We have demonstrated the direct solid state synthesis of C60H2 by controlling the amount of hydrogen introduced into the reaction with C60. Palladium hydride has been used as the source of hydrogen. The main product 1,2-C60H2 is the isomer previously predicted by computational studies to be the lowest in energy of the possible 23 isomers; in addition, small amounts of the thermodynamically most stable isomer of C60H2, 1,2,3,4-C60H2, has also been obtained. To determine structural parameters by x-ray diffraction, crystal growth from various solvents yielded complex solventcontaining crystals which were examined; however, the complex nature of these crystals have so far precluded detailed crystal structure determinations.

We investigated fullerene based catalysts for the conversion of methane into higher hydrocarbons. Fullerene soot, CO2 activated soot, and extracted soot as well as a Norit-A carbon were examined as catalysts for methane activation. The soot was found to easily activate the C-H bond of methane, allowing methane conversion at lower temperatures (lower by 250°C) than found under purely thermal conditions. Furthermore, soot catalysis appears to produce a minimal amount of aromatic hydrocarbons. Extracted soot was found to have a lower selectivity for C2 hydrocarbons than the non-extracted soot, and the CO2 activation of the soot did not appear to dramatically alter the catalytic activity.

Fullerenes have been impregnated in porous glass with little interaction with the glass noted. Concentrations as high as 3mg/ml of C60 or C70 were obtained. It was shown that the fullerenes can enhance the photo-induced charge transfer reaction of DEA with the porous glass.

Adsorption of C60, C70, C60(x)C70(1-x) and Sc2C84 on the Cu(111)1×1 and Ag(l11)1×1 surfaces has been investigated by field ion-scanning tunneling microscopy (FI-STM). On the Cu(111) and Ag(111) surfaces, the fullerene molecules are mobile on the terrace at room temperature and segregate to the steps to form linear chains then two-dimensional islands with a close-packed configuration. Upon monolayer adsorption, highly ordered 4×4 commensurate phases form in the case of the C60, C70 and C60(x)C70(1−x) adsorption on the Cu(111) surface, while close-packed hexagonal multiple phases, with nearest-neighbour distance equal to that of the bulk phase, form in the case of the C60 and Sc2C84 adsorption on the Ag(111) surface. These observations imply the competition between the adsorbate-adsorbate and adsorbate-substrate interactions. The intramolecular structures observed in the STM images of the C60 and C70 molecules in the Cu(111)-4×4 phases are analyzed to determine the adsorption geometry and are interpreted as the local density of the states of the C60 and C70 molecules.

Thin films were prepared, from C60 powders by vacuum evaporation and rf-plasma excited ion plating methods. The film structures ranged from fcc-polycrystal C60film to amorphous C60 film and to amorphous carbon films containing varying amounts of C60 molecules depending on the preparation method and conditions. Electrical conductivity of these films was found so sensitive to air that highly reproducible data were obtained only when the measurement was done by in-situ high vacuum conditions. The Co films deposited at 120°C on fused silica substrates by vacuum evaporation were amorphous and they had conductivities three orders of magnitude lower than those of fcc-polycrystal C60 films deposited on cleaved NaCl(100) substrates under the same conditions. The conductivities of both amorphous and fcc-polycrystal C60 films decreased drastically when these films were exposed to air. Partially decomposed C60 ion-plating films showed conductivities close to those of the air-exposed amorphous and fcc-polycrystal C60 films.

Films (with thicknesses about thousands A) of a new form of carbon allotrope, CIO also known as Fullerenes, are deposited on Si(111) substrates using ionized cluster beam deposition (ICBD) technique at low (65V) accelerating voltage V. X-ray &-20 diffraction (XRD) have been used to investigate the structural properties of C6Ofi lms, indicating hexagonal close-packed structure with strong (002) XRD assignment together with weak (100), (112) and(004) assignments. Raman spectra, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) are carried out to make detailed studies of the electronic properties of the films and to illustrate differences between CO films and amorphous carbon films which are deposited by ICBD at high accelerating voltage V >400V. Cio soccer-balls are found to be broken into fragments as accelerating field overtakes about 400V, indicated by the results of XPS, Raman spectra, XRD, and UV/visible absorption spectra.

