Theoretical Study of Electronic Properties of Some Aromatic Rings: B3LYP/DFT Calculations

Theoretical studies on some aromatic rings included the  pyridine, pyrimidine, pyrazine and  pyridazine molecules were performed using DFT. Based on B3LYP with 6-31(d, p)basis sets was used to investigate the effect of different position of nitrogen atom on the electronic and structure properties of benzene. The optimized structure, total energies, electronic states, energy gaps, ionization potentials, electron affinities, chemical potential, global hardness, softness, global electrophlicity, dipole moment and dipole polarizability were calculated. The harmonic vibration frequencies calculated and compared with available experimental data. The results showed a decrease in gap energies and improve the electronic properties. Keywords: B3LYP, DFT, optimization, energy gap, and vibration frequency

Optical Constants of Fe2O3 and TiO2:Fe2O3 Thin Films Prepared by Spray Pyrolysis Technique

 تم في هذا البحث دراسة الثوابت البصرية لأغشية أوكسيد الحديد (Fe2O3) النقية والمشوبة بثنائي أوكسيد التيتانيوم (TiO2) بالنسب % (1,3,5) المحضرة بطريقة الرش الكيميائي الحراري على قواعد زجاجية. تم دراسة الخصائص البصرية للأغشية المحضرة بسمك nm (10±260) باستخدام مطياف Shimadzu قيست النفاذية البصرية في المدى الطيفي nm (1100-500). وجد ان فجوة الطاقة المباشرة لغشاء (Fe2O3) تساوي eV) 2.01)، والتي تزداد مع زيادة نسبة (TiO2). وتم حساب الثوابت البصرية كمعامل الانكسار ومعامل الخمود وثوابت العزل الكهربائية لجميع الأغشية المحضرة. واظهرت النتائج أن جميع الثوابت البصرية تقل بزيادة نسب التطعيم."In the present work, optical constants have been studied for pure and titanium dioxide (TiO2) doped iron oxide (Fe2O3) thin films with different titanium dioxide dopant concentrations (1, 3 and 5 %) prepared by chemical spray pyrolysis technique on glass substrates. The optical properties of the films, which were prepared with a thickness of (260±10) nm, have been determined by using Shimadzu spectrophotometer, the optical transmittance measurements in the spectral region from (500- 1100) nm. Direct energy gap for (Fe2O3) equal (2.01) eV, it increases with increasing of TiO2%. The optical constants such as refractive index, extinction coefficient and dielectric constants have been calculated for all prepared films. The results show that all optical constants decrease with the increasing of dopant ratios.

Optical and Electrical Properties of TiO2 Doped Fe2O3 Thin Film Prepared by Spray Paralysis Technique

In this work, iron oxide (Fe2O3) and titanium oxide (TiO2) doping (Fe2O3) thin films have been prepared by spray pyrolysis technique (SPT) on a glass substrate. We have studied the effects of various doping percentage of (TiO2) on (Fe2O3) optical and electrical properties. The optical parameters of the prepared films as absorbance, absorption coefficient, optical energy gap and refractive index have been calculated for all prepared films. D.C conductivity and Hall effect for all films are measured. The results showed that absorbance of prepared films decreases with increasing percentage of (TiO2) this lead to increase the energy gap and conductivity decreased with increasing of percentage of (TiO2) as well as the results showed throughout the study that all films have tow activation energy, its value increase with increasing of percentage of (TiO2). Hall effect measurement showed all films have n-type conductivity

Design and Construction of a Testing Platform and Estimating Attenuation Painting Reflectivity to Laser Beam

The project has been described the design and construction of a reliable optical testing platform used for evaluate the reflectivity of metal surfaces treated with special paintings required for laser beam attenuation. The platform comprises an Nd-YAG laser system which has been designed and fabricated with specifications to be compatible with their corresponding in laser range finder transmitters used for various applications. The reflectivity of various attenuating paintings, at different detection angles, has been observed. Moreover, the variation of the reflected energy with painting type and metal type to be painted has been studied experimentally. Results illustrated the existence of a definite angle, at which the reflectivity was maximum (specular reflection). On the other hand, samples with attenuation paintings have constant very low diffusive reflectivity and are independent of the detection angle

The Influence of Substrate Temperature on the Structural , Morphology and Optical Properties of ZnS Thin Films Prepared by Pulsed Laser Deposition

Effects of substrate temperature on the microstructure, morphology, and optical properties of ZnS thin films were investigated. ZnS films were deposited on glass substrates by pulsed laser deposition at different substrate temperatures using a pulsed 532 nm Nd:YAG laser is presented . The structure and morphology of the film were studied by X-ray diffraction and atomic force microscopy, the average surface grain size and RMS surface roughness of the films increases with increasing substrate temperature. Optical properties of the films were determined from the transmittance data using Swanepoel model,Transmittances of film were measured by spectrophotometer. Additionally, the increase of the substrate temperatures increase the pores and the transmittance in the films, it was observed that the energy band gap is increased from 3.4 eV to 3.6 eV of the films are decreased with the increase of substrate temperature . Moreover , considerable improvement in blue response of the films was noticed with increasing substrate temperature