@article { author = {Solimannejad, Mohammad and Gholipour, Alireza}, title = {Mutual interplay between interactions of pi electrons with simultaneous σ-hole interactions: A computational Study}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {1-10}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.3817}, abstract = {In this study, the role of interaction of pi electrons on the strength of simultaneous σ-hole interactions (pnicogen, chalcogen and halogen bonds) is investigated using the quantum chemical calculations. X-ben||TAZ∙∙∙Y1,Y2,Y3 complexes (X = CN, F, Cl, Br, CH3 , OH and NH2, TAZ= s-triazine and Y1,Y2 and Y3 denotes PH2F, HSF, and ClF molecules) is introduced as a model. The results show that interaction of pi electrons of X-ben and TAZ rings in X-ben||TAZ∙∙∙Y1,Y2,Y3 complexes are effective in enhancing the strength of simultaneous σ-hole interactions than that in the TAZ∙∙∙Y1,Y2,Y3 complexes. We show that the effect of the substituents on the studied complexes strongly depends on the nature of the substituents on the X-ben ring. The electron-donor and electron-acceptor substituents increase and decrease the stability of complexes, respectively. The electronic properties of the complexes have been analyzed using molecular electrostatic potential (MEP), and the parameters were derived from the quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) methodologies.}, keywords = {σ-Hole,Cooperativity,DFT,S-triazine}, url = {https://www.physchemres.org/article_3817.html}, eprint = {https://www.physchemres.org/article_3817_729dd5cf155c897d64ecf66719e81faf.pdf} } @article { author = {Bouachrine, Mohammed and Belghiti, Najat and Nassiri Bennani, Mohammed and Bouzzine, Simohamed and Hamidi, Mohamed}, title = {The DFT chemical investigations of optoelectronic and photovoltaic properties of short-chain conjugated molecules}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {11-20}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.3819}, abstract = {The research in the short-chain organic -conjugated molecules has become one of the most interesting topics in the fields of chemistry. These compounds have become the most promising materials for the optoelectronic device technology. The use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The control of the band gap of these materials is a research issue of ongoing interest. In this work, a quantum chemical investigation has been performed to explore the optical and electronic properties of a series of different short-chain compounds based on thiophene. Different electron side groups were introduced to investigate their effects on the electronic structure. The theoretical knowledge of the HOMO and LUMO energy levels of the components is basic in studying organic solar cells so the HOMO, LUMO, Gap energy and the photovoltaic properties of the studied compounds have been calculated and reported. These properties suggest these materials as a good candidate for organic solar cells.}, keywords = {pi-conjugated molecules,organic solar cells,DFT,low band-gap,thiophene}, url = {https://www.physchemres.org/article_3819.html}, eprint = {https://www.physchemres.org/article_3819_93d1f2f4043b9a39e90968ed2581a820.pdf} } @article { author = {Bohre, Ashish and Avasthi, Kalpana and Shrivastava, O.P.}, title = {Crystal Chemistry of Immobilization of tetravalent Ce and Se in ceramic matrix of sodium zirconium phosphates}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {21-29}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.3816}, abstract = {The safe and effective management of radioactive waste has been given utmost importance from the very inception of nuclear industry in India and it covers the entire range of activities from handling, treatment, conditioning, transport, storage and finally disposal. Radioactive waste is generated at various stages of the nuclear fuel cycle, which includes the mining and milling of uranium ore, fuel fabrication, reactor operation and spent fuel reprocessing Sodium zirconium phosphate (here after NZP) is a typical host material capable of converting the intermediate level waste resulting from light water reactor (LWR) fuel reprocessing in to a single-phase material with good stability, high integrity and long durability. The crystal chemistry of NaZr1.9Ce0.1P3O12 and NaZr1.9Se0.1P3O12 phases has been investigated using general structure analysis system programming. The Se/CeNZP phases crystallize in the space group R-3c and Z = 6. Powder diffraction data have been subjected to rietveld refinement to arrive at a satisfactory structural convergence of R-factors. The PO4 stretching and bending vibrations in the infrared (IR) region have been assigned. SEM and EDAX analysis provide evidence of Ce and Se in the matrix.