Graphite oxide (GO) samples were prepared by a simplified Brodie method. Hydroxyl, epoxide, carboxyl, and some alkyl functional groups are present in the GO, as identified by solid-state 13C NMR, Fourier-transform infrared spectroscopy, and X-ray photoemission spectroscopy. Starting with pyrolytic graphite (interlayer separation 3.36 A), the average interlayer distance after 1 h of reaction, as determined by X-ray diffraction, increased to 5.62 A and then increased with further oxidation to 7.37 A after 24 h. A smaller signal in 13C CPMAS NMR compared to that in 13C NMR suggests that carboxyl and alkyl groups are at the edges of the flakes of graphite oxide. Other aspects of the chemical bonding were assessed from the NMR and XPS data and are discussed. AB stacking of the layers in the GO was inferred from an electron diffraction study. The elemental composition of GO prepared using this simplified Brodie method is further discussed.

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We have employed a classical molecular dynamics simulation for the direct pick-up reaction of adsorbates by very low energy (1-60 eV) ions scattered at a surface. The system investigated is the reactive ion scattering (RIS) of Cs+ with an adsorbate on a Pt(111) surface. The ion-dipole attraction between the projectile and the physisorbed adsorbate drives the abstraction reaction, in which the ion projectile at first collides with the surface to release a substantial amount of its kinetic energy, and subsequently pulls the adsorbate along in the outgoing trajectory. Desorption induced by the ion-dipole attraction is a precursor to the formation of the Cs(+)-adsorbate product. This Eley-Rideal-type mechanism must accommodate the inertia of the adsorbate. Consequently, a successful abstraction works well only for low mass adsorbates and slow outgoing Cs+ ions. The efficient energy transfer to the Pt(111) surface makes Cs+ a better candidate for RIS than lighter projectile ions. Optimal conditions for the efficient RIS abstraction mechanism are found for physisorbed adsorbates with a mass below 32 amu, and for 10 eV Cs+ ions at a 45 degrees incidence.

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