Browsing by Subject "Nanocluster"

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    One-pot synthesis of organic–inorganic hybrid polyhedral oligomeric silsesquioxane microparticles in a double-zone temperature controlled microfluidic reactor
    (Wiley Periodicals, Inc., 2019) Kibar, Güneş; Çalışkan, Umutcan; Erdem, E. Yegân; Çetin, Barbaros
    Polyhedral oligomeric silsesquioxane (POSS) particles are one of the smallest organosilica nano‐cage structures with high multifunctionality that show both organic and inorganic properties. Until now poly(POSS) structures have been synthesized from beginning with a methacryl‐POSS monomer in free‐radical mechanism with batch‐wise methods that use sacrificial templates or additional multisteps. This study introduces a novel one‐pot synthesis inside a continuous flow, double temperature zone microfluidic reactor where the methodology is based on dispersion polymerization. As a result, spherical monodisperse POSS microparticles were obtained and characterized to determine their morphology, surface chemical structure, and thermal behavior by SEM, FTIR, and TGA, respectively. These results were also compared and reported with the outcomes of batch‐wise synthesis.
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    Vibrational modes in small Agn, Aun clusters: A first principle calculation
    (2009) Aktürk O.U.; Gülseren O.; Tomak, M.
    Although the stable structures and other physical properties of small Agn and Aun, were investigated in the literature, phonon calculations are not done yet. In this work, we present plane-wave pseudopotential calculations based on density-functional formalism. The effect of using the generalized gradient approximation (GGA) and local density approximation (LDA) to determine the geometric and electronic structure and normal mode calculations of Agn and Aun, is studied up to eight atoms. Pure Aun and Agn clusters favor planar configurations. We calculated binding energy per atom. We have also calculated the normal mode calculations and also scanning tunneling microscope (STM) images for small clusters for the first time. © 2009 World Scientific Publishing Company.