Papers by Fatemeh Houshmand
Research Square (Research Square), Feb 1, 2023
Silica nanoparticles (SNP) are extremely promising tools in nanotechnology and nanomedicine. In t... more Silica nanoparticles (SNP) are extremely promising tools in nanotechnology and nanomedicine. In this investigation, we aim at obtaining the optimized structures and evaluate the geometries of the ground state for (SiO2) n (n = 16,20) nanoclusters. The electronic properties computed by density functional theory (DFT) with GGA approximation and also SCC-DFTB with hybrid Slater-Koster les are investigated and the effect of functionalization on such properties is discussed. Solvolysis of these structures is examined and it is shown that the highest occupied and lowest unoccupied molecular orbital states shift to obviously higher energy levels which lead to more stable hydrogenated nanoclusters. The stability of nanoclusters rises by functionalization with amino and methylamine groups. Charge analysis of functionalized systems indicates the reactivity of nanoclusters. The results obtained in this paper are useful for chemical and biochemical applications of silica nanostructures.
Frontiers in Health Informatics
Introduction: Silica nanoparticles (SNP) are extremely promising tools in nanotechnology and nano... more Introduction: Silica nanoparticles (SNP) are extremely promising tools in nanotechnology and nano medicine. In most of applications such as capture and release of bacteriophage viruses the nano-structures of silica are coated by bio-compatible groups such as amine compounds. The presence of amino groups on the surface of the biosensors enables the installation of analyte receptors and antifouling agents such as oligo (ethylene oxide). Therefore, in this study, the electronic and structural properties of Core-Shell amino- Silica Nanoparticles are investigated.Material and Methods: In this investigation, we aim at obtaining the optimized structures and evaluate the geometries of the ground state for (SiO2) n (n=16, 20) nanoclusters. The electronic properties computed by density functional theory with GGA approximation and SCC-DFTB with hybrid Slater-Koster files are investigated and the effect of functionalization on such properties is discussed.Results: Solvolysis of studied structur...
Journal of Molecular Modeling
Physica E: Low-dimensional Systems and Nanostructures, 2018
Effect of functionalization of BN-doped (6 ,3) Chi r a l single walled carbon nanotubes b y diffe... more Effect of functionalization of BN-doped (6 ,3) Chi r a l single walled carbon nanotubes b y different nitrogen containing nucleophilic groups on th ei r elect r onic p r op erti es was investigated by DFT method at B3LYP level of the theory. The binding energies for all the studied systems were between-8.70 and-15.06 kcal/mol and are in the order imidazole >Pyrazole > ammonia > pyridine, which is analogous to the pKa. Imidazole attached tube shows a smaller energy gap, 1.50 eV, respect to an isolated BN-doped (6 ,3) Chi ra l single walled carbon nanotube, 1.64 eV. For the other situations, change of the energy gaps was not considerable, which is in agreement with the results obtained for the densities of states. The natural bond orbital analysis was performed.
Asian Journal of Nanoscience and Materials, 2019
The present study is an attempt to provide an insight into the stability, in terms of interaction... more The present study is an attempt to provide an insight into the stability, in terms of interaction energy and thermodynamic parameter, and reactivity, quantified by reactivity descriptors, of the chitosan-MX and its analogous (EMX and ZMX) system. In this system a component is, MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone) a mutagenic halogenated disinfection by products which present in drinking water. And, chitosan is an eco-friendly nano-adsorbent to remove oils, grease, heavy metals and the fine particulate matter from water solution. Electronic and structural properties of chitosan during functionalization by metal were studied by density functional theory (DFT) calculations. Isolated and functionalized chitosan were optimized and their properties were evaluated. The results indicated that the properties of linking sites detect the most significant effects of functionalization process. Degradation efficiency of MX and its analogous in water solvent and also the possi...
