Yazar "Capar, Mine Ilk" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim Yok
    Öğe
    Functional-Group Effect of Ligand Molecules on the Aggregation of Gold Nanoparticles: A Molecular Dynamics Simulation Study
    (Amer Chemical Soc, 2022) Cetin, Ayse; Capar, Mine Ilk
    In this paper, atomistic molecular dynamics simulations are performed for the systems consisting of functionalized gold nanoparticles (NPs) in a toluene medium. Gold NPs are coated with ligand molecules that have different terminal groups, that is, polar carboxyl (COOH), hydroxyl (OH), amine (NH2), and nonpolar methyl (CH3). These functional groups are selected to understand the relation between the aggregation behavior of functionalized gold NPs in toluene and the polarity of terminal groups of ligand molecules. The center-of-mass distances between NP pairs, the radial distribution functions, the mean square displacements, the radius of gyration, and the number of hydrogen bonds (H-bond) between ligand molecules are computed. Our simulation results indicate that functionalized gold NPs exhibit different aggregation/dispersion behaviors depending upon the terminal group of ligands.
  • Küçük Resim Yok
    Öğe
    MD simulations of diffusion of cyanobiphenyl molecules adsorbed on the graphene surface coated with alkane and alcohol molecules
    (Wiley, 2024) Duven, Hatice E.; Capar, Mine Ilk; Zakharov, Alex V.
    Molecular dynamics simulations were carried out to study the structural and diffusion properties of a cyanobiphenyl monolayer composed of pentyl cyano biphenyl (5CB) and pentyloxy cyano biphenyl (5OCB) molecules on a graphene surface coated with alkane and alcohol molecules. To investigate the diffusion properties of 5CB and 5OCB molecules on the graphene surface, the molecules of pentane (C5$$ {\mathrm{C}}_5 $$) and dodecane (C12$$ {\mathrm{C}}_{12} $$) from alkanes and dodecanol (C12OH$$ {\mathrm{C}}_{12}\mathrm{OH} $$) from alcohols with a polar hydroxyl (-OH$$ -\mathrm{OH} $$) terminal functional group were chosen as orienting surfactant molecules. It was found that the diffusion ability of cyanobiphenyl molecules in a graphene substrate coated with alkane and alcohol molecules depends on the chain length of these molecules and on the presence of polar hydroxyl -OH terminal groups. With an increase in the length of alkane molecules from C5$$ {\mathrm{C}}_5 $$ to C12$$ {\mathrm{C}}_{12} $$, the value of the diffusion coefficient Dz5CB$$ {D}_z\left(5 CB\right) $$ (or Dz5OCB$$ {D}_z\left(5 OCB\right) $$), it decreases slightly, while the presence of the polar hydroxyl -OH$$ -\mathrm{OH} $$ terminal group leads to a significant decrease in this diffusion coefficient of cyanobiphenyl molecules. 5CB (A) and 5OCB (B) molecules. image
  • Küçük Resim Yok
    Öğe
    Molecular dynamic study of the odd-even effect in some 4-n-alkyl-4 '-cyanobiphenyls
    (Amer Physical Soc, 2006) Capar, Mine Ilk; Cebe, Emine
    Using a united atom model, we performed molecular dynamics (MD) simulations on the 4-n-alkyl-4 '-cyanobiphenyl (nCB) liquid crystal homologous series for n=5-9 at a constant reduced temperature in the nematic phase. To evaluate the rotational diffusion coefficient (RDC), the second- and fourth-rank order parameters (OP's) and correlation time were calculated from MD trajectories. We analyzed the rotational viscosity coefficient (RVC) by using the Nemtsov-Zakharov and Fialkowski methods based on statistical-mechanical approaches. The simulated RDC, RVC, and OP's were found to be reasonable when compared with previous theoretical and experimental data. These quantities were also calculated for the rigid core and alkyl chain segments separately for each mesogen, to take a closer look at the molecule tail-chain flexibility. The properties calculated for a rigid core were compared with those for an alkyl chain, and satisfactory results were obtained. Odd-even effects for RDF, RVC, and molecular ordering parameters were calculated for five mesogens.
  • Küçük Resim Yok
    Öğe
    Odd-even effects in the homologous series of alkyl-cyanobiphenyl liquid crystals: A molecular dynamic study
    (Wiley, 2007) Capar, Mine Ilk; Cebe, Emine
    For the first five members of the homologous series of 4-n-alkyl-4'-cyanobiphenyls in the nematic and isotropic phases, molecular dynamics (MD) simulations were performed by using a united atom model. An odd-even effect was seen to be found in the molecular length, width, biaxiality, and inertia tensor anisotropy with the length of alkyl chain. The distributions of the molecular length, width, and inertia tensor anisotropy were presented. The orientational distributions of the last C-C bonds in the alkyl chain were also evaluated for nematic and isotropic phases. (c) 2007 Wiley Periodicals, Inc.