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Ordered phases of ethylene adsorbed on charged fullerenes and their aggregates.

Zöttl S, Kaiser A, Daxner M, Goulart M, Mauracher A, Probst M, Hagelberg F, Denifl S, Scheier P, Echt O - Carbon N Y (2014)

Bottom Line: Experimental data also reveal the number of molecules in groove sites of the C60 dimer through tetramer.The identity of the sites, adsorption energies and orientations of the adsorbed molecules are determined by molecular dynamics calculations based on quantum chemical potentials, as well as density functional theory.The decrease in orientational order with increasing temperature is also explored in the simulations whereas in the experiment it is impossible to vary the temperature.

View Article: PubMed Central - PubMed

Affiliation: Institut für Ionenphysik und Angewandte Physik, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.

ABSTRACT

In spite of extensive investigations of ethylene adsorbed on graphite, bundles of nanotubes, and crystals of fullerenes, little is known about the existence of commensurate phases; they have escaped detection in almost all previous work. Here we present a combined experimental and theoretical study of ethylene adsorbed on free C60 and its aggregates. The ion yield of [Formula: see text] measured by mass spectrometry reveals a propensity to form a structurally ordered phase on monomers, dimers and trimers of C60 in which all sterically accessible hollow sites over carbon rings are occupied. Presumably the enhancement of the corrugation by the curvature of the fullerene surface favors this phase which is akin to a hypothetical 1 × 1 phase on graphite. Experimental data also reveal the number of molecules in groove sites of the C60 dimer through tetramer. The identity of the sites, adsorption energies and orientations of the adsorbed molecules are determined by molecular dynamics calculations based on quantum chemical potentials, as well as density functional theory. The decrease in orientational order with increasing temperature is also explored in the simulations whereas in the experiment it is impossible to vary the temperature.

No MeSH data available.


Related in: MedlinePlus

Ion yield of C60–ethylene complexes containing up to 4 C60 plotted versus the number n of adsorbed C2H4. Significant anomalies are marked; they indicate enhanced adsorption energies. (A colour version of this figure can be viewed online.)
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f0015: Ion yield of C60–ethylene complexes containing up to 4 C60 plotted versus the number n of adsorbed C2H4. Significant anomalies are marked; they indicate enhanced adsorption energies. (A colour version of this figure can be viewed online.)

Mentions: Fig. 3 provides a clearer view of the ion yield of versus n for m = 1, 2, 3, 4. The yield is shown for the isotopologues that are the most or second most abundant. Anomalies in the distributions that are deemed significant are indicated, and compiled in Table 1. The criterion is that the anomaly occurs for all isotopologues that have a significant yield. The spectra have been visually inspected to rule out artifacts, such as traces of C70 impurities in the fullerene sample.


Ordered phases of ethylene adsorbed on charged fullerenes and their aggregates.

Zöttl S, Kaiser A, Daxner M, Goulart M, Mauracher A, Probst M, Hagelberg F, Denifl S, Scheier P, Echt O - Carbon N Y (2014)

Ion yield of C60–ethylene complexes containing up to 4 C60 plotted versus the number n of adsorbed C2H4. Significant anomalies are marked; they indicate enhanced adsorption energies. (A colour version of this figure can be viewed online.)
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4375791&req=5

f0015: Ion yield of C60–ethylene complexes containing up to 4 C60 plotted versus the number n of adsorbed C2H4. Significant anomalies are marked; they indicate enhanced adsorption energies. (A colour version of this figure can be viewed online.)
Mentions: Fig. 3 provides a clearer view of the ion yield of versus n for m = 1, 2, 3, 4. The yield is shown for the isotopologues that are the most or second most abundant. Anomalies in the distributions that are deemed significant are indicated, and compiled in Table 1. The criterion is that the anomaly occurs for all isotopologues that have a significant yield. The spectra have been visually inspected to rule out artifacts, such as traces of C70 impurities in the fullerene sample.

Bottom Line: Experimental data also reveal the number of molecules in groove sites of the C60 dimer through tetramer.The identity of the sites, adsorption energies and orientations of the adsorbed molecules are determined by molecular dynamics calculations based on quantum chemical potentials, as well as density functional theory.The decrease in orientational order with increasing temperature is also explored in the simulations whereas in the experiment it is impossible to vary the temperature.

View Article: PubMed Central - PubMed

Affiliation: Institut für Ionenphysik und Angewandte Physik, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.

ABSTRACT

In spite of extensive investigations of ethylene adsorbed on graphite, bundles of nanotubes, and crystals of fullerenes, little is known about the existence of commensurate phases; they have escaped detection in almost all previous work. Here we present a combined experimental and theoretical study of ethylene adsorbed on free C60 and its aggregates. The ion yield of [Formula: see text] measured by mass spectrometry reveals a propensity to form a structurally ordered phase on monomers, dimers and trimers of C60 in which all sterically accessible hollow sites over carbon rings are occupied. Presumably the enhancement of the corrugation by the curvature of the fullerene surface favors this phase which is akin to a hypothetical 1 × 1 phase on graphite. Experimental data also reveal the number of molecules in groove sites of the C60 dimer through tetramer. The identity of the sites, adsorption energies and orientations of the adsorbed molecules are determined by molecular dynamics calculations based on quantum chemical potentials, as well as density functional theory. The decrease in orientational order with increasing temperature is also explored in the simulations whereas in the experiment it is impossible to vary the temperature.

No MeSH data available.


Related in: MedlinePlus