Masoumeh Moghimi

Islamic Azad University, Teheran, Tehrān, Iran

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Publications (24)28.7 Total impact

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    ABSTRACT: Density functional theory (DFT) calculations were performed to investigate the electronic and structural properties of pristine and Ga-doped (6,0) zigzag silicon carbide nanotubes (SiCNTs) as a p-semiconductor at the B3LYP/6-31G* level of theory in order to evaluate the influence of Ga doping on (6,0) zigzag SiCNTs. We extended the DFT calculation to predict the electronic structure properties of Ga-doped silicon carbide nanotubes, which are very important for production of solid-state devices and other applications. To this aim, pristine and Ga-doped SiCNT structures in two models (GaSi and GaC) were optimized and structural properties, the isotropic (CSI) and anisotropic (CSA) chemical shielding parameters for the sites of various 29Si and 13C atoms, and quantum molecular descriptors were calculated in the optimized structures. The optimized structures, NMR parameters, and the electronic energies for the GaSi and GaC of the (6,0) zigzag SiCNT models show that the GaSi model is a better p-semiconductor from GaC model in production of solid-state devices. Graphical Abstract
    Journal of Cluster Science 03/2013; · 1.11 Impact Factor
  • Mohammad T Baei, Ali Ahmadi Peyghan, Masoumeh Moghimi
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    ABSTRACT: Density functional theory (DFT) calculations at the B3LYP/6-31G* level were performed to investigate the electronic structure properties of Si-doped boron phosphide nanotubes (BPNTs), which are very important for production of solid-state devices and other applications, in order to evaluate the influence of Si-doped (4,4) armchair BPNTs. . The chemical shielding isotropic and anisotropic parameters at the sites of various 11B and 31P atoms, quadrupole coupling constant, and asymmetry parameter at the 11B atom sites in the two Si-doped (4,4) armchair BPNT models were calculated. The calculated results showed that the binding energies are not attractive and do not characterize a chemisorption process. In comparison to the pristine model, the band gap of the two Si-doped BPNT models is reduced and increases their electrical conductance. The dipole moment of the two Si-doped BPNT structures displays notable changes with respect to the pristine model. The NMR and NQR results indicate that in the SiB and SiP models, the electronic structure properties of the SiB model are more strongly influenced than those of the SiP model, and electronic sites of the B atoms in the SiB model show more changes than the SiP model in the Si doping processes. Decreases in global hardness, energy gap, and ionization potential because of Si doping processes lower the stability and increase the reactivity of the Si-doped BPNT models. Graphical abstract
    Monatshefte fuer Chemie/Chemical Monthly 10/2012; · 1.63 Impact Factor
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    ABSTRACT: Phenol adsorption on the external surface of H-capped pristine, Ga-doped, and Pd-decorated (6,0) zigzag boron phosphide nanotubes (BPNTs) was studied by using density functional theory (DFT) calculations. The results indicate that the hydroxyl group of phenol prefers to attach to the Ga and Pd sites and thus the Ga-doped and Pd-decorated (6,0) can be used for removing phenol. The calculated adsorption energy of phenol on the Ga-doped and Pd-decorated (6,0) BPNTs are −0.724 and −420 eV, respectively and about 0.28 and 0.27 electrons are transferred from phenol to the nanotubes. In addition, the value for the fractional number of electrons transferred is negative, indicating that phenol act as an electron donor. Frontier molecular orbital theory (FMO) and structural analyses show that the high polar surface bonds and large bond lengths of the Ga-doped and Pd-decorated (6,0) BPNT surfaces increase the adsorption of phenol on the nanotube models. This study can be useful in removing phenol and development of many catalytic processes for formation of a variety of useful compounds.
    Journal of Cluster Science 10/2012; · 1.11 Impact Factor
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    ABSTRACT: The behavior of the imidazole adsorbed on the external surface of H-capped (6,0) zigzag single-walled boron nitride nanotube as a functional group was studied by using density functional calculations in gas and solvent phases. Geometry optimizations were carried out at the B3LYP/6-31G* level of theory using a locally modified version of the GAMESS electronic structure program. Our results show that the pristine boron nitride nanotubes can significantly detect the imidazole. In both phases, the binding energy for the imidazole/BNNT complex is negative and presenting characterizes an exothermic process. The increase in global hardness and energy gap due to imidazole adsorption lead to an increasing of the stability and decrease in reactivity of the complex in the both phases. Also, presence of polar solvent increases the electron donor of imidazole and electrophilicity of the nanotube. This study may provide new insight to the development of functionalized boron nitride nanotubes as drug delivery systems for virtual applications. Graphical Abstract Graphics for use in the table of contents.
