http://www.iiste.org/Journals/index.php/APTA/issue/feedAdvances in Physics Theories and Applications2015-09-01T10:57:18+00:00Alexander Deckeradmin@iiste.orgOpen Journal Systemshttp://www.iiste.org/Journals/index.php/APTA/article/view/24611Journal Coverpage2015-08-31T02:48:45+00:00Journal Editord@d.com.http://www.iiste.org/Journals/index.php/APTA/article/view/24612Ground-State Energy Calculation of Helium Atom Using Quantum Monte Carlo CASINO-Code2015-08-31T02:48:45+00:00Sylvester A. Ekongd@d.comMariam T. Oloyeded@d.comDavid A. Oyegoked@d.com<p>We report an improved variational Monte Carlo (VMC) calculation of the ground-state energy of the helium atom, using quantum Monte Carlo (QMC) CASINO – code. The VMC ground-state energy is studied with a single determinant Slater-Jastrow trial wave-function formed from Hartree-Fock orbitals. The optimization of orbitals improved the agreement between the variational Monte Carlo and recent experiment. The calculated ground-state energy result is –2.903692762 ± 0.000023 a.u., which is in good agreement with the most recent experimental value –2.903693775 a.u. obtained by Bergeson et al. A more accurate trial function for importance sampling and the use of Jastrow–function combine to yield a ground-state energy which is 5 significant figures more accurate than that of previous quantum Monte Carlo calculations.</p> <p><strong>Keywords: </strong>CASINO code, QMC, VMC, Helium atom, Reblocked-standard-error</p>http://www.iiste.org/Journals/index.php/APTA/article/view/24613DMC and VMC Calculations of the Electric Dipole Moment and the Ground-State Total Energy of Hydrazine Molecule Using CASINO-Code2015-08-31T02:48:45+00:00Sylvester A. Ekongd@d.comVincent A. Akpand@d.comReginald A. O. Osakwed@d.comGodstime O. Okochad@d.com<p>In this study quantum Monte Carlo (QMC) calculations of the electric dipole moment and ground-state total energy of hydrazine (N<sub>2</sub>H<sub>4</sub>) molecule using CASINO-code is presented. By employing the restricted Hartree-Fock (RHF) scheme, two QMC techniques were used in this work: variational Monte Carlo (VMC) and diffusion Monte Carlo (DMC) techniques. The optimization of the Slater-Jastrow trial wave-function was done using variance-minimization scheme. The simulations require that the configurations must evolve on the time scale of the electronic motion, and after equilibration, the estimated effective time-step be obtained. In this study, the electric dipole moment of N<sub>2</sub>H<sub>4</sub> molecule was calculated using only the DMC technique. The result obtained gives an electric dipole moment value of 2.0 D, which is in good agreement with the experimental value of 1.85 D.</p> <p>Similarly, the ground-state total energy of N<sub>2</sub>H<sub>4</sub> molecule was calculated using both VMC and DMC methods. It was observed that the result obtained from the VMC technique agrees very-well with the best theoretical value while the DMC technique gave a ground-state total energy value lower than all other theoretical values in literature, suggesting that the DMC result –111.842774 ± 0.00394 a.u., should be the exact ground-state total energy of hydrazine molecule. However, the results from this study are found to be precisely approaching the required order of chemical accuracy.</p> <p><strong>Keywords: </strong>Hydrazine (N<sub>2</sub>H<sub>4</sub>), QMC, VMC, DMC, CASINO-Code. <strong></strong></p>http://www.iiste.org/Journals/index.php/APTA/article/view/24614High Voltage Transformers and Elecrtomagnetic Emissions: Consequence on Students’ Health in Apata, Ibadan, Nigeria2015-08-31T02:48:45+00:00Adekunle A.d@d.comAbimiku Y.Kd@d.comNwafor C.Od@d.comNwaigwe D.Nd@d.comAgbonkhese O.d@d.com<p>The last decade has witnessed a remarkable growth in all aspects of modern technology such as mobile phones, wireless communication links, antennas, microwave ovens, and high voltage transformers which are sources of electromagnetic radiations (EMR). This research work investigates the effect of exposing building occupants to electromagnetic emission from high voltage transformers. The sample of this study is 150 students comprising 78 males and 72 females. Spectra RF3040 was used to measure magnetic flux density in the five schools used for this research. Measurements were also taken to determine the effects of electromagnetic emission on student's tympanic temperature, blood oxygen saturation, heart pulse rate and arterial blood pressure (diastolic and systolic). Tests on health situations were done indoor four times at (9:00 – 9:30) a.m. and four times at (1:30 – 2:00) p.m. each day. The results show from analysis that the measured values of power flux density were within slight concern limit. The gradual increase in tympanic temperature, heart pulse rate, and arterial blood pressure is an indication that EMR has adverse health effects on building occupants within 200m distance from such transformers. Recommendations were given.</p> <p><strong>Keywords:</strong> High voltage, Transformer, Electromagnetic, Emission, Health effect.</p>http://www.iiste.org/Journals/index.php/APTA/article/view/24615A Review of Semiconductor Quantum Well Devices2015-08-31T02:48:45+00:00Emmanuel O. Odohd@d.comAugustine S. Njapbad@d.com<p>Quantum well devices feature very thin epitaxial layers of heterostructure III-V and II-VI semiconductor materials that are grown using Molecular Beam Epitaxy (MBE) and Metal-Organic Chemical Vapour Deposition (MOCVD) growth techniques. These devices are monolithically integrated with various optoelectronic devices to provide photonic integrated circuit with increased functionality .The quantum well structure can be realized with GaAs as wells and AlGaAs as barriers for wavelength about 0.8 μm and InGaAsP/InP offering longer wavelengths (0.9-1.6 μm). Quantum well devices find their applications in quantum well lasers or improved lasers, photodetectors, modulators and switches. These devices operate much faster, more economically and have led to a million increases in speed, a point of enormous importance to the telecommunication and computer industry.