Graphene and Fullenene Clusters: Molecular Polarizability and Ion–Di/Graphene Associations

Graphene and Fullenene Clusters: Molecular Polarizability and Ion–Di/Graphene Associations

Francisco Torrens (Universitat de València, Spain) and Gloria Castellano (Universidad Católica de Valencia, Spain)
Copyright: © 2017 |Pages: 31
DOI: 10.4018/978-1-5225-0492-4.ch015


Interacting induced-dipoles polarization in code POLAR permits calculating molecular polarizability, which is tested with endohedral metallofullerenes Scn@Cm and clusters Cn (fullerene, graphene, GR). Polarizability identifies aggregates with dissimilar numbers of atoms and separates isomers. Results are of the same order of magnitude as reference computations performed with code PAPID. Polarizability bulk limit is estimated from Clausius–Mossotti relationship. Polarizability trend for clusters vs. size is unexpected: they are more polarizable than bulk. Theory yielded the same for small Sin, Gen and GanAsm; however, experiment oppositely deferred for larger Sin, GanAsm and GenTem. Smaller clusters do not behave like intermediate sizes: polarizability of small aggregates is caused by dangling bonds at the surface that resembles metallic. Varying number of atoms, clusters show peaks indicative of particularly polarizable structures in agreement with alkalines polarizability and molar volume in the periodic table of the elements. Code AMYR calculates molecular associations on GR(2)–Mz+.
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Research opportunities in studying the role of size in modifying the properties of a material were exploited (Alford et al., 1990; Andres et al., 1989; Bloomfield et al., 1985; Jarrold, 1991). In one example, clusters were deposited on an inert substrate and probed with photons (Honea et al., 1993). In another one, a cluster beam was produced (Cheshnovsky et al., 1987). Based on interatomic potentials, the structure of Si13 is special (Chelikowsky et al., 1991). The predicted ground state is a close-packed icosahedron. Unfortunately, studies based on ab initio methods yielded a structure, which is a capped antiprism structure (Grossman & Mitás, 1995). It was proposed that current electronic structure theory is not capable of handling exchange and correlation contributions in this system (Phillips, 1993). Nanocrystalline powders were used to synthesize materials with physical processing, e.g., sintering (Brus, 1986; Kayanuma, 1988). Rutile processing reduced sintering temperatures by hundreds of degrees without sacrificing desirable mechanical properties (Siegel, et al., 1988). Quantum confinement was used to engineer excitation energy (Alivisatos, 1996). Computations predicted that crystallized C60-fullerite is a direct band-gap semiconductor like GaAs (Benning et al., 1991; Jost et al., 1991; Martins et al., 1991). Benichou et al. (1999) measured Lin (2 ≤ n ≤ 22) polarizability. Maroulis and Xenides (1999) reported ab initio calculations for Li4. Fuentealba (1998) presented a density functional theory (DFT) study of the polarizability of Cn (n ≤ 8). Fuentealba & Reyes (1999) computed the polarizability of LinHm via DFT. Jackson et al. (1999) used a DFT-based method to calculate Sin (10 ≤ n ≤ 20) polarizability. Deng et al. (2000ab) computed Sin (9 ≤ n ≤ 28) polarizability via a DFT cluster method. Hohm et al. (1998) deduced As4 experimental polarizability from the analysis of refractivity measurements in As vapour.

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