Science.gov

Sample records for 30-mev c60 clusters

  1. Light-Initiated Transformation of C60 Clusters in Water

    EPA Science Inventory

    Although Buckminster fullerene (C60) has an extremely low water solubility (~8 ng/L), the formation of stable clusters (aqu/nC60) not only greatly increases the mass of C60 dispersed in water, but also alters its physicochemical properties. This research focused on investigating ...

  2. Global minima of (C 60) nCa 2+, (C 60) nF - and (C 60) nI - clusters

    NASA Astrophysics Data System (ADS)

    Hernández-Rojas, J.; Bretón, J.; Llorente, J. M. Gomez; Wales, D. J.

    2005-07-01

    Likely candidates for the lowest potential energy minima of (C 60) nCa 2+, (C 60) nF - and (C 60) nI - clusters are located using basin-hopping global optimisation. In each case, the potential energy surface is constructed using the Girifalco form for the C 60 intermolecular interaction, an averaged Lennard-Jones C 60-ion interaction, and a polarisation potential, which depends on the first few non-vanishing C 60 multipole polarisabilities. We find that the ions generally occupy the interstitial sites of a (C 60) n cluster, the coordination shell being tetrahedral for Ca 2+ and F -. The I - ion has an octahedral coordination shell in the global minimum for (C 60) 6I -, however for 12 ⩾ n ⩾ 8 the preferred coordination geometry is trigonal prismatic.

  3. Gold Cluster Formation on C60 Surfaces: Au-Cluster Beads and Self-Organized Structures

    NASA Astrophysics Data System (ADS)

    Reinke, Petra; Liu, Hui

    2007-03-01

    Petra Reinke, Hui Liu, Department of Materials Science and Engineering, University of Virginia The investigation of C60-Au interaction is central to the advancement of solar cell and nanotechnology applications of C60. C60 grows in a quasi-layer-by-layer mode on a pristine graphite surface and form a special surface structure (coexistence of round and fractal islands). The deposition of Au leads to the formation of a complex array of different surface structures, while the basic island structure of the C60 is preserved. The Au-clusters nucleate preferentially at the graphite-first fullerene layer islands edge forming beadlike structures. A roughness analysis of the fullerene surface indicates the presence of Au atoms embedded in the fullerene surface, situated in the troughs in between the large molecules. The analysis of the spatial and size distributions of Au clusters provides the basis for the development of a qualitative model which describes the relevant surface processes in the Au-fullerene system. The simultaneous deposition of Au and C60 leads to the formation of organized structures, in which Au clusters are embedded in a ring of fullerene molecules with a constant width.

  4. Positively and Negatively Charged Cesium and (C60) m Cs n Cluster Ions.

    PubMed

    Renzler, Michael; Kranabetter, Lorenz; Goulart, Marcelo; Scheier, Paul; Echt, Olof

    2017-05-25

    We report on the formation and ionization of cesium and C60Cs clusters in superfluid helium nanodroplets. Size distributions of positively and negatively charged (C60) m Cs n(±) ions have been measured for m ≤ 7, n ≤ 12. Reproducible intensity anomalies are observed in high-resolution mass spectra. For both charge states, (C60) m Cs3(±) and (C60) m Cs5(±) are particularly abundant, with little dependence on the value of m. Distributions of bare cesium cluster ions also indicate enhanced stability of Cs3(±) and Cs5(±), in agreement with theoretical predictions. These findings contrast with earlier reports on highly Cs-doped cationic fullerene aggregates which showed enhanced stability of C60Cs6 building blocks attributed to charge transfer. The dependence of the (C60) m Cs3(-) anion yield on electron energy shows a resonance that, surprisingly, oscillates in strength as m increases from 1 to 6.

  5. Formation of clusters composed of C60 molecules via self-assembly in critical fluids

    NASA Astrophysics Data System (ADS)

    Fukuda, Takahiro; Ishii, Koji; Kurosu, Shunji; Whitby, Raymond; Maekawa, Toru

    2007-04-01

    Fullerenes are promising candidates for intelligent, functional nanomaterials because of their unique mechanical, electronic and chemical properties. However, it is necessary to invent some efficient but relatively simple methods of producing structures composed of fullerenes for the development of nanomechatronic, nanoelectronic and biochemical devices and sensors. In this paper, we show that various structures such as straight fibres, networks formed by fibres, wide sheets and helical structures, which are composed of C60 molecules, are created by placing C60-crystals in critical ethane, carbon dioxide and xenon even though C60 molecules do not dissolve or disperse in the above fluids. It is supposed, judging by the intermolecular potentials between C60 and C60, between C60 and ethane, and between ethane and ethane, that C60-clusters grow with the assistance of solvent molecules, which are trapped between C60 molecules under critical conditions. This room-temperature self-assembly cluster growth process in critical fluids may open up a new methodology of forming structures built up with fullerenes without the need for any ultra-fine processing technologies.

  6. TOF-SIMS with argon gas cluster ion beams: a comparison with C60+.

    PubMed

    Rabbani, Sadia; Barber, Andrew M; Fletcher, John S; Lockyer, Nicholas P; Vickerman, John C

    2011-05-15

    Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is an established technique for the characterization of solid sample surfaces. The introduction of polyatomic ion beams, such as C(60), has provided the associated ability to perform molecular depth-profiling and 3D molecular imaging. However, not all samples perform equally under C(60) bombardment, and it is probably naïve to think that there will be an ion beam that will be applicable in all situations. It is therefore important to explore the potential of other candidates. A systematic study of the suitability of argon gas cluster ion beams (Ar-GCIBs) of general composition Ar(n)(+), where n = 60-3000, as primary particles in TOF-SIMS analysis has been performed. We have assessed the potential of the Ar-GCIBs for molecular depth-profiling in terms of damage accumulation and sputter rate and also as analysis beams where spectral quality and secondary ion yields are considered. We present results with direct comparison with C(60) ions on the same sample in the same instrument on polymer, polymer additive, and biomolecular samples, including lipids and small peptides. Large argon clusters show reduced damage accumulation compared with C(60) with an approximately constant sputter rate as a function of Ar cluster size. Further, on some samples, large argon clusters produce changes in the mass spectra indicative of a more gentle ejection mechanism. However, there also appears to be a reduction in the ionization of secondary species as the size of the Ar cluster increases.

  7. Peptide structural analysis using continuous Ar cluster and C60 ion beams.

    PubMed

    Aoyagi, Satoka; Fletcher, John S; Sheraz Rabbani, Sadia; Kawashima, Tomoko; Berrueta Razo, Irma; Henderson, Alex; Lockyer, Nicholas P; Vickerman, John C

    2013-08-01

    A novel application of time-of-flight secondary ion mass spectrometry (ToF-SIMS) with continuous Ar cluster beams to peptide analysis was investigated. In order to evaluate peptide structures, it is necessary to detect fragment ions related to multiple neighbouring amino acid residues. It is, however, difficult to detect these using conventional ToF-SIMS primary ion beams such as Bi cluster beams. Recently, C60 and Ar cluster ion beams have been introduced to ToF-SIMS as primary ion beams and are expected to generate larger secondary ions than conventional ones. In this study, two sets of model peptides have been studied: (des-Tyr)-Leu-enkephalin and (des-Tyr)-Met-enkephalin (molecular weights are approximately 400 Da), and [Asn(1) Val(5)]-angiotensin II and [Val(5)]-angiotensin I (molecular weights are approximately 1,000 Da) in order to evaluate the usefulness of the large cluster ion beams for peptide structural analysis. As a result, by using the Ar cluster beams, peptide molecular ions and large fragment ions, which are not easily detected using conventional ToF-SIMS primary ion beams such as Bi3 (+), are clearly detected. Since the large fragment ions indicating amino acid sequences of the peptides are detected by the large cluster beams, it is suggested that the Ar cluster and C60 ion beams are useful for peptide structural analysis.

  8. Energetics and kinetics of Ti clustering on neutral and charged C60 surfaces

    NASA Astrophysics Data System (ADS)

    Yang, Shenyuan; Yoon, Mina; Wang, Enge; Zhang, Zhenyu

    2008-10-01

    Using ab initio spin density functional theory, we investigate the energetics and kinetics of Ti clustering on both neutral and charged C60 surfaces. We compare the formation energy of sparsely dispersed zero-dimensional (0D), compact single-layered two-dimensional (2D), and clustered three-dimensional (3D) TiN configurations as a function of cluster size (N⩽12) and further study the transformation kinetics between them. We find that 0D configuration is always less stable than that of 2D and 3D configurations and 0D to 2D transformation involves in a single Ti diffusion process with kinetic barrier of ⩽0.7eV. On the other hand, there exists a critical cluster size (NC) of NC=5, below which 2D layers are preferred to 3D clusters. Hole- or B-doping greatly enhance the Ti-fullerene interaction and lead to stronger dispersion of Ti atoms. Even so, for moderate charge doping (less than seven holes) the critical size of Ti atoms on neutral C60 surprisingly remains unchanged or only slightly increases to NC=6 by B-doping. However, we find that the formation of 3D clusters may be hindered by a high kinetic barrier related to the process of single Ti atoms climbing up a single Ti layer. This barrier is ˜1eV or even 1.47eV for B-doped C60 surfaces which is high enough to stabilize larger 2D structures (N⩾NC) at low temperatures. These findings may prove to be instrumental in stabilizing transition metal coated nanostructures and especially homogeneously Ti-coated fullerenes, which are believed to be a very promising material for hydrogen storage.

  9. Determination of the sputtering yield of cholesterol using Arn(+) and C60(+(+)) cluster ions.

    PubMed

    Rakowska, P D; Seah, M P; Vorng, J-L; Havelund, R; Gilmore, I S

    2016-08-02

    The sputtering yield of cholesterol films on silicon wafers is measured using Arn(+) and C60(+(+)) ions in popular energy (E) and cluster size (n) ranges. It is shown that the C60(+(+)) ions form a surface layer that stabilizes the film so that a well-behaved profile is obtained. On the other hand, the Arn(+) gas clusters leave the material very clean but, at room temperature, the layer readily restructures into molecular bilayers, so that, although a useful measure may be made of the sputtering yield, the profiles become much more complex. This restructuring does not occur at room temperature normally but results from the actions of the beams in the sputtering process for profiling in secondary ion mass spectrometry. Better profiles may be made by reducing the sample temperature to -100 °C. This is likely to be necessary for many lower molecular weight materials (below 1000 Da) to avoid the movement of molecules. Measurements for cholesterol films on 37 nm of amiodarone on silicon are even better behaved and show the same sputtering yields at room temperature as those films directly on silicon at -100 °C. The yields for both C60(+(+)) and Arn(+) fit the Universal Equation to a standard deviation of 11%.

  10. N-block separable random phase approximation: dipole oscillations in sodium clusters and {C}_{60} fullerene

    NASA Astrophysics Data System (ADS)

    Palade, D. I.; Baran, V.

    2016-09-01

    We generalize the schematic model based on the Random Phase Approximation (RPA) with separable interaction, to a collection of subspaces of ph excitations which interact with different coupling constants. This ansatz notably lowers the numerical effort involved, by reducing the RPA eigenvalue problem to a finite small dimensional system of equation. We derive the associated dispersion relation and the normalization condition for the newly defined unknowns of the system. In contrast with the standard separable approach, the present formalism is able to describe more than one collective excitation even in the degenerate limit, giving also access to the nature of the resonance. The theoretical framework is tested investigating the dipolar oscillations in various neutral and singly charged sodium clusters and C 60 fullerene with results in good agreement with full RPA calculations and experimental data. It is proven that the 40 eV resonance present in photoabsorption spectra of C 60 is a localized surface plasmon.

  11. Coupled cluster calculations for static and dynamic polarizabilities of C60

    NASA Astrophysics Data System (ADS)

    Kowalski, Karol; Hammond, Jeff R.; de Jong, Wibe A.; Sadlej, Andrzej J.

    2008-12-01

    New theoretical predictions for the static and frequency dependent polarizabilities of C60 are reported. Using the linear response coupled cluster approach with singles and doubles and a basis set especially designed to treat the molecular properties in external electric field, we obtained 82.20 and 83.62 Å3 for static and dynamic (λ =1064 nm) polarizabilities. These numbers are in a good agreement with experimentally inferred data of 76.5±8 and 79±4 Å3 [R. Antoine et al., J. Chem. Phys.110, 9771 (1999); A. Ballard et al., J. Chem. Phys.113, 5732 (2000)]. The reported results were obtained with the highest wave function-based level of theory ever applied to the C60 system.

  12. Study of Flux Ratio of C60 to Ar Cluster Ion for Hard DLC Film deposition

    NASA Astrophysics Data System (ADS)

    Miyauchi, K.; Kitagawa, T.; Toyoda, N.; Kanda, K.; Matsui, S.; Yamada, I.

    2003-08-01

    To study the influence of the flux ratio of C60 molecule to Ar cluster ion on DLC film characteristics, DLC films deposited under various flux ratios were characterized with Raman spectrometry and Near Edge X-ray Absorption Fine Structure (NEXAFS). From results of these measurements, hard DLC films were deposited when the flux ratio of C60 to Ar cluster ion was between 0.7 and 4. Furthermore the DLC film with constant sp2 content was obtained in the range of the ratio from 0.7 to 4, which contents are lower values than that of conventional films such as RF plasma. DLC films deposited under the ratio from 1 to 4 had hardness from 40 to 45GPa. It was shown that DLC films with stable properties of low sp2 content and high hardness were formed even when the fluxes were varied from 1 to 4 during deposition. It was indicated that this process was useful in the view of industrial application.

  13. Charge exchange and cluster formation in an rf Paul trap: interaction of alkali atoms with C +60

    NASA Astrophysics Data System (ADS)

    Pollack, Stuart; Cameron, Douglas; Rokni, Mordechai; Hill, Winfield; Parks, J. H.

    1996-06-01

    A Paul ion trap was used to study the formation of clusters under controlled temperature and pressure conditions. Exposure of cold C +60 ions to Li flux leads to the formation of Li nC +60 clusters ( n = 1-18) occurring by the sequential association of Li atoms. Cluster formation dependence on He pressure displayed a competition between vibrational relaxation and unimolecular dissociation. Collisions with Na, K, Rb and Cs atoms resulted in dissociative charge exchange. Decay rates of C +60 ions resulting from these low-energy charge exchange collisions were consistent with Langevin capture rates.

  14. Synthesis of gold nano-wire and nano-dumbbell shaped colloids and AuC60 nano-clusters

    NASA Astrophysics Data System (ADS)

    Landon, Preston B.; Jarvis, Brandon C.; Gilleland, Cody L.; Renfro, Tim; Gutierrez, Jose; Synowczynski, Jennifer; Hirsch, Samuel G.; Glosser, Robert

    2005-08-01

    A technique for the fabrication of colloidal gold nano-wire and nano-dumbbell shaped particles using carbon nanotubes and rod shaped viruses as templates is described. The gold (Au) encapsulation process was accomplished by the precipitation of gold chloride from aqueous solutions. When this process was conducted in the presence of hydroxylated C60, small pieces of phase-separated composites of AuC60 appeared to have formed. These nano-clusters may turn out to be large noble metal analogs of the alkali metal fullerides with the smallest geometrically possible Au aggregate consisting of 55 gold atoms. The existence of noble metal fullerene composites has been previously theorized. The alkali metal fullerides are examples of phase separated solids and have exhibited superconductivity with temperatures as high 33K. The mechanism required for the binding energy between C60 and gold has been observed to exist between C60 and many of the mirror metals (Al, Ag, Au, Cu, Ni). This binding energy is a charge transfer from the metal Fermi level into the C60 LUMO. If this bonding energy, is greater than the metals coagulation energy an Au/C60 size terminated mechanism during the formation of the gold aggregates by the adhesion of C60 to the surface is energetically favorable.

  15. Sorption of nano-C60 clusters in soil: hydrophilic or hydrophobic interactions?

    PubMed

    Forouzangohar, Mohsen; Kookana, Rai S

    2011-05-01

    We studied the sorption behaviour of fullerene nano-C(60) particles (nC(60)) in soil from binary solvent mixtures of ethanol-water in order to critically evaluate the previous reports in the literature that the partitioning mechanism explains the soil sorption of fullerene C(60) as hydrophobic molecules. The sorption of nC(60) particles was studied in a range of solvent mixtures by changing volume fractions of ethanol from 20 to 100 percent. Sorption and particle characteristics were found to be very different in ethanol : water mixtures above and below 60% ethanol. In the range of 20-60% ethanol, sorption increased from 1.2 to 14.6 L kg(-1) accompanied by a change in zeta (ζ) potential from -32.4 to -7.2 mV. This observation can be attributed to hydrophilic interactions that negatively charged nC(60) particles undergo with soil colloids and water molecules. From 60% to 100% ethanol volume fractions, hydrophobic interactions of weakly charged nanoparticles may control the overall extent of soil sorption. The findings of this study indicate the importance of hydrophilic forces in controlling the sorption behaviour of nC(60) particles which are stabilized in water dominated solvent mixtures. The validity of the partitioning mechanism and K(OC) modelling approach in describing and estimating the sorption of nC(60) particles in soil (previously suggested in the literature) are, therefore, questioned.

  16. Molecular Dynamics Simulation Study of the Influence of Cluster Geometry on Formation of C60 Fullerene Clusters in Aqueous Solution.

    PubMed

    Kim, Hojin; Bedrov, Dmitry; Smith, Grant D

    2008-02-01

    We have performed atomistic molecular dynamics simulations of linear (1-dimensional), planar (2-dimensional), and icosahedral (3-dimensional) clusters of C60 fullerenes in aqueous solution in order to investigate the influence of cluster geometry on their free energy of formation. As was found in our previous study of the potential of mean force (PMF) as a function of separation for a single pair of fullerenes in aqueous solution, the interaction between fullerenes for all cluster geometries was dominated by direct fullerene-fullerene interactions and not by water-induced hydrophobic interactions. A coarse-grained implicit solvent (CGIS) potential, given by the PMF for the fullerene pair in water obtained from atomistic simulations, was found to describe well the free energy of formation of the linear cluster, indicating that many-body effects, i.e., the influence of neighboring fullerenes on the water-induced interaction between a fullerene pair, are negligible for the 1-dimensional geometry. For the 2-dimensional and particularly the 3-dimensional geometry, however, many-body effects were found to strongly influence hydration, leading to complete dehydration of the central fullerene at close fullerene-fullerene separations for the icosahedral cluster. This strong influence of geometry on hydration translates into water-induced interactions that, while remaining repulsive, as is found for the fullerene pair, are not well described by the two-body CGIS potential obtained from the isolated fullerene pair, particularly for the 3-dimensional geometry.

  17. Lowest-energy structures of (C60)nX (X=Li+,Na+,K+,Cl-) and (C60)nYCl (Y=Li,Na,K) clusters for n⩽13

    NASA Astrophysics Data System (ADS)

    Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.; Wales, D. J.

    2004-12-01

    Basin-hopping global optimization is used to find likely candidates for the lowest minima on the potential energy surface of (C60)nX (X=Li+,Na+,K+,Cl-) and (C60)nYCl (Y=Li,Na,K) clusters with n⩽13. The energy is evaluated using the Girifalco form for the C60 intermolecular potential along with a polarization potential, which depends on the first few nonvanishing C60 multipole polarizabilities. We find that the ions occupy interstitial sites of a (C60)n cluster, the coordination shell being triangular for Li+, tetrahedral for Na+ and K+, and octahedral for Cl-. When the required coordination site does not exist in the corresponding (C60)n global minimum, the lowest minimum of the doped system may be based on an alternative geometry. This situation is particularly common in the Cl- complexes, where the (C60)n global minima with icosahedral packing change into decahedral or closed-packed forms for the ions. In all the ions we find a significant binding energy for the doped cluster. In the alkali chloride complexes the preferred coordination for the diatomic moiety is octahedral and is basically determined by the Cl- ion. However, the smaller polarization energies in this case mean that a change in structure from the (C60)n global minimum does not necessarily occur if there is no octahedral site.

  18. SERS of Gold/C 60 (/C 70) nano-clusters deposited on floppy disk and hard disk

    NASA Astrophysics Data System (ADS)

    Luo, Zhixun; Fang, Yan

    2006-01-01

    It is important to apply the surface enhanced Raman scattering (SERS) spectra to study the interfacial properties of films and the adsorption behavior of molecules on substrates. In this paper, SERS spectra of good quality of gold/C 60 (/C 70) nano-clusters deposited on floppy disk and hard disk were reported with the pyridine as a kind of solvent intermediate. The floppy disk or hard disk, as a new and effective substrate for SERS, provides a plank for C 60/C 70 molecules to adsorb on the gold nano-particles. The number of vibrational modes was greatly increased, especially some modes that were forbidden in Raman spectrum, appeared and even split as prediction of group theory. The enhancement factor is estimated to over 10 6. It provides convenience for probing the C 60/C 70 vibrational structure and the physical properties with the high sensitivity, as well as the adsorption behavior, the interaction of fullerene with gold surface and the SERS mechanism of molecules adsorbed on substrates. What's more, the SERS sensitivity of the magnetism is demonstrated by comparing the SERS of gold/C 60 (/C 70) nano-clusters deposited on floppy disk and hard disk.

  19. An experimental and theoretical view of energetic C60 cluster bombardment onto molecular solids.

    PubMed

    Brenes, Daniel A; Postawa, Zbigniew; Wucher, Andreas; Blenkinsopp, Paul; Garrison, Barbara J; Winograd, Nicholas

    2013-01-01

    Recent experimental measurements and calculations performed by molecular dynamics computer simulations indicate, for highly energetic C60 primary ions bombarding molecular solids, the emission of intact molecules is unique. An energy- and angle-resolved neutral mass spectrometer coupled with laser photoionization techniques was used to measure the polar angle distribution of neutral benzo[a]pyrene molecules desorbed by 20-keV [Formula: see text] primary ions and observed to peak at off-normal angles integrated over all possible emission energies. Similarly, computer simulations of 20-keV C60 projectiles bombarding a coarse-grained benzene system resulted in calculations of nearly identical polar angle distributions. Upon resolving the measured and calculated polar angle distributions, sputtered molecules with high kinetic energies are the primary contributors to the off-normal peak. Molecules with low kinetic energies were measured and calculated to desorb broadly peaked about the surface normal. The computer simulations suggest the fast deposition of energy from the C60 impact promotes the molecular emission by fluid-flow and effusive-type motions. The signature of off-normal emission angles is unique for molecules because fragmentation processes remove molecules that would otherwise eject near normal to the surface. Experimental measurements from a Ni {001} single crystal bombarded by 20-keV [Formula: see text] demonstrate the absence of this unique signature.

  20. Molecular dynamics study of polystyrene bond-breaking and crosslinking under C60 and Arn cluster bombardment

    NASA Astrophysics Data System (ADS)

    Czerwinski, Bartlomiej; Postawa, Zbigniew; Garrison, Barbara J.; Delcorte, Arnaud

    2013-05-01

    Molecular dynamics computer simulations are used to elucidate the bond-breaking and crosslinking processes induced by 2.5 keV C60 and Arn cluster bombardment in an amorphous sec-butyl-terminated polystyrene sample. The obtained results indicate that replacement of C60 by Ar18 or Ar60 projectiles leads to the decrease of the number of broken bonds and, hence, to the decrease of formation of new intra- and intermolecular (crosslinking) bonds. When the number of atoms in the Arn cluster is increased from 60 to 250 or more, the total number of broken bonds and the total number of newly created bonds reach a zero value. Additional comparison to the case of a fullerite crystal reveals that the change of material properties leads to almost 7.5-fold reduction of the efficiency of the crosslinking process.

  1. Molecular Depth Profiling using a C(60) Cluster Beam: the Role of Impact Energy.

    PubMed

    Wucher, Andreas; Cheng, Juan; Winograd, Nicholas

    2008-10-23

    Molecular depth profiling of organic overlayers was performed using a mass selected C(60) ion beam in conjunction with time-of-flight (TOF-SIMS) mass spectrometry. The characteristics of sputter depth profiles acquired for a 300-nm Trehalose film on silicon were studied as a function of the kinetic impact energy of the projectile ions. The results are interpreted in terms of a simple model describing the balance between sputter erosion and ion induced chemical damage. It is shown that the efficiency of the projectile to clean up the fragmentation debris produced by its own impact represents a key parameter governing the success of molecular depth profile analysis.

  2. Interaction of energetic clusters (Au 3, Au 400 and C 60) with organic material and adsorbed gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Restrepo, Oscar A.; Prabhakaran, Aneesh; Delcorte, Arnaud

    2011-07-01

    Using molecular dynamics simulations (MD), this contribution compares the interaction of three energetic clusters (Au3, Au400 and C60) with a hybrid surface of crystalline polyethylene (PE) covered by a layer of gold nanoparticles. This model system mimics the situation encountered in metal-assisted secondary ion mass spectrometry. The chosen impact points are representative of the PE surface, the metal particles and the frontier between the metal and the polymer. The simulations show the differences between the impact over the Au nanoparticle and the polymer surface, in terms of projectile penetration, crater formation and sputtering yield of PE and gold species. For C60 and Au3 projectiles, a simple correlation is found between the quantity of energy deposited in the top polymeric layers and the quantity of sputtered polymer material, including all the impact points. The results obtained with Au400 do not fit on this line, indicating that other physical parameters are prevalent. The mechanistic view of the interaction provided by the MD helps explain the differences. In short, while C60 and Au3 quickly break apart, creating energetic recoils and severing many bonds in the surface, Au400, with the largest total momentum by far (∼10 times larger than the others) and the lowest energy per atom (25 eV), tends to act and implant in the solid as a single entity, pushing the polymeric material downwards and breaking few bonds in the surface.

  3. New insight into the structure of the C60Sc20 cluster: bonding, vibrational and optical properties.

    PubMed

    Tlahuice-Flores, A

    2016-05-14

    Recently, a new stable C60Sc20 cluster has been proposed. Its structure has Th symmetry and a large HOMO-LUMO gap value. In this communication a systematic study of its bonding, IR, Raman and absorption spectra has been carried out. Its calculated absorption spectrum features four peaks located at 1.34, 1.6, 1.87 and 2.1 eV. Moreover its Raman and IR spectra are dominated by the signals of normal modes with Tu, Eg and Au irreducible representations.

  4. Effect of encapsulation (Ru & Pd) small clusters in fullerene (C60) on electronic and magnetic properties: DFT

    NASA Astrophysics Data System (ADS)

    Abdaljalil, Rana. O.; Umran, Nibras. M.

    2017-09-01

    We have done a systematic study of structural and electronic, to describe the Interaction between various atoms doped inside C60 by using Density functional theory (DFT). The foresee for carbon doping, modifies the electronic properties of fullerenes. We optimized the Run@C60 and Pdn@C60 (n=1-4) complexes, we found that endohedral metallofullerenes are stable. As well, we investigated binding energy, ionization potential, and energy gap of Ru and Pd encapsulate fullerenes. Where observed the effect modified by endohedral metallofullerenes makes C60 more reactive. Also the presence of the magnetic moment in metallofullerenes using Mulliken charge analysis.

  5. Equation of motion coupled cluster methods for electron attachment and ionization potential in fullerenes C60 and C70

    SciTech Connect

    Bhaskaran-Nair, Kiran; Kowalski, Karol; Moreno, Juana; Jarrell, Mark; Shelton, William A.

    2014-08-21

    Discovery of fullerenes has opened a entirely new chapter in chemistry due to their wide range of properties which holds exciting applications in numerous disciplines of science. The Nobel Prize in Chemistry 1996 was awarded jointly to Robert F. Curl Jr., Sir Harold W. Kroto and Richard E. Smalley in recoginition for their discovery of this new carbon allotrope. In this letter we are reporting ionization potential and electron attachment studies on fullerenes (C60 and C70) obtained with novel parallel implementation of the EA-EOM-CCSD and IP-EOM-CCSD methods in NWChem program package.

  6. New Volleyballenes: Y20C60 and La20C60

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Liu, Ying

    2016-08-01

    Two new stable Volleyballenes, the Y20C60 and La20C60 molecular clusters, are proposed on the basis of first-principles density functional theory. In conjunction with recent findings for the scandium system, these findings establish Volleyballene M20C60 molecules as a general class of stable molecules within the fullerene family. Both Y20C60 and La20C60 molecules have Th point group symmetries and relatively large HOMO-LUMO gaps.

  7. New Volleyballenes: Y20C60 and La20C60

    PubMed Central

    Wang, Jing; Liu, Ying

    2016-01-01

    Two new stable Volleyballenes, the Y20C60 and La20C60 molecular clusters, are proposed on the basis of first-principles density functional theory. In conjunction with recent findings for the scandium system, these findings establish Volleyballene M20C60 molecules as a general class of stable molecules within the fullerene family. Both Y20C60 and La20C60 molecules have Th point group symmetries and relatively large HOMO-LUMO gaps. PMID:27487765

  8. Translocation mechanism of C60 and C60 derivations across a cell membrane

    NASA Astrophysics Data System (ADS)

    Liang, Lijun; Kang, Zhengzhong; Shen, Jia-Wei

    2016-11-01

    Carbon-based nanoparticles (NPs) such as fullerenes and nanotubes have been extensively studied for drug delivery in recent years. The permeation process of fullerene and its derivative molecules through membrane is essential to the utilization of fullerene-based drug delivery system, but the mechanism and the dynamics of permeation through cell membrane are still unclear. In this study, coarse-grained molecular dynamics simulations were performed to investigate the permeation process of functionalized fullerene molecules (ca. 0.72 nm) through the membrane. Our results show that single functionalized fullerene molecule in such nanoscale could permeate the lipid membrane in micro-second time scale. Pristine C60 molecules prefer to aggregate into several small clusters while C60OH15 molecules could aggregate into one big cluster to permeate through the lipid membrane. After permeation of C60 or its derivatives into membrane, all C60 and C60OH15 molecules disaggregated and monodispersed in the lipid membrane.

  9. C60 in Photodissociation Regions

    NASA Astrophysics Data System (ADS)

    Castellanos, Pablo; Berné, Olivier; Sheffer, Yaron; Wolfire, Mark G.; Tielens, Alexander G. G. M.

    2014-10-01

    Recent studies have confirmed the presence of buckminsterfullerene (C60) in different interstellar and circumstellar environments. However, several aspects regarding C60 in space are not yet well understood, such as the formation and excitation processes, and the connection between C60 and other carbonaceous compounds in the interstellar medium, in particular polycyclic aromatic hydrocarbons (PAHs). In this paper, we study several photodissociation regions (PDRs) where C60 and PAHs are detected and the local physical conditions are reasonably well constrained to provide observational insights into these questions. C60 is found to emit in PDRs where the dust is cool (Td = 20-40 K) and even in PDRs with cool stars. These results exclude the possibility for C60 to be locked in grains at thermal equilibrium in these environments. We observe that PAH and C60 emission are spatially uncorrelated and that C60 is present in PDRs where the physical conditions (in terms of radiation field and hydrogen density) allow for full dehydrogenation of PAHs, with the exception of Ced 201. We also find trends indicative of an increase in C60 abundance within individual PDRs, but these trends are not universal. These results support models where the dehydrogenation of carbonaceous species is the first step toward C60 formation. However, this is not the only parameter involved and C60 formation is likely affected by shocks and PDR age.