}, keywords = {Ceramic,Se/CeNZP,Powder XRD,GSAS,Rietveld refinement}, url = {https://www.physchemres.org/article_3816.html}, eprint = {https://www.physchemres.org/article_3816_73c57a8c0350bba8333bd0cbb44a08bf.pdf} } @article { author = {Oftadeh, Mohsen and Gholamian, Marzieh and Abdallah, Hassan}, title = {Sulfur Dioxide Internal and External Adsorption on the Single-Walled Carbon Nanotubes: DFT Study}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {30-40}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.3824}, abstract = {Density-functional theory is used to investigate sulfur dioxide physisorption inside and outside of single-wall carbon nanotube of (5,0) and (5,5). This study is conducted at B3LYP/6-31G* level of theory. Sulfur dioxide molecule is studied with axis oriented parallel or perpendicular to the nanotube wall. Both internal and external adsorption on nanotubes is increased with the angle of interaction being at maximum of 90° to the tube axis. The harmonic frequencies are computed from analytical derivatives for all species in order to define the minimum energy structures. The lowest value of HOMO and LUMO energies is obtained in the process of the adsorption on the external wall of (5,5) nanotube. The dipole moment of the SWCNTs-SO2 system is highly increased and it is more than SWCNTs- H2S and SWCNTs- CO2. The lowest ΔGtot for SO2 on the outside wall of (5,0) is obtained while this quantity is positive and not a favorable adsorption process for H2S on the nanotubes. The NBO analysis showed the change in the electronic structure of nanotubes could be suitable for fabricating sensors.}, keywords = {sulfur dioxide (SO2),single-wall carbon nanotube (SWCNT),Adsorption energy,Density functional theory (DFT)}, url = {https://www.physchemres.org/article_3824.html}, eprint = {https://www.physchemres.org/article_3824_b8be767f2aae1e66cc7429b097736a30.pdf} } @article { author = {Sabzyan, Hassan and Taghavi, Fariba}, title = {Theoretical study of magnetic susceptibility and optical activity of small molecules containing one chiral center}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {41-52}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.3859}, abstract = {In the first part of this work, correlation between optical activity and elements of magnetic susceptibility tensor (MST) for five classes of model small molecules containing a single chiral center has been studied using quantum computational techniques at DFT-B3LYP level of theory with 6-311G basis set. Several molecular properties are used to reduce the MST elements prior to the examination of the correlation. This study showed a close correlation between optical activity and the off-diagonal MST elements reduced by the electronic spatial extent . In the second part of this work, effects of the type of substitutions and their distances from the chiral center on the optical activity of these molecules have been investigated. Results of this work show that optical activity is reduced effectively upon distancing the substitution groups from the chiral center. Furthermore, the set of substitutions with higher electron densities and larger differences in their electronic structures result in higher optical activity.}, keywords = {Optical Activity,Magnetic Susceptibility,Correlation,Electronic Spatial Extent,Chirality}, url = {https://www.physchemres.org/article_3859.html}, eprint = {https://www.physchemres.org/article_3859_7ac1f1664d0f6f2811f8af6e29f655a8.pdf} } @article { author = {mousavipour, S. Hosien and Ramazani, Shapour and Pirhadi, Fatemeh}, title = {Reaction Dynamics of NH2+OH on an Interpolated Potential Energy Surface}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {53-67}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.3827}, abstract = {QCT calculations were performed to study the behavior of energized NH2OH formed by association collision of NH2 radical with OH radical. A potential energy surface that describes the behavior of the title reaction has been constructed by interpolation of ab initio data. H2O, HON, HNO, NH3, O, H2NO, cis or trans-HONH, and H products and two vibrationally energized NH2OH and NH3O adducts were observed. The reaction probabilities and effective cross sections for different products are reported. The branching ratios for different channels are in good agreement with the previous studies. The net rate constant for consumption of the reactants is calculated as a function of effective cross section. The calculated QCT rate constant for the formation of NH2OH is lower than the calculated rate constant from our previously study based on the RRKM-TST method that could be due to ignorance of stabilization process in QCT calculations. In QCT calculations the only reason for the stabilization of these highly vibrationaly energized intermediates is intramolecular vibrational redistribution (IVR) process.