Papers by Tarek E . I . Nassar
The impact parameter formalism of the single-center close-coupling, first-, and second-order Born... more The impact parameter formalism of the single-center close-coupling, first-, and second-order Born approximations have been applied to investigate direct excitations of He+(2s) and Li++(2s) ions by colliding with protons or antiprotons. The total 3s, 3p, and 3d scaled excitation cross sections are calculated in the scaled impact energy region (2 to 1000 keV). The present work aims to explore the sensitivity of the cross sections to different electronic transition mechanisms of the considered approaches as well as the charge of each projectile and target nucleus. Also, the calculated cross sections are compared with those obtained by previous theoretical calculations.
Results in Physics
Abstract The second Born approximation has been applied to calculate the triple and double differ... more Abstract The second Born approximation has been applied to calculate the triple and double differential cross sections for ionization of hydrogen atoms by 75 keV proton and antiproton impacts. The closure relation is used to perform the summation over the intermediate states in the second Born approximation. The triple differential cross sections (TDCSs) are calculated at different values of scattering angle θ s and ejected energy E e . The double differential cross sections (DDCSs) have been measured as a function of the projectile scattering angle and the electronics eject energy. The calculations are performed for emission of the electron into the collision plane with the ejected energies 16.4, 26.4, 36.4 and 39.4 eV. The resulting differential cross sections are compared with experimental and theoretical previous available results.
Chinese Physics Letters, 2014
Ionization process of the hydrogen atom, being initially in the excited 2p-state, projected by 30... more Ionization process of the hydrogen atom, being initially in the excited 2p-state, projected by 30 keV proton and antiproton impact has been investigated. The second-Born approximation (SBA) is used to measure the triple differential cross sections (TDCSs). The closure relation is employed on the second-Born term to come over consideration of the intermediate states. The triple differential cross-sections are represented graphically against the ejection angle, for two scattering angles and ejected energies into both scattering and perpendicular geometric planes. The single differential cross-section (SDCS) is calculated in the framework of the first-Born approximation.
Reaction cross sections are calculated using the Coulomb-modified Glauber model for deformed targ... more Reaction cross sections are calculated using the Coulomb-modified Glauber model for deformed target nuclei. The deformed nuclear matter density of the target is expanded into multipoles of order k = 0, 2, 4. The reaction cross sections for 12 C + 27 Al, 20 Ne + 27 Al, 12 C + 64 Zn, 12 C + 90 Zr, 40 Ar + 238 U and 20 Ne + 235 U are studied at energy range (10–1000 MeV nucleon −1). The most significant effects in the intermediate energy range are the Coulomb field and in-medium effects that modified the trajectory of the incident beams. Introducing the deformation effect beside the Coulomb field and in-medium effects improves the agreement with the experimental data and two empirical parameterizations in the case of not finding experimental data. Moreover, it is shown that the enhancement of the reaction cross sections is attributed to fixed orientation in deformed nuclei.
The direct impact excitations of ground-state hydrogen atoms by protons and antiprotons are inves... more The direct impact excitations of ground-state hydrogen atoms by protons and antiprotons are investigated by using an impact parameter treatment. The calculations are performed within the solution of the coupled differential equations arising from the one-center atomic-orbital close-coupling approach as well as the impact parameter version of the first and second Born approximations. We have considered calculations that allow couplings to the í µí±=1–5 states (up to g sub-levels) of the target atom as well as others, which neglect the effect of all states other than the initial and final states of the target atom. The sensitivity of the cross sections to the charge of the projectile is studied. The calculated cross sections are compared with those obtained by previous theoretical and experimental results.
The fully differential cross sections (FDCSs) for ionization of hydrogen atoms, being initially i... more The fully differential cross sections (FDCSs) for ionization of hydrogen atoms, being initially in the 2s excited state, by proton and antiproton impacts are calculated in the framework of the second Born approximation. The closure relation is employed to perform the summation over the intermediate states in the second Born approximation. The calculations are performed for emission of the electron in both scattering and perpendicular planes. The dependence of calculations on the projectile's charge is investigated at different impact energies and at small scattering angles where the significant contribution to the total cross section originates. It is noticed that the influence of the electric projectile's charge on the FDCSs in the perpendicular plane is much greater than it is in the scattering plane, and it increases as the scattering angle decreases. Finally, we calculate the doubly differential cross section (DDCS) for proton-induced reactions.
Books by Tarek E . I . Nassar
Reaction cross sections are calculated using the Coulomb-modified Glauber model for deformed targ... more Reaction cross sections are calculated using the Coulomb-modified Glauber model for deformed target nuclei. The deformed nuclear matter density of the target is expanded into multipoles of order k = 0, 2, 4. The reaction cross sections for 12 C + 27 Al, 20 Ne + 27 Al, 12 C + 64 Zn, 12 C + 90 Zr, 40 Ar + 238 U and 20 Ne + 235 U are studied at energy range (10–1000 MeV nucleon −1). The most significant effects in the intermediate energy range are the Coulomb field and in-medium effects that modified the trajectory of the incident beams. Introducing the deformation effect beside the Coulomb field and in-medium effects improves the agreement with the experimental data and two empirical parameterizations in the case of not finding experimental data. Moreover, it is shown that the enhancement of the reaction cross sections is attributed to fixed orientation in deformed nuclei.
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Papers by Tarek E . I . Nassar
Books by Tarek E . I . Nassar