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Date
2018-11
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Abstract
Differential and integral cross sections for electron-atom are useful for interpretation
and understanding of electron contact with the targets and for determining dynamics of
the collision processes. They are useful in X-ray photoelectron spectroscopy (XPS),
upper atmosphere dynamics, Monte-Carlo simulation (MCS), Auger-electron
spectroscopy (AES), in gaseous-exchange, laser development, plasma physics and
fluorescent lighting. For elastic scattering of strontium very few calculations have been
performed and currently there are no known results using the present method. Also the
available theoretical results do not have other results to be compared with so it makes it
important to obtain results to compare them and to be compared with future
experimental results. In calculation of differential and integral cross section for elastic
scattering of electron by strontium atom, first-order distorted wave born approximation
method has been used to determine DCS and ICS at impact energies of 10eV to 200eV
and scattering angles ranging from 00 to 1800
. Also in this study at the initial state, both
initial and final channel distortion potential of elastic scattering of electron by a
strontium atom are taken as the static potentials since it is an elastic scattering. The
distorted waves are expanded in terms of radial wavefunctions and spherical harmonics,
Numerov method was then used to solve the radial equations to obtain the radial
wavefunctions. The Madison and Bartschat computer program DWBA1 for e-
- H
scattering was modified to perform the mathematical computations for e -
- Sr scattering
and the results for differential and integral cross sections are calculated and compared
with the available results. The integral cross sections (ICS) results agree well
qualitatively with the other theoretical results. At lower incident energies (10-30 eV),
the present differential cross section (DCS) results disagree with results obtained from
optical potential method. This is because the first order distorted wave method gives
poor results at low impact energies and also the nature of the distortion potential used.
At intermediate and higher energies (60-200 eV), the present DCS results agree well
with the results obtained from optical potential method. In conclusion, the DWBA was
developed and applied to 𝑒− - Sr scattering, changes on the DWBA1 computer program
were made for strontium, differential cross section (DCS) and integral cross section
(ICS) at impact energies 10-200eV for elastic scattering of electron-strontium were
determined using DWBA at intermediate and high energies and the results compared
with the other available results. From this work it was recommended that some
experimental studies on electron impact elastic scattering of strontium should be made
to give results for comparison with the calculated results, more theoretical studies using
other methods should be conducted on DCS and ICS for purposes of comparison with
the present results, a distortion potential that incorporates the polarization potential,
exchange potential and absorption potential should be used in the calculation and the
present method incorporating all the distortion potentials should be extended further for
electron impact elastic scattering of other alkaline earth metals such as beryllium,
cesium, ytterbium, and radium.