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Interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons

Interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons We have studied the interaction of polyaromatic hydrocarbons (PAHs) with the basal plane of graphite using thermal desorption spectroscopy. Desorption kinetics of benzene, naphthalene, coronene, and ovalene at submonolayer coverages yield activation energies of 0.50 eV, 0.85 eV, 1.40 eV, and 2.1 eV, respectively. Benzene and naphthalene follow simple first order desorption kinetics while coronene and ovalene exhibit fractional order kinetics owing to the stability of two-dimensional adsorbate islands up to the desorption temperature. Preexponential frequency factors are found to be in the range 10 14 – 10 21 s - 1 as obtained from both Falconer-Madix (isothermal desorption) analysis and Antoine’s fit to vapor pressure data. The resulting binding energy per carbon atom of the PAH is 52 ± 5 meV and can be identified with the interlayer cohesive energy of graphite. The resulting cleavage energy of graphite is 61 ± 5 meV/atom, which is considerably larger than previously reported experimental values. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Physical Review B American Physical Society (APS)

Interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons

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References (3)

Publisher
American Physical Society (APS)
Copyright
Copyright © 2004 The American Physical Society
ISSN
1550-235X
DOI
10.1103/PhysRevB.69.155406
Publisher site
See Article on Publisher Site

Abstract

We have studied the interaction of polyaromatic hydrocarbons (PAHs) with the basal plane of graphite using thermal desorption spectroscopy. Desorption kinetics of benzene, naphthalene, coronene, and ovalene at submonolayer coverages yield activation energies of 0.50 eV, 0.85 eV, 1.40 eV, and 2.1 eV, respectively. Benzene and naphthalene follow simple first order desorption kinetics while coronene and ovalene exhibit fractional order kinetics owing to the stability of two-dimensional adsorbate islands up to the desorption temperature. Preexponential frequency factors are found to be in the range 10 14 – 10 21 s - 1 as obtained from both Falconer-Madix (isothermal desorption) analysis and Antoine’s fit to vapor pressure data. The resulting binding energy per carbon atom of the PAH is 52 ± 5 meV and can be identified with the interlayer cohesive energy of graphite. The resulting cleavage energy of graphite is 61 ± 5 meV/atom, which is considerably larger than previously reported experimental values.

Journal

Physical Review B – American Physical Society (APS)

Published: Apr 15, 2004

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