  10. A Molecular Dynamics Simulation of C60-C60 Collision

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Chen, Kaitai; Li, Yufen

    1993-12-01

    The formation process of C120-complex in C60-C60 collision has been clearly demonstrated by a molecular dynamics simulation. The complex, with a peanut-shell-like structure, is in a quite stable dynamical state. The results are consistent with recent observations.

  11. Isomerization of C60 fullerenes

    NASA Astrophysics Data System (ADS)

    Yi, Jae-Yel; Bernholc, J.

    1992-06-01

    Car-Parrinello calculations show that the transformation between C60 isomers involves barriers in excess of 5 eV, although the energetic difference between the buckyball and the next lowest isomer is only 1.6 eV. C60 isomerization thus requires high temperatures and long annealing times.

  12. C60 in Reflection Nebulae

    NASA Astrophysics Data System (ADS)

    Sellgren, Kris; Werner, Michael W.; Ingalls, James G.; Smith, J. D. T.; Carleton, T. M.; Joblin, Christine

    2010-10-01

    The fullerene C60 has four infrared-active vibrational transitions at 7.0, 8.5, 17.4, and 18.9 μm. We have previously observed emission features at 17.4 and 18.9 μm in the reflection nebula NGC 7023 and demonstrated spatial correlations suggestive of a common origin. We now confirm our earlier identification of these features with C60 by detecting a third emission feature at 7.04 ± 0.05 μm in NGC 7023. We also report the detection of these three C60 features in the reflection nebula NGC 2023. Our spectroscopic mapping of NGC 7023 shows that the 18.9 μm C60 feature peaks on the central star and that the 16.4 μm emission feature due to polycyclic aromatic hydrocarbons peaks between the star and a nearby photodissociation front. The observed features in NGC 7023 are consistent with emission from UV-excited gas-phase C60. We find that 0.1%-0.6% of interstellar carbon is in C60; this abundance is consistent with those from previous upper limits and possible fullerene detections in the interstellar medium (ISM). This is the first firm detection of neutral C60 in the ISM.

  13. Photophysics of C60 Colloids

    DTIC Science & Technology

    2012-11-28

    illumination," Fullerenes, Nanotubes and Carbon Nanostructures 9(3), 351 - 361 (2001). 46. A. Kost, L. W. Tutt, M. B. Klein, T. K. Dougherty, and W. E...properties of singlewall carbon nanotubes ," Optics Communications 174(1-4), 271-275 (2000). 130. J. Williams, "Oceanographic Instrumentation," in...of C60 and carbon black suspensions (CBS). C60 in molecular form is known to exhibit strong reverse saturable absorption (RSA) and it is posited that

  14. Low-temperature plasma for compositional depth profiling of crosslinking organic multilayers: comparison with C60 and giant argon gas cluster sources.

    PubMed

    Muramoto, Shin; Rading, Derk; Bush, Brian; Gillen, Greg; Castner, David G

    2014-09-30

    For organic electronics, device performance can be affected by interlayer diffusion across interfaces. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) can resolve buried structures with nanometer resolution, but instrument artifacts make this difficult. Low-temperature plasma (LTP) is suggested as a way to prepare artifact-free surfaces for accurate determination of chemical diffusion. A model organic layer system consisting of three 1 nm delta layers of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) separated by three 30 nm layers of tris(8-hydroxyquinolinato)aluminum (Alq3) was used to evaluate the effectiveness of LTP etching for the preparation of crater edge surfaces for subsequent compositional depth profile analysis. This was compared with depth profiles obtained using an instrument equipped with an argon cluster sputter source. The quality of the depth profiles was determined by comparing the depth resolutions of the BCP delta layers. The full width at half maximum gave depth resolutions of 6.9 nm and 6.0 nm using LTP, and 6.2 nm and 5.8 nm using argon clusters. In comparison, the 1/e decay length of the trailing edge gave depth resolutions of 2.0 nm and 1.8 nm using LTP, and 3.5 nm and 3.4 nm using argon clusters. The comparison of the 1/e decay lengths showed that LTP can determine the thickness and composition of the buried structures without instrument artifacts. Although it does suffer from contaminant deposition, LTP was shown to be a viable option for preparing crater edges for a more accurate determination of buried structures. Copyright © 2014 John Wiley & Sons, Ltd.

  15. Single Photon Thermal Ionization of C60

    NASA Astrophysics Data System (ADS)

    Hansen, Klavs; Richter, Robert; Alagia, Michele; Stranges, Stefano; Schio, Luca; Salén, Peter; Yatsyna, Vasyl; Feifel, Raimund; Zhaunerchyk, Vitali

    2017-03-01

    We report on experiments which show that C60 can ionize in an indirect, quasithermal boiloff process after absorption of a single photon. The process involves a large number of incoherently excited valence electrons and yields electron spectra with a Boltzmann distribution with temperatures exceeding 104 K . It is expected to be present for other molecules and clusters with a comparatively large number of valence electrons. The astrophysical consequences are briefly discussed.

  16. Sc20C60: a volleyballene

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Ma, Hong-Man; Liu, Ying

    2016-06-01

    An exceptionally stable hollow cage containing 20 scandium atoms and 60 carbon atoms has been identified. This Sc20C60 molecular cluster has a Th point group symmetry and a volleyball-like shape that we refer to below as ``Volleyballene''. Electronic structure analysis shows that the formation of delocalized π bonds between Sc atoms and the neighboring pentagonal rings made of carbon atoms is crucial for stabilizing the cage structure. A relatively large HOMO-LUMO gap (~1.4 eV) was found. The results of vibrational frequency analysis and molecular dynamics simulations both demonstrate that this Volleyballene molecule is exceptionally stable.An exceptionally stable hollow cage containing 20 scandium atoms and 60 carbon atoms has been identified. This Sc20C60 molecular cluster has a Th point group symmetry and a volleyball-like shape that we refer to below as ``Volleyballene''. Electronic structure analysis shows that the formation of delocalized π bonds between Sc atoms and the neighboring pentagonal rings made of carbon atoms is crucial for stabilizing the cage structure. A relatively large HOMO-LUMO gap (~1.4 eV) was found. The results of vibrational frequency analysis and molecular dynamics simulations both demonstrate that this Volleyballene molecule is exceptionally stable. Electronic supplementary information (ESI) available: Sc20C60: a Volleyballene_SI. See DOI: 10.1039/c5nr07784b

  17. Adsorption of 4He on a Single C60

    NASA Astrophysics Data System (ADS)

    Szybisz, L.; Urrutia, I.

    2004-01-01

    The adsorption of $^4$He inside and outside a single fullerene C$_{60}$ is studied. A physisorption potential is proposed. The energetics and structural features of C$_{60}$-$^4$He$_N$ clusters are investigated. Particular attention is paid to the growth of the highly pronounced layered density profile. The evolution towards bulk liquid and surface thickness at the free interface are discussed.

  18. Hydrogen Diffusion in C_60

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Stephen; Sethna, Dorab; Szuts, Zoltan

    2001-03-01

    Recently^1 it has been shown that hydrogen molecules can be forced into a C_60 lattice under modest pressure. A loading pressure of 2,000 PSI is sufficient to fill almost 50 % of the available octahedral sites. Here we extend this work to consider the kinetics of the hydrogen diffusion within the C_60 lattice. In our procedure the sample is first loaded to its equilibrium H2 concentration. The confining pressure is then quickly removed and the rate at which the H2 outgasses from the powder is monitored via the slow pressure increase with time. Results show that the outgassing time constant depends critically on the particle sized distribution of the C_60. Ground powders have time-constants almost an order of magnitude faster than unground. In all cases the kinetics are consistent with a two-time constant model in which the hydrogen diffuses within the lattice and along the grain boundaries between crystallites. However, the loaded H2 concentration depends solely on the loading pressure independent of the powder type indicating that at equilibrium the H2 molecules reside exclusively at the lattice octahedral sites and not in the grain boundaries. Measurements taken at a series of different temperatures indicate that diffusion within the lattice has an activation barrier of 105 meV. This compares well with the theoretical predictions for the octahedral well depth of 110 meV^1. ^1 S. A. FitzGerald et al., Phys. Rev. B 60, 6439 (1999).

  19. Helium Droplets Doped with Sulfur and C60

    PubMed Central

    2014-01-01

    Clusters of sulfur are grown by passing superfluid helium nanodroplets through a pickup cell filled with sulfur vapor. In some experiments the droplets are codoped with C60. The doped droplets are collided with energetic electrons and the abundance distributions of positively and negatively charged cluster ions are recorded. We report, specifically, distributions of Sm+, Sm–, and C60Sm– containing up to 41 sulfur atoms. We also observe complexes of sulfur cluster anions with helium; distributions are presented for HenSm– with n ≤ 31 and m ≤ 3. The similarity between anionic and cationic C60Sm± spectra is in striking contrast to the large differences between spectra of Sm+ and Sm–. PMID:26045732

  20. Non-IPR C60 solids.

    PubMed

    Löffler, Daniel; Bajales, Noelia; Cudaj, Marcus; Weis, Patrick; Lebedkin, Sergei; Bihlmeier, Angela; Tew, David P; Klopper, Wim; Böttcher, Artur; Kappes, Manfred M

    2009-04-28

    Films comprising predominantly novel isomers of C(60) [=C(60)(nIPR)] have been generated by low energy ion beam deposition of vibronically excited C(60)(+) onto graphite followed by selective sublimation of C(60)(I(h)) from the deposited isomer mixture. The incident ions were generated by electron impact ionization/fragmentation of sublimed C(70). Images of the C(60)(nIPR) films obtained by applying atomic force microscopy show aggregates, which we attribute to covalently interlinked C(60)(nIPR) units. The covalent bonds are inferred from the significantly higher thermal stability of the C(60)(nIPR) films compared to the C(60)(I(h)) van der Waals solid-as measured by thermal desorption with mass spectrometric detection of the C(60) mass channel (the only desorbable species). In contrast to the characteristic doublet structure of the occupied valence band in the ultraviolet photoelectron spectrum of pure C(60)(I(h)), the valence band of C(60)(nIPR) films exhibits a triplet feature with the additional peak occurring at a binding energy of approximately 2.6 eV. This is an indicator of the electronic modifications induced by intermolecular bonding. C(60)(nIPR) films exhibit a narrower band gap than found for C(60)(I(h)). They also have significantly different chemical reactivity toward incorporation of thermal energy deuterium atoms. In order to model the experimental photoelectron spectra, various covalently linked oligomers of (#1809)C(60)(C(2v)), the second most stable conventional 60-atom fullerene cage, were calculated by means of the density functional theory. These spectral predictions together with analogous previous observations on related fullerene solids such as C(58) lead us to infer that C(60)(nIPR) films consist of fullerene cage isomers containing one or more adjacent pentagon pairs, which mediate covalent cage-cage interconnection.

  1. Optimal covering of C60 fullerene by rare gases

    NASA Astrophysics Data System (ADS)

    Acosta-Gutiérrez, S.; Bretón, J.; Llorente, J. M. Gomez; Hernández-Rojas, J.

    2012-08-01

    Putative global energy minima of clusters formed by the adsorption of rare gases on a C60 fullerene molecule, C60XN (X=Ne, Ar, Kr, Xe; N ⩽ 70), are found using basin-hopping global optimization in an empirical potential energy surface. The association energies per rare gas atom as a function of N present two noticeable minima for Ne and Ar and just one for Kr and Xe. The minimum with the smallest N is the deepest one and corresponds to an optimal packing monolayer structure; the other one gives a monolayer with maximum packing. For Kr and Xe, optimal and maximum packing structures coincide. By using an isotropic average form of the X-C60 interaction, we have established the relevance of the C60 surface corrugation on the cluster structures. Quantum effects are relevant for Ne clusters. The adsorption of these rare gases on C60 follows patterns that differ significantly from the ones found recently for He by means of experimental and theoretical methods.

  2. C60 on SiC nanomesh.

    PubMed

    Chen, Wei; Zhang, Hong Liang; Xu, Hai; Tok, Eng Soon; Loh, Kian Ping; Wee, Andrew Thye Shen

    2006-11-02

    A SiC nanomesh is used as a nanotemplate to direct the epitaxy of C60 molecules. The epitaxial growth of C60 molecules on SiC nanomesh at room temperature is investigated by in situ scanning tunneling microscopy, revealing a typical Stranski-Krastanov mode (i.e., for the first one or two monolayers, it is a layer-by-layer growth or 2-D nucleation mode; at higher thicknesses, it changes to island growth or a 3-D nucleation mode). At submonolayer (0.04 and 0.2 ML) coverage, C60 molecules tend to aggregate to form single-layer C60 islands that mainly decorate terrace edges, leaving the uncovered SiC nanomesh almost free of C60 molecules. At 1 ML C60 coverage, a complete wetting layer of hexagonally close-packed C60 molecules forms on top of the SiC nanomesh. At higher coverage from 4.5 ML onward, the C60 stacking adopts a (111) oriented face-centered-cubic (fcc) structure. Strong bright and dim molecular contrasts have been observed on the first layer of C60 molecules, which are proposed to originate from electronic effects in a single-layer C60 island or the different coupling of C60 molecules to SiC nanomesh. These STM molecular contrast patterns completely disappear on the second and all the subsequent C60 layers. It is also found that the nanomesh can be fully recovered by annealing the C60/SiC nanomesh sample at 200 degrees C for 20 min.

  3. C60-PMO: periodic mesoporous buckyballsilica.

    PubMed

    Whitnall, Wesley; Cademartiri, Ludovico; Ozin, Geoffrey A

    2007-12-19

    Here we report the first documented synthesis of a periodic mesoporous organosilica (PMO), that contains a multiply bonded C60 moiety integrated into the silica channel walls of the material, dubbed C60-PMO. This is accomplished through the acid-catalyzed co-assembly, of C60(NHCH2CH2CH2Si(OEt)3)x and tetraethylorthosilicate (TEOS) with a polyethyleneoxide-polylpropyleneoxide-polyethyleneoxide triblock copolymer template. The percentage of C60 in the final material was estimated to be a minimum of 63 vol %, but potentially as high as 91 vol %. The effects of the synthesis conditions on the mesostructure of the resulting materials are examined. In particular, we demonstrate that the C60 is uniformly distributed throughout the entire sample by the use of energy dispersive X-ray fluorescence (EDX) analysis and an OsO4 label bonded to the C60.

  4. [Antiamyloid properties of fullerene C60 derivatives].

    PubMed

    Bobylev, A G; Shpagina, M D; Bobyleva, L G; Okuneva, A D; Piotrovskiĭ, L B; Podlubnaia, Z A

    2012-01-01

    A comparative estimation of the ability of complexes of fullerene C60 with polyvinylpyrrolidone and fullerene C60 derivatives (the sodium salt of the polycarboxylic derivative of fullerene C60, sodium fullerenolate), has been carried out. The fullerenes destroyed amyloid fibrils of the Abeta(1-42) peptide of the brain and the muscle X-protein. A study of the effect of fullerenes on muscle actin showed that complexes of fullerene C60 with polyvinylpyrrolidone and sodium fullerenolate did not prevent the filament formation of actin, nor did they destroy its filaments in vitro. Conversely, sodium salt of the polycarboxylic derivative of fullerene C60 destroyed actin filaments and prevented their formation. It was concluded that sodium fullerenolate and complexes of fullerene C60 with polyvinylpyrrolidone are the most effective antiamyloid compounds among the fullerenes examined.

  5. Photoemission study of Li@C60

    NASA Astrophysics Data System (ADS)

    Yagi, Hajime; Ogasawara, Naoko; Zenki, Masashi; Miyazaki, Takafumi; Hino, Shojun

    2016-05-01

    Ultraviolet and X-ray photoelectron spectra (UPS and XPS) of thin films prepared by either depositing or applying [Li@C60]+(PF6)- on the substrates are presented. The UPS and XPS of [Li@C60]+(PF6)- applied films suggest that PF6- anions come out from the surface by annealing at 250 °C. The UPS and XPS of the deposited thin films indicate that the film does not contain PF6- anion but is composed of only Li@C60. Changing the sublimation temperature reveals that encapsulated Li cations begin to escape from the C60 cage when heated above 550 °C.

  6. 15 CFR 8c.60 - Communications.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Communications. 8c.60 Section 8c.60 Commerce and Foreign Trade Office of the Secretary of Commerce ENFORCEMENT OF NONDISCRIMINATION ON THE... Communications. (a) The agency shall take appropriate steps to ensure effective communication with applicants...

  7. 15 CFR 8c.60 - Communications.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Communications. 8c.60 Section 8c.60 Commerce and Foreign Trade Office of the Secretary of Commerce ENFORCEMENT OF NONDISCRIMINATION ON THE... Communications. (a) The agency shall take appropriate steps to ensure effective communication with...

  8. Non-Engineered Nanoparticles of C60

    PubMed Central

    Deguchi, Shigeru; Mukai, Sada-atsu; Sakaguchi, Hide; Nonomura, Yoshimune

    2013-01-01

    We discovered that rubbing bulk solids of C60 between fingertips generates nanoparticles including the ones smaller than 20 nm. Considering the difficulties usually associated with nanoparticle production by pulverisation, formation of nanoparticles by such a mundane method is unprecedented and noteworthy. We also found that nanoparticles of C60 could be generated from bulk solids incidentally without deliberate engineering of any sort. Our findings imply that there exist highly unusual human exposure routes to nanoparticles of C60, and elucidating formation mechanisms of nanoparticles is crucial in assessing their environmental impacts. PMID:23807024

  9. Photocycloaddition of anthracene to excited C-60

    SciTech Connect

    Gol`dshleger, N.F.; Denisov, N.N.; Lobach, A.S.

    1995-02-01

    The ability to participate in photochemical cycloaddition reactions is characteristic feature of chromophores with a carbon double bond. In this work, the authors demonstrate the formation of an adduct by cycloaddition of anthracene to the triplet-excited C-60 fullerene under anaerobic conditions, which provides a straight forward way to synthesize new derivatives of C-60 fullerenes. Reaction methods, conditions, and mechanisms are included along with the characterization of the fullerene derivative with IR, MS, and NMR methods.

  10. Solubility Characteristics of PCBM and C60.

    PubMed

    Boucher, David; Howell, Jason

    2016-11-10

    Empirical data indicate that several good solvents for C60 and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) have substantial polar and hydrogen-bonding components, which are not intrinsic to the structure of the C60 and PCBM molecules themselves. Functional solubility parameter (FSP) and convex solubility parameter (CSP) computations are performed on C60 and PCBM using solubility data available in the literature. The CSP and FSP results are compared to previously reported Hansen solubility parameters (HSPs) and to the parameters calculated using additive functional group contribution methods. The CSP and FSP methods confirm the anomalously large polar and hydrogen-bonding parameters, δP and δH, obtained experimentally for C60 and PCBM. This behavior, which is quite irregular given the structure of the molecules, is due to the fact that several good solvents have high δP and δH values. Thus, these irregularities are highlighted by the CSP and FSP calculations. Additional contradictory solubility characteristics are disclosed by comparing the experimental solubility parameters to a linear solvation energy relationship (LSER) model, additive functional group calculations, and COSMO-RS computations. The FSP solubility function strongly suggests that the solubility parameters do not accurately represent the cohesive energy density properties of C60 and PCBM, as intended, but rather they manifest the properties of the solvents, e.g., high δP and δH values, that are necessary to accommodate these molecules in the liquid phase.

  11. C60 fullerene binding to DNA

    NASA Astrophysics Data System (ADS)

    Alshehri, Mansoor H.; Cox, Barry J.; Hill, James M.

    2014-09-01

    Fullerenes have attracted considerable attention in various areas of science and technology. Owing to their exceptional physical, chemical, and biological properties, they have many applications, particularly in cosmetic and medical products. Using the Lennard-Jones 6-12 potential function and the continuum approximation, which assumes that intermolecular interactions can be approximated by average atomic surface densities, we determine the binding energies of a C60 fullerene with respect to both single-strand and double-strand DNA molecules. We assume that all configurations are in a vacuum and that the C60 fullerene is initially at rest. Double integrals are performed to determine the interaction energy of the system. We find that the C60 fullerene binds to the double-strand DNA molecule, at either the major or minor grooves, with binding energies of -4.7 eV or -2.3 eV, respectively, and that the C60 molecule binds to the single-strand DNA molecule with a binding energy of -1.6 eV. Our results suggest that the C60 molecule is most likely to be linked to the major groove of the dsDNA molecule.

  12. Near-IR Photoluminescence of C60().

    PubMed

    Strelnikov, Dmitry V; Kern, Bastian; Kappes, Manfred M

    2017-10-05

    We have observed that C60(+) ions isolated in cryogenic matrices show distinct near-IR photoluminescence upon excitation in the near-IR range. By contrast, UV photoexcitation does not lead to measurable luminescence. Near-IR C60(+) photoluminescence is a one-photon process. The emission is mainly concentrated in one band and corresponds to (2)A1u ← (2)E1g relaxation. We present experimental data for the Stokes shift, power, and temperature dependencies as well as the quantum efficiency of the photoluminescence. Our findings may be relevant for astronomy, considering recent unequivocal assignment of five diffuse interstellar bands to near-IR absorption bands of C60(+).

  13. The dipolar endofullerene HF@C60

    NASA Astrophysics Data System (ADS)

    Krachmalnicoff, Andrea; Bounds, Richard; Mamone, Salvatore; Alom, Shamim; Concistrè, Maria; Meier, Benno; Kouřil, Karel; Light, Mark E.; Johnson, Mark R.; Rols, Stéphane; Horsewill, Anthony J.; Shugai, Anna; Nagel, Urmas; Rõõm, Toomas; Carravetta, Marina; Levitt, Malcolm H.; Whitby, Richard J.

    2016-10-01

    The cavity inside fullerenes provides a unique environment for the study of isolated atoms and molecules. We report the encapsulation of hydrogen fluoride inside C60 using molecular surgery to give the endohedral fullerene HF@C60. The key synthetic step is the closure of the open fullerene cage with the escape of HF minimized. The encapsulated HF molecule moves freely inside the cage and exhibits quantization of its translational and rotational degrees of freedom, as revealed by inelastic neutron scattering and infrared spectroscopy. The rotational and vibrational constants of the encapsulated HF molecules were found to be redshifted relative to free HF. The NMR spectra display a large 1H-19F J coupling typical of an isolated species. The dipole moment of HF@C60 was estimated from the temperature dependence of the dielectric constant at cryogenic temperatures and showed that the cage shields around 75% of the HF dipole.

  14. The dipolar endofullerene HF@C60.

    PubMed

    Krachmalnicoff, Andrea; Bounds, Richard; Mamone, Salvatore; Alom, Shamim; Concistrè, Maria; Meier, Benno; Kouřil, Karel; Light, Mark E; Johnson, Mark R; Rols, Stéphane; Horsewill, Anthony J; Shugai, Anna; Nagel, Urmas; Rõõm, Toomas; Carravetta, Marina; Levitt, Malcolm H; Whitby, Richard J

    2016-10-01

    The cavity inside fullerenes provides a unique environment for the study of isolated atoms and molecules. We report the encapsulation of hydrogen fluoride inside C60 using molecular surgery to give the endohedral fullerene HF@C60. The key synthetic step is the closure of the open fullerene cage with the escape of HF minimized. The encapsulated HF molecule moves freely inside the cage and exhibits quantization of its translational and rotational degrees of freedom, as revealed by inelastic neutron scattering and infrared spectroscopy. The rotational and vibrational constants of the encapsulated HF molecules were found to be redshifted relative to free HF. The NMR spectra display a large (1)H-(19)F J coupling typical of an isolated species. The dipole moment of HF@C60 was estimated from the temperature dependence of the dielectric constant at cryogenic temperatures and showed that the cage shields around 75% of the HF dipole.

  15. Sublimation of hydrofullerenes C 60H 36 and C 60H 18

    NASA Astrophysics Data System (ADS)

    Dorozhko, P. A.; Lobach, A. S.; Popov, A. A.; Senyavin, V. M.; Korobov, M. V.

    2001-03-01

    Thermal behavior of two hydrofullerenes, C 60H 36 and C 60H 18, was studied by means of Knudsen cell mass-spectrometry and infrared spectroscopy. Vapor pressures and enthalpies of sublimation at T=550-685 K were measured. Sublimation of the hydrofullerenes was accompanied by partial loss of hydrogen. Decomposition of C 60H 36 was confirmed to be a stepwise process with formation of C 60H 18 as an intermediate product. The material of the Knudsen cell strongly affected the partial pressures and mass-spectra of the hydrofullerene vapor species.

  16. Ion bombardment of C60 films

    NASA Astrophysics Data System (ADS)

    Hobday, Steven; Smith, Roger; Gibson, Ursula; Richter, Asta

    The interaction of energetic ions with C60 films in the energy range 300-1000 eV is studied by computer simulation. It is found that the films can be subjected to much more surface damage than would be expected in other forms of carbon. Ejection of particles from the surface takes place in two ways. First, individual carbon atoms can be displaced from the lattice by ballistic collision processes. These are relatively few in number and the phenomenon occurs over a short timescale, of less than 0.5 ps. As the collision cascade develops, energy deposited in the surface region can be transferred to surface C60 molecules in sufficient quantity for some of these to be desorbed. This phenomena occurs over the order of a few picoseconds and can result in the loss of up to five C60's from the surface. The damage induced to the lattice causes C60's to be linked together in the form of polymerised chains. There is also evidence of the formation of 2- and 4-fold co-ordinated bonds in the lattice and transition to amorphous carbon.

  17. Pentaindenocorannulene: Properties, Assemblies, and C60 Complex.

    PubMed

    Lampart, Samuel; Roch, Loïc M; Dutta, Amit K; Wang, Yujia; Warshamanage, Rangana; Finke, Aaron D; Linden, Anthony; Baldridge, Kim K; Siegel, Jay S

    2016-11-14

    Pentaindenocorannulene (C50 H20  , 1), a deep bowl polynuclear aromatic hydrocarbon, accepts 4 electrons, crystallizes in columnar bowl-in-bowl assemblies and forms a nested C60 @12 complex. Spectra, structures and computations are presented. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Fullerene (C60) films for solid lubrication

    SciTech Connect

    Bhushan, B.; Gupta, B.K.; Van Cleef, G.W.; Capp, C.E.; Coe, J.V. )

    1993-10-01

    The advent of techniques for producing gram quantities of a new form of stable, pure, solid carbon, designated as fullerene, opens a profusion of possibilities to be explored in many disciplines including tribology. Fullerenes take the form of hollow geodesic domes, which are formed from a network of pentagons and hexagons with covalently bonded carbon atoms. The C60 molecule has the highest possible symmetry (icosahedral) and assumes the shape of a soccer ball. At room temperature, fullerene molecules pack in an fcc lattice bonded with weak van der Waals attractions. Fullerenes can be dissolved in solvents such as toluene and benzene and are easily sublimed. The low surface energy, high chemical stability, spherical shape, weak intermolecular bonding, and high load bearing capacity of C60 molecules offer potential for various mechanical and tribological applications. This paper describes the crystal structure and properties of fullerenes and proposes a mechanism for self-lubricating action. Sublimed films of C60 have been produced and friction and wear performance of these films in various operating environments are the subject of this paper. The results of this study indicate that C60, owing to its unique crystal structure and bonding, may be a promising solid lubricant. 31 refs.

  19. Electronic Structure of Crystalline Buckyballs: fcc-C60

    NASA Astrophysics Data System (ADS)

    Jalali-Asadabadi, Saeid; Ghasemikhah, E.; Ouahrani, T.; Nourozi, B.; Bayat-Bayatani, M.; Javanbakht, S.; Aliabad, H. A. Rahnamaye; Ahmad, Iftikhar; Nematollahi, J.; Yazdani-Kachoei, M.

    2016-01-01

    The electronic properties of pristine fcc-C60 are calculated by utilizing a variety of density functional theory (DFT) approaches including the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA), PBE-GGA+DFT-D3(vdW), Engel and Vosko GGA (EV-GGA), GGA plus Hubbard U parameter (GGA+U), hybrids Becke-Perdew-Wang hybrid functional (B3PW91), Becke-Lee-Yang-Parr hybrid functional (B3LYP), the PBE exchange-correlation functional (PBE0), and Tran and Blaha regular and non-regular modified Becke and Johnson (TB-mBJ) potential within a DFT frame work using augmented plane waves plus local orbital method. The comparison of the calculated results with the experimental values shows that the non-regular TB-mBJ method reproduces a correct experimental direct band gap of 2.12 eV at X symmetry for this compound. The effectiveness of this theoretical approach in the reproduction of the experimental band gap is due to the proper treatment of the electrons in the interstitial region of the crystal. Our results show that the C60 clusters are weakly interacting with each other in the fcc crystal. This study also reveals that the five-fold degeneracies of the isolated C60 molecule due to its icosahedral symmetry are completely lifted at an X symmetry point by the crystal field.

  20. Doping-induced distortions and bonding in K6C60 and Rb6C60

    NASA Astrophysics Data System (ADS)

    Andreoni, Wanda; Gygi, Francois; Parrinello, Michele

    1992-02-01

    The Car-Parrinello method is here used to theoretically investigate the properties of K6C60 and Rb6C60 crystals. Results are in very good agreement with available experimental data. An interesting pattern of relaxations both in the C60 fullerene cage and in the position of the K ions with respect to an ideal configuration is noted. The relaxation energy gain is about 1 eV, and is due in comparable amounts to the C60 and the K's. These energy gains are achieved by relatively small ionic displacements. Analysis of the electronic charge density reveals non-rigid-band effects. Similarities and differences with graphite intercalation compounds are discussed.

  1. Equation of state for fullerite C60

    NASA Astrophysics Data System (ADS)

    Rekhviashvili, S. Sh.

    2017-04-01

    A new equation of state for fullerite C60 is derived in the framework of the quantum-statistical method. This equation includes two Grüneisen parameters responsible for vibration-rotational and intramolecular contributions of fullerene molecules, which are represented in the form of isotropic quantum oscillators. The intramolecular vibrations of carbon atoms are described by the Debye heat capacity theory, and the cold contribution to the free energy is calculated using the Lennard-Jones pair potential for fullerene molecules. The theory is in a very good agreement with the experiment.

  2. Formation and decay of C - 60 following free electron capture by C60

    NASA Astrophysics Data System (ADS)

    Matejčik, Štefan; Märk, Tilmann D.; Španěl, Patrik; Smith, David; Jaffke, Thomas; Illenberger, Eugen

    1995-02-01

    The results of a detailed crossed electron/molecular beam study of electron attachment to C60 molecules and electron detachment from C-60 over the range of electron energies from near zero to about 15 eV are described. It is shown by comparing the experimental data for the attachment cross sections (normalized to the absolute thermal cross sections determined using the flowing afterglow/Langmuir probe apparatus) with quantum calculations that attachment occurs at low energies in the p-wave channel, and in the d- and f-wave channels (and probably higher-order partial waves) at the higher electron energies. At electron energies above 7 eV, thermal detachment of electrons from the hot C-60 negative ions is seen to occur, and the unimolecular rate coefficients for detachment, kd, have been determined as a function of the energy of the attaching electron. Hence, by relating kd to the derived temperature of the hot C-60 ions, the electron detachment energy, Ed, has been determined as 2.6 eV, which is close to the electron affinity of C60 as measured by photodetachment from cold C-60 ions. Additionally, by combining the measured attachment rate coefficients, ka, from the previous flowing afterglow/Langmuir probe study with the kd data determined in this study, equilibrium constants for the detachment/attachment reactions have been obtained which are reconciled with those calculated using total partition functions. An important conclusion to be drawn from all these studies is that C60 very efficiently captures electrons over the wide electron energy range from about 0.2 eV to around 15 eV and retains them if the energy released in the electron capture process can be removed before thermal detachment can occur.