}, keywords = {Reaction dynamics,Amidogen radical,hydroxyl Radical}, url = {https://www.physchemres.org/article_3827.html}, eprint = {https://www.physchemres.org/article_3827_780c87bf6f3b723f1b0a89d4e494315d.pdf} } @article { author = {Chahkandi, Behzad and Chahkandi, Mohammad and Ashrafi, Bentolhoda}, title = {Conformational analysis of N- and C-terminally protected tripeptide model glycyl-isoleucine-glycyl: An ab initio and DFT study}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {68-75}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.3858}, abstract = {An ab initio and density functional theory (DFT) study about conformational analysis of tripeptide model HCO−GLY−L−ILE−GLY−NH2 is presented. The tripeptide was scanned about initial, central, and final residues, separately while for every scanning procedure the two other residues had been kept in the β conformation and side chain (SC) dihedral angles were maintained on the gauche− (g‾) state (χ1, χ2 = ‒60). Conformers (L, L, D, D, D), (L, L, D), and (L, L, D, L) were found through scanning of the tripeptide about initial, central, and the last amino acids, respectively. At first, geometries of all conformers were optimized at the HF/6-31G (d) and B3LYP/6-31G (d) levels of theory. In the followings, their thermodynamic properties were obtained with performing of the frequency calculations at the same levels used for optimization. Finally, comparison of the calculated thermodynamic results of the found conformers to the tripeptide minima on Ramachandran map as the standard criteria proposed LLL as the most stable one.}, keywords = {Tripeptide structures,Ab initio calculations,DFT,Ramachandran map,conformers}, url = {https://www.physchemres.org/article_3858.html}, eprint = {https://www.physchemres.org/article_3858_f0021f04dc86b1a7ccda83f975d2728d.pdf} } @article { author = {Habibi-Yangjeh, Aziz and Poormohammadi-Ahandani, Zahra and Pirhashemi, Mahsa}, title = {Ultrasonic-assisted Method for Preparation of Cu-doped ZnS Nanoparticles in Water as a Highly Efficient Visible Light Photocatalyst}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {76-89}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.4012}, abstract = {Ultrasonic-assisted method was applied for preparation of Cu+2-doped ZnS nanoparticles (mole fractions of Cu+2 ions are 0.000, 0.015, 0.030 and 0.060) in water as a template-free and green method at 30 min. The prepared nanoparticles were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and UV–Vis diffuse reflectance spectra (DRS) techniques. In the prepared nanoparticles, Cu+2 ions are incorporated into the ZnS lattice. The nanoparticles have absorption edges at visible light region. The SEM images demonstrate that size of the nanoparticles decreases with Cu+2 content. To achieve maximum degradation efficiency, the influence of various operational parameters such as mole fraction of Cu+2 ions, ultrasonic irradiation time, catalyst weight, calcination temperature, concentration of methylene blue (MB) and pH of solution on the degradation rate constant was investigated under visible light irradiation and the results discussed. It was found that the degradation reaction followed pseudo first-order kinetics. The nanoparticles with 0.015 mole fraction of Cu+2 ions exhibit highest activity among the prepared samples.}, keywords = {Cu-doped ZnS,Photocatalysis,Ultrasonic irradiation,Nanoparticles}, url = {https://www.physchemres.org/article_4012.html}, eprint = {https://www.physchemres.org/article_4012_b57a8b92685862baca5c38bd6cba44d3.pdf} } @article { author = {Bordbar, Gholam and Mashayekhizadeh, N.