Marvdasht Branch, Islamic Azad UniversityJournal of Physical Chemistry & Eleectrochemistry2008-92282120140101Solitonic States in Organic Conducting Polymers172296ENJournal Article20140617In a typical solitonic distribution, the soliton density is distributed over the entire molecule<br />and the present work shows how its density can be decomposed into solitonic and antisolitonic<br />components. It is found that there exists a unique electron as soliton over the anionic<br />nanoconductor, while there are many other solitons and antisolitons. The solitonic states are further<br />decomposed to the canonical molecule orbitals including the highest occupied molecular orbital<br />(HOMO) and lowest unoccupied molecular orbital (LUMO), and it is concluded that LUMO is not<br />necessarily occupied by one electron in the studied molecules. Also, analogous electrons were<br />found to be responsible for spin separation which is revealed from distinct contributions in different<br />molecular regions of the nanoconductor.Marvdasht Branch, Islamic Azad UniversityJournal of Physical Chemistry & Eleectrochemistry2008-92282120140101Theoretical investigation on the aromaticity of mono-substituted benzene derivatives by using cyclic reference7277136ENJournal Article20131012The degree of aromaticity of mono-substituted derivatives of benzene has been<br />investigated using a new index based on electric field gradient index, by using two mechanical<br />quantum methods with Gaussian 03. Two different basis sets have applied to study and the<br />results compared. This strategy has demonstrated that, due to violation of symmetry in have pisystems,<br />how the degree of aromaticity can have been changed. A comparison of the values of<br />our aromaticity index with other indices reveals a good correlation for these compoundsMarvdasht Branch, Islamic Azad UniversityJournal of Physical Chemistry & Eleectrochemistry2008-92282120140101Voltammetric determination of cysteine at a carbon paste electrode modified with Cu(II)-salen complex7881137ENJournal Article20131012The electrochemical behavior of a modified carbon paste electrode (MCPE) with N,N′<br />ethylenbis(salicylideneiminato)copper(II) complex ([Cu(II)-Salen]) was investigated as a new<br />sensor for cystein. The Britton-Robinson buffer with pH 5, 10% modifier in electrode, potential<br />scanning rate of 20 mVs-1 and puls height of 50 mV were used as the optimum condition for the<br />determination of cysteine using carbon paste electrode modified with Cu(II)-Salen complex. Under<br />these optimum conditions, the resulting electrode demonstrated linear response with cysteine<br />concentration in the range of 1-10 and 10-80 μM. The effects of potential interfering species were<br />studied and it was found that only thiocyanate ion interfered in cysteine determination and the<br />proposed procedure was free from most other interferences.Marvdasht Branch, Islamic Azad UniversityJournal of Physical Chemistry & Eleectrochemistry2008-92282120140101Study of lone pair description in molecules by the modified delocalized floating spherical Gaussian orbital method.8288138ENJournal Article20131012This research has been carried out to study and find a rather general description for a lone pair<br />orbital in molecules. Since the orbital parameters must be manageable in advance, and correct<br />geometry of the molecule (bond lengths) is depend on the appropriate lone pair description; the<br />FSGO method including optimization has been used to obtain orbital parameters and energy. The<br />proposed models for lone pair description have been tested by two molecules: HF and NH.29<br />models for HF and 23 models for NH have been used to obtain simultaneously correct bond length<br />and dipole momentum. We show that contribution of lone pair electrons in binding gives<br />satisfactory results. An approach which we called “Modified Delocalized Floating spherical<br />Gaussian orbital (MDFSGO)” method was performed for these molecules. The linear combination<br />of p-type and s-type orbital are tested. They can predict only correct bond length or dipole<br />momentum, but the contribution of lone pair electrons in binding can predict rather satisfactory<br />results for both bond length and dipole momentum. By using this method, the error of dipole<br />moment and bond length decrease from 229.75% to %9.72 and from 27.28% to 4.03% in HF<br />molecule. For NH, the error of dipole momentum changes from 256.45% to 8.023% and for bond<br />length from 32.84% to 1.92%.Marvdasht Branch, Islamic Azad UniversityJournal of Physical Chemistry & Eleectrochemistry2008-92282120140101Ion-Selective Carbon Paste Electrode Based on 2-Amino-N-benzthioazolyl Benzamide (ABTB) for Determination of Copper (II) by Potentiometric Method8996139ENJournal Article201310122-Amino-N-benzthioazolyl benzamide (ABTB) was synthesized, characterized and used for the<br />fabrication of a potentiometric sensor for Cu2+ metal ions. The electrode exhibits linear response to Cu<br />(II) over a wide concentration range (4.79×10 -8 – 1.85×10 -1 M) with Nernstian slope of 30 ± 1.5 mV<br />per decade. The electrode can be used in the pH range from 2 to 9. It has a fast response time of about<br />10 s and can be used for a period of four months with good reproducibility. The detection limit of this<br />electrode was 2.91×10 - 8 M. The proposed electrode shows a very good selectivity for Cu (II) over a<br />wide variety of metal ions. This chemically modified carbon paste electrode was successfully used for<br />the determination of Cu (II) in electronics waste sample solution.Marvdasht Branch, Islamic Azad UniversityJournal of Physical Chemistry & Eleectrochemistry2008-92282120140101A numerical renormalization group approach for calculating the spectrum of a vibronic system occurring in molecules or impurities in insulators97102140ENJournal Article20131012Theoretically, in order to describe the behavior of a spectrum, a mathematical model which<br />could predict the spectrum characteristics is needed. Since in this study a Two-state system has been<br />used like models which was introduced previously past and could couple with the environment, the<br />former ideas have been extended in this study. we use the second quantized version for writing this<br />Hamiltonian. First, the Hamiltonian of a rotational system is considered in a classic scale,<br />afterwards it is brought to a quantum scale. In the first step, the vibrations and quantum rotation is<br />illustrated for two atom molecules. Then it is devoted to Two-state system and dissipative Twostate<br />system.<br />In the second step, the rotation of a molecular group in a hindering potential is studied in the<br />classic and quantum scales. Finally, at the present of strong coupling constant the Hamiltonian has<br />been applied and a numerical renormalization group approach has been used for numerical solution.<br />Then, by using Hubbard operators, dynamical functions of this oprators are written. The fourier<br />transform of the Greens function is developed, then density of state is calculated.Marvdasht Branch, Islamic Azad UniversityJournal of Physical Chemistry & Eleectrochemistry2008-92282120140101Electrochemical fabrication of polypyrrole nanofibers and their characterization103108141ENJournal Article20131012Polypyrrole (PPy) nanofibers have been fabricated on glassy carbon electrode (GCE) using<br />electrochemical technique. Electropolymerization of pyrrole (Py) for the fabrication of PPy nanofibers<br />was occurred on GCE by applying a fixed potential of about 0.85 V for 120 sec in a mild basic solution<br />containing sodium carbonate and sodium perchlorate. In the mild basic media, the monomer, Py, is<br />oxidized on GCE at a potential of about 0.85 V vs. Ag/AgCl and the oxidation product of Py i.e.<br />polypyrrole nanofibers is strictly adsorbed on the electrode surface. Cyclic voltammetry,<br />electrochemical impedance spectroscopy and scanning electron microscopy were used for studying the<br />electrochemical and morphological properties of electropolymerized PPy conducting polymer. These<br />techniques confirm the electropolymerization of Py as PPy nanofibers on the electrode surface.Marvdasht Branch, Islamic Azad UniversityJournal of Physical Chemistry & Eleectrochemistry2008-92282120140101An equation of state for argon109113142ENJournal Article20131012An analytical equation of state was applied to calculate the thermodynamic properties for argon.<br />The equation of state is that of Song and Mason. It is based on a statistical-mechanical perturbation<br />theory of the hard convex bodies and can be written as fifth-order polynomial in the density. There<br />exist three temperature-dependent parameters: the second virial coefficient, an effective molecular<br />volume, and a scaling factor for the average contact pair distribution function of hard convex<br />bodies. We used Lennard-Jones (12-6) potential for calculation of temperature-dependent<br />parameters. The equation of state has been applied to calculate thermodynamic properties including<br />the vapor pressure curve, the compressibility factor, fugacity coefficient for argon. The agreement<br />with experiment is good.