Hewa Y. Abdullah

B(E2) value of even-even 108?112Pd isotopes by interacting boson model-1

This work studies the systematic reduced transition probabilities B(E2)↓, intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from N = 62 to 66. The downward reduced transition probabilities B(E2)↓ from gamma transition 8+ to 6+, 6+ to 4+, 4+ to 2+ and 2+ to 0+ states of even-even 108–112Pd isotopes were calculated by the Interacting Boson Model (IBM-1) and compared with the available previous experimental results. The ratio of the excitation energies of the first 4+ and the first 2+ excited states, R4/2, is also studied for the classification of symmetry of these nuclei. Furthermore we have studied systematically the transition rate R = B(E2: L+ → (L−2)+)/B(E2:2+ →0+) of some of the low-lying quadrupole collective states in comparison with the available experimental data. The associated quadrupole moments and deformation parameters have been calculated. The results of this calculation are in good agreement with the corresponding available experimental data. The 108–112Pd isotopes show the O(6) symmetry.

Ground-state energy band of even 104-122Cd isotopes under the framework of interacting boson model-1: a review

In this paper, the nuclear structure of ground-state bands of even-even 104-122Cd isotopes has been reviewed under the framework of interacting boson model-1 (IBM-1). The theoretical energy levels for Z = 48, even N = 56–74 up to 8+ state have been obtained by using the PHINT computer program. The values of the parameters in the IBM-1 Hamiltonian yield the best fit to the experimental energy spectrum. The results are compared with the most recent experimental values where an acceptable degree of agreement is achieved. In this paper, the properties of even 104-122Cd isotopes have been considered to the U(5) ~ SO(6) transitional region of the IBM-1.

Theoretical study of the syn- and anti-conformers of 2,2ʹ-bifuran derivatives: rotational barrier and solvent effect

ABSTRACT The optimised molecular structures, vibrational wavenumbers and corresponding vibrational assignments of the syn- and anti-conformers of 2,2ʹ-bifuran and its nitro, fluoro, methyl and hydroxyl derivatives were obtained using density functional theory. The starting structures with C2 symmetry of all the ground state structures were considered and the transition state arising from syn-anti isomerisation was also modelled. All structures were fully optimised, and the geometries, dipole moments, charge, thermodynamic properties, and energies are reported. The calculated vibrational wavenumbers were assigned to the various fundamental modes of vibrations. The integral Equation Formalism Polarisation Continuum Model (IEF-PCM) was used to calculate the optimised geometry and the vibrational wavenumbers for all the compounds in different solvents. The results indicate that in the gas phase, the syn-conformer is more stable while in solution phases the conformational preference depends on the polarity of the solvent.

Theoretical study of the adsorption energy of some linear saturated hydrocarbons on SWCNT: DFT calculations

Adsorption of a single molecule of saturated linear hydrocarbons, CnH2n+2 where n=1, 2, 3 and 4 in the gas phase on the surface of a tube of Al-doped (5,0) single-walled carbon nanotubes (Al-CNT) was investigated using Density Function Theory (DFT) at the B3LYP/6-31G(d) level. The results showed that adsorption of Al-CNT is independent of special orientation and all guest molecules prefer to be adsorbed into the surface of Al-CNT rather than into the CNT tube. Upon adsorption of the guest molecules, the charge energy gap of Al-CNT was considerably reduced, resulting in improved electrical conductivity. Chemical reactivity was investigated in terms of chemical hardness, softness and absolute electronegativity.

Contrastive studies of potential energy functions of some diatomic molecules

It was proposed that iron hydride, FeH, would be formed only on grains at the clouds through the reaction of the adsorbed H atoms or H2 molecules with the adsorbed Fe atoms on the grains. The importance of FeH in Astrophysics presents an additional motivation to study its energetic, spectroscopic constants and Potential Energy Curves. The structural optimization for ground state of FeH was calculated by different theoretical methods, namely, Hartree-Fock (HF), the density functional theory (DFT), B3LYP, MP2 method and QCISD(T) methods and compared with available data from the literature. The single ionized forms, cation and anion, were also obtained at the same level of calculations. Charges, dipole moment, geometrical parameters, molecular orbital energies and spectroscopic parameters were calculated and reported. In addition, the molecular ionization potential, electron affinity and dissociation energy were investigated.

Compton scattering of 662 kev gamma rays by aluminium and copper materials using NAI(TI) detector

A rotating NaI(TI) scintillator detector and a collimated Cs 137 source producing gamma rays with an energy of 662 keV scattered incoherently by aluminum (Al) and copper (Cu) scatterers through the angles from 0 to 120° are used to study Compton scattering. The Compton scattering effect is investigated and found that the energy of scattered gamma ray decreases as the scattering angles increases. The differential scattering cross-section as a function of scattering angles is also measured. The experimental results of differential scattering cross-sections for Al and Cu scatterers were compared as a function of scattering angle and found to coincide at the higher angle region, although scattering cross-section for Cu are larger than Al scatterer at the lower angles region.