    Journal of Cluster Science 10/2012; · 1.11 Impact Factor
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    ABSTRACT: Density functional theory (DFT) calculations at the B3LYP/6-31G* level were performed to investigate the adsorption of phenol on the pristine, Ga-, and In-doped (4,4) armchair single-walled boron nitride nanotubes (BNNTs). In comparison with the weak physical adsorption on the pristine BNNT, the hydroxyl group of phenol can lead to significant absorption on the BNNTs, thus suggesting a means for phenol storage. Binding energies corresponding to adsorption of phenol on the Ga and In sites in the model nanotubes was calculated to be −1.18 and −0.93 eV, respectively, and about 0.11 and 0.17 electron are transferred from phenol to the model nanotubes. In addition, the value for the fractional number of electrons transferred is negative, indicating that phenol acts as an electron donor. Frontier molecular orbital theory (FMO) and structural analyses show that the low energy level of the LUMO, high polar surface bonds, and large bond lengths of the Ga and In-doped (4,4) BNNT surfaces increase the adsorption of phenol on the model nanotubes.
    Computational and Theoretical Chemistry 09/2012; 997:63–69. · 1.14 Impact Factor
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    ABSTRACT: An efficient synthesis of thiazines from the three component reactions between dialkyl acetylenedicarboxylates, arylisothiocyanates and N-nucleophiles at room temperature in water as the solvent is described.
    Chinese Chemical Letters 09/2012; 23(9):1007–1010. · 1.18 Impact Factor
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    ABSTRACT: We have analyzed the effect of external electric field on the zigzag (6,0) single-wall BC(2)N nanotube using density functional theory calculations. Analysis of the structural parameters indicates that the nanotube is resistant against the external electric field strengths. Analysis of the electronic structure of the nanotube indicates that the applied parallel electric field strengths have a much stronger interaction with the nanotube with respect to the transverse electric field strengths and the nanotube is easier to modulate by the applied parallel electric field. Our results show that the properties of the nanotube can be controlled by the proper external electric field for use in nano-electronic circuits.
    Journal of Molecular Modeling 07/2012; · 1.98 Impact Factor
  • Mohammad T Baei, Ali Ahmadi Peyghan, Masoumeh Moghimi
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    ABSTRACT: Structural, electronic, and electrical responses of the H-capped (6,0) zigzag single-walled aluminum nitride nanotube was studied under the parallel and transverse electric fields with strengths 0-140 × 10(-4) a.u. by using density functional calculations. Geometry optimizations were carried out at the B3LYP/6-31G* level of theory using a locally modified version of the GAMESS electronic structure program. The dipole moments, atomic charge variations, and total energy of the (6,0) zigzag AlNNT show increases with increase in the applied external electric field strengths. The length, tip diameters, electronic spatial extent, and molecular volume of the nanotube do not significantly change with increasing electric field strength. The energy gap of the nanotube decreases with increases of the electric field strength and its reactivity is increased. Increase of the ionization potential, electron affinity, chemical potential, electrophilicity, and HOMO and LUMO in the nanotube with increase of the applied parallel electric field strengths shows that the parallel field has a much stronger interaction with the nanotube with respect to the transverse electric field strengths. Analysis of the parameters indicates that the properties of AlNNTs can be controlled by the proper external electric field.
    Journal of Molecular Modeling 05/2012; 18(9):4477-89. · 1.98 Impact Factor
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    ABSTRACT: Density functional theory (DFT) calculations were performed to investigate the electronic structure properties of pristine and Si-doped aluminum nitride nanotubes as n or P-semiconductors at the B3LYP/6-31G* level of theory in order to evaluate the influence of Si-doped in the (6,0) zigzag AlNNTs. We extended the DFT calculation to predict the electronic structure properties of Si-doped aluminum nitride nanotubes, which are very important for production of solid-state devices and other applications. To this aim, pristine and Si-doped AlNNT structures in two models (Si(N) and Si(Al)) were optimized, and then the electronic properties, the isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (27)Al and (14)N atoms, NQR parameters for the sites of various of (27)Al and (14)N atoms, and quantum molecular descriptors were calculated in the optimized structures. The optimized structures, the electronic properties, NMR and NQR parameters, and quantum molecular descriptors for the Si(N) and Si(Al) models show that the Si(N) model is a more reactive material than the pristine or Si(Al) model.
    Journal of Molecular Modeling 05/2012; 18(9):4427-36. · 1.98 Impact Factor
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    ABSTRACT: Nitrous oxide adsorption on the pristine (6,0) magnesium oxide nanotube was studied by using density functional theory calculations. We present the nature of the N2O interaction in selected sites of the nanotube. Adsorption energies corresponding to adsorption of the N2O on the nanotube were calculated to be in the range −11.67 to −22.21 kJ mol−1. Our results indicate that the N2O molecule has a weak physical adsorption on the pristine models due to weak Van der Waals interaction between the nanotubes and N2O molecule. The important results can be useful in production of the N2O sensors.
