Nuclear matter distributions of neutron rich 6He, 11Li, 14Be and 17B halo nuclei studied by the Bear–Hodgson potential

The radial wave functions of the Bear–Hodgson potential have been used to study the ground state features such as the proton, neutron and matter densities and the associated rms radii of two neutrons halo 6He, [Formula: see text]Li, [Formula: see text]Be and [Formula: see text]B nuclei. These halo nuclei are treated as a three-body system composed of core and outer two-neutron [Formula: see text]. The radial wave functions of the Bear–Hodgson potential are used to describe the core and halo density distributions. The interaction of core-neutron takes the Bear–Hodgson potential form. The outer two neutrons of 6He and [Formula: see text]Li interact by the realistic interaction REWIL whereas those of [Formula: see text]Be and [Formula: see text]B interact by the realistic interaction of HASP. The obtained results show that this model succeeds in reproducing the neutron halo in these nuclei. From the calculated densities, it is found that 6He, [Formula: see text]Li, [Formula: see text]Be and [Formula: see text]B have a long tail in neutron and matter densities which is consistent with the experimental data. Elastic charge form factors for these halo nuclei are analyzed via the plane wave Born approximation.

The Electron Impact Ionization Cross Sections of Methanol, Ethanol and 1-Propanol

In the present investigation, the plane-wave Born approximation was employed to calculate the total ionization cross sections by electron impact of methanol, ethanol and 1-propanol from the threshold of ionization to 10 MeV. This method requires continuum generalized oscillator strengths (CGOSs). The two different semi-phenomenological expressions of CGOS, given by Mayol and Salvat and Weizsacker and Williams, along with approximated form of the continuum optical oscillator strength (COOS) by Khare et al. were used. Furthermore, the average of the above two CGOSs was also used. The calculated ionization cross sections were compared to the available previous theoretical results and experimental data. Out of three CGOSs, the present results with the average CGOS were found in good agreement with the available experimental results for all the considered molecules. Collision parameters CRP were also calculated from 0.1 to 100 MeV and the calculations were found to be in excellent agreement with the experimental results of Reike and Prepejchal.

Elastic transverse electron scattering form factors of 11Li exotic nucleus

The elastic transverse electron scattering form factors have been studied for the 11Li nucleus using the Two- Frequency Shell Model (TFSM) approach. The single-particle wave functions of harmonic-oscillator (HO) potential are used with two different oscillator parameters bcore and bhalo. According to this model, the core nucleons of 9Li nucleus are assumed to move in the model space of spsdpf. The outer halo (2-neutron) in 11Li is assumed to move in the pure 1p1/2, 1d5/2, 2s1/2 orbit. The shell model calculations are carried out for core nucleons using the spsdpf-interaction. The elastic magnetic electron scattering of the stable 7Li and exotic 11Li nuclei are also investigated through Plane Wave Born Approximation (PWBA). It is found that the difference between the total form factors of unstable isotope (11Li halo) and stable isotope 7Li is in magnitude. The measured value of the magnetic moment is also reproduced.

The Nuclear Structure for Exotic Neutron-Rich of 42, 43, 45,47K Nuclei

In this paper the proton, neutron and matter density distributions and the corresponding root mean square (rms) radii of the ground states and the elastic magnetic electron scattering form factors and the magnetic dipole moments have been calculated for exotic nucleus of potassium isotopes K (A= 42, 43, 45, 47) based on the shell model using effective W0 interaction. The single-particle wave functions of harmonic-oscillator (HO) potential are used with the oscillator parameters b. According to this interaction, the valence nucleons are asummed to move in the d3f7 model space. The elastic magnetic electron scattering of the exotic nuclei 42K (J?T= 2- 2), 43K(J?T=3/2+ 5/2), 45K (J?T= 3/2+ 7/2) and 47K (J?T= 1/2+ 9/2) investigated through Plane Wave Born Approximation (PWBA). The inclusion of core polarization effect through the effective g-factors is adequate to obtain a good agreement between the predicted and the measured magnetic dipole moments.

ENERGY-LOSS EFFECT IN K-SHELL IONIZATION

The energy-loss effect of the projectile for direct inner-shell ionization cross sections by charged-particle impact has been examined. The relativistic and nonrelativistic calculations for K-shell ionization with and without the energy-loss effect are made in the plane-wave Born approximation and compared with the Brandt-Lapicki theory for the corrections of the relativistic and energy-loss effect. It is demonstrated that the Brandt-Lapicki method gives a good approximation to both relativistic and nonrelativistic cross sections, which implicitly take into account the energy-loss effect. However, the use of the Brandt-Lapicki relativistic correction method in the nonrelativistic theory with the exact integration limits for energy and momentum transfer overestimates the relativistic calculations for low-energy projectiles. This indicates that the Brandt-Lapicki method for correction of the electronic relativistic effect should be used only with their energy-loss correction method.

K-, L-, and M-shell ionization of atoms by electron and positron impact

The plane-wave Born approximation with Coulomb, relativistic, and exchange corrections is employed to obtain the K-, L1-, L2-, L3-, and M-shell ionization cross sections of a number of atoms bombarded by electrons and positrons in the energy range varying from the threshold of ionization to 1 GeV. Transverse interaction of virtual photons with atoms is also included and it is found to be of great significance for impact energies greater than about 1 MeV. For K- and L-shell ionization, good agreement between the theoretical values and various experimental data for electron-impact cross sections is obtained. However, for the M shell, the theory overestimates the experimental cross sections. For positron impact the agreement between the present results and the limited experimental data is found to be quite satisfactory.

Systematic ion-atom interaction cross sections and stopping powers in the plane wave Born approximation

In Chapter 14 of Atomic and Molecular Processes, Bates (1962) outlines a procedure for calculating ion-atom cross sections in the plane-wave Born approximation (pwBa). The procedure involves integration over the product of elastic scattering factors or generalized oscillator strengths for excitation or ionization from both projectile and target. We have programmed this procedure to use our large database of excitation and ionization generalized oscillator strengths (GOS). The program calculates both cross sections (CS) and stopping power (SP) on a subshell basis. The calculations are done in the center of mass system where the distinction between projectile and target is lost. Thus, the SP in the laboratory frames of both target and projectile are symmetrical in nuclear and net charges. The traditional simple modeling of SP, using scaled proton SP and an effective projectile charge, is unsymmetrical, and therefore dubious as a guide for extrapolating to ion-ion SP. At high projectile energy, the SP curves, as a function of increasing projectile charge, approach the scaled protonic result from above, indicating that lowering the average charge raises the SP, in contradiction to the traditional picture that the projectile SP increases with increasing effective charge (assuming there is an underlying physical reality relating the effective and average charge). Comparison with experimental SP data (mostly from 30 years ago) shows generally poor agreement for Li ion projectiles in the 1–10 MeV range.