Accurate electron densities and X-ray form factors of Li, Be, F and their ions have been calculated. Electron correlation, crystal fields and ionic charge transfer change the form factors by up to a few percent, mainly in the range of sin 0 /k < | Ä " 1 . Although electron correlation and crystal fields are small perturbations, their effects on the density and form factor are not additive. Dens...

the term electronegativity .was introduced by linus pauling, who characterized on the basis ofthermodynamic data from the energies of the single bonds. in present study, the density functional theory(dft) was used to calculate electronegativity of atoms. the base of calculation is similar to pauling andmulliken methods. the results indicate that the largest value of electronegativity for fluori...

The effect of hydrogen gas on the plasma and its influence on acid interferences in plasma atomic emission spectrometry was studied. The study was performed with HCl and HNO(3) in the concentration range of 0-2 mol l(-1). Vanadium and magnesium were used as test elements, the study was extended to other several elements. The effects of hydrogen gas on the plasma were studied by measuring excita...

Introduction: Globally, the need for radiotherapy as a part of cancer management increases every year. Thus, the shielding for megavoltage radiotherapy rooms is of great importance. Materials and Methods: In the present study, 14 types of developed high-density concrete with densities ranging from 2.45 to 5.11 were simulated by using Monte Carlo method. The linear attenuation coefficient and t...

Mean free path of inelastic electron scattering has been measured with a 200 keV transmission electron microscope for the majority of stable elemental solids and their oxides. An oscillating behavior vs atomic number Z has been revealed, such that within one row of the Periodic Table, the minimum maximum of is observed for elements with completed empty outer d shells. A significantly weaker Z d...

Background: The aim of present study was to analyze the effectiveness of electron filters in the Telecobalt radiotherapy treatment by simulation technique.  Materials and Methods: The BEAMnrc Monte Carlo code was used to simulate the electron filters of thickness of 0.5 gm/cm2 below the trimmer bar for 35 × 35 cm2 field size in Theratron Equinox-80 telecobalt unit. The electron filters were mad...