  3. Optical High Harmonic Generation in C60

    NASA Astrophysics Data System (ADS)

    Zhang, Guoping

    2005-03-01

    C60 et al. Physical Review Letters Physical Review B High harmonic generation (HHG) requires a strong laser field, but in a relatively weak laser field is sufficient. Numerical results presented here show while its low order harmonics result from the laser field, its high order ones are mainly from the multiple excitations. Since high order harmonics directly correlate electronic transitions, the HHG spectrum accurately measures transition energies. Therefore, is not only a promising material for HHG, but may also present an opportunity to develop HHG into an electronic structure probing tool. References: G. P. Zhang, 91, 176801 (2003); G. P. Zhang and T. F. George, 68, 165410 (2003); P. B. Corkum, 71, 1994 (1993); G. P. Zhang and Thomas F. George, 93, 147401 (2004); H. Niikura ,ature 417, 917 (2002); ibid. 421, 826 (2003); Y. Mairesse ,cience 302, 1540 (2003); A. Baltuska ,ature 421, 611 (2003).

  4. Antiferromagnetic resonance in Rb1C60

    NASA Astrophysics Data System (ADS)

    Bennati, M.; Griffin, R. G.; Knorr, S.; Grupp, A.; Mehring, M.

    1998-08-01

    High-frequency (94 and 140 GHz) ESR was used to investigate the magnetic properties of the low-dimensional conductor Rb1C60. Below 35 K new features of the electron spin resonance are distinguished from the CESR signal of the conducting phase. The analysis of the resonance linewidth and line shift allows a clear identification of a frequency-dependent antiferromagnetic resonance line (AFMR) below 25 K. The characteristic temperature TN for the ordering transition is 25 K. Between 25 K

  5. Transformation of aggregated C60 in the aqueous phase by UV irradiation.

    PubMed

    Lee, Jaesang; Cho, Min; Fortner, John D; Hughes, Joseph B; Kim, Jae-Hong

    2009-07-01

    This study demonstrates that water-stable C60 cluster (nC60) undergoes a photochemical transformation(s) when irradiated with monochromatic UV light at 254 nm. Upon UV exposure, characteristic absorption of nC60 in the visible (ca. 450-550 nm, indicative of a cluster structure) and UV regions (indicative of underivatized molecular C60) gradually disappeared. Concurrently, a new product with absorption centered at 210 nm formed. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses confirmed a complete reduction in aggregation and formation of a soluble product. Negligible loss of total organic carbon (TOC) and drastic retardation in degradation kinetics in the absence of oxygen collectively implied that photochemical transformation was accomplished via oxidative pathway without carbon mineralization. MS (LDI), FTIR, and XPS analyses indicated a 60 carbon cage product, containing various oxygen functional groups such as epoxides and ethers. In addition, this product demonstrated significantly less antibacterial effects on Escherichia coli when compared to the parent nC60. The results of this study suggest that accurate assessment of C60 in environmental life cycles and impact should consider the light-mediated transformation of C60 in the aqueous phase and resulting water-soluble products.

  6. Mapping intermolecular bonding in C60

    PubMed Central

    Sundqvist, Bertil

    2014-01-01

    The formation of intermolecular bonds in C60 has been investigated in detail at pressures below 2.2 GPa and up to 750 K. Fullerene samples were heated in a temperature gradient to obtain data on the formation of dimers and low-dimensional polymers along isobars. Intermolecular bonding was analyzed ex situ by Raman scattering, using both intramolecular modes and intermolecular stretching modes. Semi-quantitative reaction maps are given for the formation of dimers and chains. The activation energy for dimer formation decreases by 0.2 meV pm−1 when intermolecular distances decrease and dimer formation is noticeably affected by the rotational state of molecules. Above 400–450 K larger oligomers are formed; below 1.4 GPa most of these are disordered, with small domains of linear chains, but above this the appearance of stretching modes indicates the existence of ordered one-dimensional polymers. At the highest pressures and temperatures two-dimensional polymers are also observed. PMID:25145952

  7. C60 fullerene promotes lung monolayer collapse

    PubMed Central

    Barnoud, Jonathan; Urbini, Laura; Monticelli, Luca

    2015-01-01

    Airborne nanometre-sized pollutants are responsible for various respiratory diseases. Such pollutants can reach the gas-exchange surface in the alveoli, which is lined with a monolayer of lung surfactant. The relationship between physiological effects of pollutants and molecular-level interactions is largely unknown. Here, we determine the effects of carbon nanoparticles on the properties of a model of lung monolayer using molecular simulations. We simulate phase-separated lipid monolayers in the presence of a model pollutant nanoparticle, C60 fullerene. In the absence of nanoparticles, the monolayers collapse only at very low surface tensions (around 0 mN m−1). In the presence of nanoparticles, instead, monolayer collapse is observed at significantly higher surface tensions (up to ca 10 mN m−1). Collapse at higher tensions is related to lower mechanical rigidity of the monolayer. It is possible that similar mechanisms operate on lung surfactant in vivo, which suggests that health effects of airborne carbon nanoparticles may be mediated by alterations of the mechanical properties of lung surfactant. PMID:25589571

  8. Preparation and biodistribution of radiolabeled fullerene C60 nanocrystals

    NASA Astrophysics Data System (ADS)

    Nikolić, Nadežda; Vranješ-Ðurić, Sanja; Janković, Drina; Ðokić, Divna; Mirković, Marija; Bibić, Nataša; Trajković, Vladimir

    2009-09-01

    The present study describes for the first time a procedure for the radiolabeling of fullerene (C60) nanocrystals (nanoC60) with Na 125I, as well as the biodistribution of radiolabeled nanoC60 (125I-nanoC60). The solvent exchange method with tetrahydrofuran was used to make colloidal water suspensions of radiolabeled nanoC60 particles. The radiolabeling procedure with the addition of Na 125I to tetrahydrofuran during dissolution of C60 gave a higher radiochemical yield of radiolabeled nanoC60 particles in comparison to the second option, in which Na 125I was added after C60 was dissolved. Using photon correlation spectroscopy and transmission electron microscopy, 125I-nanoC60 particles were found to have a crystalline structure and a mean diameter of 200-250 nm. The 125I-nanoC60 had a particularly high affinity for human serum albumin, displaying 95% binding efficiency after 1 h. Biodistribution studies of 125I-nanoC60 in rats indicated significant differences in tissue accumulation of 125I-nanoC60 and the radioactive tracer Na 125I. The higher accumulation of radiolabeled nanoC60 was observed in liver and spleen, while accumulation in thyroid, stomach, lungs and intestines was significantly lower in comparison to Na 125I. In addition to being useful for testing the biological distribution of nanoC60, the described radiolabeling procedure might have possible applications in cancer radiotherapy.

  9. A High Thrust Density, C60 Cluster, Ion Thruster.

    DTIC Science & Technology

    1996-09-01

    spacecraft mission and hence, the amount stored. Fundamentally they can be divided into: (1) heating the entire fuel storage in which case the storage tank...with the aid of Eqs. [3.1] and [3.2]. 4.2.2 Future Vaporizer and Feeding System Concept The fundamental options of heating all propellant in a single...hollow cathode the carbon residue inside the discharge chamber was very small relative to that observed when using heated tungsten filament cathode. This

  10. A High Thrust Density, C60 Cluster, Ion Thruster

    DTIC Science & Technology

    1993-02-28

    C70. The vapor mass flow is given by(1 2 ) 1= PAN•N 27rRT [51 3 where A is the flow area which can also be viewed as the minimum vaporization surface ...the successful application of fullerenes as electrostatic thruster propellant is a predictable and real time adjustable fullerene vapor mass flow rate...SBIR Phase I Final Report, Busek #029 I flow . Torres( 16 ) however, predicted high fullerene propellant utili.,ation (Fig. 7.6) which gives credence to

  11. Comparative Computational Study of Interaction of C60-Fullerene and Tris-Malonyl-C60-Fullerene Isomers with Lipid Bilayer: Relation to Their Antioxidant Effect

    PubMed Central

    Bozdaganyan, Marine E.; Orekhov, Philipp S.; Shaytan, Alexey K.; Shaitan, Konstantin V.

    2014-01-01

    Oxidative stress induced by excessive production of reactive oxygen species (ROS) has been implicated in the etiology of many human diseases. It has been reported that fullerenes and some of their derivatives–carboxyfullerenes–exhibits a strong free radical scavenging capacity. The permeation of C60-fullerene and its amphiphilic derivatives–C3-tris-malonic-C60-fullerene (C3) and D3-tris-malonyl-C60-fullerene (D3)–through a lipid bilayer mimicking the eukaryotic cell membrane was studied using molecular dynamics (MD) simulations. The free energy profiles along the normal to the bilayer composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) for C60, C3 and D3 were calculated. We found that C60 molecules alone or in clusters spontaneously translocate to the hydrophobic core of the membrane and stay inside the bilayer during the whole period of simulation time. The incorporation of cluster of fullerenes inside the bilayer changes properties of the bilayer and leads to its deformation. In simulations of the tris-malonic fullerenes we discovered that both isomers, C3 and D3, adsorb at the surface of the bilayer but only C3 tends to be buried in the area of the lipid headgroups forming hydrophobic contacts with the lipid tails. We hypothesize that such position has implications for ROS scavenging mechanism in the specific cell compartments. PMID:25019215

  12. Comparative computational study of interaction of C60-fullerene and tris-malonyl-C60-fullerene isomers with lipid bilayer: relation to their antioxidant effect.

    PubMed

    Bozdaganyan, Marine E; Orekhov, Philipp S; Shaytan, Alexey K; Shaitan, Konstantin V

    2014-01-01

    Oxidative stress induced by excessive production of reactive oxygen species (ROS) has been implicated in the etiology of many human diseases. It has been reported that fullerenes and some of their derivatives-carboxyfullerenes-exhibits a strong free radical scavenging capacity. The permeation of C60-fullerene and its amphiphilic derivatives-C3-tris-malonic-C60-fullerene (C3) and D3-tris-malonyl-C60-fullerene (D3)-through a lipid bilayer mimicking the eukaryotic cell membrane was studied using molecular dynamics (MD) simulations. The free energy profiles along the normal to the bilayer composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) for C60, C3 and D3 were calculated. We found that C60 molecules alone or in clusters spontaneously translocate to the hydrophobic core of the membrane and stay inside the bilayer during the whole period of simulation time. The incorporation of cluster of fullerenes inside the bilayer changes properties of the bilayer and leads to its deformation. In simulations of the tris-malonic fullerenes we discovered that both isomers, C3 and D3, adsorb at the surface of the bilayer but only C3 tends to be buried in the area of the lipid headgroups forming hydrophobic contacts with the lipid tails. We hypothesize that such position has implications for ROS scavenging mechanism in the specific cell compartments.

  13. Ionization energies of the C60 fullerene and its hydrogenated derivatives C60H18 and C60H36 determined by electron ionization

    NASA Astrophysics Data System (ADS)

    Pogulay, Andrey V.; Abzalimov, Rinat R.; Nasibullaev, Shamil'k.; Lobach, Anatoly S.; Drewello, Thomas; Vasil'Ev, Yury V.

    2004-04-01

    Modification of a method for processing positive ion ionization efficiency curves of polyatomic molecules, as developed earlier by Märk and coworkers, has been described. Based on the method, the first, second, and third ionization energies of C60 have been re-examined and found to be in excellent agreement with the most reliable literature data. The ionization energies for C60H18 and C60H36 have been measured for the first time and were established as 7.3+/-0.3 eV and 7.01+/-0.25 eV, respectively. Although the appearance energy of C60H362+ (18.7+/-0.2 eV) has been determined to be lower than that of C602+ (18.98+/-0.35 eV), the reverse scenario is true for the second ionization energies of C60H36 and C60.

  14. High-Pressure Synthesis of Superhard Material from C60

    NASA Astrophysics Data System (ADS)

    Horikawa, Takashi; Suito, Kaichi; Kobayashi, Michihiro; Oshima, Ryuichiro

    2005-05-01

    Fullerene, C60, has been investigated at a high pressure of 15 GPa and at a high temperature of 800°C using an octahedral anvil press. Samples retrieved after being heated to temperatures between 165 and 700°C under pressures from 10 to 15 GPa were found to be very hard, exhibiting micro-Vickers hardness ranging from 40 to 100 GPa. The hardness was governed by the pressure and temperature conditions studied as well as the duration of the high-temperature treatment. X-ray diffraction analysis and Raman scattering studies revealed that the hard products contained amorphous carbon consisting of sp2-bonded clusters with a small persistence of unknown phase.

  15. Raman rotational spectra of endohedral C60 fullerene complexes

    NASA Astrophysics Data System (ADS)

    Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.

    1996-09-01

    Low-temperature (T=50 K) Raman rotational spectra are calculated for the endohedral complexes Li+@C60, Na+@C60, CO@C60, LiF@C60, and LiH@C60. The systems Na+@C60 and CO@C60 produce very similar spectra dominated by pure rotational bands. The other systems present more complex and dissimilar spectra which suggest librational motions and hindered rotations. An assignment of these spectra is provided by analyzing the structure of the low energy rotational eigenvalues and eigenfunctions. Rotational energy quasiband and quasiresonance-band structures are found to be the origin of the features observed in the more complex spectra. Out of these analyses, a classification of the low-temperature rotational spectra of endohedral C60 complexes in two basic classes emerges.

  16. Retention of Aqu/C60 Nanoparticles on Quartz Surfaces

    EPA Science Inventory

    Studies have shown that C60 fullerene can form stable suspensions of colloidal sized particles in water resulting in C60 aqueous concentrations many orders of magnitude above C60’s aqueous solubility. These studies have raised concern over the mobility and distribution of fuller...

  17. Retention of Aqu/C60 Nanoparticles on Quartz Surfaces

    EPA Science Inventory

    Studies have shown that C60 fullerene can form stable suspensions of colloidal sized particles in water resulting in C60 aqueous concentrations many orders of magnitude above C60’s aqueous solubility. These studies have raised concern over the mobility and distribution of fuller...

  18. Investigation of Photochemical Properties of C60 Aggregates in Water

    EPA Science Inventory

    As an emerging new material with unique structure and properties, the behavior and fate of Buckminster fullerene (C60) in natural waters has gained increasing attention. Although the water solubility of C60 is extremely low, the formation of C60 aggregates in water could alter th...

  19. Investigation of Photochemical Properties of C60 Aggregates in Water

    EPA Science Inventory

    As an emerging new material with unique structure and properties, the behavior and fate of Buckminster fullerene (C60) in natural waters has gained increasing attention. Although the water solubility of C60 is extremely low, the formation of C60 aggregates in water could alter th...

  20. Growth of C 60 films on silicon surfaces

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Sarid, Dror

    1994-10-01

    The growth of crystalline C 60 films on Si(111) and Si (100) surfaces has been studied using scanning tunneling microscopy and atomic force microscopy. It is found that the films on these two silicon substrates, which consist of both partially ordered monolayer and crystalline islands, differ in their morphologies. The results are explained in terms of the relative strength of interaction of the first monolayer of C 60 molecules with the silicon substrate and the C 60 islands above it. Annealing the samples to elevated temperatures causes the C 60 islands to evaporate, leaving a full layer of C 60 molecules capped on the substrate.

  1. Evaluation of C60 secondary ion mass spectrometry for the chemical analysis and imaging of fingerprints.

    PubMed

    Sisco, Edward; Demoranville, Leonard T; Gillen, Greg

    2013-09-10

    The feasibility of using C60(+) cluster primary ion bombardment secondary ion mass spectrometry (C60(+) SIMS) for the analysis of the chemical composition of fingerprints is evaluated. It was found that C60(+) SIMS could be used to detect and image the spatial localization of a number of sebaceous and eccrine components in fingerprints. These analyses were also found to not be hindered by the use of common latent print powder development techniques. Finally, the ability to monitor the depth distribution of fingerprint constituents was found to be possible - a capability which has not been shown using other chemical imaging techniques. This paper illustrates a number of strengths and potential weaknesses of C60(+) SIMS as an additional or complimentary technique for the chemical analysis of fingerprints.

  2. Colloidal Properties of Aqueous Fullerenes: Isoelectric Points and Aggregation Kinetics of C60 and C60 Derivatives

    EPA Science Inventory

    Aqueous colloidal suspensions of C-60 (aqu/C-60) and the C-60 derivatives PCBM ([6,6]-phenyl C-61-butyric acid methyl ester) and the corresponding butyl and octyl esters, PCBB and PCBO (aqu/PCB-R, where R is an alkyl group), were produced by stirring in double deionized water for...

  3. Colloidal Properties of Aqueous Fullerenes: Isoelectric Points and Aggregation Kinetics of C60 and C60 Derivatives

    EPA Science Inventory

    Aqueous colloidal suspensions of C-60 (aqu/C-60) and the C-60 derivatives PCBM ([6,6]-phenyl C-61-butyric acid methyl ester) and the corresponding butyl and octyl esters, PCBB and PCBO (aqu/PCB-R, where R is an alkyl group), were produced by stirring in double deionized water for...

  4. Search for Hydrogenated C60 (Fulleranes) in Circumstellar Envelopes

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Sadjadi, SeyedAbdolreza; Hsia, Chih-Hao; Kwok, Sun

    2017-08-01

    The recent detection of fullerene (C60) in space and the positive assignment of five diffuse interstellar bands to {{{C}}}60+ reinforce the notion that fullerene-related compounds can be efficiently formed in circumstellar envelopes and be present in significant quantities in the interstellar medium. Experimental studies have shown that C60 can be readily hydrogenated, raising the possibility that hydrogenated fullerenes (or fulleranes, C60H m , m = 1-60) may be abundant in space. In this paper, we present theoretical studies of the vibrational modes of isomers of C60H m . Our results show that the four mid-infrared bands from the C60 skeletal vibrations remain prominent in slightly hydrogenated C60, but their strengths diminish in different degrees with increasing hydrogenation. It is therefore possible that the observed infrared bands assigned to C60 could be due to a mixture of fullerenes and fulleranes. This provides a potential explanation for the observed scatter of the C60 band ratios. Our calculations suggest that a feature around 15 μm due to the breathing mode of heavily hydrogenated C60 may be detectable astronomically. A preliminary search for this feature in 35 C60 sources is reported.

  5. Synthesis and high pressure induced amorphization of C60 nanosheets

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Liu, Bingbing; Liu, Dedi; Yao, Mingguang; Yu, Shidan; Hou, Yuanyuan; Zou, Bo; Cui, Tian; Zou, Guangtian; Sundqvist, Bertil; Luo, Zongju; Li, Hui; Li, Yanchun; Liu, Jing; Chen, Shijian; Wang, Guorui; Liu, Yichun

    2007-09-01

    C60 nanosheets with thicknesses in the nanometer range were synthesized by a simple method. Compared to bulk C60, the lattice of the nanosheets is expanded by about 0.4%. In situ Raman spectroscopy and energy-dispersive x-ray diffraction under high pressures have been employed to study the structure of the nanosheets. The studies indicate that the bulk modulus of the C60 nanosheets is significantly larger than that of bulk C60. The C60 cages in nanosheets can persist at pressures over 30GPa, 3GPa higher than for bulk C60. These results suggest that C60 crystals in even small size will be a potential candidate of superhard materials.

  6. Ground State Reactions of nC60 with Free Chlorine in Water.

    PubMed

    Wu, Jiewei; Benoit, Denise; Lee, Seung Soo; Li, Wenlu; Fortner, John D

    2016-01-19

    Facile, photoenhanced transformations of water-stable C60 aggregates (nC60) to oxidized, soluble fullerene derivatives, have been described as key processes in understanding the ultimate environmental fate of fullerene based materials. In contrast, fewer studies have evaluated the aqueous reactivity of nC60 during ground-state conditions (i.e., dark conditions). Herein, this study identifies and characterizes the physicochemical transformations of C60 (as nC60 suspensions) in the presence of free chlorine, a globally used chemical oxidant, in the absence of light under environmentally relevant conditions. Results show that nC60 undergoes significant oxidation in the presence of free chlorine and the oxidation reaction rates increase with free chlorine concentration while being inversely related to solution pH. Product characterization by FTIR, XPS, Raman Spectroscopy, TEM, XRD, TOC, collectively demonstrates that oxidized C60 derivatives are readily formed in the presence of free chlorine with extensive covalent oxygen and even chlorine additions, and behave as soft (or loose) clusters in solution. Aggregation kinetics, as a function of pH and ionic strength/type, show a significant increase in product stabilities for all cases evaluated, even at pH values approaching 1. As expected with increased (surface) oxidation, classic Kow partitioning studies indicate that product clusters are relatively more hydrophilic than parent (reactant) nC60. Taken together, this work highlights the importance of understanding nanomaterial reactivity and the identification of corresponding stable daughter products, which are likely to differ significantly from parent material properties and behaviors.

  7. C60 -induced Devil's Staircase transformation on a Pb/Si(111) wetting layer

    DOE PAGES

    Wang, Lin -Lin; Johnson, Duane D.; Tringides, Michael C.

    2015-12-03

    Density functional theory is used to study structural energetics of Pb vacancy cluster formation on C60/Pb/Si(111) to explain the unusually fast and error-free transformations between the “Devil's Staircase” (DS) phases on the Pb/Si(111) wetting layer at low temperature (~110K). The formation energies of vacancy clusters are calculated in C60/Pb/Si(111) as Pb atoms are progressively ejected from the initial dense Pb wetting layer. Vacancy clusters larger than five Pb atoms are found to be stable with seven being the most stable, while vacancy clusters smaller than five are highly unstable, which agrees well with the observed ejection rate of ~5 Pbmore » atoms per C60. Furthermore, the high energy cost (~0.8 eV) for the small vacancy clusters to form indicates convincingly that the unusually fast transformation observed experimentally between the DS phases, upon C60 adsorption at low temperature, cannot be the result of single-atom random walk diffusion but of correlated multi-atom processes.« less

  8. C60-induced Devil's Staircase transformation on a Pb/Si(111) wetting layer

    NASA Astrophysics Data System (ADS)

    Wang, Lin-Lin; Johnson, Duane D.; Tringides, Michael C.

    2015-12-01

    Density functional theory is used to study structural energetics of Pb vacancy cluster formation on C60/Pb /Si (111 ) to explain the unusually fast and error-free transformations between the "Devil's Staircase" (DS) phases on the Pb/Si(111) wetting layer at low temperature (˜110 K ). The formation energies of vacancy clusters are calculated in C60/Pb /Si (111 ) as Pb atoms are progressively ejected from the initial dense Pb wetting layer. Vacancy clusters larger than five Pb atoms are found to be stable with seven being the most stable, while vacancy clusters smaller than five are highly unstable, which agrees well with the observed ejection rate of ˜5 Pb atoms per C60. The high energy cost (˜0.8 eV) for the small vacancy clusters to form indicates convincingly that the unusually fast transformation observed experimentally between the DS phases, upon C60 adsorption at low temperature, cannot be the result of single-atom random walk diffusion but of correlated multi-atom processes.

  9. C60-Induced Devil's Staircase Transformation on Pb/Si(111) Wetting Layer

    NASA Astrophysics Data System (ADS)

    Wang, Lin-Lin; Johnson, Duane D.; Tringides, Michael C.

    Density functional theory is used to study structural energetics of Pb vacancy cluster formation on C60/Pb/Si(111) to explain the unusually fast and error-free transformations between the ``Devil's Staircase'' (DS) phases on the Pb/Si(111) wetting layer at low temperature (~110 K). The formation energies of vacancy clusters are calculated in C60/Pb/Si(111) as Pb atoms are progressively ejected from the initial dense Pb wetting layer. Vacancy clusters larger than 5 Pb atoms are found to be stable with 7 being the most stable, while vacancy clusters smaller than 5 are highly unstable, which agrees well with the observed ejection rate of ~5 Pb atoms per C60. The high energy cost (~0.8 eV) for the small vacancy clusters to form indicates convincingly that the unusually fast transformation observed experimentally between the DS phases, upon C60 adsorption at low temperature, cannot be the result of single-atom random walk diffusion but correlated multi-atom processes. DOE Office of Science, Basic Energy Sciences from the Divisions of MSE (DE-AC02-07CH1135) and Ames Lab LDRD. Ames Laboratory is operated for DOE by Iowa State University under contract DE-AC02-07CH11358.

  10. Stability of (C60)2 and epoxide dimers, (C60)2ON, and their anions.

    PubMed

    Owens, Frank J

    2005-06-01

    The PM3, AM1, and MINDO3 semiemperical methods are used to calculate the the energy difference between C60ON and C60ON- and the bond dissociation energy necessary to cleave neutral and negatively charged (C60)2 dimers and epoxide dimers, (C60)2ON, to their respective monomers C60, and C60ON/2. The results show that the anions of the dimers are significantly more stable than neutral dimers. This result may explain the higher thermal stability of the observed ferromagnetic phase in photolyzed C60. which has been attributed to epoxide dimers and oligomers. It also provides an explanation for the origin of unpaired electron spin necessary for ferromagnetism.

  11. Adlayers of C60-C60 and C60-C70 fullerene dimers formed on au(111) in benzene solutions studied by STM and LEED.

    PubMed

    Matsumoto, Masashi; Inukai, Junji; Tsutsumi, Eishi; Yoshimoto, Soichiro; Itaya, Kingo; Ito, Osamu; Fujiwara, Koichi; Murata, Michihisa; Murata, Yasujiro; Komatsu, Koichi

    2004-02-17

    Scanning tunneling microscopy (STM) and low-energy electron diffraction were used to reveal the structures of ordered adlayers of [2+2]-type C60-C60 fullerene dimer (C120) and C60-C70 cross-dimer (C130) formed on Au(111) by immersingit in abenzene solution containing C120 or C130 molecules. High-resolution STM images clearly showed the packing arrangements and the electronic structures of C120 and C130 on the Au(111) surface in ultrahigh vacuum. The (2 square root3 x 4square root3)R30 degrees, (2square root3 x 5square root3)R30 degrees, and (7 x 7) structures were found for the C120 adlayer on the Au(111) surface, whereas C130 molecules were closely packed on the surface. Each C60 or C70 monomer cage was discerned in the STM image of a C130 molecule.

  12. Buckminsterfullerene's (C60) octanol-water partition coefficient (Kow) and aqueous solubility.

    PubMed

    Jafvert, Chad T; Kulkarni, Pradnya P

    2008-08-15

    To assess the risk and fate of fullerene C60 in the environment, its water solubility and partition coefficients in various systems are useful. In this study, the log Kow of C60 was measured to be 6.67, and the toluene-water partition coefficient was measured at log Ktw = 8.44. From these values and the respective solubilities of C60 in water-saturated octanol and water-saturated toluene, C60's aqueous solubility was calculated at 7.96 ng/L(1.11 x 10(-11) M) for the organic solvent-saturated aqueous phase. Additionally, the solubility of C60 was measured in mixtures of ethanol-water and tetrahydrofuran-water and modeled with Wohl's equation to confirm the accuracy of the calculated solubility value. Results of a generator column experiment strongly support the hypothesis that clusters form at aqueous concentrations below or near this calculated solubility. The Kow value is compared to those of other hydrophobic organic compounds, and bioconcentration factors for C60 were estimated on the basis of Kow.

  13. Theoretical characterisation of irreversible and reversible hydrogen storage reactions on Ni-doped C60 fullerene

    NASA Astrophysics Data System (ADS)

    Shalabi, A. S.; El Mahdy, A. M.; Soliman, K. A.; Taha, H. O.

    2014-12-01

    An attempt has been made to characterise the irreversible and reversible hydrogen storage reactions on Ni-doped C60 fullerene by using the state of the art density functional theory calculations. The single Ni atom prefers to bind at the bridge site between two hexagonal rings of C60 fullerene, and can bind up to four hydrogen molecules with average adsorption energies of -0.85, -0.83, -0.58, and -0.31 eV per hydrogen molecule. No evidence for metal clustering in the ideal circumstances and the hydrogen storage capacity is expected to be as large as 8.9 wt%. While the desorption activation barriers of the complexes nH2NiC60 (n = 1, 2) are outside the desirable energy window recommended by the department of energy for practical applications (-0.2 to -0.6 eV), the desorption activation barriers of the complexes nH2NiC60 (n = 3, 4) are inside this window. The irreversible 2H2 + NiC60 and reversible 3H2 + NiC60 interactions are characterised in terms of several theoretical parameters such as: (1) densities of states and projected densities of states, (2) pairwise and non-pairwise additivity, (3) infrared, Raman, and proton magnetic resonance spectra, (4) electrophilicity, and (5) statistical thermodynamic stability.

  14. Cooperative Assembly of Magic Number C60-Au Complexes

    NASA Astrophysics Data System (ADS)

    Xie, Yang-Chun; Tang, Lin; Guo, Quanmin

    2013-11-01

    We report the assembly of magic number (C60)m-(Au)n complexes on the Au(111) surface. These complexes have a unique structure consisting of a single atomic layer Au island wrapped by a self-selected number (seven, ten, or twelve) of C60 molecules. The smallest structure consisting of 7 C60 molecules and 19 Au atoms, stable up to 400 K, has a preferred orientation on the surface. We propose a globalized metal-organic coordination mechanism for the stability of the (C60)m-(Au)n complexes.

  15. Electronic Structure Investigation of Doping C60 with Metal Oxide

    NASA Astrophysics Data System (ADS)

    Wang, Chenggong; Gao, Yongli

    2014-03-01

    Fullerene (C60) has been used extensively as an acceptor material in organic photovoltaic (OPV) cells. Other applications including n-channel organic thin film transistors (OTFT) and C60 based organic superconductors have been reported more than a decade ago. We have investigated p-doping of C60 with molybdenum oxide (MoOx) with ultra-violet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IPES) and atomic force microscopy (AFM). Both surface doping and bulk doping by MoOx are studied. It was found that the thermally evaporated MoOx inter-layer substantially increased the surface workfunction. This increased surface workfunction strongly attract electrons towards the MoOx layer at the C60/MoOx interface, resulting in strong inversion of C60. Energy levels of C60 relax gradually as the thickness of C60 increases. An exceptionally long (greater than 400 Angstrom) band bending is observed during this relaxation in C60. Such a long band bending has not been observed for other organic/MoOx interface. For the bulk doping, MoOx doping ratios from 1% to over 100% were investigated. The saturation occurs at approximately 20 %, when the highest occupied molecular level (HOMO) of C60 starts to be pinned at the Fermi level. These studies demonstrate effective ways to manipulate the electronic structures of the fullerene. This work is supported by the National Science Foundation Grant No. DMR-1303742.

