Yazar "Dalgic, Seyfettin" seçeneğine göre listele
Listeleniyor 1 - 7 / 7
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A comparative DFT study on Al- and Si- doped single-wall carbon nanotubes (SWCNTs) for Ribavirin drug sensing and detection(Elsevier Sci Ltd, 2023) Dalgic, Serap Senturk; Al-Sawaff, Zaid H.; Dalgic, Seyfettin; Kandemirli, FatmaIn this work, we have presented a comparative study on Ribavirin (RBV) drug sensing and detection on the pristine and functionalized single-wall carbon nanotubes (f-SWCNTs) by Density Functional Theory (DFT) method. The pristine and metal-doped zigzag (4,0) and (6,0) SWCNTs were first considered for the RBV adsorption. All the probable positions of RBV adsorption were investigated to find which one is energetically favourable. The topology analysis of the Quantum theory of atoms in a molecule (QTAIM) with non-covalent interactions (NCI-RDG), Frontier molecular orbitals (FMO), Density of states (DOS), and non-linear optical (NLO) analysis were carried out to understand the molecular structure, electrical, electronic and optical prop-erties of complexes. The charge analysis indicates that charge transfer is from the adsorbed RBV to the pristine and metal-doped (4,0) and (6,0) SWCNTs. The highest values of adsorption energies for Al-, Si-doped and pristine (4,0) SWCNTs were determined as-34.688,-87.999 and-10.382 kcal/mol, respectively, whereas corre-sponding values for metal-doped and pristine (6,0) SWCNTs are about-43.592,-20.661 and-12.414 kcal/mol, respectively. The results suggest that those bare and metal-doped (4,0) SWCNTs and (6,0) Si-SWCNTs can serve as promising sensors in practical applications to detect, recognize and carrier RBV drug for its medicinal drug delivery applications. Based on the NLO properties of (6,0) Si-SWCNTs and pristine (6,0) SWCNT (with an acceptable recovery time of 279s and first hyper polarizability value of & beta; = 229.25 x 10-30 cm5 esu- 1), those nanotubes may be possible candidates to be used as the optoelectronic sensor for RBV drug. The appropriate short length of nanotubes was obtained.Öğe A DFT study on the size and defect induced properties of 2H-Au nano surface by small molecules adsorption(Elsevier, 2023) Sakarya, Alev; Dalgic, Serap Senturk; Dalgic, Seyfettin; Kandemirli, FatmaThe size effect and defect-related properties of the Au nanosurface in the hexagonal phase (Au2H) have been investigated by Density Functional Theory (DFT) using the adsorption of small molecules. The OH, H2O, H2O2, C2H5OH, H2 and O2 molecules were considered. The atomic H and O adsorption were also taken into account for comparison. The adsorption distances, energies, frontier molecular orbitals and density of state analysis of small molecules on top, bridge and hollow sites of the Au2H surfaces were computed in conjunction with charge dis-tribution analysis. The size, dimension and phase-dependent adsorption energies were obtained by comparison with previous calculations. The complexes' stability changes with the sites and interacting groups. Apart from H2O2 and C2H5OH on top site of Au2H, all studied groups' adsorption shows exothermic character. The adsorption energies reveal the order O > OH > H > H2O> O2. The Au2H surface is most sensitive to H, O, OH and O2. Therefore, the Au2H can serve as a promising sensor to detect and recognize those atoms/molecules in practical applications. The Au2H also has potential applications as a work function-type sensor for H, OH and C2H5OH. The size limit of Au2H was defined.Öğe Electronic band structures of Te-doped GaN nanowires(Elsevier Science Bv, 2017) Ozkisi, Harun; Ozkapi, Baris; Ozkapi, Sena Guler; Dalgic, SeyfettinIn this study, we investigate electronic band structures of Te-doped GaN nanowires with three different radii using the first principles methods, which is based on the density functional theory. The relaxed structures, total energies and electronic band structures of pure and Te-doped GaN nanowires are calculated. The results show that the energy band gap values reduce when GaN nanowires are doped with a Te atom. While the band gap values of pure GaN nanowires increase with increasing nanowire radius, they present a decrease for Te-doped GaN nanowires. (C) 2016 Elsevier Ltd. All rights reserved.Öğe First principles study on the electronic properties of BN nanowires(Elsevier Science Bv, 2017) Ozkapi, Sena Guler; Ozkapi, Baris; Ozkisi, Harun; Dalgic, SeyfettinThe electronic and structural properties of BN nanowires are studied by using first principles calculations based on density functional theory. In order to understand dependence of the electronic band structures and density of states on nanowire diameters and shapes, we consider BN nanowires with various diameters in the [001] growth direction. Our results reveal that the effect of changing diameter on electronic properties plays an important role and the band gap can be tuned by changing the wire diameter. (C) 2016 Elsevier Ltd. All rights reserved.Öğe An Investigation on the Local Structure of Silicon: Liquid to Undercooled Regime(Trans Tech Publications Ltd, 2010) Dalgic, Seyfettin; Colakogullari, MutluUndercooled Silicon, Modelling, Reverse Monte Carlo, Atomic Structure. Abstract. We present the modelled local structure for undercooled silicon beginning from its liquid state, similar to 1730K to similar to 1550K. The modelling procedure was achieved by using reverse Monte Carlo (RMC) modelling technique fitting to x-ray static structure factors. The calculated radial distribution functions satisfied experimental observes either liquid or undercooled region. To make a detailed analysis on the modelled local environment we have focused on the distributions both average numbers of atoms within first coordination shell and bond angles whereas the uniqueness of model is discussible. In order to construct model that is more close to nature, the minimum and maximum bond lengths and the average coordination number constraints could have been used. The predicted results using RMC technique show that there is a possible structural transition and it slightly transforms into covalent-like bounded open network structure from its metallic structure, while decreasing temperature.Öğe Self-Diffusion Coefficients in Liquid Ag Using the Embedded Atom Model Based Effective Pair Potentials(Tubitak Scientific & Technological Research Council Turkey, 2006) Dalgic, Seyfettin; Colakogullari, MutluWe present the dynamical properties of liquid Ag at different temperatures, using the Mishin and Doyoma-Kagure version of the Embedded Atom Model (EAM) potentials. They have been evaluated within the framework of the mode-coupling theory, using a self-consistent scheme that uses as input data only the static structure functions and the interatomic pair potentials of the liquid Ag. We have computed single-particle and collective time dependent properties of liquid Ag, and thereby calculated its self-diffusion constants. We have also discussed our results comparing with both experimental data and results of molecular dynamic simulation.Öğe The structural properties of the liquid CdTe based on Reverse Monte Carlo modelling(Elsevier, 2007) Dalgic, Seyfettin; Colakogullari, MutluThe Reverse Monte Carlo (RMC) method only provides information on structure, not on dynamics, and so has restricted applicability. We have only attempted to describe the trends in structural terms. The static structure of liquid Cadmium Telluride is performed using RMC modelling technique fitting to neutron diffraction data. In order to retain its tetrahedral environment with the co-ordination number about four in its liquid state, we have used some plausible physical constraints. In this way, it is possible to derive static structure of liquid CdTe with analysing the experimental data. We have shown the results for the partial static structure factors S-ij(q) and the partial pair distribution functions g(ij)(r). We have also determined the distribution of the number of neighbors within the first co-ordination shell and calculated the bond angle distribution. A good agreement with the experiment is observed for the structural properties of liquid CdTe. (c) 2007 Elsevier B.V. All rights reserved.