Copolymerization of C60 with paracyclophane at high temperature was investigated by DSC in situ. Situ DSC profiles of mixed solids with different mole ratio of C60/paracyclophane(2:1, 1:1; 1:2; 1:4; 1:10) were determined. Experimental results show that C60 first dissolves in melting paracyclophane (280-330°C) then reacts with paracyclophane at 400-520°C. Copolymerization reaction is a stepwise and continued process. The reaction does not take place when the temperature is lower than 400 °C. The ratio of C60/paracyclophane affects the copolymerization process which is the reaction of C60 with p-xylylenediradical and also affects the structure of the resulting product. Semi-quantitative analysis of DSC profiles indicates every C60 molecule reacts with about 4-5 paracyclophane molecules to form crosslinking elastic copolymer. The structure of the copolymer may be like starburst dendrimer polymer. The copolymer was also characterized by IR, UV-VIS, and ESR.

Thin-film Al-C60-Al trilayered structures were sublimated under ultra high vacuum (UHV) conditions for the purpose of investigating their current-voltage (I-V) properties. These metal-semiconductor-metal devices exhibited rapid and irreversible drop in resistance of about two orders of magnitude under an applied voltage of 0.67 to 0.75V. Approximate initial and final resistances were 1050 Ω and 8 Ω respectively. Wavelength Dispersive Spectroscopy (WDS) indicated no noticeable change in phase of the fullerene inter-layer after the irreversible drop in resistance. These results, SEM micrographs and concentration profiles were concordant with diffusion of top layer Al through the fullerene layer as the most likely cause of the change in resistance.

Since the success of synthesis the molecular structure of the endohedral metallofullerene is a most interesting subject in relation to the electronic state of metal and carbon cage. Highquality crystals of endohedral metallofullerene La@C82 have been synthesized by the arc discharge and HPLC method. The x-ray powder diffraction and the precession photograph of a tiny single crystal have revealed the cubic structure with the space group I43d and the lattice constant ao = 25.72 ± 0.007 Å at room temperature. The structure is characterized by the molecular arrangement in which the molecules align in the [111] direction with the molecular axis orienting in the same [111] direction; this structure suggests the existence of a dipole interaction between the molecules. The metal position in the cage is also discussed on the basis of an ellipsoidal model of molecule.

We have calculated the structure and electronic properties of several metallo-carbohedrenes within the local density-functional approximation, using both methods of a linear combination of atomic orbitals and full-potential muffin-tin orbitals. The calculated density of states and Mulliken population of double cage Ti14C21 and triple cage Ti18C29 are quite similar to that of single cage Ti8C12. There is no additional cohesion in multicage structure, which may explain why there is not a strong tendency to form larger, multi-cage structures. A new stable structure for Ti8C12 is also proposed and structures Ti10C12+x (x=1, 2, 3, 4, 5) have also been discussed.

Recent studies of electronic structure of solid fullerenes have revealed many interesting properties of these systems. In the present paper, the effects of substitution of carbon atoms by nitrogen and/or boron. We have modified our C60 fcc band-structure program to calculate the electronic properties of the C58BN fcc crystal, where we adopt the mixed-basis approach in which the Is, 2s, and 2p orbitals in addition to about 2000 plane waves are included. The band structure and the charge density distribution are calculated for the first time. When B and N are substituted in places of two C atoms sharing a double bond in C60, we found that there is no donor nor accepter level, and no net charge transfer between B and N. This character is considerably different from the boron-substituted fullerenes.

Purification process to obtain nanotubes out of the cathode product mostly including fragments of graphitic sheet and/or amorphous carbon has been established. Structures and electronic properties of carbon nanotubes were studied. By the Raman scattering measurement, only one peak at 1581 cm−1 akin to that of graphite was found out. It was confirmed by STM observation of purified nanotubes. Purified nanotubes was semiconductor or semimetal.