  16. Production of Self-Assembled Fullerene (C60) Nanocrystals at Liquid-Liquid Interface.

    PubMed

    Shrestha, Rekha Goswami; Shrestha, Lok Kumar; Abe, Masahiko; Ariga, Katsuhiko

    2015-03-01

    Here we present self-assembled nanostructure of functional molecule fullerene (C60) at liquid-liquid interface. The nanostructured nanocrystals were grown at liquid-liquid interface of isopropyl alcohol (IPA) and C60 solution in butylbenzene under ambient condition of temperature and pressure, and characterized by Raman scattering, power X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The crystal formation mechanism is driven by supersaturation related to the low solubility of C60 in IPA. A slow diffusion of IPA towards the C60 solution causes unsaturation of C60 at the liquid-liquid interface and consequently small clusters of C60 is formed at the interface, which acts as the nucleation site. Further diffusion of IPA supplies the C60 molecules from bulk to the interface promoting the crystal growth. Based on SEM and TEM observation, the average size of the individual hexagonal bipyramid nanocrystal is found to be ca. 1.4 µm and the average size of their assembly is found to be approximately 2 µm. XRD measurements have shown that these materials are crystalline with mixed face-centered cubic (cell dimension: a = 1.352 nm, and V = 2.475 nm3) and hexagonal (cell dimension: a = 1.452 nm, c = 1.207 nm, c/a = 0.831, and V = 2.475 nm3) structures. Raman scattering measurements showed two Ag and six Hg vibration bands, which are similar to those obtained in the pristine C60.

  17. Excess electron is trapped in a large single molecular cage C60F60.

    PubMed

    Wang, Yin-Feng; Li, Zhi-Ru; Wu, Di; Sun, Chia-Chung; Gu, Feng-Long

    2010-01-15

    A new kind of solvated electron systems, sphere-shaped e(-)@C60F60 (I(h)) and capsule-shaped e(-)@C60F60 (D6h), in contrast to the endohedral complex M@C60, is represented at the B3LYP/6-31G(d) + dBF (diffusive basis functions) density functional theory. It is proven, by examining the singly occupied molecular orbital (SOMO) and the spin density map of e(-)@C60F60, that the excess electron is indeed encapsulated inside the C60F60 cage. The shape of the electron cloud in SOMO matches with the shape of C60F60 cage. These cage-like single molecular solvated electrons have considerably large vertical electron detachment energies VDE of 4.95 (I(h)) and 4.67 eV (D6h) at B3LYP/6-31+G(3df) + dBF level compared to the VDE of 3.2 eV for an electron in bulk water (Coe et al., Int Rev Phys Chem 2001, 20, 33) and that of 3.66 eV for e(-)@C20F20 (Irikura, J Phys Chem A 2008, 112, 983), which shows their higher stability. The VDE of the sphere-shaped e(-)@C60F60 (I(h)) is greater than that of the capsule-shaped e(-)@C60F60 (D6h), indicating that the excess electron prefers to reside in the cage with the higher symmetry to form the more stable solvated electron. It is also noticed that the cage size [7.994 (I(h)), 5.714 and 9.978 A (D6h) in diameter] is much larger than that (2.826 A) of (H2O)20- dodecahedral cluster (Khan, Chem Phys Lett 2005, 401, 85).

  18. Surfactant-Triggered Nanoarchitectonics of Fullerene C60 Crystals at a Liquid-Liquid Interface.

    PubMed

    Shrestha, Lok Kumar; Shrestha, Rekha Goswami; Hill, Jonathan P; Tsuruoka, Tohru; Ji, Qingmin; Nishimura, Toshiyuki; Ariga, Katsuhiko

    2016-11-29

    Here, we report the structural and morphological modulation of fullerene C60 crystals induced by nonionic surfactants diglycerol monolaurate (C12G2) and monomyristate (C14G2). C60 crystals synthesized at a liquid-liquid interface comprising isopropyl alcohol (IPA) and a saturated solution of C60 in ethylbenzene (EB) exhibited a one-dimensional (1D) morphology with well-defined faceted structure. Average length and diameter of the faceted rods were ca. 4.8 μm and 747 nm, respectively. Powder X-ray diffraction pattern (pXRD) confirmed a hexagonal-close packed (hcp) structure with cell dimensions ca. a = 2.394 nm and c = 1.388 nm. The 1D rod morphology of C60 crystals was transformed into "Konpeito candy-like" crystals (average diameter ca. 1.2 μm) when the C60 crystals were grown in the presence of C12G2 or C14G2 surfactant (1%) in EB. The pXRD spectra of "Konpeito-like" crystals could be assigned to the face-centered cubic (fcc) phase with cell dimensions ca. a = 1.4309 nm (for C12G2) and a = 1.4318 nm (for C14G2). However, clusters or aggregates of C60 lacking a uniform morphology were observed at lower surfactant concentrations (0.1%), although these crystals exhibited an fcc crystal structure. The self-assembled 1D faceted C60 crystals and "Konpeito-like" C60 crystals exhibited intense photoluminescence (PL) (∼35 times greater than pC60) and a blue-shifted PL intensity maximum (∼15 nm) compared to those of pC60, demonstrating the potential use of this method for the control of the optoelectronic properties of fullerene nanostructures. The "Konpeito-like" crystals were transformed into high surface area nanoporous carbon with a graphitic microstructure upon heat-treatment at 2000 °C. The heat-treated samples showed enhanced electrochemical supercapacitance performance (specific capacitance is ca. 175 F g(-1), which is about 20 times greater than pC60) with long cyclic stability demonstrating the potential of the materials in supercapacitor device

  19. Adsorption of sodium and cesium on aggregates of C60

    NASA Astrophysics Data System (ADS)

    Harnisch, Martina; Daxner, Matthias; Scheier, Paul; Echt, Olof

    2016-09-01

    We explore the formation of C60 sodium and C60 cesium complexes in superfluid helium nanodroplets. Anomalies in mass spectra of these doped droplets reveal anomalies in the stability of ions. (C60) m Cs+ n ions ( m ≤ 6) are particularly abundant if they contain n = 6 m + 1 cesium atoms; (C60) m Cs2+ n dications ( m ≤ 3 or 5) are abundant if n = 6 m + 2. These findings are consistent with the notion that alkali metal atoms (A) transfer their valence electrons into the three-fold degenerate lowest unoccupied orbital of C60, resulting in particularly stable C60A6 building blocks. However, (C60) 4CsCs2+ n dications display an entirely different pattern; instead of an expected anomaly at n = 6 × 4 + 2 = 26 we observe a strong odd-even alternation starting at n = 6. Also surprising is the effect of adding one H2O or CO2 molecule to (C60) m Cs n mono- or dications; anomalies shift by two units as if the impurity were acting as an acceptor for two valence electrons from the alkali metal atoms.

  20. Entanglement of Spin States in 15N@C60

    NASA Astrophysics Data System (ADS)

    Scherer, W.; Weidinger, A.; Mehring, M.

    2004-09-01

    The endohedral fullerene 15N@C60 comprises an electron spin S = 3/2 coupled to a nuclear spin I = 1/2 and is therefore ideally suited for experimental testing of basic properties of quantum mechanics. We will show that the 15N@C60 molecule represents a multi qubit system where different kinds of entangled states can be generated.

  1. Rotational dynamics of endohedral C60 fullerene complexes

    NASA Astrophysics Data System (ADS)

    Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.

    1997-11-01

    The structure of the rotational low-energy eigenvalue spectrum and eigenfunction of endohedral C60 fullerene complexes is investigated. The selected systems are Li+@C60, Na+@C60, CO@C60, and LiH@C60. The eigenvalue spectra may be classified basically into two types. Below some critical degree of anisotropy in the guest-cage interaction the spectrum looks rather simple, and similar to that of an effective diatomic molecule. For high enough anisotropic interactions, the low-energy eigenvalue spectrum is characterized by a double-band structure: a ground band localized around the fullerene hexagon centers, and an excited band embedded in a rotational quasi-continuum and localized at the unstable equilibrium regions around the fullerene pentagon centers. The cage rotation makes the transition from one type to the other much sharper type. Rotation dipole and Raman spectra are assigned in terms of these two types of structure in the eigenvalue spectrum.

  2. Structural and elastic anisotropy of carbon phases prepared from fullerite C60

    NASA Astrophysics Data System (ADS)

    Lyapin, A. G.; Mukhamadiarov, V. V.; Brazhkin, V. V.; Popova, S. V.; Kondrin, M. V.; Sadykov, R. A.; Tat'yanin, E. V.; Bayliss, S. C.; Sapelkin, A. V.

    2003-11-01

    We show that application of nonhydrostatic pressure to cluster-based molecular material, like fullerite C60, provides an opportunity to create elastically and structurally anisotropic carbon materials, including two-dimensional polymerized rhombohedral C60 and superhard graphite-type (sp2) disordered atomic-based phases. There is direct correlation between textured polymerized and/or textured covalent structure and anisotropic elasticity. Whereas this anisotropy is induced by the uniaxial pressure component, in the case of disordered atomic-based phases, it may be governed by the uniform pressure magnitude.

  3. On the action of UV photons on hydrogenated fulleranes C60H36 and C60D36

    NASA Astrophysics Data System (ADS)

    Cataldo, Franco; Iglesias-Groth, Susana

    2009-11-01

    Fulleranes, the hydrogenated fullerenes C60H36 and C60D36 have been synthesized in n-hexane where they show an absorption maximum at 217 nm in their electronic absorption spectra with molar extinction coefficients ɛ217 = 17140 and 16480L cm-1 mol-1, respectively, which correspond to absorption cross-sections of order 6500 Mbarn, about 10 times higher than for C60. We find that the absorption curves measured for these two fulleranes fit well the wavelength, width and shape of the ultraviolet (UV) bump (217 nm) in the extinction curve of the diffuse interstellar medium. If present in the interstellar medium these fulleranes would contribute significantly to the bump extinction, although interstellar carbon budget considerations indicate that C60H36 cannot be the only contributor. The photolysis of fulleranes with monochromatic light at 245 nm causes a shift of the absorption maximum from 217 nm to longer wavelengths. This band shift of the absorption maximum has already been observed in the photolysis or in the thermal processing of hydrogenated carbon dust. The band shift is due to the release of molecular hydrogen, a process which causes the aromatization of the carbon dust. C60H36 and C60D36 are photolyzed at a rate kC60H36 = 2.45 × 10-3 s-1 while kC60D36 = 2.27 × 10-3 s-1. This implies an isotope effect so that C60H36 is photolyzed 1.08 times faster than C60D36. In the interstellar medium, this implies a deuterium enrichment of the hydrogenated interstellar carbon dust. The presence of a measurable isotope effect suggests that the photolysis of C60H36 and C60D36 involves the rupture of the C-H and C-D bond with release of H2. C60H36 releases completely hydrogen when heated to 630°C under inert atmosphere producing back C60 as shown by FT-IR spectroscopy. Thus in the interstellar medium an equilibrium should occur between the hydrogenation of C60 with atomic hydrogen and the emission of molecular hydrogen because of the action of UV photons or thermal

  4. 13C and 23Na NMR studies of Na2C60 and Na6C60 fullerides

    NASA Astrophysics Data System (ADS)

    Rachdi, F.; Hajji, L.; Galtier, M.; Yildirim, T.; Fischer, J. E.; Goze, C.; Mehring, M.

    1997-10-01

    We report on 13C and 23Na NMR measurements on Na2C60 and Na6C60 compounds. The room-temperature 13C NMR spectra of Na2C60 and Na6C60 samples present a narrow isotropic line at 172 and 176 ppm, respectively. The Na6C60 resonance is shifted 20 ppm more down field than the resonances of A6C60 compounds with heavier alkalis, indicating a partial charge transfer to the threefold degenerate t1u level which is totally filled in the latter compounds. The 23Na NMR spectrum of A2C60 shows one line at 73 ppm and the one of A6C60 presents two lines at 73 and 147 ppm. The intensity ratio of the latter lines is about 2:1. According to previously reported x-ray data we attribute the line at 147 ppm to the Na tetramers in the octahedral sites and the line at 73 ppm to the Na cations in the tetrahedral ones which are singly occupied.

  5. Negative differential resistance in C60-based electronic devices.

    PubMed

    Zheng, Xiaohong; Lu, Wenchang; Abtew, Tesfaye A; Meunier, Vincent; Bernholc, Jerry

    2010-12-28

    Unlike single-C(60)-based devices, molecular assemblies based on two or more appropriately connected C(60) molecules have the potential to exhibit negative differential resistance (NDR). In this work, we evaluate electron transport properties of molecular devices built from two C(60) molecules connected by an alkane chain, using a nonequilibrium Green function technique implemented within the framework of density functional theory. We find that electronic conduction in these systems is mediated by the lowest unoccupied molecular orbitals (LUMOs) of C(60), as in the case of a single-C(60)-based device. However, as the positions of the LUMOs are pinned to the chemical potentials of their respective electrodes, their relative alignment shifts with applied bias and leads to a NDR at a very low bias. Furthermore, the position and magnitude of the NDR can be tuned by chemical modification of the C(60) molecules. The role of the attached molecules is to shift the LUMO position and break the symmetry between the forward and reverse currents. The NDR feature can also be controlled by changing the length of the alkane linker. The flexibility and richness of C(60)-based molecular electronics components point to a potentially promising route for the design of molecular devices and chemical sensors.

  6. Optimal High-TC Superconductivity in Cs3C60

    NASA Astrophysics Data System (ADS)

    Harshman, Dale; Fiory, Anthony

    The highest superconducting transition temperatures in the (A1-xBx)3C60 superconducting family are seen in the A15 and FCC structural phases of Cs3C60 (optimized under hydrostatic pressure), exhibiting measured values for near-stoichiometric samples of TC0 meas . = 37.8 K and 35.7 K, respectively. It is argued these two Cs-intercalated C60 compounds represent the optimal materials of their respective structures, with superconductivity originating from Coulombic e- h interactions between the C60 molecules, which host the n-type superconductivity, and mediating holes associated with the Cs cations. A variation of the interlayer Coulombic pairing model [Harshman and Fiory, J. Supercond. Nov. Magn. 28 ̲, 2967 (2015), and references therein] is introduced in which TC0 calc . ~ 1 / lζ , where l relates to the mean spacing between interacting charges on surfaces of the C60 molecules, and ζ is the average radial distance between the surface of the C60 molecules and the neighboring Cs cations. For stoichiometric Cs3C60, TC0 calc . = 38.08 K and 35.67 K for the A15 and FCC macrostructures, respectively; the dichotomy is attributable to differences in ζ.

  7. C60 as a Probe for Astrophysical Environments

    NASA Astrophysics Data System (ADS)

    Brieva, A. C.; Gredel, R.; Jäger, C.; Huisken, F.; Henning, T.

    2016-08-01

    The C60 molecule has been recently detected in a wide range of astrophysical environments through its four active intramolecular vibrational modes (T 1u) near 18.9, 17.4, 8.5, and 7.0 μm. The strengths of the mid-infrared emission bands have been used to infer astrophysical conditions in the fullerene-rich regions. Widely varying values of the relative intrinsic strengths (RIS) of these four bands are reported in laboratory and theoretical papers, which impedes the derivation of the excitation mechanism of C60 in the astrophysical sources. The spectroscopic analysis of the C60 samples produced with our method delivers highly reproducible RIS values of 100, 25 ± 1, 26 ± 1 and 40 ± 4. A comparison of the inferred C60 emission band strengths with the astrophysical data shows that the observed strengths cannot be explained in terms of fluorescent or thermal emission alone. The large range in the observed 17.4 μm/18.9 μm emission ratios indicates that either the emission bands contain significant contributions from emitters other than C60, or that the population distribution among the C60 vibrational modes is affected by physical processes other than thermal or UV excitation, such as chemo-luminescence from nascent C60 or possibly Poincaré fluorescence resulting from an inverse internal energy conversion. We have carefully analyzed the effect of the weakly active fundamental modes and second order modes in the mid-infrared spectrum of C60, and propose that neutral C60 is the carrier of the unidentified emission band at 6.49 μm which has been observed in fullerene-rich environments.

  8. Dispersion-corrected DFT calculations on C(60)-porphyrin complexes.

    PubMed

    Liao, Meng-Sheng; Watts, John D; Huang, Ming-Ju

    2009-06-07

    The quality of the newly added, empirical dispersion correction in density functional theory (DFT) calculations is examined for several supramolecular complexes of fullerene (C(60)) with free-base and metal porphyrins (Por). The benzene dimer (C(6)H(6))(2), naphthalene dimer (C(10)H(8))(2), and anthracene dimer (C(14)H(10))(2) were also included in the study for comparison. Three density functionals, two damping functions, and two types of basis sets were employed in the computations. The estimated dispersion energies in the fullerene-porphyrin systems are rather large, ranging from 0.5 eV in C(60).ZnP to 1 eV in C(60).H(2)TPP. Any dispersion-corrected DFT (DFT + E(disp)) method is shown to perform well for C(60).H(2)TPP, C(60).ZnTPP, and C(60).ZnP, where the intermolecular distances are relatively large. But large basis sets, e.g. TZP (triple-zeta + one polarization function), are required in order to obtain reliable results with DFT + E(disp). In the case of C(60).FeP, where the intermolecular distance R is short, the DFT + E(disp) calculated R depends on the damping function as well as on the DFT method, and all the DFT + E(disp) calculations lead to significant changes in the relative energies of the various spin states. The quality of the DFT + E(disp) calculated results on C(60).FeP is hard to judge here without detailed experimental data on a C(60).FePor complex. Owing to error cancellation, the pure DFT calculations with a smaller DZP (double-zeta + one polarization function) basis set without any correction are shown to give quite accurate results.

  9. Aggregation and Deposition of C60 in Aqueous Systems

    EPA Science Inventory

    The extremely low water solubility of many fullerenes precludes aqueous solution processing for engineering applications and minimizes the potential for fullerene environmental effects in aqueous environments. However, studies have shown that C60 fullerene can form stable colloi...

  10. Production of C59N:C60 solid solution

    NASA Astrophysics Data System (ADS)

    Fülöp, Ferenc; Rockenbauer, Antal; Simon, Ferenc; Pekker, Sándor; Korecz, László; Garaj, Slaven; Jánossy, András

    2001-10-01

    We describe a simple way to produce large quantities of solid solutions of monomer C59N in pure C60 using an electric gas discharge tube. Typical concentrations are 10-5 to 10-4 C59N with respect to C60. The 14N and several 13C hyperfine constants were measured by ESR. These are a sensitive test for electronic structure calculations of the monomer. As the temperature is raised towards the sc to fcc structural transition at 261 K, the ESR spectrum motionally narrows and the activation energy for reorientation is measured. The rotational dynamics of the C59N monomer between 130 and 600 K parallels that of C60 in the bulk thus interactions between C59N and C60 are surprisingly weak.

  11. Aggregation and Deposition of C60 in Aqueous Systems

    EPA Science Inventory

    The extremely low water solubility of many fullerenes precludes aqueous solution processing for engineering applications and minimizes the potential for fullerene environmental effects in aqueous environments. However, studies have shown that C60 fullerene can form stable colloi...

  12. Paper Models for Fullerenes C60-C84.

    ERIC Educational Resources Information Center

    Beaton, John M.

    1995-01-01

    Describes a system to construct paper models of all 51 of the possible fullerene isomers from C60 through C84. Provides students, teachers, and specialists with an inexpensive mechanism to follow the literature interplay on fullerene structures. (JRH)

  13. Superintermolecular orbitals in the C60-pentacene complex

    NASA Astrophysics Data System (ADS)

    Zhang, G. P.; Gardner, A.; Latta, T.; Drake, K.; Bai, Y. H.

    2016-12-01

    We report a group of unusually big molecular orbitals in the C60-pentacene complex. Our first-principles density-functional calculation shows that these orbitals are very delocalized and cover both C60 and pentacene, which we call superintermolecular orbitals (SIMOs). Their spatial extension can reach 1 nm or larger. Optically, SIMOs are dark. Different from ordinary unoccupied molecular orbitals, SIMOs have a very weak Coulomb and exchange interaction. Their energy levels are very similar to the native superatomic molecular orbitals in C60and can be approximately characterized by orbital angular momentum quantum numbers. They have a distinctive spatial preference. These features fit the key characters of charge-generation states that channel initially bound electrons and holes into free-charge carriers. Thus, our finding is important for C60-pentacene photovoltaics.

  14. Paper Models for Fullerenes C60-C84.

    ERIC Educational Resources Information Center

    Beaton, John M.

    1995-01-01

    Describes a system to construct paper models of all 51 of the possible fullerene isomers from C60 through C84. Provides students, teachers, and specialists with an inexpensive mechanism to follow the literature interplay on fullerene structures. (JRH)

  15. Formation of buckminsterfullerene (C60) in interstellar space

    PubMed Central

    Berné, Olivier; Tielens, A. G. G. M.

    2012-01-01

    Buckminsterfullerene (C60) was recently confirmed as the largest molecule identified in space. However, it remains unclear how and where this molecule is formed. It is generally believed that C60 is formed from the buildup of small carbonaceous compounds in the hot and dense envelopes of evolved stars. Analyzing infrared observations, obtained by Spitzer and Herschel, we found that C60 is efficiently formed in the tenuous and cold environment of an interstellar cloud illuminated by strong ultraviolet (UV) radiation fields. This implies that another formation pathway, efficient at low densities, must exist. Based on recent laboratory and theoretical studies, we argue that polycyclic aromatic hydrocarbons are converted into graphene, and subsequently C60, under UV irradiation from massive stars. This shows that alternative—top-down—routes are key to understanding the organic inventory in space. PMID:22198841

  16. Striped domains at the pentacene:C60 interface

    NASA Astrophysics Data System (ADS)

    Dougherty, Daniel B.; Jin, Wei; Cullen, William G.; Reutt-Robey, Janice E.; Robey, Steven W.

    2009-01-01

    Scanning tunneling microscopy observations of the initial growth stages of the first layer of pentacene on a monolayer film of C60 on Ag(111) are presented. Pentacene films nucleate and grow with molecules standing up at the pentacene:C60 interface similar to thin film phases observed on weakly interacting substrates such as SiO2. Unlike reported thin film pentacene phases, those on 1 monolayer C60/Ag(111) exhibit a striated morphology with domains of 4 nm nominal width. This long range pattern of periodic pentacene displacements relative to the substrate is the response to stress induced in the pentacene film by its interaction with the rigid C60 support.

  17. Electrical conductivity of polyazomethine/fullerene C60 nanocomposites

    NASA Astrophysics Data System (ADS)

    Bronnikov, Sergei; Podshivalov, Aleksandr; Kostromin, Sergei; Asandulesa, Mihai; Cozan, Vasile

    2017-02-01

    We prepared the polyazomethine/fullerene C60 nanocomposites varying in C60 loading. With a broadband dielectric relaxation spectrometer, we measured their electrical conductivity σm being a sum of dc conductivity σdc and ac conductivity σac. A small C60 content (0.25 and 0.5 wt.%) was shown to decrease σdc, whereas a larger amount of C60 (2.5 wt.%) was found to increase σdc of the nanocomposite. The temperature dependences of σac were described with the Arrhenius equation, while the frequency dependences of σac were characterized with a power function. The correlated barrier hopping was accepted as the most suitable mechanism to explain the σac behavior of the nanocomposites.

  18. Research on Electrostatic Propulsion Using C60 Molecules.

    DTIC Science & Technology

    2007-11-02

    fullerene extract containing C60 and C70 in a ratio of approximately 85% to 15%. The fullerene mix was Soxhlet extracted with toluene from soot. Pure C60...The objective of this program has been to determine properties of fullerenes relevant for electrostatic propulsion, to demonstrate ion extraction ...electrostatic propulsion, to demonstrate ion extraction from a discharge, and to assess the implications for fullerene ion thrusters. The experiments we

  19. Optical limiting behavior of C 60 doped ethylenepropylenediene polymethylene polymer

    NASA Astrophysics Data System (ADS)

    Zidan, M. D.; Ajji, Z.; Allaf, A. W.; Allahham, A.

    2010-06-01

    Optical limiting measurements on C 60 in toluene-ethylenepropylenediene polymethylene (EPDM) polymer blends and in EPDM polymer films at three different concentrations have been carried out. The measurements were undertaken using 532 nm wavelength, 10 ns pulses from a frequency-doubled Nd-YAG Laser. The results show that the optical limiting efficiency is concentration dependent and that the limiting efficiency for C 60 in toluene-EPDM polymer blends is better than in EPDM polymer film samples.

  20. Infrared spectroscopy of fullerene C60/anthracene adducts

    NASA Astrophysics Data System (ADS)

    García-Hernández, D. A.; Cataldo, F.; Manchado, A.

    2013-09-01

    Recent Spitzer Space Telescope observations of several astrophysical environments such as planetary nebulae, reflection nebulae and R Coronae Borealis stars show the simultaneous presence of mid-infrared features attributed to neutral fullerene molecules (i.e. C60) and polycyclic aromatic hydrocarbons (PAHs). If C60 fullerenes and PAHs coexist in fullerene-rich space environments, then C60 may easily form adducts with a number of different PAH molecules, at least with catacondensed PAHs. Here we present the laboratory infrared spectra (˜2-25 μm) of C60 fullerene and anthracene Diels-Alder mono- and bis-adducts as produced by sonochemical synthesis. We find that C60/anthracene Diels-Alder adducts display spectral features strikingly similar to those from C60 (and C70) fullerenes and other unidentified infrared emission features. Thus, fullerene adducts - if formed under astrophysical conditions and are stable/abundant enough - may contribute to the infrared emission features observed in fullerene-containing circumstellar/interstellar environments.

  1. Soil microbial response to photo-degraded C60 fullerenes.

    PubMed

    Berry, Timothy D; Clavijo, Andrea P; Zhao, Yingcan; Jafvert, Chad T; Turco, Ronald F; Filley, Timothy R

    2016-04-01

    Recent studies indicate that while unfunctionalized carbon nanomaterials (CNMs) exhibit very low decomposition rates in soils, even minor surface functionalization (e.g., as a result of photochemical weathering) may accelerate microbial decay. We present results from a C60 fullerene-soil incubation study designed to investigate the potential links between photochemical and microbial degradation of photo-irradiated C60. Irradiating aqueous (13)C-labeled C60 with solar-wavelength light resulted in a complex mixture of intermediate products with decreased aromaticity. Although addition of irradiated C60 to soil microcosms had little effect on net soil respiration, excess (13)C in the respired CO2 demonstrates that photo-irradiating C60 enhanced its degradation in soil, with ∼ 0.78% of 60 day photo-irradiated C60 mineralized. Community analysis by DGGE found that soil microbial community structure was altered and depended on the photo-treatment duration. These findings demonstrate how abiotic and biotic transformation processes can couple to influence degradation of CNMs in the natural environment.

  2. High-T C superconductivity in Cs3C60 compounds governed by local Cs-C60 Coulomb interactions

    NASA Astrophysics Data System (ADS)

    Harshman, Dale R.; Fiory, Anthony T.

    2017-04-01

    Unique among alkali-doped A 3C60 fullerene compounds, the A15 and fcc forms of Cs3C60 exhibit superconducting states varying under hydrostatic pressure with highest transition temperatures at T\\text{C}\\text{meas}   =  38.3 and 35.2 K, respectively. Herein it is argued that these two compounds under pressure represent the optimal materials of the A 3C60 family, and that the C60-associated superconductivity is mediated through Coulombic interactions with charges on the alkalis. A derivation of the interlayer Coulombic pairing model of high-T C superconductivity employing non-planar geometry is introduced, generalizing the picture of two interacting layers to an interaction between charge reservoirs located on the C60 and alkali ions. The optimal transition temperature follows the algebraic expression, T C0  =  (12.474 nm2 K)/ℓζ, where ℓ relates to the mean spacing between interacting surface charges on the C60 and ζ is the average radial distance between the C60 surface and the neighboring Cs ions. Values of T C0 for the measured cation stoichiometries of Cs3-x C60 with x  ≈  0 are found to be 38.19 and 36.88 K for the A15 and fcc forms, respectively, with the dichotomy in transition temperature reflecting the larger ζ and structural disorder in the fcc form. In the A15 form, modeled interacting charges and Coulomb potential e2/ζ are shown to agree quantitatively with findings from nuclear-spin relaxation and mid-infrared optical conductivity. In the fcc form, suppression of T\\text{C}\\text{meas} below T C0 is ascribed to native structural disorder. Phononic effects in conjunction with Coulombic pairing are discussed.

  3. High-T C superconductivity in Cs3C60 compounds governed by local Cs-C60 Coulomb interactions.

    PubMed

    Harshman, Dale R; Fiory, Anthony T

    2017-04-12

    Unique among alkali-doped A 3C60 fullerene compounds, the A15 and fcc forms of Cs3C60 exhibit superconducting states varying under hydrostatic pressure with highest transition temperatures at [Formula: see text]  =  38.3 and 35.2 K, respectively. Herein it is argued that these two compounds under pressure represent the optimal materials of the A 3C60 family, and that the C60-associated superconductivity is mediated through Coulombic interactions with charges on the alkalis. A derivation of the interlayer Coulombic pairing model of high-T C superconductivity employing non-planar geometry is introduced, generalizing the picture of two interacting layers to an interaction between charge reservoirs located on the C60 and alkali ions. The optimal transition temperature follows the algebraic expression, T C0  =  (12.474 nm(2) K)/ℓζ, where ℓ relates to the mean spacing between interacting surface charges on the C60 and ζ is the average radial distance between the C60 surface and the neighboring Cs ions. Values of T C0 for the measured cation stoichiometries of Cs3-x C60 with x  ≈  0 are found to be 38.19 and 36.88 K for the A15 and fcc forms, respectively, with the dichotomy in transition temperature reflecting the larger ζ and structural disorder in the fcc form. In the A15 form, modeled interacting charges and Coulomb potential e(2)/ζ are shown to agree quantitatively with findings from nuclear-spin relaxation and mid-infrared optical conductivity. In the fcc form, suppression of [Formula: see text] below T C0 is ascribed to native structural disorder. Phononic effects in conjunction with Coulombic pairing are discussed.

  4. Electron-paramagnetic-resonance scattering rates in metallic RbC60 and CsC60

    NASA Astrophysics Data System (ADS)

    Rahmer, J.; Grupp, A.; Mehring, M.

    2001-12-01

    We derive conduction-electron scattering rates in the metallic polymer phase of RbC60 and CsC60 from the investigation of the temperature-dependent conduction electron-spin-resonance linewidth at X- (9 GHz) and W-band (94 GHz) frequencies by applying the Elliott theory. We obtain scattering rates that favor an essentially isotropic electronic structure of the polymer phase.

  5. Polarons in endohedral Li+@C60- dimers and in 1D and 2D crystals

    NASA Astrophysics Data System (ADS)

    Kawazoe, Yoshiyuki; Belosludov, Vladimir R.; Zhdanov, Ravil K.; Belosludov, Rodion V.

    2017-10-01

    The electron charge distribution and polaron formation on the carbon sites of dimer clusters Li+@C60- and of 1D or 2D Li+@C60- periodic systems are studied with the use of the generalized Su-Schrieffer-Heeger model with respect to the intermolecular and intramolecular degrees of freedom. The charge distributions over the molecular surface and Jahn-Teller bond distortions of carbon atoms are calculated using the self-consistent iterative methods. Polarons formed in periodic 1D and 2D systems (chains and planar layers) as well as in dimer cluster system are examined. In the periodic systems polaron formation may be described by the cooperative Jahn-Teller effect. Orientation of the polarons on the molecule surface depends on the doping of the system, moreover, electron doping changes the energy levels in the system.

