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Positronium Formation From Li And Na Atoms By Use Of Pseudopotential, Sultana N. Nahar, J M. Wadehra
Positronium Formation From Li And Na Atoms By Use Of Pseudopotential, Sultana N. Nahar, J M. Wadehra
Physics and Astronomy Faculty Research Publications
The differential and total cross sections for the formation of positronium in its ground state from Li and Na atoms by the impact of intermediate-energy positrons are calculated in the first Born and distorted-wave Born approximations. Hellmann-type pseudopotentials are used to represent the alkali-metal ion cores. The difference in the use of pseudopotentials and the static potential for the core representation for evaluating various rearrangement cross sections is discussed.
Exact Evaluation And Recursion Relations Of Two-Center Harmonic Oscillator Matrix Elements, P. J. Drallos, J. M. Wadehra
Exact Evaluation And Recursion Relations Of Two-Center Harmonic Oscillator Matrix Elements, P. J. Drallos, J. M. Wadehra
Physics and Astronomy Faculty Research Publications
Using vibrational wave functions of two relatively displaced harmonic oscillators of arbitrary frequencies, Franck–Condon overlap integrals and matrix elements of x^l, exp(−2cx), and exp(−cx^2) (x is the internuclear separation) are obtained. Useful three‐term, four‐term, and five‐term recursion relations among these matrix elements are derived. It is shown that all of the relevant matrix elements can be obtained from a mere knowledge of the lowest two Franck–Condon overlap integrals. Results are illustrated by computation of Franck–Condon factors for the A ^1∑^+_u –X ^1∑^+_g and the B ^1Π_u –X ^1∑^+_g systems of ^7Li_2.
Elastic Scattering Of Positrons And Electrons By Argon, Sultana N. Nahar, J. M. Wadehra
Elastic Scattering Of Positrons And Electrons By Argon, Sultana N. Nahar, J. M. Wadehra
Physics and Astronomy Faculty Research Publications
Differential and integrated cross sections for the elastic scattering of low- and intermediate-energy (3–300 eV) positrons and electrons by argon atoms are calculated. Higher transport cross sections, representing moments of 1-(costheta)^n, for these systems are also obtained for n=1–4. Model potentials are used to represent the interactions between positrons or electrons and argon atoms. For each impact energy, the phase shifts of the lower partial waves are obtained exactly by numerical integration of the radial equation. The Born approximation is used to obtain the contribution of the higher partial waves to the scattering amplitude. The phase shifts of the seven …