}, title = {Thermodynamic properties of the ionized gas 3He}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {90-95}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.4560}, abstract = {In this article, we have calculated some thermodynamic properties for a system consisting of singy ionized 3He atoms and their corresponding removed electrons by employing the second quantization method at finite temperature. To perform the calculations, we have considered the kinetic term, and Coulomb interaction between the particles in our Hamiltonian. The calculated properties are free energy, specific heat and pressure. It is shown that all these properties are very temperature sensitive. For all temperatures and densities, we have seen that the main contribution to the internal energy comes from the kinetic term. Abstract Abstract Abstract Abstract Abstract Abstrac tAbstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstrac tAbstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstrac tAbstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstrac tAbstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstrac tAbstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract}, keywords = {Ionized gas,3He,second quantization method}, url = {https://www.physchemres.org/article_4560.html}, eprint = {https://www.physchemres.org/article_4560_012f23d2fa7ae56f43d0018f900c5641.pdf} } @article { author = {Zafarani-Moattar, Mohammed and Jafari, Parisa}, title = {Modeling of liquid–liquid equilibria of aqueous alcohol + salt systems using amodified NRTL}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {96-115}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.4533}, abstract = {The modified NRTL (m-NRTL) model is used to represent the excess Gibbs free energy of aqueous (alcohol + electrolyte) solutions. In this work, the m-NRTL model previously developed for representation of vapor-liquid equilibria for (polymer + salt + water) systems has been extended to represent liquid-liquid equilibria of (alcohol + salt + water) systems. The proposed extension is a modified of the extended NRTL model. The model provides a thermodynamic framework for both correlating and predicting the phase equilibrium of complex systems containing both electrolytes and alcohol. The utility of the model is demonstrated with successful representation of (liquid + liquid) equilibrium of several (alcohol + salt + H2O) systems at different temperatures. The liquid–liquid equilibria of the ternary systems involved and the mean activity coefficients of the salt + water systems were used simultaneously to obtain the adjustable parameters. For the several aqueous systems containing an alcohol and a salt the performance of this m-NRTL model was examined at the correlation of LLE data. In addition, the results of suggestion model were compared with those obtained using the Setschenow-type equation, extended Wilson (e-Wilson) and extended NRTL (e-NRTL) models.}, keywords = {Gibbs energy,Two-phase system,Alcohol + salt,m-NRTL model,e-Wilson model}, url = {https://www.physchemres.org/article_4533.html}, eprint = {https://www.physchemres.org/article_4533_bed8e85ce409b58c29bfa2e83d3a0bae.pdf} } @article { author = {Mahjani, Mohamad Ghasem and Moshrefi, Reza and Jafarian, Majid and Neshati, Jaber}, title = {Detecting pitting corrosion and its severity using wavelet entropy in electrochemical noise measurement}, journal = {Physical Chemistry Research}, volume = {2}, number = {1}, pages = {116-122}, year = {2014}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2014.4561}, abstract = {Entropy as a measure of uncertainty was used to represent the results of the wavelet technique in electrochemical noise analysis. The experimental signals were obtained by recording the electrochemical potential and current noise of 7075 aluminum alloy in 3.5% NaCl solution. The electrochemical potential and current noise were decomposed into 16 levels using Daubechies wavelets. Wavelet output etropy was calculated using a kernel density estimator and the Shanon equation. It was demonstrated that low frequency scales had the highest entropy magnitude for passivation of aluminum surfaces in all experiments. The entropy contribution to high frequency scales decreased with the appearance of pits and as the pits increased and enlarged on the electrode surfaces (detected by scanning electron microscopy). The amount of reduction in entropy magnitude was attributed to the severity of pitting corrosion. It appears that a wavelet-entropy plot is a promising method to differentiate between different types and the severity of corrosion.}, keywords = {Electrochemical noise,Entropy,Kernel density estimator,Corrosion type,Aluminum alloys}, url = {https://www.physchemres.org/article_4561.html}, eprint = {https://www.physchemres.org/article_4561_5b595c10fa30bfb5e7d8487b933d8bd0.pdf} }