  6. An STM study of C 60 adsorption on Si(100)-(2 × 1) surfaces: from physisorption to chemisorption

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Sarid, Dror

    1995-05-01

    The adsorption of C 60 molecules on Si(100)-(2 × 1) surfaces before and after annealing has been studied using scanning tunneling microscopy (STM). For room temperature deposition, the STM images reveal that the C 60 molecules adsorb predominantly at the four-dimer sites in the troughs between dimer rows. C 60 molecules bonded to two-dimer sites are also observed in small molecular clusters forming even at a low coverage. The nature of the interaction between the adsorbates and the Si(100)-(2 × 1) surface is explained in terms of a dipole-induced dipole interaction. Subsequent annealing of the samples to 600°C changes the adsorption characteristics of the C 60 molecules. First, the annealing causes a strong covalent bonding between the carbon atoms of the C 60 molecules and the silicon atoms of the substrate, and modifies the bonding sites of the adsorbates from locations in the troughs to locations on the dimer rows. Second, the annealing causes some initial surface diffusion and clustering of the C 60 molecules, which now tend to stick to the ends, rather than the sides, of the dimer rows. Furthermore, after the annealing process, it is observed that small silicon islands form on the substrate terraces along with isolated and clustered adsorbates.

  7. An Ab Initio Study of Alkali-C60 Complexes

    NASA Astrophysics Data System (ADS)

    Frick, Nathan; Hira, A. S.; Ray, A. K.

    2003-03-01

    We extend our previous work on fullerene-alkali complexes1-2 by presenting the results of an ab initio theoretical study of the alkali LiC60+, LiC60, NaC60+, NaC60, KC60+, and KC60 complexes. In the endohedral complexes for Li and Na, there is displacement of the adatom from the center. Of the ions, exohedral Li+ will sit closest to the cage, and among the neutrals, exohedral K remains closest. Bond lengths are consistently longer for the fivefold and threefold approaches. Adsorbates inside the fullerene donate negative charge to the carbons, but ions outside obtain a small amount, resulting in a polarization of the molecule. In the ion complexes, there is lowering of the orbital energy levels by 3 to 4 eV, resulting in an increase in the number of bound, but unoccupied, electronic orbitals. The HOMO-LUMO gap, of interest in superconductivity studies, is reduced by about 50 1. A.S. Hira and A.K. Ray, Phys. Rev. A 52, 141(1995); A 54, 2205(1996). 2. Ajit Hira and A. K. Ray, "An Initio Modeling of the Endohedral and Exohedral Complexes of C60Na2+ Complexes", Bull. Am. Phys. Soc. 47 (March 2002).

  8. Effective intermolecular potential and critical point for C60 molecule

    NASA Astrophysics Data System (ADS)

    Ramos, J. Eloy

    2017-07-01

    The approximate nonconformal (ANC) theory is applied to the C60 molecule. A new binary potential function is developed for C60, which has three parameters only and is obtained by averaging the site-site carbon interactions on the surface of two C60 molecules. It is shown that the C60 molecule follows, to a good approximation, the corresponding states principle with n-C8H18, n-C4F10 and n-C5F12. The critical point of C60 is estimated in two ways: first by applying the corresponding states principle under the framework of the ANC theory, and then by using previous computer simulations. The critical parameters obtained by applying the corresponding states principle, although very different from those reported in the literature, are consistent with the previous results of the ANC theory. It is shown that the Girifalco potential does not correspond to an average of the site-site carbon-carbon interaction.

  9. Target Plate Material Influence on Fullerene-C60 Laser Desorption/Ionization Efficiency.

    PubMed

    Zeegers, Guido P; Günthardt, Barbara F; Zenobi, Renato

    2016-04-01

    Systematic laser desorption/ionization (LDI) experiments of fullerene-C60 on a wide range of target plate materials were conducted to gain insight into the initial ion formation in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The positive and negative ion signal intensities of precursor, fragment, and cluster ions were monitored, varying both the laser fluence (0-3.53 Jcm(-2)) and the ion extraction delay time (0-950 ns). The resulting species-specific ion signal intensities are an indication for the ionization mechanisms that contribute to LDI and the time frames in which they operate, providing insight in the (MA)LDI primary ionization. An increasing electrical resistivity of the target plate material increases the fullerene-C60 precursor and fragment anion signal intensity. Inconel 625 and Ti90/Al6/V4, both highly electrically resistive, provide the highest anion signal intensities, exceeding the cation signal intensity by a factor ~1.4 for the latter. We present a mechanism based on transient electrical field strength reduction to explain this trend. Fullerene-C60 cluster anion formation is negligible, which could be due to the high extraction potential. Cluster cations, however, are readily formed, although for high laser fluences, the preferred channel is formation of precursor and fragment cations. Ion signal intensity depends greatly on the choice of substrate material, and careful substrate selection could, therefore, allow for more sensitive (MA)LDI measurements. Graphical Abstract ᅟ.

  10. Target Plate Material Influence on Fullerene-C60 Laser Desorption/Ionization Efficiency

    NASA Astrophysics Data System (ADS)

    Zeegers, Guido P.; Günthardt, Barbara F.; Zenobi, Renato

    2016-04-01

    Systematic laser desorption/ionization (LDI) experiments of fullerene-C60 on a wide range of target plate materials were conducted to gain insight into the initial ion formation in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The positive and negative ion signal intensities of precursor, fragment, and cluster ions were monitored, varying both the laser fluence (0-3.53 Jcm-2) and the ion extraction delay time (0-950 ns). The resulting species-specific ion signal intensities are an indication for the ionization mechanisms that contribute to LDI and the time frames in which they operate, providing insight in the (MA)LDI primary ionization. An increasing electrical resistivity of the target plate material increases the fullerene-C60 precursor and fragment anion signal intensity. Inconel 625 and Ti90/Al6/V4, both highly electrically resistive, provide the highest anion signal intensities, exceeding the cation signal intensity by a factor ~1.4 for the latter. We present a mechanism based on transient electrical field strength reduction to explain this trend. Fullerene-C60 cluster anion formation is negligible, which could be due to the high extraction potential. Cluster cations, however, are readily formed, although for high laser fluences, the preferred channel is formation of precursor and fragment cations. Ion signal intensity depends greatly on the choice of substrate material, and careful substrate selection could, therefore, allow for more sensitive (MA)LDI measurements.

  11. Elucidating the Significance of the ``Nano-Effect'' in Determining the Mobility of C60 Nanoparticles in Saturated Porous Media

    NASA Astrophysics Data System (ADS)

    Jia, Q.; Brant, J.

    2010-12-01

    Fullerenes are all carbon molecules that may exist in a variety of geometries, such as cages, cylinders, and planar sheets. Buckminsterfullerene (C60) is one type of fullerene that has received considerable interest from the scientific community for its use in commercial applications (bio-medical technologies, electronics, optics, and composites) and environmental implications (toxicity, mobility). Once released into the environment, the toxicity and bioavailability of C60 nanoparticles will be largely influenced by transport and retention processes in porous media. To date, many studies have investigated C60 mobility in saturated porous media, which has relevance to both groundwater protection and potable treatment by filtration methods. Previous research efforts have determined that the technique used for dispersing the C60 in water, chemistry of the dispersion solution (pH, ionic composition/strength), and Darcy velocity all affect C60 mobility. However, far less attention has been directed toward determining the impact of nanoparticle size. In other words, is there a nano-effect for C60, and if it exists to what extent does it alter C60 mobility in saturated porous media. The overall objective of this study was to explore to what extent the size of the C60 clusters (nC60) affects their mobility in saturated porous media in order to determine if the nano-effect does indeed exist for these systems. Nanoparticle mobility in two relatively well-characterized porous media, glass spheres and quartz sand, was assessed as a function of solution chemistry and Darcy velocity. The surface charge of the collector media was modified to elucidate the significance of charge interactions for nanoparticles. Preliminary results suggest that nC60 mobility increases as particle size decreases, supporting the belief that the nano-effect is indeed a real phenomenon.

  12. ESR study of superconducting K-doped C 60 "polymer"

    NASA Astrophysics Data System (ADS)

    Kinoshita, N.; Grigoryan, L. S.; Kinoshita, T.; Tokumoto, M.

    1997-03-01

    ESR measurements of the superconducting K-doped C 60 "polymer" were carried out, in order to clarify the difference from ordinary K-doped C 60, i.e. monomer. Observed ESR spectrum was simulated by four Lorentzian lines. The temperature dependences of the ESR linewidth, g factor and spin susceptibility are obtained for each ESR line. At room temperature the linewidth and g factor of the broadest ESR absorption line are, about 400 G and 2.01, respectively. The linewidths for other lines are 150, 53 and 16 G with the common g factor of 2.000. The linewidths of the ESR spectrum of superconducting K-doped C 60 "polymer" are found to be much broader than those of monomer sample. Similar to monomer sample, two absorption lines with weakly temperature-dependent intensity were observed, one of which disappeared (150 G width) below the super-conducting transition temperature ( Tc = 15 K).

  13. Physical properties of highly-oriented rhombohedral C60 polymer

    NASA Astrophysics Data System (ADS)

    Tokumoto, M.; Narymbetov, B.; Kobayashi, H.; Makarova, T. L.; Davydov, V. A.; Rakhmania, A. V.; Kashevarova, L. S.

    2000-11-01

    Rhombohedral phase of pressure-temperature treated C60 polymer was investigated by resistivity, X-ray diffraction and ESR measurements. The pure rhombohedral phase of C60 polymer displays highly anisotropic electrical properties, and the conductivity in the polymerized 2D plane exhibits a metallic feature with weak localization. X-ray diffraction measurements have revealed that the diffraction patterns are essentially anisotropic. We have carried out the scanning of a reciprocal space in order to reveal the distribution of diffraction intensities. The result testifies to the high degree of mutual orientations of crystallites in the sample not only along the [001] direction but also in the (001) plane. Apparently the observed mosaicity of the crystal is connected with the highly anisotropic electrical properties of the rhombohedral phase of pressure-treated C60 polymer. A Dysonian ESR absorption lineshape consistent with the metallic nature was observed.

  14. A search for C60 in carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    De Vries, M. S.; Reihs, K.; Wendt, H. R.; Golden, W. G.; Hunziker, H. E.; Fleming, R.; Peterson, E.; Chang, S.

    1993-01-01

    Analysis of interior samples of the Murchison meteorite by two routes yielded an upper limit of 2 ppb for its C60 content, as compared to parts per million levels for individual polycyclic aromatic hydrocarbons (PAHs ). Provided the samples contain an interstellar component, which is probable since Murchison hydrocarbons contain excess deuterium, this result argues against the ubiquitous presence of C60 in the interstellar medium. A possible explanation for the absence of C60 was found in experiments showing how PAHs replace fullerenes as stable end products when hydrogen is present during carbon condensation. As a secondary result we found high molecular weight PAHs in the Murchison and Allende meteorites. Coronene and its methyl derivatives are especially interesting since features in the coronene spectrum have been shown to match some of the unidentified interstellar infrared emission bands.

  15. A search for C60 in carbonaceous chondrites

    NASA Astrophysics Data System (ADS)

    de Vries, M. S.; Reihs, K.; Wendt, H. R.; Golden, W. G.; Hunziker, H. E.; Fleming, R.; Peterson, E.; Chang, S.

    1993-02-01

    Analysis of interior samples of the Murchison meteorite by two routes yielded an upper limit of 2 ppb for its C60 content, as compared to parts per million levels for individual polycyclic aromatic hydrocarbons (PAHs ). Provided the samples contain an interstellar component, which is probable since Murchison hydrocarbons contain excess deuterium, this result argues against the ubiquitous presence of C60 in the interstellar medium. A possible explanation for the absence of C60 was found in experiments showing how PAHs replace fullerenes as stable end products when hydrogen is present during carbon condensation. As a secondary result we found high molecular weight PAHs in the Murchison and Allende meteorites. Coronene and its methyl derivatives are especially interesting since features in the coronene spectrum have been shown to match some of the unidentified interstellar infrared emission bands.

  16. Tunneling anisotropic magnetoresistance in C60-based organic spintronic systems

    NASA Astrophysics Data System (ADS)

    Wang, K.; Sanderink, J. G. M.; Bolhuis, T.; van der Wiel, W. G.; de Jong, M. P.

    2014-05-01

    C60 fullerenes are interesting molecular semiconductors for spintronics since they exhibit weak spin-orbit and hyperfine interactions, which is a prerequisite for long spin lifetimes. We report spin-polarized transport in spin-valve-like structures containing ultrathin (<10 nm) C60 layers, ferromagnetic (FM) epitaxial face-centered-cubic (fcc) Co (111) contacts, AlOx tunnel barriers, and nonmagnetic Al counter electrodes. Even though genuine spin-valve behavior cannot occur for only one FM contact, we find significant tunneling anisotropic magnetoresistance (TAMR) upon rotating the in-plane magnetization, originating from spin-orbit interaction (SOI) induced anisotropy of the fcc (111) Co bands. The uniaxial magnetocrystalline anisotropy of the Co electrodes results in a predominantly twofold symmetric in-plane TAMR effect. We investigated the TAMR effect in the direct tunneling regime (2 nm C60), at the transition point to two-step tunneling (4 nm C60), and in the multistep regime (8 nm C60). A sizable TAMR of 4.5% is found at 5 K under application of a 500-mT in-plane magnetic field for C60 layers of 2 nm, which is strongly suppressed at 8 nm thickness, indicating that TAMR may strongly contribute to the "spin-valve" signal for direct tunneling, but not for multistep tunneling. The TAMR effect is proposed to be due to a combination of SOI induced modulation of the tunneling DOS upon rotating the in-plane magnetization of the fcc epitaxial Co thin film, resonant tunneling processes involving interfacial states, and different Bychkov-Rashba SOI at the different interfaces.

  17. Polarization effects in C60 fullerene complexes of alkali ions

    NASA Astrophysics Data System (ADS)

    Ruiz, A.; Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.

    1998-09-01

    We introduce a secular semiempirical model of the Pariser-Parr-Pople type to reproduce the electronic structure and polarizability of the C60 fullerene. The model is then used to simulate the response of this molecule to an electric charge and estimate its polarization energy. By expressing the charge potential at the C60-cage surface as a multipole expansion, an analytical form is obtained for the polarization energy. Application of these results to endo- and exohedral complexes of alkali ions gives data in rather good agreement with recent ab initio calculations [Hira and Ray, Phys. Rev. A 52, 141 (1995)].

  18. Chemical effects in C 60 irradiation of polymers

    NASA Astrophysics Data System (ADS)

    Möllers, R.; Tuccitto, N.; Torrisi, V.; Niehuis, E.; Licciardello, A.

    2006-07-01

    The C 60 erosion behaviour of poly(methyl)methacrylate (PMMA), poly(α-methyl)styrene (PAMS) and polystyrene (PS) has been studied at various temperatures and compared with that under Ga + irradiation. Strong variations of erosion yields are observed, indicating that chemical degradation mechanisms are operating. In particular, our results suggest that fast depolymerization mechanisms are important in leaving the surface of the sputter crater virtually undamaged. Since such mechanisms are connected with the chemical nature of the polymer, the possibility of performing molecular depth profiling of polymers with C 60 appears to depend strongly on the chemical nature of the system under study.

  19. Protective Fullerene (C60) Packaging System for Microelectromechanical Systems Applications

    NASA Technical Reports Server (NTRS)

    Olivas, John D. (Inventor)

    2001-01-01

    The invention involves a method for locating the probe of a scanning tunneling micrograph a predetermined distance from its conducting surface, and specifically the deposition of a monolayer of fullerene C60 onto the conducting plate. The Fullerene C60 molecule is approximately spherical and a monolayer of fullerene has a thickness of one nanometer. By providing a monolayer of fullerene on the conducting surface and locating the probe on the surface of the monolayer, a distance of one nanometer can be established between the probe tip and the conducting surface.

  20. Structure and dynamics of C60 molecules on Au(111)

    SciTech Connect

    Shin, Heekeun; Schwarze, A; Diehl, R D; Pussi, K; Colombier, A; Gaudry, E.; Ledieu, J; McGuirk, G M; Serkovic Loli, L N; Fournee, V; Wang, Lin-Lin; Schull, G; Berndt, R

    2014-06-01

    Earlier studies of C60 adsorption on Au(111) reported many interesting and complex features. We have performed coordinated low-energy electron diffraction, scanning tunneling microscopy (STM), and density functional theory studies to elucidate some of the details of the monolayer commensurate (2√3 × 2√3)R30° phase. We have identified the adsorption geometries of the two states that image as dim and bright in STM. These consist of a C60 molecule with a hexagon side down in a vacancy (hex-vac) and a C60 molecule with a carbon-carbon 6:6 bond down on a top site (6:6-top), respectively. We have studied the detailed geometries of these states and find that there is little distortion of the C60 molecules, but there is a rearrangement of the substrate near the C60 molecules. The two types of molecules differ in height, by about 0.7 Å, which accounts for most of the difference in their contrast in the STM images. The monolayer displays dynamical behavior, in which the molecules flip from bright to dim, and vice versa. We interpret this flipping as the result of the diffusion of vacancies in the surface layers of the substrate. Our measurements of the dynamics of this flipping from one state to the other indicate that the activation energy is 0.66 ± 0.03 eV for flips that involve nearest-neighbor C60 molecules, and 0.93 ± 0.03 for more distant flips. Based on calculated activation energies for vacancies diffusing in Au, we interpret these to be a result of surface vacancy diffusion and bulk vacancy diffusion. These results are compared to the similar system of Ag(111)-(2√3 × 2√3)R30°-C60. In both systems, the formation of the commensurate C60 monolayer produces a large number of vacancies in the top substrate layer that are highly mobile, effectively melting the interfacial metal layer at temperatures well below their normal melting temperatures.

  1. Protective Fullerene (C60) Packaging System for Microelectromechanical Systems Applications

    NASA Technical Reports Server (NTRS)

    Olivas, John D. (Inventor)

    2001-01-01

    The invention involves a method for locating the probe of a scanning tunneling micrograph a predetermined distance from its conducting surface, and specifically the deposition of a monolayer of fullerene C60 onto the conducting plate. The Fullerene C60 molecule is approximately spherical and a monolayer of fullerene has a thickness of one nanometer. By providing a monolayer of fullerene on the conducting surface and locating the probe on the surface of the monolayer, a distance of one nanometer can be established between the probe tip and the conducting surface.

  2. Electronic structure and optical properties of solid C 60

    NASA Astrophysics Data System (ADS)

    Mattesini, M.; Ahuja, R.; Sa, L.; Hugosson, H. W.; Johansson, B.; Eriksson, O.

    2009-06-01

    The electronic structure and the optical properties of face-centered-cubic C 60 have been investigated by using an all-electron full-potential method. Our ab initio results show that the imaginary dielectric function for high-energy values looks very similar to that of graphite, revealing close electronic structure similarities between the two systems. We have also identified the origin of different peaks in the dielectric function of fullerene by means of the calculated electronic density of states. The computed optical spectrum compares fairly well with the available experimental data for the Vis-UV absorption spectrum of solid C 60.

  3. Determination of the equilibrium constant of C60 fullerene binding with drug molecules.

    PubMed

    Mosunov, Andrei A; Pashkova, Irina S; Sidorova, Maria; Pronozin, Artem; Lantushenko, Anastasia O; Prylutskyy, Yuriy I; Parkinson, John A; Evstigneev, Maxim P

    2017-03-01

    We report a new analytical method that allows the determination of the magnitude of the equilibrium constant of complexation, Kh, of small molecules to C60 fullerene in aqueous solution. The developed method is based on the up-scaled model of C60 fullerene-ligand complexation and contains the full set of equations needed to fit titration datasets arising from different experimental methods (UV-Vis spectroscopy, (1)H NMR spectroscopy, diffusion ordered NMR spectroscopy, DLS). The up-scaled model takes into consideration the specificity of C60 fullerene aggregation in aqueous solution and allows the highly dispersed nature of C60 fullerene cluster distribution to be accounted for. It also takes into consideration the complexity of fullerene-ligand dynamic equilibrium in solution, formed by various types of self- and hetero-complexes. These features make the suggested method superior to standard Langmuir-type analysis, the approach used to date for obtaining quantitative information on ligand binding with different nanoparticles.

  4. The role of the auxiliary atomic ion beam in C60(+)-Ar+ co-sputtering.

    PubMed

    Lin, Wei-Chun; Liu, Chi-Ping; Kuo, Che-Hung; Chang, Hsun-Yun; Chang, Chi-Jen; Hsieh, Tung-Han; Lee, Szu-Hsian; You, Yun-Wen; Kao, Wei-Lun; Yen, Guo-Ji; Huang, Chih-Chieh; Shyue, Jing-Jong

    2011-03-07

    Cluster ion sputtering has been proven to be an effective technique for depth profiling of organic materials. In particular, C(60)(+) ion beams are widely used to profile soft matter. The limitation of carbon deposition associated with C(60)(+) sputtering can be alleviated by concurrently using a low-energy Ar(+) beam. In this work, the role of this auxiliary atomic ion beam was examined by using an apparatus that could analyze the sputtered materials and the remaining target simultaneously using secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectrometry (XPS), respectively. It was found that the auxiliary 0.2 kV Ar(+) stream was capable of slowly removing the carbon deposition and suppresses the carbon from implantation. As a result, a more steady sputtering condition was achieved more quickly with co-sputtering than by using C(60)(+) alone. Additionally, the Ar(+) beam was found to interfere with the C(60)(+) beam and may lower the overall sputtering rate and secondary ion intensity in some cases. Therefore, the current of this auxiliary ion beam needs to be carefully optimized for successful depth profiling.

  5. Different contact formations at the interfaces of C60/LiF/Al and C60/LiF/Ag

    NASA Astrophysics Data System (ADS)

    Jeon, Pyungeun; Kang, Seong Jun; Lee, Hyunbok; Lee, Jeihyun; Jeong, Kwangho; Lee, JinWoo; Yi, Yeonjin

    2012-04-01

    C60 has been used as an electron accepting and transporting material in various organic electronic devices. In such devices, Al and Ag have been adopted as a common cathode in combination with electron injection layers (EIL), e.g., LiF. We found that the initial interface formations of C60/LiF/Al and C60/LiF/Ag are quite different in terms of interfacial electronic structures. We measured the interfacial electronic structures with photoemission spectroscopy and found that LiF works well as an EIL on Al but performs poorly on Ag. The origin of this difference could be attributed to the larger interface dipole on Al, highlighting the importance of the choice of cathode materials.

  6. Comparative analysis of two aqueous-colloidal solutions of C 60 fullerene with help of FTIR reflectance and UV-Vis spectroscopy

    NASA Astrophysics Data System (ADS)

    Andrievsky, G. V.; Klochkov, V. K.; Bordyuh, A. B.; Dovbeshko, G. I.

    2002-09-01

    Two types of fullerene-water colloidal systems: molecular-colloidal C 60 solution in water (C 60FWS) and typical monodisperse C 60 hydrosol are compared in this work. It was confirmed that C 60FWS consists of isolated C 60 molecules in hydrated state, C 60@{H 2O} n, and of their small spherical C 60 clusters of different sizes. It was shown that C 60FWS simultaneously has the properties of both true solutions and colloidal systems. The origin of supramolecular complexes C 60@{H 2O} n stabilization is explained both by the weak donor-acceptor interactions of unpaired electrons of H 2O oxygen atoms with fullerene molecule and by formation of ordered, H-bounded and sphere-like hydrated shells around the fullerene. Spectra of surface enhanced infrared absorption (SEIRA) of C 60 on gold substrate were recorded in FTIR reflectance mode. In the 400-900 cm -1 region some additional vibration bands of C 60, which are forbidden in IR spectra, have been registered. Earlier the similar bands had been observed in inelastic neutron scattering.

  7. Angular resolved photoionization of C60 by femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Li, Hui; Wang, Zhenhua; Suessmann, Frederik; Zherebtsov, Sergey; Skruszewicz, Slawomir; Tiggesbaeumker, Josef; Fennel, Thomas; Meiwes-Broer, Karl-Heinz; Cocke, C.; Kling, Matthias; JRM laboratory, Kansas State University Team; University of Rostock Collaboration; Max-Planck InstitutQuantumoptik Collaboration

    2013-03-01

    Neutral C60 molecules are ionized by intense femtosecond laser pulses around the wavelength of 800 nm with pulse durations 4 fs and 30 fs. We measure photoelectrons utilizing velocity-map imaging (VMI) and analyze the photoelectron angular distributions. For particular photoelectron energies, these distributions might reflect the excitation and ionization of superatomic molecular orbitals (SAMOs) which have been theoretically predicted and only recently experimentally observed. SAMOs arise from the hollow core spherical structures of the C60 molecules and differ from Rydberg states of C60 by their potential to exhibit electron density within the C60 cage. We have recorded the carrier envelope phase (CEP) dependence of the electron emission for 4 fs pulses using single shot CEP-tagging. The CEP-dependent asymmetry in the electron emission is observed to strongly depend on the laser polarization. Furthermore, the amplitudes and phases of the CEP-dependent electron emission are analyzed and show that thermal electron emission can be avoided enabling a more direct comparison to theory.

  8. Protective Fullerene (C60) Packaging System for Microelectromechanical Systems Applications

    NASA Technical Reports Server (NTRS)

    Olivas, John D. (Inventor)

    2004-01-01

    The invention involves tunneling tips to their conducting surface, and specifically the deposition of a monolayer of fullerene C60 onto the conducting plate surface to protect the tunneling tip from contact. The Fullerene C60 molecule is approximately spherical, and a monolayer of fullerene has a thickness of one nanometer, such that a monolayer thereby establishing the theoretical distance desired between the MEMS tunneling tip and the conducting plate. Exploiting the electrical conductivity of C60 the tip can be accurately positioned by simply monitoring conductivity between the fullerene and the tunneling tip. By monitoring the Conductivity between the tip and the fullerene layer as the tip is brought in proximity, the surfaces can be brought together without risk of contacting the underlying conducting surface. Once the tunneling tip is positioned at the one nanometer spacing, with only the monolayer of fullerene between the tunneling tip and the conducting plate, the monolayer of C60, can be broken down thermally and removed chemically leaving only the tunneling tip and the conducting plate at the ideal tunneling spacing. Alternatively, the properties of fullerene allow the tunneling process to occur directly across the fullerene monolayer.

  9. Molecular depth profiling in ice matrices using C 60 projectiles

    NASA Astrophysics Data System (ADS)

    Wucher, A.; Sun, S.; Szakal, C.; Winograd, N.

    2004-06-01

    The prospects of molecular sputter depth profiling using C 60+ projectiles were investigated on thick ice layers prepared by freezing aqueous solutions of histamine onto a metal substrate. The samples were analyzed in a ToF-SIMS spectrometer equipped with a liquid metal Ga + ion source and a newly developed fullerene ion source. The C 60+ beam was used to erode the surface, while static ToF-SIMS spectra were taken with both ion beams alternatively between sputtering cycles. We find that the signals both related to the ice matrix and to the histamine are about two orders of magnitude higher under 20-keV C 60 than under 15-keV Ga bombardment. Histamine related molecular signals are found to increase drastically if the freshly introduced surface is pre-sputtered with C 60 ions, until at a total ion fluence of about 10 13 cm -2 the spectra are completely dominated by the molecular ion and characteristic fragments of histamine. At larger fluence, the signal is found to decrease with a disappearance cross section of approximately 10 -14 cm 2, until at total fluences of about 10 14 cm -2 a steady state with stable molecular signals is reached. In contrast, no appreciable molecular signal could be observed if Ga + ions were used to erode the surface.

  10. Protective Fullerene (C60) Packaging System for Microelectromechanical Systems Applications

    NASA Technical Reports Server (NTRS)

    Olivas, John D. (Inventor)

    2004-01-01

    The invention involves tunneling tips to their conducting surface, and specifically the deposition of a monolayer of fullerene C60 onto the conducting plate surface to protect the tunneling tip from contact. The Fullerene C60 molecule is approximately spherical, and a monolayer of fullerene has a thickness of one nanometer, such that a monolayer thereby establishing the theoretical distance desired between the MEMS tunneling tip and the conducting plate. Exploiting the electrical conductivity of C60 the tip can be accurately positioned by simply monitoring conductivity between the fullerene and the tunneling tip. By monitoring the Conductivity between the tip and the fullerene layer as the tip is brought in proximity, the surfaces can be brought together without risk of contacting the underlying conducting surface. Once the tunneling tip is positioned at the one nanometer spacing, with only the monolayer of fullerene between the tunneling tip and the conducting plate, the monolayer of C60, can be broken down thermally and removed chemically leaving only the tunneling tip and the conducting plate at the ideal tunneling spacing. Alternatively, the properties of fullerene allow the tunneling process to occur directly across the fullerene monolayer.

  11. Confirmation of C60 in the Reflection Nebula NGC 7023

    NASA Astrophysics Data System (ADS)

    Sellgren, K.; Werner, M. W.; Ingalls, J. G.; Smith, J. D. T.; Carleton, T. M.; Joblin, C.

    2011-03-01

    The fullerene C60 has four infrared active vibrational transitions at 7.0, 8.5, 17.5 and 18.9 μm. We have previously observed emission features at 17.4 and 18.9 μm in the reflection nebula NGC 7023 and demonstrated spatial correlations suggestive of a common origin. We now confirm the identification of these features with C60 by detecting a third emission feature at 7.04 ± 0.05μm at a position of strong 18.9 μm emission in NGC 7023. We also report the detection of these three features in the reflection nebula NGC 2023. We show with spectroscopic mapping of NGC 7023 that the 18.9 μm feature peaks on the central star, that the 16.4 μm emission feature due to PAHs peaks between the star and a nearby photodissociation front, and that the 17.4 μm feature is a blend of a PAH feature and C60. The derived C60 abundance is consistent with that from previous upper limits and possible fullerene detections in the interstellar medium.

  12. Electronically Excited C2 from Laser Photodissociated C60

    NASA Technical Reports Server (NTRS)

    Arepalli, Sivaram; Scott, Carl D.; Nikolaev, Pavel; Smalley, Richard E.

    1999-01-01

    Spectral and transient emission measurements are made of radiation from products of laser excitation of buckminsterfullerene (C60) vapor diluted in argon at 973 K. The principal radiation is from the Swan band system of C2 and, at early times, also from a black body continuum. The C2 radiation is observed only when C60 is excited by green (532 nm) and not with IR (1064 nm) laser radiation at energy densities of about 1.5 J/square cm. Transient measurements indicate that there are two characteristic periods of decay of radiation. The first period, lasting about 2 micro seconds, has a characteristic decay time of about 0.3 micro seconds. The second period, lasting at least 50 micro seconds, has a characteristic decay time of about 5 micro seconds. These characteristic times are thought to be associated with cooling of C60 molecules or nanosized carbon particles during the early period; and with electronically excited C2 that is a decomposition product of laser excited C60, C58, ... molecules during the later period.