Journal of Molecular Modeling, 2020
Graphdiyne-based nanotubes (GDNTs) are a novel type of carbon nanotubes. While conventional carbo... more Graphdiyne-based nanotubes (GDNTs) are a novel type of carbon nanotubes. While conventional carbon nanotubes (CNTs) are generated by rolling graphene sheets, GDNTs are generated by rolling sheets that are similar to graphene but where the edges are elongated by the introduction of additional acetylene bonds between vertices (C 6 aromatic rings). Such nanotubes are predicted to have many useful practical applications, but a thorough understanding of the relationship between their structure and their physical properties is still missing. We present a theoretical study of the electronic and optical properties of GDNTs. The structural, electronic, and optical properties of GDNTs with different diameters (i.e., 2-10 additional acetylene bonds) have been studied systematically by using density function theory (DFT) and self-consistent charge density functional tight-binding (SCC-DFTB) and by solving the Bethe-Salpeter equation (BSE), with and without considering the electron-hole interactions. The results indicate that the GDNTs are semiconductors with the direct band gap in close range, which is beneficial for photoelectronic devices and applications. Moreover, the absorption spectra of the GDNTs with different edge structures, (armchair, and zigzag) revealed little differences between the optical spectra of armchair and zigzag GDNTs, which could mean that fine separation between those structures (a process that is likely difficult and expensive in practice) will not be necessary. Importantly, the nanotubes were highly stable based on their cohesive energies, and their exciton binding energies were as large as about~1 eV. From a methodological point of view, SCC-DFTB was found to be in agreement with more elaborate DFT calculations for most systems.
International Journal of Hydrogen Energy, 2018
Graphdiyne (GDY) is a new member of carbon allotropes consisting of sp and sp 2 hybridized carbon... more Graphdiyne (GDY) is a new member of carbon allotropes consisting of sp and sp 2 hybridized carbon atoms. In this work, the hydrogen adsorption on Calcium (Ca) decorated GDY and the influence of adatom on structural properties of GDY are investigated, using first principles plane wave calculations with Van der Waals corrections. The results show that similar to graphyne (GY) and unlike carbon nanotube (CNT), fullerene and graphene, clustering of Ca on GDY hinders due to the higher binding energy of the adatom to the carbon frame than the Ca cohesive energy. It can be seen that the Ca-decoration promotes hydrogen storage capacity of GDY, extremely (E ads ¼ À0.266 and À0.066 eV for Ca-decorated and pristine GDY, respectively). It is concluded that, the best site for the Ca trapping is 18membered ring in which, Ca lies in-plane of GDY (E ads ¼ À3.171 eV). Fourteen H 2 molecules (with the average adsorption energy of~0.2 eV/H 2) can be adsorbed on the Ca atom from one side. The hydrogen storage capacity is estimated to be as high as 17.95 wt% for the both sides of GDY. So, the Ca-decorated GDY is offered as a promising candidate for hydrogen storage applications.
Graphyne and graphdiyne families of flat carbon (sp 2 /sp) networks with high degrees of π-conjun... more Graphyne and graphdiyne families of flat carbon (sp 2 /sp) networks with high degrees of π-conjunction are attracting much attention due to their promising electronic, optical, and mechanical properties. In the present investigation we have studied the structural, mechanical, electrical and optical properties of halogenated graphdiyne and graphyne. The optical spectra of pure and halogenated structures are calculated. The optical absorption is dominated by excitonic effects with a high electron-hole binding energy within the Bethe-Salpeter equation. Band structures of graphdiyne and halogenated graphdiyne show that these nanostructures are semiconductors with a direct band gap of ~0.5 eV at the center of Brillouin zone. Halogenation of graphdiyne can effectively modulate the band gap. The second-order elastic constants and other related quantities such as the Young’s modulus and Poisson’s ratio have also been calculated in the present work.
Asian Journal of Nanoscience and Materials, 2019
The present study is an attempt to provide an insight into the stability, in terms of interaction... more The present study is an attempt to provide an insight into the stability, in terms of interaction energy and thermodynamic parameter, and reactivity, quantified by reactivity descriptors, of the chitosan-MX and its analogous (EMX and ZMX) system. In this system a component is, MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone) a mutagenic halogenated disinfection by products which are present in drinking water. In this sense, chitosan is an eco-friendly nano-adsorbent to remove oils, grease, heavy metalsand the fine particulate matter from water solution. Electronic and structural properties of chitosan during functionalization by metal were studied by density functional theory (DFT) calculations. Isolated and functionalized chitosan were optimized and their properties were evaluated. The results indicated that the properties of linking sites detect the most significant effects of functionalization process. Degradation efficiency of MX and its analogous in water solvent and a...
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Papers by Fatemeh Houshmand