After the discovery of the C60 molecule a lot of attention has been given to its optical and collective properties. The latest development in fullerene related research was the synthesis of coaxial carbon sheets called carbon or nano tubes and also spherical concentric graphitic shells called carbon onions. With a model describing the collective dynamics of electrons we may gain insight in the physics of the collective resonances. Based on a simple equation of motion for the induced density in a carbon particle we demonstrate the existence of a rich spectrum of collective resonances for both carbon onions and carbon tubes.

We use the local-density-approximation to the density-functional theory to determine the axial polarizabilities of fullerene tubules as a function of length and winding topologies. Specifically, we present linear polarizabilities for tubules of composition C12H24, C36H24, C40H20 and C60H24. The size-dependent variation in the dipole-coupled gaps between pairs of occupied and unoccupied levels leads to enhancements in the polarizability per valence electron as the length of the tubule increases. The results are compared to recent densityfunctional based calculations of the linear and nonlinear polarizabilities for fullerene and benzene molecules.

The full spectrum of occupied and unoccupied σ and Π orbitals is presented for solid C60, C70, and graphite, using C1s emission and absorption spectroscopy. There are significant differences between C60 and C70, and even larger changes relative to their infinite analog graphite C∞. A comparison is made with photoemission and inverse photoemission results, along with first principles quasiparticle calculations.

Carbon nanofibers and nanotubes have been prepared from the decomposition of carbon containing gases with the aid of an iron catalyst particle. The physical characteristics as well as the degree of crystalline perfection of the structures were found to be dependent on the nature of the metal particle and the conditions at which the material was grown. Transmission electron microscopy revealed that nanofibers were obtained from large catalyst particles (>20 nm), whereas nanotubes were formed by the aid of smaller particles (<20 nm). The orientation of the graphitc platelets in the carbon nanofibers was dependent on the alignment of the planes at the rear faces of the iron particle that were responsible for the precipitation of carbon. Carbon nanofibers exhibited reactivity in carbon dioxide comparable to that of single crystal graphite under the same conditions.

Based on the high resolution TEM observations, we report here on the nonconcentric growth phenomena of carbon nanotubes from the arc-discharge. We also report on a novel form of carbon nanoclusters - the strings of carbon nanobeads - produced by the catalytic arc-discharge with Ni as the catalyst, and on the bundles of single-walled carbon nanotubes, synthesized with YC2 as the catalyst, growing radially out from YC2 particles.

Catalytically grown carbon fibers approximately 10 nm in diameter and several microns long were characterized by transmission electron microscopy and determined to be multiple-walled nanotubes, and a technique was developed to measure the conductivity of an individual nanotube. Nanotubes were dispersed in solvents and precipitated onto lithographically defined gold contacts to make a ‘nano-wire’ circuit. Non-contact AFM was used to image the nano-wires, and a resistance of 11.4 (± 1.0) MΩ was measured through a single nanotube at 23°C. A resistivity of 9.5×10−5 Ω m was estimated for carbon conducting along the axis of a fiber. Local heating of nanotubes appeared to occur at high current densities. The nanotubes could sustain currents on the order of 10 μA per fiber, but application of currents on the order of 100 μA per fiber resulted in rapid decomposition in air and breaking of the circuit.

Nanostructured carbon has been deposited in silica aerogels by chemical vapor infiltration using acetylene or ferrocene at moderate temperatures. Using analytical electron microscopy and high-resolution electron microscopy, we have observed various carbon rings and nanotubes in the silica aerogel-based carbon composite. Both X-ray microanalysis and nano-probe diffraction techniques have been used to confirm the presence of those carbon nanostructures. The morphologies and structural properties of the carbon nanotubes and rings have also been examined in detail.

We report here a study of alternative methods for producing single walled buckytubes. In this study, we prepared graphite electrodes packed with different metal or metal combinations. These electrodes were arced under similar conditions and the products so formed characterized with TEM. The results demonstrate that single walled tubes can be synthesized in many ways and at high yields. The results also suggest that the use of more than a single dopant may provide significant advantages in the commercial synthesis of buckytubes.