  13. Structure and dynamics in self-organized C60 fullerenes.

    PubMed

    Patnaik, Archita

    2007-01-01

    This manuscript on 'structure and dynamics in self-organized C60 fullerenes' has three sections dealing with: (A) pristine C60 aggregate structure and geometry in solvents of varying dielectric constant. Here, using positronium (Ps) as a fundamental probe which maps changes in the local electron density of the microenvironment, the onset concentration for stable C60 aggregate formation and its phase behavior is deduced from the specific interactions of the Ps atom with the surrounding. (B) A novel methanofullerene dyad, based on a hydrophobic (acceptor C60 moiety)-hydrophilic (bridge with benzene and ester functionalities)-hydrophobic (donor didodecyloxybenzene) network is chosen for investigation of characteristic self-assembly it undergoes leading to supramolecular aggregates. The pi-electronic amphiphile, necessitating a critical dielectric constant epsilon > or = 30 in binary THF-water mixtures, dictated the formation of bilayer vesicles as precursors for spherical fractal aggregates upon complete dyad extraction into a more polar water phase. (C) While the molecular orientation is dependent on the packing density, the ordering of the molecular arrangement, indispensable for self-assembly depends on the balance between the structures demanded by inter-molecular and molecule-substrate interactions. The molecular orientation in a monolayer affects the orientation in a multilayer, formed on the monolayer, suggesting the possibility of the latter to act as a template for controlling the structure of the three dimensionally grown self-assembled molecular aggregation. A systematic study on the electronic structure and orientation associated with C60 functionalized aminothiol self-assembled monolayers on Au(111) surface is presented using surface sensitive Ultra-Violet Photoelectron Spectroscopy (UPS) and C-K edge Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. The results revealed drastic modifications to d-band structure of Au(111) and the

  14. Shock-wave processing of C60 in hydrogen

    NASA Astrophysics Data System (ADS)

    Biennier, L.; Jayaram, V.; Suas-David, N.; Georges, R.; Singh, M. Kiran; Arunan, E.; Kassi, S.; Dartois, E.; Reddy, K. P. J.

    2017-02-01

    Context. Interstellar carbonaceous particles and molecules are subject to intense shocks in astrophysical environments. Shocks induce a rapid raise in temperature and density which strongly affects the chemical and physical properties of both the gas and solid phases of the interstellar matter. Aims: The shock-induced thermal processing of C60 particles in hydrogen has been investigated in the laboratory under controlled conditions up to 3900 K with the help of a material shock-tube. Methods: The solid residues generated by the exposure of a C60/H2 mixture to a millisecond shock wave were collected and analyzed using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman micro-spectroscopy, and infrared micro-spectroscopy. The gaseous products were analyzed by Gas Chromatography and Cavity Ring Down Spectroscopy. Results: Volatile end-products appear above reflected shock gas temperatures of 2540 K and reveal the substantial presence of small molecules with one or two C atoms. These observations confirm the role played by the C2 radical as a major product of C60 fragmentation and less expectedly highlight the existence of a single C atom loss channel. Molecules with more than two carbon atoms are not observed in the post-shock gas. The analysis of the solid component shows that C60 particles are rapidly converted into amorphous carbon with a number of aliphatic bridges. Conclusions: The absence of aromatic CH stretches on the IR spectra indicates that H atoms do not link directly to aromatic cycles. The fast thermal processing of C60 in H2 over the 800-3400 K temperature range leads to amorphous carbon. The analysis hints at a collapse of the cage with the formation of a few aliphatic connections. A low amount of hydrogen is incorporated into the carbon material. This work extends the range of applications of shock tubes to studies of astrophysical interest.

  15. The low-temperature heat capacity of fullerite C60

    NASA Astrophysics Data System (ADS)

    Bagatskii, M. I.; Sumarokov, V. V.; Barabashko, M. S.; Dolbin, A. V.; Sundqvist, B.

    2015-08-01

    The heat capacity at constant pressure of fullerite C60 has been investigated using an adiabatic calorimeter in a temperature range from 1.2 to 120 K. Our results and literature data have been analyzed in a temperature interval from 0.2 to 300 K. The contributions of the intramolecular and lattice vibrations into the heat capacity of C60 have been separated. The contribution of the intramolecular vibration becomes significant above 50 K. Below 2.3 K the experimental temperature dependence of the heat capacity of C60 is described by the linear and cubic terms. The limiting Debye temperature at T →0 K has been estimated (Θ0 = 84.4 K). In the interval from 1.2 to 30 K the experimental curve of the heat capacity of C60 describes the contributions of rotational tunnel levels, translational vibrations (in the Debye model with Θ0 = 84.4 K), and librations (in the Einstein model with ΘE,lib = 32.5 K). It is shown that the experimental temperature dependences of heat capacity and thermal expansion are proportional in the region from 5 to 60 K. The contribution of the cooperative processes of orientational disordering becomes appreciable above 180 K. In the high-temperature phase the lattice heat capacity at constant volume is close to 4.5 R, which corresponds to the high-temperature limit of translational vibrations (3 R) and the near-free rotational motion of C60 molecules (1.5 R).

  16. Ultraviolet-visible absorption spectrum of C60 vapor and determination of the C60 vaporization enthalpy

    NASA Astrophysics Data System (ADS)

    Dai, Sheng; Mac Toth, L.; Del Cul, G. D.; Metcalf, David H.

    1994-09-01

    Ultraviolet-visible absorption spectroscopic studies of C60 vapor were carried out in the temperature range 400 °C-720 °C. The enthalpy of sublimation (180±10 kJ/mol) was obtained through the use of the Clausius-Clapeyron equation.

  17. Silver nanoparticles sensitized C60(Ag@C60) as efficient electrocatalysts for hydrazine oxidation: Implication for hydrogen generation reaction

    NASA Astrophysics Data System (ADS)

    Narwade, Shankar S.; Mulik, Balaji B.; Mali, Shivsharan M.; Sathe, Bhaskar R.

    2017-02-01

    Herein, we report the synthesis of silver nanoparticles (Ag NPs; 10 ± 0.5 nm) sensitized Fullerene (C60; 15 ±2 nm) nanocatalysts (Ag@C60) for the first time showing efficient electroatalytic activity for the oxidation of hydrazine demonstrating activity comparable to that of Pt in acidic, neutral and basic media. The performance is comparable with the best available electrocatalytic system and plays a vital role in the overall hydrogen generation reactions from hydrazine as a one of the fuel cell reaction. The materials are synthesized by a simple and scalable synthetic route involving acid functionalization of C60 followed by chemical reduction of Ag+ ions in ethylene glycol at high temperature. The distributation of Silver nanoparticles (Ag NPs) (morphological information) on C60, bonding, its crystal structure, along with activity towards hydrazine oxidation (electrocatalytic) is studied using TEM, XRD, UV-vis, XPS, FTIR and electrochemical (cyclic voltammetry) studies, respectively. The observed efficient electrocatalytic activity of the as-synthesized electrode is attributed to the co-operative response and associated structural defects due to their oxidative functionalization along with thier cooperative functioning at nanodimensions.

  18. Nitrogen-embedded buckybowl and its assembly with C60

    PubMed Central

    Yokoi, Hiroki; Hiraoka, Yuya; Hiroto, Satoru; Sakamaki, Daisuke; Seki, Shu; Shinokubo, Hiroshi

    2015-01-01

    Curved π-conjugated molecules have attracted considerable interest because of the unique properties originating from their curved π surface. However, the synthesis of such distorted molecules requires harsh conditions, which hamper easy access to heteroatom-containing curved π systems. Here we report the synthesis of a π-extended azacorannulene with nitrogen in its centre. The oxidation of 9-aminophenanthrene provides tetrabenzocarbazole, which is converted to the azabuckybowl through palladium-catalysed intramolecular coupling. The electron-donating nature and curved π surface of the azabuckybowl enable its tight association with C60 in solution and solid states. High charge mobility is observed for the azabuckybowl/C60 assembly. This compound may be of interest in the fields of curved π systems as fullerene hosts, anisotropic π donors and precursors to nitrogen-containing nanocarbon materials. PMID:26337912

  19. Complexation of C60 fullerene with aromatic drugs.

    PubMed

    Evstigneev, Maxim P; Buchelnikov, Anatoly S; Voronin, Dmitry P; Rubin, Yuriy V; Belous, Leonid F; Prylutskyy, Yuriy I; Ritter, Uwe

    2013-02-25

    The contributions of various physical factors to the energetics of complexation of aromatic drug molecules with C(60) fullerene are investigated in terms of the calculated magnitudes of equilibrium complexation constants and the components of the net Gibbs free energy. Models of complexation are developed taking into account the polydisperse nature of fullerene solutions in terms of the continuous or discrete (fractal) aggregation of C(60) molecules. Analysis of the energetics has shown that stabilization of the ligand-fullerene complexes in aqueous solution is mainly determined by intermolecular van der Waals interactions and, to lesser extent, by hydrophobic interactions. The results provide a physicochemical basis for a potentially new biotechnological application of fullerenes as modulators of biological activity of aromatic drugs.

  20. Cu-C60 nanocomposite with suppressed recrystallization

    NASA Astrophysics Data System (ADS)

    Medvedev, V. V.; Popov, M. Y.; Mavrin, B. N.; Denisov, V. N.; Kirichenko, A.; Tat'yanin, E. V.; Ivanov, L. A.; Aksenenkov, V. V.; Perfilov, S. A.; Lomakin, R.; Blank, V. D.

    2011-10-01

    Cu matrix composite reinforced with fullerene (C60) was fabricated by ball milling, followed by hot pressing techniques. The microstructure characteristics of the composite were investigated at different temperatures. The mechanical properties of the composite were measured at room temperature. The experimental result showed that the composite temperature recrystallization is impeded by carbon modification of copper grain boundaries. Furthermore, the nanocomposite possesses a very high hardness (up to 4 GPa).

  1. Fullerenes C60 and C70 in flames

    NASA Astrophysics Data System (ADS)

    Howard, Jack B.; McKinnon, J. Thomas; Makarovsky, Yakov; Lafleur, Arthur L.; Johnson, M. Elaine

    1991-07-01

    THE fullerenes C60 and C70 were first identified1 in carbon vapour produced by laser irradiation of graphite, and have recently been produced in macroscopic quantities2-5 by vaporization of graphite with resistive heating. It has also been suggested6-9 that fullerenes might be formed in sooting flames, and indeed all-carbon ions with mass/charge ratios suggestive of fullerenes have been detected in flames10-12. These species were assumed to have the cage structures of fullerenes, but the mass spectroscopic evidence could not establish this conclusively. We have now collected samples of condensible compounds and soot from hydrocarbon combustion under a range of conditions, and analysed these using conventional techniques in an effort to detect fullerenes. Spectroscopic studies reveal the presence of C60 and C70 in yields and ratios that depend on temperature, pressure, carbon/oxygen ratio and residence time in the flame. Control of these conditions allows optimal yields of 3 g of fullerenes per kilogram of fuel carbon burned, and variation of the C70/C60 ratio over the range 0.26-5.7.

  2. Enhancing superconductivity in A3C60 fullerides

    NASA Astrophysics Data System (ADS)

    Kim, Minjae; Nomura, Yusuke; Ferrero, Michel; Seth, Priyanka; Parcollet, Olivier; Georges, Antoine

    2016-10-01

    Motivated by the recent experimental report of a possible light-induced superconductivity in K3C60 at high temperature [Mitrano et al., Nature 530, 451 (2016), 10.1038/nature16522], we investigate theoretical mechanisms for enhanced superconductivity in A3C60 fullerenes. We find that an "interaction imbalance" corresponding to a smaller value of the Coulomb matrix element for two of the molecular orbitals in comparison to the third one, efficiently enhances superconductivity. Furthermore, we perform first-principle calculations of the changes in the electronic structure and in the screened Coulomb matrix elements of K3C60 , brought in by the deformation associated with the pumped T1 u intramolecular mode. We find that an interaction imbalance is indeed induced, with a favorable sign and magnitude for superconductivity enhancement. The physical mechanism responsible for this enhancement consists of a stabilization of the intramolecular states containing a singlet pair, while preserving the orbital fluctuations allowing for a coherent interorbital delocalization of the pair. Other perturbations have also been considered and found to be detrimental to superconductivity. The light-induced deformation and ensuing interaction imbalance is shown to bring superconductivity further into the strong-coupling regime.

  3. Nanobionics of Pharmacologically Active Derivatives of Fullerene C60

    NASA Astrophysics Data System (ADS)

    Kotelnikova, R. A.; Bogdanov, G. N.; Frog, E. C.; Kotelnikov, A. I.; Shtolko, V. N.; Romanova, V. S.; Andreev, S. M.; Kushch, A. A.; Fedorova, N. E.; Medzhidova, A. A.; Miller, G. G.

    2003-12-01

    The physical-chemical mechanisms of pharmacologic functioning of amino acid derivatives of fullerene C60 (ADF) have been studied. ADF were shown to penetrate through the lipid bilayer of liposomes without destruction of membrane integrity. ADF are able to carry bivalent metal ions through phospholipid bilayer owing to the formation of complexes. It was shown that stereoisomers of ADF selectively penetrate into phospholipid membranes. In contrast to D-isomers, L-isomers penetrate through the phosphatidylcholine membrane into liposome interior. Stereo-specific effect of ADF enantiomers was also observed in reaction of peroxidation of lipids. Besides that, ADF bring about a substantial increase in the catalytic activity of monoaminoxidases A and B. The directed intraprotein electron transfer was studied by creating a donor-acceptor pair in a water solution in the presence of ADF. To realize the intraprotein electron transfer, the model system was produced on the base of apomyoglobin by incorporating ADF (electron acceptor) into the heme pocket of protein instead of removed heme. It was established that the fullerene C60 and its derivatives did not produce specific anti-C60 antibodies, both IgG and IgE classes, while ADF themselves are efficient adjuvants, i.e. they increased the antibody response to poor antigens. Some ADF were found to inhibit the human immunodeficiency virus and human cytomegalovirus infection.

  4. Continuous symmetry of C60 fullerene and its derivatives.

    PubMed

    Sheka, E F; Razbirin, B S; Nelson, D K

    2011-04-21

    Conventionally, the I(h) symmetry of fullerene C(60) is accepted, which is supported by numerous calculations. However, this conclusion results from the consideration of the molecule electron system, of its odd electrons in particular, in a closed-shell approximation without taking the electron spin into account. Passing to the open-shell approximation has led to both the energy and the symmetry lowering up to C(i). Seemingly contradicting to a high-symmetry pattern of experimental recording, particularly concerning the molecule electronic spectra, the finding is considered in this Article from the continuous symmetry viewpoint. Exploiting continuous symmetry measure and continuous symmetry level approaches, it was shown that formal C(i) symmetry of the molecule is by 99.99% I(h). A similar continuous symmetry analysis of the fullerene monoderivatives gives a reasonable explanation of a large variety of their optical spectra patterns within the framework of the same C(1) formal symmetry exhibiting a strong stability of the C(60) skeleton. TOC color pictures present chemical portrait of C(60) in terms of atomic chemical susceptibility (Sheka, E. Fullerenes: Nanochemistry, Nanomagnetism, Nanomedicine, Nanophotonics; CRC Press: Taylor and Francis Group, Boca Raton, 2011).

  5. The Environmental Fate of C60 Fullerenes: A Holistic Approach

    NASA Astrophysics Data System (ADS)

    Schreiner, K. M.; Filley, T. R.; Blanchette, R. A.; Jafvert, C.; Bolskar, R.

    2007-12-01

    The manufacture and use of carbon-based nanoparticles, for which C60 fullerenes can be considered a proxy, has grown exponentially in the past decade, and nanotechnology is now a multi-billion dollar industry, spanning disciplines such as cosmetics, biotechnology, and agriculture. Despite this, almost nothing is known of the fate of these compounds in the environment. Based upon the strong radical scavenging properties of many of these substances there are a variety of microbial and photochemical-mediated oxidative fates that will transform the physicochemical properties and control the residence time of these compounds in nature. It is essential that these fates, as well as the fates of the products of the degradation of carbon nanoparticles, are known. For instance, conversion of C60 fullerenes to hydroxylated or carboxylated analogs will shift the manner in which they partition between soils and sediments and water as well as how they interact with cell membranes. This paper combines our findings on the microbial activity of C60 fullerenes, one of the most common types of manufactured carbon nanoparticles, along with recent literature to develop potential chemical decay trajectories in oxidative environmental settings. We show what is known about the environmental fate of this type of nanomaterial and also areas where further research is needed.

  6. On the nature of electron correlation in C60

    NASA Astrophysics Data System (ADS)

    Stück, David; Baker, Thomas A.; Zimmerman, Paul; Kurlancheek, Westin; Head-Gordon, Martin

    2011-11-01

    The ground state restricted Hartree Fock (RHF) wave function of C60 is found to be unstable with respect to spin symmetry breaking, and further minimization leads to a significantly spin contaminated unrestricted Hartree Fock (UHF) solution ( = 7.5, 9.6 for singlet and triplet, respectively). The nature of the symmetry breaking in {C_{60}} relative to the radicaloid fullerene, {C_{36}}, is assessed by energy lowering of the UHF solution, , and the unpaired electron number. We conclude that the high value of each of these measures in {C_{60}} is not attributable to strong correlation behavior as is the case for {C_{36}}. Instead, their origin is from the collective effect of relatively weak, global correlations present in the π space of both fullerenes. Second order perturbation (MP2) calculations of the singlet triplet gap are significantly more accurate with RHF orbitals than UHF orbitals, while orbital optimized opposite spin second order correlation (O2) performs even better.

  7. Photophysics of pristine and C60-doped disubstituted polyacetylene

    NASA Astrophysics Data System (ADS)

    Gontia, I. I.; Vardeny, Z. V.; Masuda, T.; Yoshino, K.

    2002-08-01

    Using a variety of steady-state spectroscopies we studied the long-lived photoexcitations and electronic excited states of poly disubstituted acetylene (PDPA-nBu), the backbone structure of which is a disubstituted trans-polyacetylene, as well as PDPA-nBu/C60 blends. The cw spectroscopies include absorption, photoluminescence (PL), photoinduced absorption (PA), and PA-detected magnetic resonance (PADMR). Although PDPA-nBu is a degenerate ground-state polymer, nevertheless, and in contrast to trans-polyacetylene, we found that it has a strong PL band with quantum efficiency larger than 60%. From polarized PL studies on stretched oriented films we conclude that the PL emission originates from intrachain excitons rather than the polymer side groups. This shows that the lowest-lying exciton in PDPA-nBu is a Bu state rather than an Ag state, in contrast to the order of the lowest-lying excitonic states in trans-polyacetylene. The polarized absorption in PDPA-nBu contains three distinctly different bands with different polarization properties, which are interpreted according to the model of Shukla and Mazumdar. The PA spectra of pristine and photo-oxidized PDPA-nBu films show neutral and charged solitons as well as polaron excitations, whereas the long-lived photoexcitations in PDPA-nBu in solution are mainly polarons. This may be due to destabilization of the soliton-antisoliton pairs in the polymer chains in solution caused by short conjugation length. From the PA and PADMR spectroscopies of PDPA-nBu/C60 blends we conclude that a photoinduced charge-transfer reaction takes place, again in contrast to blends of other nonluminescent polymers. Interestingly the PA spectrum of PDPA-nBu/C60 blends shows both charged polarons and charged solitons that are correlated with the PA band of C-60. We found that the ratio between charged solitons and polaron excitations depends on the C60 concentration in the blend, the film morphology, and temperature. It is shown that the

  8. Temperature effects of adsorption of C60 molecules on Si(111)-(7×7) surfaces

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Sarid, Dror

    1994-03-01

    The adsorption of submonolayers C60 molecules on Si(111)-(7×7) surfaces, deposited at room temperature and then annealed to various elevated temperatures, is studied using scanning tunneling microscopy. For room temperature adsorption, the C60 molecules were observed to favor bonding to adatom bridge sites within a triangular half cell. After annealing to 600 °C, however, they were found to bond dominantly to adatom or restatom sites. The adsorbate-substrate interaction at room temperature is characterized by charge transfer from the substrate to the molecules. After the annealing process, however, the adsorbates bond covalently to the substrate. It is found that the desorption of the submonolayer adsorbates due to the annealing process is minimal. The surface diffusion of the adsorbates begins when annealing the sample to 700 °C, at which point the initial clustering of the adsorbates takes place. When annealing the sample to 850 °C, the C60 molecules decomposed on the sample surface and reacted with the Si atoms to form SiC islands.

  9. Energetic ion bombardment of Ag surfaces by C60+ and Ga+ projectiles.

    PubMed

    Sun, Shixin; Szakal, Christopher; Winograd, Nicholas; Wucher, Andreas

    2005-10-01

    The ion bombardment-induced release of particles from a metal surface is investigated using energetic fullerene cluster ions as projectiles. The total sputter yield as well as partial yields of neutral and charged monomers and clusters leaving the surface are measured and compared with corresponding data obtained with atomic projectile ions of similar impact kinetic energy. It is found that all yields are enhanced by about one order of magnitude under bombardment with the C60+ cluster projectiles compared with Ga+ ions. In contrast, the electronic excitation processes determining the secondary ion formation probability are unaffected. The kinetic energy spectra of sputtered particles exhibit characteristic differences which reflect the largely different nature of the sputtering process for both types of projectiles. In particular, it is found that under C60+ impact (1) the energy spectrum of sputtered atoms peaks at significantly lower kinetic energies than for Ga+ bombardment and (2) the velocity spectra of monomers and dimers are virtually identical, a finding which is in pronounced contrast to all published data obtained for atomic projectiles. The experimental findings are in reasonable agreement with recent molecular dynamics simulations.

  10. Electronic structures and nonlinear optical properties of highly deformed halofullerenes C(3v) C60F18 and D(3d) C60Cl30.

    PubMed

    Tang, Shu-Wei; Feng, Jing-Dong; Qiu, Yong-Qing; Sun, Hao; Wang, Feng-Di; Chang, Ying-Fei; Wang, Rong-Shun

    2010-11-15

    Electronic structures and nonlinear optical properties of two highly deformed halofullerenes C(3v) C(60)F(18) and D(3d) C(60)Cl(30) have been systematically studied by means of density functional theory. The large energy gaps (3.62 and 2.61 eV) between the highest occupied and lowest unoccupied molecular orbitals (HOMOs and LUMOs) and the strong aromatic character (with nucleus-independent chemical shifts varying from -15.08 to -23.71 ppm) of C(60)F(18) and C(60)Cl(30) indicate their high stabilities. Further investigations of electronic property show that C(60)F(18) and C(60)Cl(30) could be excellent electron acceptors for potential photonic/photovoltaic applications in consequence of their large vertical electron affinities. The density of states and frontier molecular orbitals are also calculated, which present that HOMOs and LUMOs are mainly distributed in the tortoise shell subunit of C(60)F(18) and the aromatic [18] trannulene ring of C(60)Cl(30), and the influence from halogen atoms is secondary. In addition, the static linear polarizability and second-order hyperpolarizability of C(60)F(18) and C(60)Cl(30) are calculated using finite-field approach. The values of and for C(60)F(18) and C(60)Cl(30) molecules are significantly larger than those of C(60) because of their lower symmetric structures and high delocalization of pi electrons.

  11. Electronic correlations and magnetic ordering in CsC60

    NASA Astrophysics Data System (ADS)

    Thier, K.-F.; Mehring, M.; Rachdi, F.

    1998-08-01

    We investigate the spin arrangement in the magnetically ordered orthorhombic phase of CsC60 by a comparison of 133Cs NMR data and simulations of a 3D ordered anisotropic antiferromagnet. Consistent results are obtained for two different magnetic ordering vectors. The agreement between simulation and experiment can be further improved by including a substantial amount of magnetic disorder. In addition, the metastable low temperature cubic phase is investigated using 13C NMR. We find a strongly correlated metallic system that transforms to the semiconducting dimer phase at T=140 K.

  12. Complex interplay between formation routes and natural organic matter modification controls capabilities of C60 nanoparticles (nC60) to accumulate organic contaminants.

    PubMed

    Hou, Lei; Fortner, John D; Wang, Ximeng; Zhang, Chengdong; Wang, Lilin; Chen, Wei

    2017-01-01

    Accumulation of organic contaminants on fullerene nanoparticles (nC60) may significantly affect the risks of C60 in the environment. The objective of this study was to further understand how the interplay of nC60 formation routes and humic acid modification affects contaminant adsorption of nC60. Specifically, adsorption of 1,2,4,5-tetrachlorobenzene (a model nonionic, hydrophobic organic contaminant) on nC60 was greatly affected by nC60 formation route - the formation route significantly affected the aggregation properties of nC60, thus affecting the available surface area and the extent of adsorption via the pore-filling mechanism. Depending on whether nC60 was formed via the "top-down" route (i.e., sonicating C60 powder in aqueous solution) or "bottom-up" route (i.e., phase transfer from an organic solvent) and the type of solvent involved (toluene versus tetrahydrofuran), modification of nC60 with Suwannee River humic acid (SRHA) could either enhance or inhibit the adsorption affinity of nC60. The net effect depended on the specific way in which SRHA interacted with C60 monomers and/or C60 aggregates of different sizes and morphology, which determined the relative importance of enhanced adsorption from SRHA modification via preventing C60 aggregation and inhibited adsorption through blocking available adsorption sites. The findings further demonstrate the complex mechanisms controlling interactions between nC60 and organic contaminants, and may have significant implications for the life-cycle analysis and risk assessment of C60.

  13. Anti-Influenza Activity of C60 Fullerene Derivatives

    PubMed Central

    Shoji, Masaki; Takahashi, Etsuhisa; Hatakeyama, Dai; Iwai, Yuma; Morita, Yuka; Shirayama, Riku; Echigo, Noriko; Kido, Hiroshi; Nakamura, Shigeo; Mashino, Tadahiko; Okutani, Takeshi; Kuzuhara, Takashi

    2013-01-01

    The H1N1 influenza A virus, which originated in swine, caused a global pandemic in 2009, and the highly pathogenic H5N1 avian influenza virus has also caused epidemics in Southeast Asia in recent years. Thus, the threat from influenza A remains a serious global health issue, and novel drugs that target these viruses are highly desirable. Influenza A RNA polymerase consists of the PA, PB1, and PB2 subunits, and the N-terminal domain of the PA subunit demonstrates endonuclease activity. Fullerene (C60) is a unique carbon molecule that forms a sphere. To identify potential new anti-influenza compounds, we screened 12 fullerene derivatives using an in vitro PA endonuclease inhibition assay. We identified 8 fullerene derivatives that inhibited the endonuclease activity of the PA N-terminal domain or full-length PA protein in vitro. We also performed in silico docking simulation analysis of the C60 fullerene and PA endonuclease, which suggested that fullerenes can bind to the active pocket of PA endonuclease. In a cell culture system, we found that several fullerene derivatives inhibit influenza A viral infection and the expression of influenza A nucleoprotein and nonstructural protein 1. These results indicate that fullerene derivatives are possible candidates for the development of novel anti-influenza drugs. PMID:23785493

  14. Two-dimensional van der Waals C60 molecular crystal

    PubMed Central

    Reddy, C. D.; Gen Yu, Zhi; Zhang, Yong-Wei

    2015-01-01

    Two-dimensional (2D) atomic crystals, such as graphene and transition metal dichalcogenides et al. have drawn extraordinary attention recently. For these 2D materials, atoms within their monolayer are covalently bonded. An interesting question arises: Can molecules form a 2D monolayer crystal via van der Waals interactions? Here, we first study the structural stability of a free-standing infinite C60 molecular monolayer using molecular dynamic simulations, and find that the monolayer is stable up to 600 K. We further study the mechanical properties of the monolayer, and find that the elastic modulus, ultimate tensile stress and failure strain are 55–100 GPa, 90–155 MPa, and 1.5–2.3%, respectively, depending on the stretching orientation. The monolayer fails due to shearing and cavitation under uniaxial tensile loading. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the monolayer are found to be delocalized and as a result, the band gap is reduced to only 60% of the isolated C60 molecule. Interestingly, this band gap can be tuned up to ±30% using strain engineering. Owing to its thermal stability, low density, strain-tunable semi-conducting characteristics and large bending flexibility, this van der Waals molecular monolayer crystal presents aplenty opportunities for developing novel applications in nanoelectronics. PMID:26183501

  15. Hot electron spin transport in C60 fullerene

    NASA Astrophysics Data System (ADS)

    Hueso, Luis Eduardo; Gobbi, Marco; Bedoya-Pinto, Amilcar; Golmar, Federico; Llopis, Roger; Casanova, Felix

    2012-02-01

    Carbon-based molecular materials are interesting for spin transport application mainly due to their small sources of spin relaxation [1]. However, spin coherence lengths reported in many molecular films do not exceed a few tens of nanometers [2]. In this work we will present results showing how hot spin-polarized electrons injected well above the Fermi level in C60 fullerene films travel coherently for hundreds of nanometers. We fabricated hot-electron vertical transistors, in which the current created across an Al/Al2O3 junction is polarized by a metallic Co/Cu/Py spin valve trilayer and subsequently injected in the molecular thin film. This geometry allows us to determine the energy level alignment at each interface between different materials. Moreover, the collector magnetocurrent excess 85%, even for C60 films thicknesses of 300 nm. We believe these results show the importance of hot spin-polarized electron injection and propagation in molecular materials. [1] V. Dediu, L.E. Hueso, I. Bergenti, C. Taliani, Nature Mater. 8, 707 (2009) [2] M. Gobbi, F. Golmar, R. Llopis, F. Casanova, L.E. Hueso, Adv. Mater. 23, 1609 (2011)

  16. Electronic and ionic conductivities in superionic Li4C60

    NASA Astrophysics Data System (ADS)

    Quintavalle, D.; Márkus, B. G.; Jánossy, A.; Simon, F.; Klupp, G.; Győri, M. A.; Kamarás, K.; Magnani, G.; Pontiroli, D.; Riccò, M.

    2016-05-01

    The 10 GHz microwave conductivity, σ (T ) and high field, 222 GHz electron spin resonance (HF-ESR) of Li4C60 fulleride is measured in a wide temperature range. We suggest that the majority of ESR active sites and at least some of the charge carriers for σ (T ) are electrons bound to a small concentration of surplus or vacancy ions in the polymer phase. Both σ (T ) and the ESR line shape depend on ionic motion. A change of the activation energy of σ (T ) at 125 K coincides with the onset of the ionic DC conductivity. The ESR line shape is determined mainly by Li ionic motion within octahedral voids below 150 K. At higher temperatures, fluctuations due to ionic diffusion change the environment of defects from axial to effectively isotropic on the ESR time scale. σ (T ) data up to 700 K through the depolymerization transition confirm that the monomeric phase of Li4C60 is a metal.

  17. High-field ESR in TDAE-C60

    NASA Astrophysics Data System (ADS)

    Blinc, R.; Cevc, P.; Arčon, D.; Omerzu, A.; Mehring, M.; Knorr, S.; Grupp, A.; Barra, A.-L.; Chouteau, G.

    1998-12-01

    The ESR spectra of TDAE-C60 single crystals have been measured between 30 MHz and 245 GHz both above and below Tc=16 K. No separate TDAE+ ESR signal has been seen even at high fields suggesting that the TDAE+ and C-60 spins are either strongly exchange coupled or that spin cancellation and charge separation of the TDAE ions take place. The nonlinear variation of the resonance frequency versus resonance field relation characteristic of ferromagnetic resonance has been observed only in the radio frequency but not in the microwave region. No second ``hard'' mode characteristic for a spin-canted ``weak'' ferromagnet could be observed between 0 and 100 kG. The additional fine structure seen in the high-field ESR spectra below Tc is due to standing spin-wave resonance. It allows for the determination of the exchange coupling constant J=60 K. The exchange field HE=448 kG is thus much larger than the anisotropy field HK=29 G determined from the ferromagnetic resonance data. The temperature dependence of the magnetization determined from the spin-wave resonance data can be indeed described by the Bloch T3/2 law as expected for an isotropic or nearly isotropic Heisenberg ferromagnet.

