The effect of O{sub 2} intercalation on the rotational dynamics and the ordering transition of C{sub 60}

Conference · Sun Jan 01 00:00:00 EST 1995

OSTI ID:10108382

Myers, S A; Assink, R A; Schirber, J E; Loy, D A

We have used {sup 13}C magic-angle spinning (MAS) nuclear magnetic resonance (NMR) to characterize the structure and rotational dynamics of C{sub 60} containing oxygen molecules located in the interstitial sites of the fcc lattice. Under normal conditions, a narrow peak at 143.7 ppm is observed for C{sub 60}. When exposed to oxygen at moderate pressures, several additional resonances appear in the {sup 13}C MAS NMR spectrum. These secondary resonances are shifted downfield from the main peak at 143.7 ppm and are due to the Fermi-contact interaction of the paramagnetic oxygen molecules with the {sup 13}C nuclear spins. The presence of oxygen depresses the orientational ordering transition by ca. 20 K as observed by DSC. The spin-lattice relaxation time (T{sub 1}) of each secondary peak shows a minimum near the ordering transition, indicating that this transition is not dependent on the number of oxygen molecules surrounding an individual C{sub 60} molecule. The T{sub 1}, due to paramagnetic relaxation, normalized by the number of surrounding oxygen molecules, is constant. This observation demonstrates that within a given sample, the dynamics of C{sub 60} molecules are independent of the number of surrounding oxygen molecules.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 10108382
• Report Number(s): SAND-94-3147C; CONF-941144-27; ON: DE95004765; TRN: 95:001348
• Resource Relation: Conference: Fall meeting of the Materials Research Society (MRS),Boston, MA (United States),28 Nov - 9 Dec 1994; Other Information: PBD: [1995]
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
FULLERENES
STRUCTURAL CHEMICAL ANALYSIS
FERMI INTERACTIONS
OXYGEN
SPIN-LATTICE RELAXATION
SPIN ORIENTATION
CARBON 13
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
RELAXATION TIME
MOLECULAR STRUCTURE
STRUCTURE FACTORS
400102
CHEMICAL AND SPECTRAL PROCEDURES