    Chinese Chemical Letters 02/2012; 23:1275–1278. · 1.18 Impact Factor
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    ABSTRACT: Thiophene adsorption on pristine (6,0) aluminum nitride nanotubes was studied by using density functional theory calculations, by means of B3LYP and M06-L functionals. We present the nature of the thiophene interaction in different sites of the nanotube. Adsorption energies corresponding to adsorption of thiophene are calculated to be in the range −18.90 to −21.06 kJ mol−1. It has been shown that the thiophene molecule has a weak physical adsorption on the pristine models due to weak Van der Waals interaction between the nanotubes and thiophene molecule. The charge transfer between thiophene and the AlNNT is minimal and the electronic properties of the nanotubes are not affected by the thiophene adsorption. Also, with change of tube type, more efficient binding could not be achieved. The results indicate that transition metal nanoclusters are more suitable catalyst with respect to nontransition metal nanotubes in the petroleum industry.
    Phosphorus Sulfur and Silicon and the Related Elements 01/2012; · 0.60 Impact Factor
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    ABSTRACT: Density functional theory (DFT) calculations at the B3LYP/6-31G∗ level were performed to investigate the effect of external electric field on the H-capped (6, 0) zigzag single-walled germanium carbide nanotube (GeCNT). With increase in the applied external electric field strengths, the energy gap, dipole moment, and total energy of the (6, 0) zigzag CNT is increased. The length, tip diameters, and electronic spatial extent of the nanotube do not significantly change with increasing electric field strength. Analysis of the structural parameters indicates that the resistance of nanotube against the applied parallel electric field is less than the resistance of nanotube against the applied transverse electric field. The large variations of energy gap, quantum molecular descriptors, dipole moment, molecular orbital energy, and total energy of the (6, 0) zigzag germanium carbide nanotube with increase of the transverse electric field strengths shows that the transverse electric field has a much stronger interaction with the nanotube with respect to the parallel electric field strengths. Analysis of the parameters indicates that the properties of GeCNTs can be controlled by the proper external electric field for use in nano-electronic circuits.
    Superlattices and Microstructures 01/2012; 52(6):1119-1130. · 1.56 Impact Factor
  • Chin. Chem. Lett. 01/2012; 23:1275–1278.
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    ABSTRACT: The behavior of the cyano radical (·C≡N) adsorbed on the external surface of a (6,0) zigzag single-walled carbon nanotube was studied by using density functional calculations. Geometry optimizations were carried out at the B3LYP/6-31G* level of theory using the Gaussian 03 suite of programs. Our results show that the pristine carbon nanotubes can detect a ·CN. The calculated binding energy of the ·CN-attached (6,0) single-walled carbon nanotube indicates that the ·CN can be best adsorbed at a carbon site in a C-down orientation (binding energy −356.5 kJ mol−1) and can thus be used in detection and storage of this species. The density of the state spectra, electron density plot, and HOMO and LUMO for the adsorbed species characterize it as a chemisorption process. The increase in global hardness, energy gap, and ionization potential because of the ·CN functional group point to an increase of stability and decrease in reactivity and electrophilicity of the ·CN-attached (6,0) CNT model. In addition, the ΔN value for the ·CN/CNT complex is positive, indicating that the ·CN acts as an electron acceptor. Graphical Abstract
    Monatshefte fuer Chemie/Chemical Monthly 01/2012; · 1.63 Impact Factor
  • Journal of Cluster Science 01/2012; · 1.11 Impact Factor
  • Mohammad T. Baei, Masoumeh Moghimi, Jamal Kazemi Asl
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    ABSTRACT: The behavior of the adsorptions of the H2O2 inside the BNNT through DFT calculations was studied by using density functional calculations. Geometry optimizations were carried out at the B3LYP/6-31G* level of theory using the Gaussian 98 suites of programs. Taking the torsional motion of H2O2 inside the (5, 5) armchair boron nitride nanotube as a sample, the interaction between the guest species and the nanotube and the dipole moment of the different geometries are discussed. Various orientations of H2O2 inside the (5, 5) boron nitride nanotube are considered. Among the three types of orientations AT, PTA, and PTP for the (5, 5) armchair boron nitride nanotube, the AT-state geometries shows stabilization of the guest species inside the nanotube. We also provide the effects of H2O2 adsorption on the electronic properties of the nanotube.
