Structural characterization of C[sub 60] and C[sub 70] fullerenes by small-angle neutron scattering
- Chemical Technology Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)
- Biology Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)
- Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)
- Health and Science Research Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)
Small-angle neutron scattering (SANS) is a proven tool for examining the structure and interactions of particles in solution, though the dimensions of carbon-cage molecules are close to the lower resolution limit of the technique. Deuterated solvents (toluene-[ital d][sub 8] and benzene-[ital d][sub 6]) have virtually no scattering contrast with carbon, and the high incoherent cross section of protonated (hydrogen containing) solvents severely limits the path length of solutions by reducing the sample transmission. We have circumvented these difficulties by using CS[sub 2] as a solvent which has good contrast with carbon, and a low incoherent cross section which allows the use of long sample path lengths (up to [similar to]10 cm). In addition, CS[sub 2] has good solubility for fullerenes and these properties permit the measurement of the radii of gyration ([ital R][sub [ital g]]) of both C[sub 60] ([ital R][sub [ital g]]=3.82[plus minus]0.05 A) and C[sub 70] ([ital R][sub [ital g]]=4.13[plus minus]0.05 A). These dimensions are similar to those calculated from the atomic coordinates after allowing for a solvent exclusion volume. Close agreement between the measured absolute scattering cross sections and the values calculated from the particle and solvent scattering length densities serves as a cross check on the validity of this methodology. To our knowledge, this represents the first successful application of SANS for the characterization of fullerenes. SANS makes it possible to study the size and shapes of modified buckyballs, solute/solvent interactions, crystal growth from saturated solutions, and temperature dependent transitions in solutions.
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5959211
- Journal Information:
- Journal of Chemical Physics; (United States), Vol. 99:11; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Characterization of fullerenes and fullerene derivatives by small-angle neutron scattering and transmission measurements
Characterization of fullerenes and fullerene derivatives by small-angle neutron scattering and transmission measurements
Related Subjects
FULLERENES
COUPLING
STRUCTURE FACTORS
SOLUTIONS
BENZENE
CESIUM
CROSS SECTIONS
DEUTERATION
NEUTRON DIFFRACTION
SMALL ANGLE SCATTERING
SOLUBILITY
SOLVENTS
TOLUENE
ALKALI METALS
ALKYLATED AROMATICS
AROMATICS
CARBON
CHEMICAL REACTIONS
COHERENT SCATTERING
DIFFRACTION
DISPERSIONS
ELEMENTS
HYDROCARBONS
METALS
MIXTURES
NONMETALS
ORGANIC COMPOUNDS
SCATTERING
360602* - Other Materials- Structure & Phase Studies