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.

Elastic Scattering of Electrons by Helium Atoms at Intermediate Energies

1993 ◽  
Vol 48 (3) ◽  
pp. 465-468
Author(s):  
V. M. Chhaya ◽  
J. J. Tarwadi ◽  
Smita Chhag
Keyword(s):  
Elastic Scattering ◽  
Energy Range ◽  
Cross Sections ◽  
Differential Cross ◽  
Hydrogen Atoms ◽  
Helium Atoms ◽  
Intermediate Energies ◽  
Born Series ◽  
Electrons And Positrons ◽  
Theoretical Results

Abstract The unitarised Eikonal Born series (UEBS) method has been used successfully by Byron et al. for elastic scattering of electrons and positrons by hydrogen atoms. Here an attempt is made to apply the UEBS method in the case of elastic scattering of electrons by helium atoms. The total and differential cross sections are calculated for the energy range 100-700 eV. The results are compared with experimental and other theoretical results. It is found that the results obtained with the UEBS method agree best with the experimental results.

scholarly journals Total Electron Scattering Cross Sections of He, Ne, Ar, Kr and Xe in the Energy Range 100 eV to 10 000 eV

2009 ◽  
Vol 64 (9-10) ◽  
pp. 665-670
Author(s):  
Xiao-Ming Tan ◽  
Chuan-Lu Yang ◽  
Mei-Shan Wang ◽  
Zhi-Hong Zhang
Keyword(s):  
Energy Range ◽  
Electron Scattering ◽  
Cross Sections ◽  
Model Potential ◽  
Total Electron ◽  
Total Cross Sections ◽  
Optical Model Potential ◽  
Scattering Cross Sections ◽  
Experimental And Theoretical Studies ◽  
Theoretical Results

The total cross sections for electron scattering from He, Ne, Ar, Kr and Xe in the energy range from 100 eV to 10 000 eV have been calculated based on the optical-model potential. Our theoretical results are compared with the available experimental data. The consistency between them is also discussed. At higher energies (over 2000 eV for He, over 5000 eV for Ne, Ar, Kr and Xe), the total cross sections of electron scattering from these atoms are scarce, so our calculations will give a reference for further experimental and theoretical studies.

scholarly journals The role of N*(2120) nucleon resonance in KΛ(1520) photon and hadronic productions

2014 ◽  
Vol 29 ◽  
pp. 1460244
Author(s):  
Ju-Jun Xie ◽  
En Wang ◽  
Bo-Chao Liu ◽  
J. Nieves
Keyword(s):  
Experimental Data ◽  
Invariant Mass ◽  
Cross Sections ◽  
Dalitz Plot ◽  
Total Cross Sections ◽  
Effective Lagrangian ◽  
Hadronic Production ◽  
Current Experimental Data ◽  
Theoretical Results

The associate KΛ(1520) photon and hadronic production in the γp → K+Λ(1520), pp → pK+Λ(1520) and π-p → K0Λ(1520) reactions are investigated within the effective Lagrangian approach and the isobar model. We are interested in the contribution from the N*(2120) (previously called N*(2080)) resonance, which has a significant coupling to the KΛ(1520) channel. The theoretical results show that the current experimental data for the γp → K+Λ(1520) reaction favor the existence of the N*(2120) resonance, and that these measurements can be used to further constrain its properties. We present results, including the N*(2120) contribution, for total cross sections of the γp → K+Λ(1520), π-p → K0Λ(1520), and pp → pK+Λ(1520) reactions. For this latter one, we also calculate invariant mass and Dalitz plot distributions.

Absolute total cross sections for scattering of hydrogen atoms by argon, krypton and xenon

1972 ◽  
Vol 15 (2) ◽  
pp. 305-308 ◽  
Author(s):  
V. Aquilanti ◽  
G. Liuti ◽  
F. Vecchio-Cattivi ◽  
G.G. Volpi
Keyword(s):  
Cross Sections ◽  
Hydrogen Atoms ◽  
Total Cross Sections

The elastic scattering of slow positrons by hydrogen atoms

1964 ◽  
Vol 278 (1375) ◽  
pp. 479-489 ◽  
Keyword(s):  
Elastic Scattering ◽  
Hydrogen Atom ◽  
Differential Equations ◽  
Cross Sections ◽  
Hydrogen Atoms ◽  
Elastic Collisions