  18. Anti-influenza activity of c60 fullerene derivatives.

    PubMed

    Shoji, Masaki; Takahashi, Etsuhisa; Hatakeyama, Dai; Iwai, Yuma; Morita, Yuka; Shirayama, Riku; Echigo, Noriko; Kido, Hiroshi; Nakamura, Shigeo; Mashino, Tadahiko; Okutani, Takeshi; Kuzuhara, Takashi

    2013-01-01

    The H1N1 influenza A virus, which originated in swine, caused a global pandemic in 2009, and the highly pathogenic H5N1 avian influenza virus has also caused epidemics in Southeast Asia in recent years. Thus, the threat from influenza A remains a serious global health issue, and novel drugs that target these viruses are highly desirable. Influenza A RNA polymerase consists of the PA, PB1, and PB2 subunits, and the N-terminal domain of the PA subunit demonstrates endonuclease activity. Fullerene (C60) is a unique carbon molecule that forms a sphere. To identify potential new anti-influenza compounds, we screened 12 fullerene derivatives using an in vitro PA endonuclease inhibition assay. We identified 8 fullerene derivatives that inhibited the endonuclease activity of the PA N-terminal domain or full-length PA protein in vitro. We also performed in silico docking simulation analysis of the C60 fullerene and PA endonuclease, which suggested that fullerenes can bind to the active pocket of PA endonuclease. In a cell culture system, we found that several fullerene derivatives inhibit influenza A viral infection and the expression of influenza A nucleoprotein and nonstructural protein 1. These results indicate that fullerene derivatives are possible candidates for the development of novel anti-influenza drugs.

  19. In situ x-ray photoelectron spectroscopic and density-functional studies of Si atoms adsorbed on a C60 film.

    PubMed

    Onoe, Jun; Nakao, Aiko; Hara, Toshiki

    2004-12-08

    The interaction between C(60) and Si atoms has been investigated for Si atoms adsorbed on a C(60) film using in situ x-ray photoelectron spectroscopy (XPS) and density-functional (DFT) calculations. Analysis of the Si 2p core peak identified three kinds of Si atoms adsorbed on the film: silicon suboxides (SiO(x)), bulk Si crystal, and silicon atoms bound to C(60). Based on the atomic percent ratio of silicon to carbon, we estimated that there was approximately one Si atom bound to each C(60) molecule. The Si 2p peak due to the Si-C(60) interaction demonstrated that a charge transfer from the Si atom to the C(60) molecule takes place at room temperature, which is much lower than the temperature of 670 K at which the charge transfer was observed for C(60) adsorbed on Si(001) and (111) clean surfaces [Sakamoto et al., Phys. Rev. B 60, 2579 (1999)]. The number of electrons transferred between the C(60) molecule and Si atom was estimated to be 0.59 based on XPS results, which is in good agreement with the DFT result of 0.63 for a C(60)Si with C(2v) symmetry used as a model cluster. Furthermore, the shift in binding energy of both the Si 2p and C 1s core peaks before and after Si-atom deposition was experimentally obtained to be +2.0 and -0.4 eV, respectively. The C(60)Si model cluster provides the shift of +2.13 eV for the Si 2p core peak and of -0.28 eV for the C 1s core peak, which are well corresponding to those experimental results. The covalency of the Si-C(60) interaction was also discussed in terms of Mulliken overlap population between them. (c) 2004 American Institute of Physics.

  20. Energy distributions of atomic and molecular ions sputtered by C 60+ projectiles

    NASA Astrophysics Data System (ADS)

    Delcorte, A.; Poleunis, C.; Bertrand, P.

    2006-07-01

    In the process of investigating the interaction of fullerene projectiles with adsorbed organic layers, we measured the kinetic energy distributions (KEDs) of fragment and parent ions sputtered from an overlayer of polystyrene (PS) oligomers cast on silver under 15 keV C 60+ bombardment. These measurements have been conducted using our TRIFT™ spectrometer, recently equipped with the C 60+ source developed by Ionoptika, Ltd. For atomic ions, the intensity corresponding to the high energy tail decreases in the following order: C +( E-0.4) > H +( E-1.5) > Ag +( E-3.5). In particular, the distribution of Ag + is not broader than those of Ag 2+ and Ag 3+ clusters, in sharp contrast with 15 keV Ga + bombardment. On the other hand, molecular ions (fragments and parent-like species) exhibit a significantly wider distribution using C 60+ instead of Ga + as primary ions. For instance, the KED of Ag-cationized PS oligomers resembles that of Ag + and Ag n+ clusters. A specific feature of fullerene projectiles is that they induce the direct desorption of positively charged oligomers, without the need of a cationizing metal atom. The energy spectrum of these PS + ions is significantly narrower then that of Ag-cationized oligomers. For characteristic fragments of PS, such as C 7H 7+ and C 15H 13+ and polycyclic fragments, such as C 9H 7+ and C 14H 10+, the high energy decay is steep ( E-4 - E-8). In addition, reorganized ions generally show more pronounced high energy tails than characteristic ions, similar to the case of monoatomic ion bombardment. This observation is consistent with the higher excitation energy needed for their formation. Finally, the fraction of hydrocarbon ions formed in the gas phase via unimolecular dissociation of larger species is slightly larger with gallium than with fullerene projectiles.

  1. Reducing HAuCl4 by the C60 dianion: C60-directed self-assembly of gold nanoparticles into novel fullerene bound gold nanoassemblies

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Gao, Xiang

    2008-10-01

    The C60 dianion is used to reduce tetrachloroauric acid (HAuCl4) for the first time; three-dimensional C60 bound gold (Au-C60) nanoclusters are obtained from C60-directed self-assembly of gold nanoparticles due to the strong affinities of Au-C60 and C60-C60. The process was monitored in situ by UV-vis-NIR spectroscopy. The resulting Au-C60 nanoclusters were characterized using transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive spectroscopy (EDS), x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and FT-IR and Raman spectroscopies. TEM demonstrates the formation of 3D nanonetwork aggregates, which are composed of discrete gold nanocores covered with a C60 monolayer. The SAED and XRD patterns indicate that the gold nanocores inside the capped C60 molecules belong to the face-centred cubic crystal structure, while the C60 molecules are amorphous. The EDS and XPS measurements validate that the Au-C60 nanoclusters contain only Au and C elements and Au3+ is reduced to Au0. FT-IR spectroscopy shows the chemiadsorption of C60 to the gold nanocores, while Raman spectroscopy demonstrates the electron transfer from the gold nanocores to the chemiadsorbed C60 molecules. Au-C60 nanoclusters embedded in tetraoctyl-n-ammonium bromide (TOAB) on glassy carbon electrodes (GCEs) have been fabricated and have shown stable and well-defined electrochemical responses in aqueous solution.

  2. Theoretical study of the structures and first hyperpolarizabilities of C60Cl n and Li@C60Cl n (n = 4, 6, 8, 10).

    PubMed

    Song, Yao-Dong; Wang, Liang; Wu, Li-Ming

    2016-06-01

    We recently reported (Song Y-D et al., 2016, J Mol Model 22:50) that doping with Li greatly affects the static first hyperpolarizability of C60Cl2. In this work, with a view to creating nonlinear optical materials with high thermodynamic stability and wide transparent regions, a series of Li@C60Cl n (n = 4, 6, 8, 10) were designed. The structures, electrostatic potentials, electronic structures, absorption spectra, and linear and nonlinear optical properties of C60Cl n and Li@C60Cl n were systematically investigated using density functional theory (DFT) methods. The results of our calculations indicated that the stability of these molecules decreases in the order Li@C60Cl10 > Li@C60Cl8 > Li@C60Cl6 > Li@C60Cl4. It is clear that the number of Cl atoms greatly influences the stability of Li@C60Cl n . Li@C60Cl n showed greater thermodynamic stability than Li@C60Cl2. We also investigated the first hyperpolarizabilities of Li@C60Cl n and found them to be 2973, 3640, 4307, and 2627 au for n = 4, 6, 8, and 10, respectively-higher than that of Li@C60Cl2. Finally, we noted that the transparent region could be modulated by increasing the number of Cl atoms: Li@C60Cl n possess wider transparent regions than that of Li@C60Cl2. We therefore believe that this study has highlighted an effective method for designing nonlinear optical materials with high thermodynamic stability and wide transparent regions.

  3. C60-dyad aggregates: Self-organized structures in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Guskova, O. A.; Varanasi, S. R.; Sommer, J.-U.

    2014-10-01

    Extensive full-atomistic molecular dynamics simulations are performed to study the self-organization of C60-fullerene dyad molecules in water, namely phenyl-C61-butyric acid methyl ester and fulleropyrrolidines, which have two elements of ordering, the hydrophobic fullerene cage and the hydrophilic/ionic group. While pristine fullerene or phenyl-C61-butyric acid methyl ester forms spherical droplets in order to minimize the surface tension, the amphiphilic nature of charged solute molecules leads to the formation of supramolecular assemblies having cylindrical shape driven by charge repulsion between the ionic groups located on the surface of the aggregates. We show that formation of non-spherical micelles is the geometrical consequence if the fullerene derivatives are considered as surfactants where the ionized groups are only hydrophilic unit. The agglomeration behavior of fullerenes is evaluated by determining sizes of the clusters, solvent accessible surface areas, and shape parameters. By changing the size of the counterions from chloride over iodide to perchlorate we find a thickening of the cylinder-like structures which can be explained by stronger condensation of larger ions and thus partial screening of the charge repulsion on the cluster surface. The reason for the size dependence of counterion condensation is the formation of a stronger hydration shell in case of small ions which in turn are repelled from the fullerene aggregates. Simulations are also in good agreement with the experimentally observed morphologies of decorated C60-nanoparticles.

  4. C60 Secondary Ion Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    SciTech Connect

    Smith, Donald F.; Robinson, Errol W.; Tolmachev, Aleksey V.; Heeren, Ronald M.; Pasa-Tolic, Ljiljana

    2011-12-15

    Secondary ion mass spectrometry (SIMS) has seen increased application for high spatial chemical imaging of complex biological surfaces. The advent and commercial availability of cluster and polyatomic primary ion sources (e.g. Au and Bi cluster and buckminsterfullerene (C60)) provide improved secondary ion yield and decreased fragmentation of surface species, thus accessibility to intact molecular ions. Despite developments in primary ion sources, development of mass spectrometers to fully exploit their advantages has been limited. Tandem mass spectrometry for identification of secondary ions is highly desirable, but implementation has proven to be difficult. Similarly, high mass resolution and high mass measurement accuracy would greatly improve the chemical specificity of SIMS. Here we combine, for the first time, the advantages of a C60 primary ion source with the ultra-high mass resolving power and high mass measurement accuracy of Fourier transform ion cyclotron resonance mass spectrometry. Mass resolving power in excess of 100,000 (m/Δm50%) is demonstrated, with mass measurement accuracies below 3 parts-per-million. Imaging of mouse brain tissue at 40 μm pixel size is shown. Tandem mass spectrometry of ions from biological tissue is demonstrated and molecular formulae can be assigned to fragment ions.

  5. Multiscale dynamics of C60 from attosecond to statistical physics

    NASA Astrophysics Data System (ADS)

    Lépine, F.

    2015-06-01

    C60 is a fascinating object that has become remarkably useful for experimentalists and theoreticians to study photo-induced processes in large many-particle systems. In this review article, we discuss how the knowledge accumulated over the past 30 years on this molecule provides a large panel of mechanisms that occur from the intrinsic time scale of electronic motion that is attosecond, to long ‘macroscopic’ time scale (second). This illustrates the multiscale aspect of dynamics in photo-excited systems, which connects coherent quantum processes to classical and statistical mechanisms. This also shines light onto future experiments and theoretical work required to complete the global picture of light-induced mechanisms in fullerenes.

  6. The effect of solvent ratio and water on the growth of C 60 nanowhiskers

    NASA Astrophysics Data System (ADS)

    Miyazawa, Kun'ichi; Hotta, Kayoko

    2010-09-01

    The growth of C 60 nanowhiskers (C 60NWs) prepared by a modified liquid-liquid interfacial precipitation method is investigated, focusing on the effect of solvent ratio and water content in the C 60-toluene-isopropyl alcohol (IPA) solution system. The precipitation of C 60NWs was markedly influenced by the solvent ratio of toluene to IPA, and the C 60NWs were found to grow longer above a critical diameter ( Dc), which depends on the solvent ratio. The addition of a small amount of H 2O to the C 60-toluene-IPA solution promoted the growth of C 60NWs. This catalytic effect of water on the growth of C 60NWs was confirmed also by the experiment using heavy water (D 2O) and by the decrease of growth activation energy of C 60NWs with increase of H 2O content in the C 60-toluene-IPA solution.

  7. Evidence for endohedral muonium in K(x) C60 and consequences for electronic structure

    NASA Technical Reports Server (NTRS)

    Kiefl, R. F.; Duty, T. L.; Schneider, J. W.; Macfarlane, A.; Chow, K.; Elzey, J. W.; Mendels, P.; Morris, G. D.; Brewer, J. H.; Ansaldo, E. J.

    1992-01-01

    Positive muons injected into solid C60, K4C60, and K6C60 form vacuumlike muonium with a (6-12) percent probability. Observation of coherent spin precession of muonium establishes that all three materials are nonmagnetic and nonconducting at low temperatures. From the temperature dependence of the signals we estimate the electronic band gaps in K4C60 and K6C60 to be considerably smaller than in C60. The similarity of the muonium centers supports a model in which a muonium atom is caged inside the C60 molecule in pure C60 or the C60 exp -x molecular ion in K(x)C60.

  8. First-principles investigation of organic photovoltaic materials C60, C70, [C60]PCBM , and bis-[C60]PCBM using a many-body G0W0 -Lanczos approach

    NASA Astrophysics Data System (ADS)

    Qian, Xiaofeng; Umari, Paolo; Marzari, Nicola

    2015-06-01

    We present a first-principles investigation of the excited-state properties of electron acceptors in organic photovoltaics including C60, C70, [6,6]-phenyl-C61-butyric-acid-methyl-ester ([C60]PCBM ), and bis-[C60]PCBM using many-body perturbation theory within the Hedin's G0W0 approximation and an efficient Lanczos approach. Calculated vertical ionization potentials (VIP) and vertical electron affinities (VEA) of C60 and C70 agree very well with experimental values measured in the gas phase. The density of states of all three molecules is also compared to photoemission and inverse photoemission spectra measured on thin films, and they exhibit a close agreement—a rigid energy-gap renormalization owing to intermolecular interactions in the thin films. In addition, it is shown that the low-lying unoccupied states of [C60]PCBM are all derived from the highest-occupied molecular orbitals and the lowest-unoccupied molecular orbitals of fullerene C60. The functional side group in [C60]PCBM introduces a slight electron transfer to the fullerene cage, resulting in small decreases of both VIP and VEA. This small change of VEA provides a solid justification for the increase of open-circuit voltage when replacing fullerene C60 with [C60]PCBM as the electron acceptor in bulk heterojunction polymer solar cells.

  9. Photoelectron spectroscopy of C60Fn- and C60Fm2- (n = 17, 33, 35, 43, 45, 47; m = 34, 46) in the gas phase and the generation and characterization of C1-C60F47- and D2-C60F44 in solution.

    PubMed

    Wang, Xue-Bin; Chi, Chaoxian; Zhou, Mingfei; Kuvychko, Igor V; Seppelt, Konrad; Popov, Alexey A; Strauss, Steven H; Boltalina, Olga V; Wang, Lai-Sheng

    2010-02-04

    A photoelectron spectroscopy investigation of the fluorofullerene anions C(60)F(n)(-) (n = 17, 33, 35, 43, 45, 47) and the doubly charged anions C(60)F(34)(2-) and C(60)F(46)(2-) is reported. The first electron affinities for the corresponding neutral molecules, C(60)F(n), were directly measured and were found to increase as n increased, reaching the extremely high value of 5.66 +/- 0.10 eV for C(60)F(47). Density functional calculations suggest that the experimentally observed species C(60)F(17)(-), C(60)F(35)(-), and C(60)F(47)(-) were each formed by reductive defluorination of the parent fluorofullerene, C(3v)-C(60)F(18), C(60)F(36) (a mixture of isomers), and D(3)-C(60)F(48), respectively, without rearrangement of the remaining fluorine atoms. The DFT-predicted stability of C(60)F(47)(-) was verified by its generation by chemical reduction from D(3)-C(60)F(48) in chloroform solution at 25 degrees C and its characterization by mass spectrometry and (19)F NMR spectroscopy. Further reductive defluorination of C(60)F(47)(-) in solution resulted in the selective generation of a new fluorofullerene, D(2)-C(60)F(44), which was also characterized by mass spectrometry and (19)F NMR spectroscopy.

  10. Depth profiling of organic films with X-ray photoelectron spectroscopy using C60+ and Ar+ co-sputtering.

    PubMed

    Yu, Bang-Ying; Chen, Ying-Yu; Wang, Wei-Ben; Hsu, Mao-Feng; Tsai, Shu-Ping; Lin, Wei-Chun; Lin, Yu-Chin; Jou, Jwo-Huei; Chu, Chih-Wei; Shyue, Jing-Jong

    2008-05-01

    By sputtering organic films with 10 kV, 10 nA C60+ and 0.2 kV, 300 nA Ar+ ion beams concurrently and analyzing the newly exposed surface with X-ray photoelectron spectroscopy, organic thin-film devices including an organic light-emitting diode and a polymer solar cell with an inverted structure are profiled. The chemical composition and the structure of each layer are preserved and clearly observable. Although C60+ sputtering is proven to be useful for analyzing organic thin-films, thick organic-devices cannot be profiled without the low-energy Ar+ beam co-sputtering due to the nonconstant sputtering rate of the C60+ beam. Various combinations of ion-beam doses are studied in this research. It is found that a high dosage of the Ar+ beam interferes with the C60+ ion beam, and the sputtering rate decreases with increasing the total ion current. The results suggest that the low-energy single-atom projectile can disrupt the atom deposition from the cluster ion beams and greatly extend the application of the cluster ion-sputtering. By achievement of a steady sputtering rate while minimizing the damage accumulation, this research paves the way to profiling soft matter and organic electronics.

  11. Graphene oxide-fullerene C60 (GO-C60) hybrid for photodynamic and photothermal therapy triggered by near-infrared light.

    PubMed

    Li, Qian; Hong, Liang; Li, Hongguang; Liu, Chenguang

    2017-03-15

    Photodynamic therapy (PDT) and photothermal therapy (PTT) are two promising methodologies for cancer therapy. Although a variety of materials which can be used in PDT and PTT have been developed in the past decades, those showing the combined effect of PDT and PTT under NIR irradiation are rare. Graphene oxide (GO) and fullerene C60 (denoted as C60 hereafter) with unique physical and chemical properties are promising candidates for PTT and PDT, respectively. Here, by using a stepwise conjugation method, a new GO-C60 hybrid which contains hydrophilic methoxypolyethylene glycol (mPEG) and mono-substituted C60 was constructed for combined PDT and PTT. The hybrid shows good solubility in different environments including physiological solutions. The introduction of C60 to GO did not decrease the photothermal properties of GO, while the conjugation of GO to C60 activated the ability of C60 to generate singlet oxygen ((1)O2) in near infrared (NIR) region in aqueous solution. The GO-C60 hybrid also shows good ability to induce the generation of reactive oxygen species (ROS) in Hela cells. Due to the synergistic effect between GO and C60, GO-C60 hybrid exhibits superior performance in the inhibition of cancer cells compared to both individuals, indicating its high potential in practical applications.

  12. C60 fullerene localization and membrane interactions in RAW 264.7 immortalized mouse macrophages

    NASA Astrophysics Data System (ADS)

    Russ, K. A.; Elvati, P.; Parsonage, T. L.; Dews, A.; Jarvis, J. A.; Ray, M.; Schneider, B.; Smith, P. J. S.; Williamson, P. T. F.; Violi, A.; Philbert, M. A.

    2016-02-01

    There continues to be a significant increase in the number and complexity of hydrophobic nanomaterials that are engineered for a variety of commercial purposes making human exposure a significant health concern. This study uses a combination of biophysical, biochemical and computational methods to probe potential mechanisms for uptake of C60 nanoparticles into various compartments of living immune cells. Cultures of RAW 264.7 immortalized murine macrophage were used as a canonical model of immune-competent cells that are likely to provide the first line of defense following inhalation. Modes of entry studied were endocytosis/pinocytosis and passive permeation of cellular membranes. The evidence suggests marginal uptake of C60 clusters is achieved through endocytosis/pinocytosis, and that passive diffusion into membranes provides a significant source of biologically-available nanomaterial. Computational modeling of both a single molecule and a small cluster of fullerenes predicts that low concentrations of fullerenes enter the membrane individually and produce limited perturbation; however, at higher concentrations the clusters in the membrane causes deformation of the membrane. These findings are bolstered by nuclear magnetic resonance (NMR) of model membranes that reveal deformation of the cell membrane upon exposure to high concentrations of fullerenes. The atomistic and NMR models fail to explain escape of the particle out of biological membranes, but are limited to idealized systems that do not completely recapitulate the complexity of cell membranes. The surprising contribution of passive modes of cellular entry provides new avenues for toxicological research that go beyond the pharmacological inhibition of bulk transport systems such as pinocytosis.There continues to be a significant increase in the number and complexity of hydrophobic nanomaterials that are engineered for a variety of commercial purposes making human exposure a significant health concern

  13. C60 fullerene localization and membrane interactions in RAW 264.7 immortalized mouse macrophages.

    PubMed

    Russ, K A; Elvati, P; Parsonage, T L; Dews, A; Jarvis, J A; Ray, M; Schneider, B; Smith, P J S; Williamson, P T F; Violi, A; Philbert, M A

    2016-02-21

    There continues to be a significant increase in the number and complexity of hydrophobic nanomaterials that are engineered for a variety of commercial purposes making human exposure a significant health concern. This study uses a combination of biophysical, biochemical and computational methods to probe potential mechanisms for uptake of C60 nanoparticles into various compartments of living immune cells. Cultures of RAW 264.7 immortalized murine macrophage were used as a canonical model of immune-competent cells that are likely to provide the first line of defense following inhalation. Modes of entry studied were endocytosis/pinocytosis and passive permeation of cellular membranes. The evidence suggests marginal uptake of C60 clusters is achieved through endocytosis/pinocytosis, and that passive diffusion into membranes provides a significant source of biologically-available nanomaterial. Computational modeling of both a single molecule and a small cluster of fullerenes predicts that low concentrations of fullerenes enter the membrane individually and produce limited perturbation; however, at higher concentrations the clusters in the membrane causes deformation of the membrane. These findings are bolstered by nuclear magnetic resonance (NMR) of model membranes that reveal deformation of the cell membrane upon exposure to high concentrations of fullerenes. The atomistic and NMR models fail to explain escape of the particle out of biological membranes, but are limited to idealized systems that do not completely recapitulate the complexity of cell membranes. The surprising contribution of passive modes of cellular entry provides new avenues for toxicological research that go beyond the pharmacological inhibition of bulk transport systems such as pinocytosis.

  14. C60 Fullerene Localization and Membrane Interactions in RAW 264.7 Immortalized Mouse Macrophages

    PubMed Central

    Russ, K. A.; Elvati, P.; Parsonage, T. L.; Dews, A.; Jarvis, J. A.; Ray, M.; Schneider, B.; Smith, P. J. S.; Williamson, P. T. F.; Violi, A.; Philbert, M. A.

    2016-01-01

    There continues to be a significant increase in the number and complexity of hydrophobic nanomaterials that are engineered for a variety of commercial purposes making human exposure a significant health concern. This study uses a combination of biophysical, biochemical and computational methods to probe potential mechanisms for uptake of C60 nanoparticles into various compartments of living immune cells. Cultures of RAW 264.7 immortalized murine macrophage were used as a canonical model of immune-competent cells that are likely to provide the first line of defense following inhalation. Modes of entry studied were endocytosis/pinocytosis and passive permeation of cellular membranes. The evidence suggests marginal uptake of C60 clusters is achieved through endocytosis/pinocytosis, and that passive diffusion into membranes provides a significant source of biologically-available nanomaterial. Computational modeling of both a single molecule and a small cluster of fullerenes predicts that low concentrations of fullerenes enter the membrane individually and produce limited perturbation; however, at higher concentrations the clusters in the membrane causes deformation of the membrane. These findings are bolstered by nuclear magnetic resonance (NMR) of model membranes that reveal deformation of the cell membrane upon exposure to high concentrations of fullerenes. The atomistic and NMR models fail to explain escape of the particle out of biological membranes, but are limited to idealized systems that do not completely recapitulate the complexity of cell membranes. The surprising contribution of passive modes of cellular entry provides new avenues for toxicological research that go beyond the pharmacological inhibition of bulk transport systems such as pinocytosis. PMID:26866469

  15. On structural features of fullerene C60 dissolved in carbon disulfide: Complementary study by small-angle neutron scattering and molecular dynamic simulations

    NASA Astrophysics Data System (ADS)

    Avdeev, M. V.; Tropin, T. V.; Bodnarchuk, I. A.; Yaradaikin, S. P.; Rosta, L.; Aksenov, V. L.; Bulavin, L. A.

    2010-04-01

    The parameters of fullerene C60 dissolved in carbon disulfide CS2 are analyzed by small-angle neutron scattering (SANS) in a wide interval of momentum transfer. To exclude the influence of nonequilibrium conditions, the solutions are prepared without applying shaking, stirring or ultrasound. No indication of the equilibrium cluster state of C60 (with the cluster size below 60 nm) in the final solutions is revealed. Molecular dynamic simulations are complementary used to find out the partial volume of C60 in CS2 and the scattering contribution of the solvent organization at the interface with the fullerene molecule, which is shown to be small. Among several approaches for describing SANS data the preference is given to the model, which takes into account the presence of stable C60 dimers (comprising 10% of the total particle number density) in the solution.

  16. COLLISION DYNAMICS OF X@C60(X = He, Ne, Ar) AT LOW ENERGIES

    NASA Astrophysics Data System (ADS)

    Zhao, Qiang; Zhang, Feng-Shou; Zhou, Hong-Yu

    2013-12-01

    In this paper, a semi-empirical molecular dynamics model is developed. The central collisions of C60 + C60 and X@C60 + X@C60 (X = He, Ne, Ar) at various incident energy are investigated within this model. The fullerene dimers like a "dumbbell" can be formed by a self-assembly of C60 fullerene and X@C60 (X = He, Ne) endohedral fullerenes, and the new fullerene structure like "peanut" can be formed by a self-assembly of Ar@C60. It is found that Ar atom plays a great role in the collision of Ar@C60 + Ar@C60 because of its size effect. The energy effect is found that various incident energies cannot change the final structure at low energies if they are below a certain energy.

  17. Influence of endohedral confinement of atoms on structural and dynamical properties of the C60 fullerene

    NASA Astrophysics Data System (ADS)

    Etindele, A. J.; Maezono, R.; Melingui Melono, R. L.; Motapon, O.

    2017-10-01

    The influence of encapsulated atoms in the structural and dynamical properties of C60 in A@C60 complexes is studied in the framework of the Density Functional Theory using Density of states and the theoretical Electron Energy Loss Spectroscopy. It is shown that C60 preserves its spherical geometry no matter the equilibrium position of the encapsulated atom. The Infrared and Raman spectra of the H@C60, He@C60 and Ne@C60 complexes are found not to differ significantly from that of C60 whereas those for Li@C60 and Na@C60 exhibit more peaks. The analysis shows that the changes on the cage properties come from inside it.

  18. Laser desorption of NO from a thick C 60 film

    NASA Astrophysics Data System (ADS)

    Hoger, T.; Marzok, C.; Jongma, R. T.; Zacharias, H.

    2006-09-01

    The desorption of NO molecules from a thick C 60 film is reported. A thermal desorption spectrum indicates two adsorption sites with binding energies of Eb = 0.30 eV and 0.55 eV. For laser desorption the fullerene surface is exposed to NO and excited by 7 ns UV laser pulses. Desorbing NO molecules are recorded state selectively as well as time resolved. The time-of-flight measurement indicates three different desorption pathways. A fast channel shows rovibronic temperatures of Trot( v″ = 0) = 370 K, Trot( v″ = 1) = 390 K and Tvib = 610 K as well as strong rotational-translational coupling. The desorption yield for the fast channel increases linearly with pulse energy with a desorption cross section of σ = (5.1 ± 0.9) × 10 -17 cm 2. Dominating the signal for small J″ values is a slow channel with low rotational and translational temperatures of about 110 K. We assign this peak to a laser-induced thermal desorption. For large pump-probe delays the data deviate from the Maxwellian flux distribution and a third channel appears with extremely late arrival times.

  19. Thermoelectricity in vertical graphene-C60-graphene architectures.

    PubMed

    Wu, Qingqing; Sadeghi, Hatef; García-Suárez, Víctor M; Ferrer, Jaime; Lambert, Colin J

    2017-09-15

    Recent studies of single-molecule thermoelectricity have identified families of high-performance molecules. However, in order to translate this discovery into practical thin-film energy-harvesting devices, there is a need for an understanding of the fundamental issues arising when such junctions are placed in parallel. This is relevant because controlled scalability might be used to boost electrical and thermoelectric performance over the current single-junction paradigm. As a first step in this direction, we investigate here the properties of two C60 molecules placed in parallel and sandwiched between top and bottom graphene electrodes. In contrast with classical conductors, we find that increasing the number of parallel junctions from one to two can cause the electrical conductance to increase by more than a factor of 2. Furthermore, we show that the Seebeck coefficient is sensitive to the number of parallel molecules sandwiched between the electrodes, whereas classically it should be unchanged. This non-classical behaviour of the electrical conductance and Seebeck coefficient are due to inter-junction quantum interference, mediated by the electrodes, which leads to an enhanced response in these vertical molecular devices.

  20. Variation of excited-state dynamics in trifluoromethyl functionalized C60 fullerenes.

    PubMed

    Park, Jaehong; Ramirez, Jessica J; Clikeman, Tyler T; Larson, Bryon W; Boltalina, Olga V; Strauss, Steven H; Rumbles, Garry

    2016-08-17

    We report on electronically excited-state dynamics of three different trifluoromethyl C60 fullerenes (TMFs, C60(CF3)n: C60/4-1, C60/6-2, and C60/10-1, featuring four, six, and ten trifluoromethyl groups, respectively) using steady-state and time-resolved optical spectroscopy as well as ultrafast pump/probe transient absorption spectroscopy. C60/4-1 and C60/6-2 dissolved in toluene solvent show near-unity S1 → T1 intersystem crossing quantum yield (ΦISC), ca. 1 ns S1-state lifetimes, and microsecond-timescale T1-state lifetimes, which are typical of the fullerene class. On the other hand, C60/10-1 exhibits a dominant sub-nanosecond nonradiative S1 → S0 relaxation mechanism and negligible ΦISC, therefore decreasing the average excited-state lifetime (τavg) by about 5 orders of magnitude compared to that of C60/4-1 and C60/6-2 (τavg ≈ 17 μs and 54 μs for C60/4-1 and C60/6-2, respectively, whereas τavg ≈ 100 ps for C60/10-1). These excited-state characteristics of C60/4-1 and C60/6-2 are preserved in polymer matrix, suggesting that fullerene/polymer interactions do not modulate intrinsic photophysics of trifluoromethyl-substituted fullerenes. The contrasting excited-state study results of C60/4-1 and C60/6-2 to that of C60/10-1 infer that intrinsic optical properties and excited-state dynamics can be affected by the substitution on the fullerene.

