Infinite-Channel Close-Coupling Approximation in the Second Born Approximation. II. Treatment of Charge Polarization in Elastic Scattering by Use of theT-Matrix Formalism

1971 ◽  
Vol 3 (6) ◽  
pp. 1958-1968 ◽  
Author(s):  
R. A. Bonham
Keyword(s):  
Elastic Scattering ◽  
Born Approximation ◽  
Matrix Formalism ◽  
Close Coupling ◽  
Charge Polarization ◽  
Coupling Approximation

Excitation of Ne VIII by electron impact

1976 ◽  
Vol 54 (20) ◽  
pp. 2019-2023 ◽  
Author(s):  
W. L. van Wyngaarden ◽  
Ronald J. W. Henry
Keyword(s):  
Electron Impact ◽  
Born Approximation ◽  
Experimental Error ◽  
Rate Coefficient ◽  
Impact Excitation ◽  
Rate Coefficients ◽  
Electron Impact Excitation ◽  
Close Coupling ◽  
Coupling Approximation ◽  
Made In

Collision strengths for electron impact excitation of Ne VIII are calculated at 14, 18, and 30 Ry in a 5-state close coupling expansion and the unitarized Coulomb–Born approximation. To assess the importance of exchange and coupling beyond the 5 states, additional calculations are made at 18 Ry in 5-state and 8-state close coupling expansions without exchange. For the 2s–2p excitation, calculations below the 3s threshold at 10.0 Ry are made in a 2-state close coupling expansion at 1.6, 3.2, and 8.0 Ry. In most instances the close coupling method gives results which differ by 15% or less from those of the unitarized Coulomb–Born approximation and by 20–70% from the CBI (Coulomb–Born) results of Bely. Rate coefficients which are calculated from the results obtained in the close coupling approximation agree within experimental error with the experimental results of Kunze and Johnston and Haddad and McWhirter with the exception of the rate coefficient for the 2p → 3d excitation.

The elastic scattering of fast electrons and positrons by hydrogen and helium atoms

1959 ◽  
Vol 250 (1262) ◽  
pp. 337-345 ◽  
Keyword(s):  
Elastic Scattering ◽  
Cross Sections ◽  
Differential Cross ◽  
Born Approximation ◽  
Logarithmic Singularity ◽  
Hydrogen Atoms ◽  
Fast Electrons ◽  
Helium Atoms ◽  
Electrons And Positrons ◽  
Angle Scattering

A simplification of the second Born approximation due to Massey & Mohr is used to calculate the differential cross-sections for the elastic scattering of fast electrons and fast positrons by hydrogen atoms and helium atoms, the method of Dalitz being applied to evaluate all the relevant integrals. Although the logarithmic singularity which is found in the differential cross-section for zero-angle scattering is shown to be absent in the true second Born approximation the use of the simplification of this approximation is justified at sufficiently high impact energies provided the angle of scattering is not too small. The results of the calculations for incident electrons in helium are compared with the available experimental data.

R-matrix calculations of photoionization cross section of Ne-like tungsten

2015 ◽  
Vol 93 (11) ◽  
pp. 1221-1226 ◽  
Author(s):  
Indu Khatri ◽  
Arun Goyal ◽  
Sunny Aggarwal ◽  
A.K. Singh ◽  
Man Mohan
Keyword(s):  
Cross Section ◽  
Energy Levels ◽  
Resonance Energy ◽  
Photoionization Cross Section ◽  
Distorted Wave ◽  
Rydberg Series ◽  
Close Coupling ◽  
R Matrix ◽  
Coupling Approximation ◽  
Wave Methods

The photoionization cross section calculation for the ground state 1s22s22p6 1S (J = 0) of Ne-like W64+ has been performed in the close-coupling approximation using the Dirac–Coulomb R-matrix method. The resonance structures are analysed and described by finding the resonance energy positions of prominent Rydberg series 2s2p6(2S)np 1P0 for W LXV ion. To calculate fine structure energy levels, multi-configuration Dirac–Fock and relativistic distorted-wave methods have been employed. Wherever possible we have compared our work with the available data. The present results will be useful for diagnostics and modeling of plasma in ITER and other fusion devices.

scholarly journals Electron-ion recombination in the close-coupling approximation

1992 ◽  
Vol 68 (10) ◽  
pp. 1488-1491 ◽  
Author(s):  
Sultana N. Nahar ◽  
Anil K. Pradhan
Keyword(s):  
Close Coupling ◽  
Coupling Approximation ◽  
Ion Recombination

scholarly journals Scattering of Alpha-particles by a Vibrational Nucleus

1962 ◽  
Vol 15 (2) ◽  
pp. 135 ◽  
Author(s):  
LJ Tassie
Keyword(s):  
Elastic Scattering ◽  
Plane Wave ◽  
Experimental Test ◽  
Born Approximation ◽  
Alpha Particles ◽  
Nuclear Surface ◽  
Vibrational States ◽  
Phonon Excitation ◽  
Plane Wave Born Approximation ◽  
Good Agreement

The elastic and inelastic scattering of cx-particles by a vibrational nucleus is calculated using plane-wave Born approximation. The excitation of both single-phonon and twophonon states is considered. The effect of the diffuseness of the nuclear surface is included. The result for elastic scattering and the excitation of the single-phonon 2+ and 3- states is in good agreement with experiment for .oNi. The approximations used are discussed, and it is suggested that excitation of 0+, 1-, and 5- states should provide the best experimental test of the theory of two-phonon excitation of nuclei. The energies of the vibrational states are also considered.

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