Effect of Absorption and Polarization Potentials in the Distorted Wave Calculation of Position Impact Excitation of Autoionizing State of Positron Impact Excitation of Autoionizing State of Rubidium
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Date
2024-01
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Kenyatta University
Abstract
Studies have been done involving positron and electron impact on alkali atoms. However, for positron impact excitation of the autoionizing state of rubidium atom, there are only few results available. The positron impact excitation ofrubidium's lowest autoionrzing state has been investigated in this work with inclusion of absorption and polarization potentials as distortion potential. Differential cross sections, integral cross sections and angular parameters have been calculated using the distorted wave method and compared with available results. With all the potentials - static, absorption, polarization included, the current results for cross sections and angular parameters are qualitatively in good agreement with the results available in the literature. The absorption potential reduces the magnitude of both integral and differential cross sections, whereas the polarization potential increases the magnitude of both integral and differential cross sections at low impact energies. As the impact energy increases, the effect of these two potentials becomes insignificant because the projectile moves at a high speed and hence spends very little time in the interaction region. Inclusion of polarization potential also introduces resonance near the excitation threshold. The results of the alignment parameter indicate that there is a higher degree of scattering from the magnetic sub state m = 0 for impact energies below 400 eV. On the other hand, the lambda parameter results suggest that the scattering of particles alternates between the two magnetic sub states m = 0 and Nl = l . The present results demonstrate that the incorporation of polarization and absorption potentials greatly enhances cross sections and angular parameters.
Description
A Thesis Submitted in Partial Fulfillment of the
Requirements for the Award of the Degree of Master of
Science in the School of Pure and Applied Sciences of
Kenyatta University