies to obtain the transition matrix that gives partial and total cross sections. Present results give reasonable agreement with previous results.

Formation of ground and excited hydrogen atoms in proton–rubidium inelastic scattering

2016 ◽  
Vol 94 (4) ◽  
pp. 431-436
Author(s):  
S.A. Elkilany
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Incident Energy ◽  
Computer Code ◽  
Inelastic Collisions ◽  
Hydrogen Atoms ◽  
Total Cross Sections ◽  
Rubidium Atoms ◽  
Wide Range ◽  
First Time

Inelastic collisions of protons with rubidium atoms are treated for the first time within the framework of the three channel coupled static, and frozen core approximations. The method is used for calculating partial and total cross sections with the assumption that only three channels (elastic; non-excited hydrogen, 1s-state; and excited hydrogen, 2s-state) are open. We have used the Lipmann–Schwinger equation and the Green’s functions iterative numerical method technique to solve the derived coupled integro-differential equations to obtain the computer code. The present results for total hydrogen formation cross sections are in agreement with results of other available ones in a wide range of incident energy.

scholarly journals Formation of non-excited and excited hydrogen in proton–lithium inelastic scattering

2016 ◽  
Vol 94 (1) ◽  
pp. 75-78 ◽  
Author(s):  
S.A. Elkilany ◽  
A.A. Al-Dhawi
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Lithium Atom ◽  
Basis Functions ◽  
Hydrogen Formation ◽  
Electron Model ◽  
Static Approximation ◽  
Total Cross Sections ◽  
First Time ◽  
Good Agreement

The collisions of a proton with a lithium atom are treated for the first time as a three-channel problem under the assumption that the elastic and hydrogen formation in non-excited, H(1s), and excited, H(2s), channels are open. The effect of polarization potentials of the target and hydrogen formation is considered. A one-valence-electron model for the target, based on the Clementi–Roetti Slater-type basis functions, as well as a modified coupled-static approximation are used to calculate the partial and total cross sections of seven partial waves (0 ≤ ℓ ≤ 6, where ℓ is the total angular momentum) at incident energies between 50 and 500 keV. Our values of the total cross section are in good agreement with previous results.

POSSIBLE POSITRONIUM FORMATION IN THE COLLISIONS OF POSITRONS WITH CALCIUM AND STRONTIUM POSITIVE IONS

2009 ◽  
Vol 23 (11) ◽  
pp. 2535-2549
Author(s):  
SALAH YASEEN EL-BAKRY
Keyword(s):  
Cross Sections ◽  
Incident Energy ◽  
Total Angular Momentum ◽  
Inelastic Collisions ◽  
Positronium Formation ◽  
Ionization Threshold ◽  
Scattering Problems ◽  
Total Cross Sections ◽  
Positive Ions ◽  
First Time

The inelastic collisions of positrons with calcium and strontium positive ions are treated for the first time as a three-channel problem within the framework of the improved coupled-static and frozen-core approximations with the assumption that the elastic, ground positronium and excited-positronium formation channels are open. The calculations of the partial and total cross sections are carried out for eight values of the total angular momentum ℓ (0 ≤ ℓ ≤7), at 20 values of the incident energy lying above the excited positronium formation threshold and extending to a wide region above the ionization threshold of the target ion. The total collisional positronium formation cross sections of e+– Sr + scattering show a peak around the ionization threshold of Sr + but display a peak at 30 eV for e+– Ca + scattering. In both scattering problems the total excited Ps formation cross sections have considerable values in the energy range [Formula: see text].

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

Two-centre wavefunctions in the theory of electron scattering by hydrogen atoms

1975 ◽  
Vol 341 (1627) ◽  
pp. 491-515 ◽  
Keyword(s):  
Differential Equations ◽  
Cross Sections ◽  
Partial Wave Analysis ◽  
Charge Ratio ◽  
Orbital Method ◽  
Mathieu Function ◽  
Hydrogen Atoms ◽  
Numerical Work ◽  
Total Cross Sections ◽  
Theoretical Results

The scattering wavefunctions of the H – ion are expanded in a basis of two-centre wavefunctions with radial components. Two expansions are considered characterized by the charge ratio q being either – 1 or + 1. These expansions may be regarded as an extension of the polarized-orbital method. The q = + 1 expansion has some novel features. The radial components are determined as the solutions of a set of coupled radial differential equations. Imposition of exchange antisymmetry transforms these equations into integro-differential equations for the q = - 1 expansion, but for the q = + 1 expansion the equations remain simply differential. The cross-sections are determined by partial wave analysis, utilizing the Mathieu function form of the radial wavefunctions at moderately large values of R. Numerical work is reported based upon truncation of the q = + 1 expansion after two terms. Phase shifts derived from static and adiabatic q = + 1 potentials for the l = 0 - 7 partial waves are presented for 59 values of the energy between 0 and 13.6eV. The corresponding differential and total cross-sections are compared with experimental, and other theoretical results.

The Scattering of Positrons by Helium: Total Cross Sections up to 270 eV

1975 ◽  
Vol 53 (10) ◽  
pp. 962-967 ◽  
Author(s):  
B. Jaduszliwer ◽  
A. Nakashima ◽  
D. A. L. Paul
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Reasonable Agreement ◽  
Experimental Results ◽  
Formation Cross Section ◽  
Sum Rule ◽  
Total Cross Sections ◽  
High Energies

The total cross sections for the scattering of positrons by helium have been measured by the method of transmission in the 16 to 270 eV energy range. The experimental results are higher than those of Canter et al. but are in reasonable agreement with recent results of Griffith et al., and at high energies tend towards Born approximation calculations. The integral of the cross section over positron momentum is smaller than the sum rule estimate made by Bransden et al. A tentative value of (0.034 ± 0.017)πa02 is assigned to the positronium formation cross section at threshold.

Born Cross Sections for Inelastic Scattering of Electrons by Hydrogen Atoms. II.4s,4p,4d,4fStates

1960 ◽  
Vol 119 (1) ◽  
pp. 153-155 ◽  
Author(s):  
Leonard Fisher ◽  
S. N. Milford ◽  
Frank R. Pomilla
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Hydrogen Atoms

Born Cross Sections for Inelastic Scattering of Electrons by Hydrogen Atoms. III.5s,5p,5d,5f,5gStates

1960 ◽  
Vol 120 (5) ◽  
pp. 1715-1717 ◽  
Author(s):  
S. N. Milford ◽  
John J. Morrissey ◽  
Joseph H. Scanlon
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Hydrogen Atoms
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