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The doping of single-walled carbon nanotubes (SWNTs) under ultrahigh vacuum by Li atoms has been explored experimentally and theoretically. The chemical effect of Li in breaking the C−Cl bond in chloromethane has been observed. Temperature programmed desorption (TPD) experiments show that at low coverage CH3Cl is physisorbed to the undoped SWNT sample, exhibiting a desorption process near 178 K. The CH3Cl desorption peak shifts to about 240 K for lithiated SWNTs, indicating an increase in binding energy of about 0.16 eV. More importantly, the integrated intensity of the CH3Cl desorption peak is dramatically reduced in the lithiated SWNT case, and CH3, C2H6, or related species are not observed in significant quantities in the TPD experiments up to a temperature of 500 K. This strongly indicates that CH3Cl reacts on lithiated SWNTs to produce an irreversibly bound species. Products LiCl and Li2Cl2 are observed to desorb near 700 K. Density functional theory calculations present possible reaction mechanisms ...

Fullerene thin films are deposited on defect-rich Highly Oriented Pyrolitic Graphite (HOPG) and investigated by scanning tunneling microscopy (STM). These films exhibit a wealth of novel structural...

Doping of opened single-walled carbon nanotubes (SWNTs) with metallic Li has been carried out under ultrahigh vacuum. Li atoms enter into the interior sites of the SWNTs by surface migration with an activation energy of 0.3 ± 0.04 eV. Density functional theory calculations indicate that the Li atoms ionize inside the SWNTs to produce Li+ ions. The Li-doped SWNTs exhibit an ∼10% enhancement of the van der Waals bonding for n-heptane molecules, a model for volatile organic compounds, within the interior due to polarization of the alkane molecules in the strong electrostatic field around the Li+ ions. The investigations reveal the utility of temperature-programmed desorption from SWNTs for understanding the energetics of confined molecule adsorption in pristine and doped SWNTs. Statistical mechanical simulations using a polarizable potential for alkanes give increases in isosteric heats of adsorption at high alkane loading that are in excellent agreement with experiments. Our simulations predict that the bin...