    Fullerenes Nanotubes and Carbon Nanostructures - FULLER NANOTUB CARBON NANOSTR. 01/2012; 20(3):243-248.
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    ABSTRACT: Electronic structure properties including bond lengths, bond angles, tip diameters, dipole moments (μ), energies, band gaps, NMR, and NQR parameters were calculated using density functional theory for Ge-doped boron phosphide nanotubes (BPNTs). Geometry optimizations were carried out at the B3LYP/6-31G∗ level of theory the Gaussian 03 program suites. The isotropic (CSI) and anisotropic (CSA) chemical shielding parameters for the sites of various 11B and 31P atoms, and quadrupole coupling constant (CQ) and asymmetry parameter (ηQ) at the sites of various 11B nuclei were calculated for Ge-doped (6,0) zigzag BPNT models. The calculations indicated that average B–P bond lengths of the GeB model are larger than average B–P bond lengths of pristine and the GeP models. For the GeB and GeP models, the diameters values changes were almost negligible. The dipole moments of the two Ge-doped BPNT structures show slightly changes due to the Ge-doping with respect to the pristine model. In comparison with the pristine model, band gaps of the two Ge-doped models are reduced and increase their electrical conductance. The changes in the NMR and NQR parameters due to the Ge-doping are more significant for the GeB model than for the GeP model with respect to the pristine model.
    Computational and Theoretical Chemistry. 10/2011; 972(s 1–3).
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    ABSTRACT: The structural properties, NMR and NQR parameters in the pristine and NH3-attached (6,0) zigzag BPNTs model were calculated using DFT methods in order to evaluate the influence of NH3-attached on the (6,0) zigzag BPNTs for the first time. Geometry optimizations were carried out at the BLYP, B3LYP/6-31G* levels of theory using the Gaussian 03 program suites. The chemical shielding (CS) parameters for the sites of various 11B and 31P atoms and quadrupole coupling constant (CQ), and asymmetry parameter (ηQ) at the sites of various 11B nuclei were calculated in the pristine and the NH3-attached (6,0) zigzag BPNTs model. The values of dipole moments detect notable changes due to direct effect of the NH3-attached on the BPNTs; however, the tip diameters are slightly significant changed in comparison to the pristine models and the gap energies of the NH3-attached BPNT do not detect any changes in comparison to the pristine model. For the NH3-attached BPNT, the NMR values for the 11B14 atom which is directly bonded to the NH3 molecule and the 31P atoms that directly bonded to the 11B14 atom in the BPNT are significantly changed. CSI parameters of the atoms are increased whereas CSA parameters of the atoms are decreased. The NQR results showed that in BPNTs, the B atoms at the edges of nanotubes play dominant roles in determining the electronic behaviors of BPNTs and the average value of CQ (11B) and ηQ for the NH3-attached (6,0) zigzag BPNTs is further in comparison to the pristine model.
    Computational and Theoretical Chemistry. 07/2011; 967(1).
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    ABSTRACT: Protonation of the highly reactive 1:1 intermediate produced in the reaction between triphenylphosphite and activated acetylene by sulfonamide leads to a phosphonate ylide, which undergoes methanol elimination in the presence of moisture to produce a highly functionalized sulfonamide phosphonate diester. A dynamic nuclear magnetic resonance (NMR) effect is observed in the H NMR spectra of this compound as a result of restricted rotation around the single C‒N bond. The coalescence temperature was observed at TC = 352.5 K, and the free energy of activation (ΔG) for this process is 75.6 ± 2 kJ.mol.GRAPHICAL ABSTRACT
    Phosphorus Sulfur and Silicon and the Related Elements 01/2011; 186(7):1428-1435. · 0.60 Impact Factor
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    ABSTRACT: Abstract Nuclear magnetic resonance (NMR) parameters including isotropic and anisotropic chemical shielding parameters and electronic structures were calculated using density functional theory (DFT) for silicon–carbide-doped boron phosphide nanotubes. Geometry optimizations were carried out at the B3LYP/6-31G* level of theory using the Gaussian 03 program suite. The isotropic and anisotropic chemical shielding parameters were calculated for the sites of various 13C, 29Si, 11B, and also 31P atoms in pristine and SiC-doped (6,0) zigzag boron phosphide nanotube models. The calculations indicated that doping of 11B and 31P atoms by C and Si atoms had a more significant influence on the calculated shielding tensors than did doping of the B and P atoms by Si and C atoms. In comparison with the pristine model, Si- and C-doping of P and B sites of the zigzag nanotubes reduces the energy gaps of the nanotubes and increases their electrical conductance. Graphical Abstract
    Monatshefte fuer Chemie/Chemical Monthly 01/2011; 142(8):783-788. · 1.63 Impact Factor