Cross-sections are calculated for the elastic collisions of slow positrons by hydrogen atom s by the use of an approximation in which virtual positronium production and polarization of the atom by the positron are allowed for, the latter by the method of polarized orbitals. The coupled integro-differential equations involved are solved by electronic computation. Very satisfactory results are obtained as judged by comparison with other methods.

scholarly journals Positron Impact Excitation of the nS States of Atomic Hydrogen

Atoms ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 9 ◽  
Author(s):  
Anand K. Bhatia
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Atomic Hydrogen ◽  
Impact Excitation ◽  
Orbital Method ◽  
Positron Impact ◽  
Excitation Cross Sections ◽  
Theoretical Results ◽  
Incident Positron

The excitation cross sections of the nS states, n = 2 to 6, of atomic hydrogen at various incident positron energies (10.23 to 300 eV) were calculated using the variational polarized-orbital method. Nine partial waves were used to obtain converged cross sections. The present results should be useful for comparison with results obtained from other theories and approximations. The positron-impact cross section was found to be higher than the electron-impact cross sections. Experimental and other theoretical results are discussed. The threshold law of excitation is discussed and the cross sections in this region were seen to obey the threshold law proportional to ( ln k f ) − 2 . Cross sections were calculated in the Born approximation also and compared to those obtained using the variational polarized orbital method.

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.

Measurements of total and (or) positronium-formation cross sections for positrons scattered by alkali, magnesium, and hydrogen atoms

1996 ◽  
Vol 74 (7-8) ◽  
pp. 313-333 ◽  
Author(s):  
T. S. Stein ◽  
J. Jiang ◽  
W. E. Kauppila ◽  
C. K. Kwan ◽  
H. Li ◽  
...  
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Positronium Formation ◽  
Projectile Energy ◽  
Hydrogen Atoms ◽  
Positron Energy ◽  
Total Cross Sections ◽  
Alkali Atoms ◽  
Low Energies

Recent developments in measurements of total and (or) positronium-formation cross sections for positrons (in the range of 1 to 300 eV) scattered by alkali, magnesium, and hydrogen atoms are reviewed. Measurements of total and positronium (Ps)-formation cross sections for positrons scattered by sodium, potassium, and rubidium have revealed an interesting pattern of differences and similarities between these collision systems. These measurements, together with recent calculations, provide evidence that coupling effects between Ps formation and other scattering channels are very important at low energies for the alkali atoms. The calculations also indicate that formation of Ps in excited states in the cases of potassium and rubidium is more likely than formation in the ground state when the positron energy is greater than about 5 eV. Measurements of total and Ps-formation cross sections for positrons scattered by magnesium are in a preliminary stage, but the differences between them and the results of available theoretical calculations are providing a strong incentive to intensify experimental and theoretical investigations of this collision system. Refinements in a recently developed technique for measuring total cross sections for positrons and electrons scattered by atomic hydrogen have led to preliminary new results for these systems that are in very good agreement with recent theoretical calculations. These measurements, together with the calculations with which they agree, indicate that as the projectile energy is increased through the higher energy range (above 50 eV), the total cross sections for positrons approach the corresponding results for electrons from above, which is the reverse of the relationship between the positron and electron total cross sections in this energy range for all of the room-temperature gases that have been investigated, except possibly for molecular hydrogen.

scholarly journals Positronium Formation Cross Sections for Scattering of Positrons from Potassium and Rubidium

1994 ◽  
Vol 47 (3) ◽  
pp. 265
Author(s):  
N Ranjit Singh ◽  
NC Deb ◽  
Th Subodh Chandra Singh ◽  
M Babuyaima Singh ◽  
PS Mazumdar
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
Positronium Formation ◽  
Distorted Wave ◽  
Total Cross Sections ◽  
Wave Approximation ◽  
Theoretical Results

Total cross sections for positronium formation in positron-potassium and positron-rubidium scattering have been calculated in a distorted wave approximation for incident positrons in the energy range 1 to 50 eV. The present results are compared with other theoretical results and with measurement where available.

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