</p> <p><strong>Keywords</strong>: Quantum well, Semiconductor, Heterostructures, Lasers, Detectors, Modulators.</p>http://www.iiste.org/Journals/index.php/APTA/article/view/24616Approximate bound state solutions of nonrelativistic Schrödinger equation with q-deformed Hulthen plus modified inversely quadratic Yukawa potential within the framework of Nikiforov-Uvarov method2015-08-31T02:48:45+00:00Akaninyene D. Antiad@d.comIta O. Akpand@d.com<p>We study the nonrelativistic Schrödinger equation for q-deformed Hulthen plus modified inversely quadratic Yukawa potential using the generalized parametric form of NIkiforov-Uvarov method. The energy eigenvalues and the corresponding normalized wave functions expressed in terms of hypergeometric function are obtained. We have also discussed four (4) special cases of this potential, i.e. Woods-Saxon, Hulthen, Morse and inversely quadratic potentials.</p> <p><strong>Keywords: </strong>Nonrelativistic Schrödinger equation, q-deformed Hulthen potential, modified inversely quadratic Yukawa potential, parametric Nikiforov-Uvarov method.</p>http://www.iiste.org/Journals/index.php/APTA/article/view/24617The Effect of the Concentration Chang of Reinforcing Materials on the Values of Some Theoretical Attenuation Parameters2015-08-31T02:48:45+00:00Ahmed Fadhil Mkhaiberd@d.comAbdulraheem Dheyaa Ibrahimd@d.com<p>In this paper, some theoretical attenuation parameters was calculated for shields made up of composite materials basis polymer (Epoxy ) with added materials (C,Ni,PbO,Bi) with different concentrations (10,20,30,40,50)wt% , where the effect of concentrations variation on the attenuation coefficients values , effective atomic number and shields density has been studying. The computer program code X-Com was used to calculate the attenuation parameter values at different energies (0.662,1.173,1.332)MeV .Results shows that there is a clear change in the values of these parameters with the change of concentration ratios.</p>http://www.iiste.org/Journals/index.php/APTA/article/view/24618Study of Transition Metal Nitride Ti1-xZrxN Alloy at High Pressure2015-08-31T02:48:45+00:00Abdul Shukoord@d.comPurvee Bhardwajd@d.comSadhna Singhd@d.com<p>The structural properties of transition metal nitride using have been explored in the present paper. The study has been extended to Ti<sub>1-x</sub>Zr<sub>x</sub>N<strong> </strong>alloy (0 ≤ x≤ 1) alloy and the effect of composition on structural, and elastic properties are investigated. Phase transition pressure and related volume collapses [ΔV (Pt)/V(0)] calculated from this approach are in good agreement with available literature for the parent compounds (x=0 and x=1). The present compounds exhibit in rock salt (NaCl) structure at ambient condition, it transforms to cesium chloride (CsCl) structure under high pressure. The results for the mixed crystal counter parts are also in fair agreement with experimental data generated from the application of Vegard’s law to data for the parent compounds.</p> <p><strong>Keywords</strong><strong>, </strong>Alloy, Crystal structure, Phase transitions, High pressure Elastic property.</p>http://www.iiste.org/Journals/index.php/APTA/article/view/24619Effect of Temperature on Structural Properties of Rare Erath Chalcogenides2015-08-31T02:48:45+00:00Purvee Bhardwajd@d.comSadhna Singhd@d.com<p>In this study, the calculated results of the structural properties of ThX (X=S and Se) rare earth chalcogenides in rocksalt structure (B1) are presented. The Realistic Interaction Potential Approach (RIPA) model has been developed and used. A sudden collapse in volume has been occurred at phase transition pressures. At compressed volumes, these compounds are found in CsCl phase. Phase transition pressures have been reported at room and high temperature range 0-1000K. The phase transition pressures and associated volume collapses obtained from present potential model show a generally better agreement with available experimental and others results.</p> <p><strong>Keywords: </strong>Phase transition, High pressure, Crystal structure, Elastic properties.<strong> </strong></p>http://www.iiste.org/Journals/index.php/APTA/article/view/25353Electron Momentum Density in Nickel (Ni)2015-09-01T10:57:18+00:00Abdul Hadi M . Ghalebd@d.comFareed M. Mohammedd@d.comMuataz A. Majeedd@d.comMohammad N. Mohammedd@d.comNawras S. Mohammedd@d.com<p>In this paper, Compton profile of (Ni) was Calculated by employing both the renormalized-free atom(RFA) model and free electron(FE) model setting several configurations in subset (3d-4s). The results were compared with recent data ,It shows that the RFA calculation in(3d8.8-4s1.2) gives a better agreement with experiment.The calculated data used for the first time also to compute the cohesive energy of Nickle and compared it with available data. The Band structure and Density of state of Nickel crystals(DFT-LDA) also calculated by using code Quantum wise.</p><p><strong>Keywords</strong>: Compton profile,Electron momentum density, Cohesive energy, Band structure, Density of state.</p>