Ethylene on graphite: A low-energy electron-diffraction study

Eden, V. L.; Fain, Samuel C.

doi:10.1103/physrevb.43.10697

Cited by 9 publications

(10 citation statements)

References 23 publications

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“…One was observed when the low-density phase undergoes a transition from orientationally disordered incommensurate to orientationally disordered commensurate, although not to the commensurate

phase because the molecules are too large when they lie flat. Contrary to conclusions drawn in earlier work the authors argued that this phase melts discontinuously [16,17] . Two additional commensurate, orientationally disordered phases were identified by Eden and Fain at high density, with the molecules being in the T-shaped configuration [16,17] .…”

Section: Introductioncontrasting

confidence: 96%

“…Contrary to conclusions drawn in earlier work the authors argued that this phase melts discontinuously [16,17] . Two additional commensurate, orientationally disordered phases were identified by Eden and Fain at high density, with the molecules being in the T-shaped configuration [16,17] . One of them, the commensurate

phase, formed at temperatures above 58 K and densities ≈0.9 ⩽ x ⩽ ≈1.03.…”

Section: Introductioncontrasting

confidence: 96%

“…As discussed in Section 4 , the estimated vibrational temperature of C 60 Et 32 in the experiment is 110 K. This value is some 60% higher than the temperature at which a submonolayer of ethylene on graphite melts [12,13,16] . However, the enhanced corrugation over the curved surface of C 60 may significantly increase the melting temperature.…”

Section: Theoretical Results and Discussionmentioning

confidence: 80%

“…Above 35 K the molecules rotate freely around an axis normal to the surface thus destroying the herringbone pattern. According to an electron diffraction study by Eden and Fain [16,17] , the commensurate

phase appears at temperatures above 58 K and densities ≈0.9 ⩽ x ⩽ ≈1.03; the phase melts below 70 K.…”

Section: Theoretical Results and Discussionmentioning

confidence: 99%

“…Molecular dynamics studies supported the idea that the corrugation of the graphite surface has a negligible effect on the structure of the ethylene adsorbate [7,13,15] . However, in 1991 Eden and Fain published low-energy electron diffraction data which revealed the existence of three additional solid phases at high temperatures [16,17] . One was observed when the low-density phase undergoes a transition from orientationally disordered incommensurate to orientationally disordered commensurate, although not to the commensurate

phase because the molecules are too large when they lie flat.…”

Section: Introductionmentioning

confidence: 99%

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Ordered phases of ethylene adsorbed on charged fullerenes and their aggregates

Zöttl

Kaiser

Daxner

et al. 2014

Carbon

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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 (C60)m(C2H4)n+ 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.

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“…One was observed when the low-density phase undergoes a transition from orientationally disordered incommensurate to orientationally disordered commensurate, although not to the commensurate

Section: Introductioncontrasting

confidence: 96%

phase, formed at temperatures above 58 K and densities ≈0.9 ⩽ x ⩽ ≈1.03.…”

Section: Introductioncontrasting

confidence: 96%

Section: Theoretical Results and Discussionmentioning

confidence: 80%

phase appears at temperatures above 58 K and densities ≈0.9 ⩽ x ⩽ ≈1.03; the phase melts below 70 K.…”

Section: Theoretical Results and Discussionmentioning

confidence: 99%

phase because the molecules are too large when they lie flat.…”

Section: Introductionmentioning