  1. Effect of incarcerated HF on the exohedral chemical reactivity of HF@C60.

    PubMed

    Vidal, Sara; Izquierdo, Marta; Alom, Shamim; Garcia-Borràs, Marc; Filippone, Salvatore; Osuna, Sílvia; Solà, Miquel; Whitby, Richard J; Martín, Nazario

    2017-10-05

    The first chemical modification on the brand new endohedral HF@C60 is reported. In particular, the isomerization from optically pure (2S,5S)-cis-pyrrolidino[3,4:1,2][60]fullerene 2b to (2S,5R)-trans-pyrrolidino[3,4:1,2][60]fullerene 2b has been studied and compared with empty C60 (2a) and endohedral H2O@C60 (3). The comparative study shows a kinetic order for the isomerization process of H2O@C60 > HF@C60 > C60, thus confirming the effect of the incarcerated species on the zwitterionic intermediate stability.

  2. Superconductivity of Fullerides with Composition AGaxC_{60} and AGaxMyC_{60} (A = K, Rb; M = In, Sn, Bi)

    NASA Astrophysics Data System (ADS)

    Kulbachinskii, V. A.; Lunin, R. A.; Velikodny, Yu. A.; Bulychev, B. M.

    2016-12-01

    The new heterofullerides with the composition AGaxC_{60} and AGaxMyC_{60} (A = K, Rb; M = In, Sn, Bi; x,y<1) have been synthesized by a new method using liquid alloys of alkali metal with gallium or gallams. The temperature dependence of the magnetic susceptibility was measured in the temperature range from 4.2 to 100 K, and transitions to a superconducting state were observed at temperatures Tc ranging from 7 to 17.5 K. The superconductivity was found for fullerides RbGaxC_{60} and RbGaxInyC_{60} with orthorhombic lattice.

  3. High resolution 13C NMR investigation of A6C 60 ( A=K, Rb, Cs) and Ba 3C 60

    NASA Astrophysics Data System (ADS)

    Hajji, L.; Rachdi, F.; Goze, C.; Mehring, M.; Fischer, J. E.

    1996-11-01

    We report the result of 13C nuclear magnetic resonance (NMR) measurements on A6C 60 ( A=K, Rb, Cs) and Ba 3C 60. By using high-resolution magic angle spinning, we were able to identify an isotropic line around 156 ppm for all investigated compounds. NMR spectra of the saturated alkali compounds are quite similar. The corresponding isotropic lines show three narrow components consistent with orientationally ordered C 60 molecules leading to three non-equivalent carbon sites in these compounds as reported by x-ray studies. No line splitting was observed for the Ba 3C 60 isotropic line.

  4. Geochemistry and cosmochemistry of fullerenes 3: Reaction of C60 and C70 with ozone

    NASA Technical Reports Server (NTRS)

    Heymann, D.; Chibante, L. P. F.

    1993-01-01

    C60 and C70 dissolved in toluene were treated with O2 gas containing 2.6 volume percent ozone and with O3-free oxygen. No reaction products were detected for 0.1 mole of O2 passed through the solution, but destruction of C60 was clearly detectable for a dose of 10(exp -6) moles of O3. C70 was destroyed more slowly than C60. Among the substances remaining in solution, we identified C60O, C70O, C60O2, C60O3, and C60O4. C60 crystals exposed to O3 at room temperature became less soluble in toluene in a matter of days, but oxides were apparently not formed.

  5. Electronic transitions and band offsets in C60:SubPc and C60:MgPc on MoO3 studied by modulated surface photovoltage spectroscopy

    NASA Astrophysics Data System (ADS)

    Fengler, S.; Dittrich, Th.; Rusu, M.

    2015-07-01

    Electronic transitions at interfaces between MoO3 layers and organic layers of C60, SubPc, MgPc, and nano-composite layers of SubPc:C60 and MgPc:C60 have been studied by modulated surface photovoltage (SPV) spectroscopy. For all systems, time dependent and modulated SPV signals pointed to dissociation of excitons at the MoO3/organic layer interfaces with a separation of holes towards MoO3. The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps (EHL) of C60, SubPc, and MgPc and the effective EHL of SubPc:C60 and MgPc:C60 were measured. The offsets between the LUMO (ΔEL) or HOMO (ΔEH) bands were obtained with high precision and amounted to 0.33 or 0.73 eV for SubPc:C60, respectively, and to -0.33 or 0.67 eV for MgPc:C60, respectively. Exponential tails below EHL and most pronounced sub-bandgap transitions were characterized and ascribed to disorder and transitions from HOMO bands to unoccupied defect states.

  6. Structural transformation of biochar black carbon by C60 superstructure: Environmental implications

    USDA-ARS?s Scientific Manuscript database

    Aqueous fullerene C60 nanoparticles (nC60) are frequently considered within the environmental engineering community as the aggregate of 60-carbon molecules. This study employed transmission electron microscopy (TEM) and x-ray diffraction (XRD) to demonstrate that nC60 formed via prolonged stirring ...

  7. Ground state of orthorhombic RbC60: A high-field electron-spin-resonance investigation

    NASA Astrophysics Data System (ADS)

    Bennati, M.; Griffin, R. G.; Knorr, S.; Grupp, A.; Mehring, M.

    1998-12-01

    We report on electron paramagnetic resonance in the low-temperature phase of orthorhombic RbC60 at 94 and 140 GHz microwave frequencies. Below about 25-30 K characteristic features that could be related to antiferromagnetic resonance (AFMR) or alternatively to spin clusters are clearly distinguished from the conduction-electron spin resonance signal above 50 K. The different scenarios, AFMR vs spin glass or spin clusters, are discussed. If the experimental data are interpreted within the AFMR scenario the corresponding spin-flop field can be estimated to be about 0.34 T.

  8. Molecular-dynamics simulations of energetic C60 impacts on (2×1)-(100) silicon

    NASA Astrophysics Data System (ADS)

    Hu, Xiaoyuan; Albe, Karsten; Averback, Robert S.

    2000-07-01

    Single impacts of energetic C60 clusters on (2×1)-(100) silicon substrates are studied by molecular-dynamics simulations. The role of impact energies and internal cluster energy are investigated in detail. Six different energy regimes can be identified at the end of the ballistic phase: At thermal energies below 20 eV the fullerene cages undergo elastic deformation, while impinging on the surface, and are mostly chemisorpted on top of the (2×1)-dimer rows. Between 20 and 100 eV the cage structure is preserved after the collision, but the cluster comes to rest within a few monolayers of the silicon surface. At energies of 100-500 eV the cluster partially decomposes and small coherent carbon caps are embedded in the surface. At higher energies up to 1.5 keV complete decomposition of the fullerene cluster occurs and an amorphous zone is formed in the subsurface area. At energies greater than approximately 1.5 keV craters form and above 6 keV sputtering becomes significant. In all cases the substrate temperature is of minor influence on the final result, but the projectile temperature is important for impacts at lower energies (<1.5 keV). For high energy impacts the ballistics resemble that of single atom impacts. Nearly 1:1 stoichiometry is obtained for impact energies around 1 keV. These results reveal an interesting possibility for controlled implantation of C in Si at high local concentrations, which might allow the formation of silicon carbide.

  9. Reactivity and regioselectivity of noble gas endohedral fullerenes Ng@C(60) and Ng(2)@C(60) (Ng=He-Xe).

    PubMed

    Osuna, Sílvia; Swart, Marcel; Solà, Miquel

    2009-12-07

    Recently, it was shown that genuine Ng-Ng chemical bonds are present in the endohedral fullerenes Ng(2)@C(60) in the case of Ng=Xe, while it is more debatable whether a chemical bond exist for Ng=Ar and Kr. The lighter homologues with helium and neon are weakly bonded van der Waals complexes. The presence of a noble gas dimer inside the cage is expected to modify the exohedral reactivity of the C(60) cage with respect to that of free C(60). To investigate the impact of encapsulated diatomic noble gas molecules on the chemical reactivity of C(60), we analyzed the thermodynamics and the kinetics of [4+2] Diels-Alder cycloaddition of 1,3-cis-butadiene at all nonequivalent bonds in free C(60), Ng@C(60), and Ng(2)@C(60) (Ng=He, Ne, Ar, Kr, and Xe). Our BP86/TZP calculations reveal that introduction of single noble gas atoms in Ng@C(60) and noble gas dimers He(2) and Ne(2) in Ng(2)@C(60) has almost no effect on the exohedral reactivity compared to free C(60), in agreement with experimental results. In all these cases cycloaddition is clearly favored at the [6,6] bonds in the fullerene cage. For the endohedral compounds He(2)@C(60) and Ne(2)@C(60) a slight preference (by less than 2 kcal mol(-1)) for bonds closer to the C(5) symmetry axis is found. This picture changes dramatically for the endohedral compounds with heavier noble gas dimers. Encapsulation of these noble gas dimers clearly enhances the reaction, both under thermodynamic and kinetic control. Moreover, in the case of Xe(2)@C(60), addition to [6,6] and [5,6] bonds becomes equally viable. These reactivity changes in endohedral fullerenes are attributed to stabilization of the LUMO, increased fullerene strain energy, and greater compression of the encapsulated Ng(2) unit along the He to Xe series.

  10. One-step synthesis of fullerene hydride C(60)H2 via hydrolysis of acylated fullerenes.

    PubMed

    Tzirakis, Manolis D; Alberti, Mariza N; Nye, Leanne C; Drewello, Thomas; Orfanopoulos, Michael

    2009-08-07

    The hitherto unexplored class of acylated fullerene compounds has been shown to be excellent C(60)H2 precursors. Upon a simple treatment with basic Al2O3, they are hydrolyzed quantitatively into C(60)H2. This key feature led to the development of a new, straightforward protocol for the selective synthesis of the simplest [60]fullerene hydride, C(60)H2. This protocol may offer an advantageous alternative to previously known methods for the synthesis of C(60)H2 allowing for a rapid access to C(60)H2 in good yield and high purity without tedious separating processes.

  11. Si-C 60-Si (111)-(7 × 7) interactions: a scanning tunneling microscopy study

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Chen, Jian; Sarid, Dror

    1994-12-01

    Scanning tunneling microscopy (STM) has been used to study the interaction of deposited silicon atoms with C 60 molecules adsorbed on Si(111)-(7 × 7) surfaces. In spite of the known strong bonding of C 60 molecules to the silicon surfaces, we find the unexpected result of lack of bonding of the deposited silicon atoms to the adsorbed C 60 molecules, at temperatures up to 600°C. The strong C 60-substrate interaction is revealed from the excessive substrate surface strain induced by the C 60 adsorbates, which creates a variety of metastable structures on the silicon surface.

  12. C60-Fullerenes: detection of intracellular photoluminescence and lack of cytotoxic effects

    PubMed Central

    Levi, Nicole; Hantgan, Roy R; Lively, Mark O; Carroll, David L; Prasad, Gaddamanugu L

    2006-01-01

    We have developed a new method of application of C60 to cultured cells that does not require water-solubilization techniques. Normal and malignant cells take-up C60 and the inherent photoluminescence of C60 is detected within multiple cell lines. Treatment of cells with up to 200 μg/ml (200 ppm) of C60 does not alter morphology, cytoskeletal organization, cell cycle dynamics nor does it inhibit cell proliferation. Our work shows that pristine C60 is non-toxic to the cells, and suggests that fullerene-based nanocarriers may be used for biomedical applications. PMID:17169152

  13. Effect of K doping on CuPc: C60 heterojunctions

    NASA Astrophysics Data System (ADS)

    Cheng, Chiu-Ping; Chen, Wen-Yen; Wei, Ching-Hsuan; Pi, Tun-Wen

    2011-12-01

    Here, the electronic properties of K-doped copper phthalocyanine (CuPc): C60 heterojunctions are studied via synchrotron-radiation photoemission. The K-doped heterointerfaces were obtained by means of C60 on K1.5CuPc and CuPc on K3C60. The photoelectron spectra show that the potassium prefers to combine with C60. At the C60/K1.5CuPc interface, the K diffuses and transfers negative charge into the C60 overlayer, while no strong chemical reaction could be found at the CuPc/K3C60 interface. A significant shift of the vacuum level was observed in both cases, which was caused by the charge transfer for the C60/K1.5CuPc and by the induced density of interface states (IDIS) dipole for the CuPc/K3C60. The energy level diagrams show that using C60 adsorption on a K-doped CuPc film is good for the improvement of photovoltaic devices. However, the inverse process, that of CuPc on a K-doped C60, is unfavorable for the photovoltaic effect.

  14. Oxidative stress-mediated hemolytic activity of solvent exchange-prepared fullerene (C60) nanoparticles

    NASA Astrophysics Data System (ADS)

    Trpkovic, Andreja; Todorovic-Markovic, Biljana; Kleut, Duska; Misirkic, Maja; Janjetovic, Kristina; Vucicevic, Ljubica; Pantovic, Aleksandar; Jovanovic, Svetlana; Dramicanin, Miroslav; Markovic, Zoran; Trajkovic, Vladimir

    2010-09-01

    The present study investigated the hemolytic properties of fullerene (C60) nanoparticles prepared by solvent exchange using tetrahydrofuran (nC60THF), or by mechanochemically assisted complexation with macrocyclic oligosaccharide gamma-cyclodextrin (nC60CDX) or the copolymer ethylene vinyl acetate-ethylene vinyl versatate (nC60EVA-EVV). The spectrophotometrical analysis of hemoglobin release revealed that only nC60THF, but not nC60CDX or nC60EVA-EVV, was able to cause lysis of human erythrocytes in a dose- and time-dependent manner. Atomic force microscopy revealed that nC60THF-mediated hemolysis was preceded by erythrocyte shrinkage and increase in cell surface roughness. A flow cytometric analysis confirmed a decrease in erythrocyte size and demonstrated a significant increase in reactive oxygen species production in red blood cells exposed to nC60THF. The nC60THF-triggered hemolytic activity was efficiently reduced by the antioxidants N-acetylcysteine and butylated hydroxyanisole, as well as by serum albumin, the most abundant protein in human blood plasma. These data indicate that nC60THF can cause serum albumin-preventable hemolysis through oxidative stress-mediated damage of the erythrocyte membrane.

  15. Synthesis and structural analysis of C60-C70 two-component fullerene nanowhiskers

    NASA Astrophysics Data System (ADS)

    Konno, Toshio; Wakahara, Takatsugu; Miyazawa, Kun'ichi

    2015-04-01

    C60-C70 two-component fullerene nanowhiskers (C60-C70NWs) were synthesized by liquid-liquid interfacial precipitation (LLIP) using various ratios of C70 to C60 and then analyzed using a focused ion beam processing apparatus (FIB-SEM), scanning electron microscopy (SEM), Raman spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD) and high-performance liquid chromatography (HPLC). Both C60 and C70 were saturated in the supernatant solutions with fullerene compositions in the mother solutions ranging from 12.4 mass% C70 to 73.4 mass% C70. C60-C70NWs contained a small amount of rhombohedral phase, indicating polymerization of C60. The solid solubility limit of C70 in the C60 matrix was found to be 13.7 mass%. In addition to fine C60-C70NWs, thick C60-C70 needle-like crystals were formed. The thick C60-C70 needle-like crystals were fractured using a molybdenum probe in the FIB. The fractured surfaces of the C60-C70 needle-like crystals showed modulated structures with chemical compositions characteristic of spinodal decomposition. The activation energy of diffusion was determined to be 37.1 kJ/mol.

  16. Synthesis of C60-decorated SWCNTs (C60-d-CNTs) and its TiO2-based nanocomposite with enhanced photocatalytic activity for hydrogen production.

    PubMed

    Chai, Bo; Peng, Tianyou; Zhang, Xiaohu; Mao, Jing; Li, Kan; Zhang, Xungao

    2013-03-14

    A novel nanostructured carbon/TiO(2) nanocomposite photocatalyst is firstly fabricated via a facile hydrothermal process by using fullerene (C(60)) decorated single-walled carbon nanotubes (SWCNTs) as carbon source, which is denoted as C(60)-d-CNTs. The obtained nanostructured carbon/TiO(2) nanocomposites are characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectra (DRS), Raman spectra, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectra (PL), and then are used as catalysts for photocatalytic hydrogen production. It is found that the kinds and contents of various carbon nanostructured materials (such as SWCNTs, C(60) and C(60)-d-CNTs) coupled with TiO(2) can significantly enhance the photoactivity for hydrogen production, and the 5 wt% C(60)-d-CNTs/TiO(2) nanocomposite exhibits the best performance. Experimental results suggest that the C(60)-d-CNTs as a novel carbon nanostructured material could be more beneficial for the photogenerated carrier separation than SWCNTs and C(60) when these carbon nanostructured materials are coupled with TiO(2).

  17. On observing C60+ and C602+ in laboratory and space

    NASA Astrophysics Data System (ADS)

    Strelnikov, D.; Kern, B.; Kappes, M. M.

    2015-12-01

    Recently, we have measured the IR absorptions of C60+, C60-, and C602+ in neon matrixes. Many previously unknown absorptions were established. Here we compare our laboratory IR absorption spectra for C60+ and C602+ to the IR emission spectra of several astronomical objects that show C60 emission. We find that IR bands of C60+ are possibly present in the objects Tc1, SMP SMC 16, NGC 7023, NGC 2244, and SMP LMC 02. Infrared emission features possibly due to C602+ were identified in NGC 7023. To help with future observations of fullerene-related DIBs, we also revisited the oscillator strengths of the NIR absorptions of C60+, and report significantly revised values. Additionally, we report the UV oscillator strengths of C60+.

  18. Energy level alignment between C 60 and Al using ultraviolet photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Seo, J. H.; Kang, S. J.; Kim, C. Y.; Cho, S. W.; Yoo, K.-H.; Whang, C. N.

    2006-09-01

    The energy level alignment between C 60 and Al has been investigated by using ultraviolet photoelectron spectroscopy. To obtain the interfacial electronic structure between C 60 and Al, C 60 was deposited on a clean Al substrate in a stepwise manner. The valence-band spectra were measured immediately after each step of C 60 deposition without breaking the vacuum. The measured onset of the highest occupied molecular orbital energy level was located at 1.59 eV from the Fermi level of Al. The vacuum level was shifted 0.68 eV toward lower binding energy with additional C 60 layers. The observed vacuum level shift means that the interface dipole exists at the interface between C 60 and Al. The barrier height of electron injection from Al to C 60 is 0.11 eV, which is smaller value than that of hole injection.

  19. C60 superstructure and carbide formation on the Al-terminated Al9Co2(001 ) surface

    NASA Astrophysics Data System (ADS)

    Ledieu, J.; Gaudry, É.; de Weerd, M.-C.; Gille, P.; Diehl, R. D.; Fournée, V.

    2015-04-01

    We report the formation of an ordered C60 monolayer on the Al9Co2 (001) surface using scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), x-ray and ultraviolet photoelectron spectroscopy (XPS/UPS), and ab initio calculations. Dosing fullerenes at 300 K results in a disordered overlayer. However, the adsorption of C60 with the sample held between 573-673 K leads to a [4, -2 ∣1 ,3 ] phase. The growth of C60 proceeds with the formation of two domains which are mirror symmetric with respect to the [100] direction. Within each domain, the superstructure unit cell contains six molecules and this implies an area per fullerene equal to 91 Å2. The molecules exhibit two types of contrast (bright and dim) which are bias dependent. The adsorption energies and preferred molecular configuration at several possible adsorption sites have been determined theoretically. These calculations lead to a possible scheme describing the configuration of each C60 in the observed superstructure. Several defects (vacancies, protrusions,…) and domain boundaries observed in the film are also discussed. If the sample temperature is higher than 693 K when dosing, impinging C60 molecules dissociate at the surface, hence leading to the formation of a carbide film as observed by STM and LEED measurements. The formation of Al4C3 domains and the molecular dissociation are confirmed by XPS/UPS measurements acquired at different stages of the experiment. The cluster substructure present at the Al9Co2 (001) surface dictates the carbide domain orientations.

  20. Photochemical properties of C 60. Triplet-excited C 60 quenching by electron acceptors TCNQ and TCNE in solution. Laser photolysis study

    NASA Astrophysics Data System (ADS)

    Nadtochenko, Victor A.; Denisov, Nikolai N.; Rubtsov, Igor V.; Lobach, Anatolii S.; Moravskii, Alexander P.

    1993-06-01

    The quenching of triplet-excited 3C 60 by electron acceptors TCNQ and TCNE has been established in nonpolar toluene and moderately polar benzonitrile solutions. The quenching constants kq are 5.5 × 10 9 in toluene, 2.2 × 10 9 in benzonitrile for TCNQ and 7.9 × 10 5 in toluene, 4.2 × 10 8 (M s) -1 in benzonitrile for TCNE. The 3C 60 quenching can be explained by triplet exciplex formation. The time-resolved spectra of the C 60/TCNE system exhibit a well pronounced charge-transfer excited state [C δ60 … TCNE δ-] in benzonitrile.

  1. Accurate Intermolecular Potential for the C60 Dimer: The Performance of Different Levels of Quantum Theory.

    PubMed

    Sharapa, Dmitry I; Margraf, Johannes T; Hesselmann, Andreas; Clark, Timothy

    2017-01-10

    The self-assembly of molecular building blocks is a promising route to low-cost nanoelectronic devices. It would be very appealing to use computer-aided design to identify suitable molecules. However, molecular self-assembly is guided by weak interactions, such as dispersion, which have long been notoriously difficult to describe with quantum chemical methods. In recent years, several viable techniques have emerged, ranging from empirical dispersion corrections for DFT to fast perturbation and coupled-cluster theories. In this work, we test these methods for the dimer of the prototypical building block for nanoelectronics, C60-fullerene. Benchmark quality data is obtained from DFT-based symmetry-adapted perturbation theory (SAPT), the adiabatic-connection fluctuation dissipation (ACFD) theorem using an adiabatic LDA kernel, and domain-based local pair natural orbital (DLPNO) coupled-pair and coupled-cluster methods. These benchmarks are used to evaluate economical dispersion-corrected DFT methods, double-hybrid DFT functionals, and second-order Møller-Plesset theory. Furthermore, we provide analytical fits to the benchmark interaction curves, which can be used for a coarse-grain description of fullerene self-assembly. These analytical expressions differ significantly from those reported previously based on bulk data.

  2. Formation of a new adduct based on fullerene tris-malonate samarium salt C60-[C60(=C(COO)2)3]Sm2

    NASA Astrophysics Data System (ADS)

    Petrov, A. A.; Keskinov, V. A.; Semenov, K. N.; Charykov, N. A.; Letenko, D. G.; Nikitin, V. A.

    2017-03-01

    Gram quantities of a new adduct based on light fullerene tris-malonate samarium salt C60 [C60(=C(COO)2)3]Sm2 are obtained via the reaction of ion exchange. The obtained adduct is studied by means of electron and infrared spectroscopy, X-ray and elemental analysis, electron microscopy, and thermogravimetry. The polythermal solubility of [C60(=C(COO)2)3]Sm2 in water is determined in ampoules via saturation within 20-70°C. The composition of crystalline hydrate [C60(=C(COO)2)3]Sm2 · 36H2O, which exists in equilibrium with the saturated solution, is estimated.

  3. Ortho-para conversion of endohedral water in the fullerene C60 at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Shugai, Anna; Nagel, U.; Rõõm, T.; Mamone, S.; Concistrè, M.; Meier, B.; Krachmalnicoff, A.; Whitby, R. J.; Levitt, M. H.; Lei, Xuegong; Li, Yongjun; Turro, N. J.

    2015-03-01

    Water displays the phenomenon of spin isomerism in which the two proton spins either couple to form a triplet (ortho water, I = 1) or a singlet nuclear spin state (para water, I = 0). Here we study the interconversion of para and ortho water. The exact mechanism of this process is still not fully understood. In order to minimize interactions between molecules we use a sample where a single H2O is trapped in the C60 molecular cage (H2O@C60)andH2O@C60iscrystallized.H2O@C60 has long-lived ortho state and ortho-para conversion kinetics is non-exponential at LHeT. We studied mixtures of H2O@C60, D2O@C60 and C60 using IR absorption, NMR and dielectric measurements. We saw the speeding up of the interconversion with the growth of H2O@C60 concentration in C60 or when D2O@C60 was added. At some temperatures the kinetics is exponential. Models are discussed in order to explain the T and concentration dependence of ortho-para interconversion kinetics. This work was supported by institutional research funding IUT23-3 of the Estonian Ministry of Education and Research.

  4. Largely enhanced thermal and mechanical properties of polymer nanocomposites via incorporating C60@graphene nanocarbon hybrid

    NASA Astrophysics Data System (ADS)

    Song, Ping'an; Liu, Lina; Huang, Guobo; Yu, Youming; Guo, Qipeng

    2013-12-01

    Although considerable progress has been achieved to create advanced polymer nanocomposites using nanocarbons including fullerene (C60) and graphene, it remains a major challenge to effectively disperse them in a polymer matrix and to fully exert their extraordinary properties. Here we report a novel approach to fabricate the C60@graphene nanocarbon hybrid (C60: ˜47.9 wt%, graphene: ˜35.1%) via three-step reactions. The presence of C60 on a graphene sheet surface can effectively prevent the aggregation of the latter which in turn helps the dispersion of the former in a polymer matrix during melt-processing. C60@graphene is found to be uniformly dispersed in a polypropylene (PP) matrix. Compared with pristine C60 or graphene, C60@graphene further improves the thermal stability and mechanical properties of PP. The incorporation of 2.0 wt% C60@graphene (relative to PP) can remarkably increase the initial degradation temperature by around 59 ° C and simultaneously enhance the tensile strength and Young’s modulus by 67% and 76%, respectively, all of which are higher than those of corresponding PP/C60 (graphene) nanocomposites. These significant performance improvements are mainly due to the free-radical-trapping effect of C60, and the thermal barrier and reinforcing effects of graphene nanosheets as well as the effective stress load transfer. This work provides a new methodology to design multifunctional nanohybrids for creating advanced materials.

  5. Dispersion of C(60) in natural water and removal by conventional drinking water treatment processes.

    PubMed

    Hyung, Hoon; Kim, Jae-Hong

    2009-05-01

    The first objective of this study is to examine the fate of C(60) under two disposal scenarios through which pristine C(60) is introduced to water containing natural organic matter (NOM). A method based on liquid-liquid extraction and HPLC to quantify nC(60) in water containing NOM was also developed. When pristine C(60) was added to water either in the form of dry C(60) or in organic solvent, it formed water stable aggregates with characteristics similar to nC(60) prepared by other methods reported in the literature. The second objective of this study is to examine the fate of the nC(60) in water treatment processes, which are the first line of defense against ingestion from potable water -- a potential route for direct human consumption. Results obtained from jar tests suggested that these colloidal aggregates of C(60) were efficiently removed by a series of alum coagulation, flocculation, sedimentation and filtration processes, while the efficiency of removal dependent on various parameters such as pH, alkalinity, NOM contents and coagulant dosage. Colloidal aggregates of functionalized C(60) could be well removed by the conventional water treatment processes but with lesser efficiency compared to those made of pristine C(60).

  6. Characteristics of multivalent impurity doped C 60 films grown by MBE

    NASA Astrophysics Data System (ADS)

    Nishinaga, Jiro; Aihara, Tomoyuki; Kawaharazuka, Atsushi; Horikoshi, Yoshiji

    2007-04-01

    Metal-doped C 60 films (aluminum, gallium and germanium) are grown on GaAs and quartz glass substrates by solid source molecular beam epitaxy. Mechanical and optical properties of the films are investigated by Vickers hardness test and photoluminescence (PL) measurement. Vickers hardness values of all the impurity-doped C 60 films are considerably enhanced. PL peaks of the electron transition between the highest occupied molecular orbital and the lowest unoccupied molecular orbital states of C 60 molecules are confirmed in Al-doped and Ga-doped C 60 films, but not in Ge-doped C 60 films. Optimized bonding structures of these impurity atoms to C 60 molecules are determined by using ab initio calculations. Stable covalent bonds between impurities and C 60 molecules are verified to be formed. The impurity atoms may act as bridges between C 60 molecules. The distortion of C 60 cages due to the bonding with metals is confirmed. In the Al- and Ga-doped C 60 films, this distortion probably makes the dipole forbidden transition relieved. The binding energies are found to be related to the experimentally determined Vickers hardness.

  7. Inhalation toxicity and lung toxicokinetics of C60 fullerene nanoparticles and microparticles.

    PubMed

    Baker, Gregory L; Gupta, Amit; Clark, Mark L; Valenzuela, Blandina R; Staska, Lauren M; Harbo, Sam J; Pierce, Judy T; Dill, Jeffery A

    2008-01-01

    While several recent reports have described the toxicity of water-soluble C60 fullerene nanoparticles, none have reported the toxicity resulting from the inhalation exposures to C60 fullerene nanoparticles or microparticles. To address this knowledge gap, we exposed male rats to C60 fullerene nanoparticles (2.22 mg/m3, 55 nm diameter) and microparticles (2.35 mg/m3, 0.93 microm diameter) for 3 h a day, for 10 consecutive days using a nose-only exposure system. Nanoparticles were created utilizing an aerosol vaporization and condensation process. Nanoparticles and microparticles were subjected to high-pressure liquid chromatography (HPLC), XRD, and scanning laser Raman spectroscopy, which cumulatively indicated no chemical modification of the C60 fullerenes occurred during the aerosol generation. At necropsy, no gross or microscopic lesions were observed in either group of C60 fullerene exposures rats. Hematology and serum chemistry results found statistically significant differences, although small in magnitude, in both exposure groups. Comparisons of bronchoalveolar (BAL) lavage fluid parameters identified a significant increase in protein concentration in rats exposed to C60 fullerene nanoparticles. BAL fluid macrophages from both exposure groups contained brown pigments, consistent with C60 fullerenes. C60 lung particle burdens were greater in nanoparticle-exposed rats than in microparticle-exposed rats. The calculated lung deposition rate and deposition fraction were 41 and 50% greater, respectively, in C60 fullerene nanoparticle-exposed group than the C60 fullerene microparticle-exposed group. Lung half-lives for C60 fullerene nanoparticles and microparticles were 26 and 29 days, respectively. In summary, this first in vivo assessment of the toxicity resulting from inhalation exposures to C60 fullerene nanoparticles and microparticles found minimal changes in the toxicological endpoints examined. Additional toxicological assessments involving longer duration

  8. Distribution and biomarker of carbon-14 labeled fullerene C60 ([(14) C(U)]C60 ) in pregnant and lactating rats and their offspring after maternal intravenous exposure.

    PubMed

    Snyder, Rodney W; Fennell, Timothy R; Wingard, Christopher J; Mortensen, Ninell P; Holland, Nathan A; Shannahan, Jonathan H; Pathmasiri, Wimal; Lewin, Anita H; Sumner, Susan C J

    2015-12-01

    A comprehensive distribution study was conducted in pregnant and lactating rats exposed to a suspension of uniformly carbon-14 labeled C60 ([(14) C(U)]C60 ). Rats were administered [(14) C(U)]C60 (~0.2 mg [(14) C(U)]C60 kg(-1) body weight) or 5% polyvinylpyrrolidone (PVP)-saline vehicle via a single tail vein injection. Pregnant rats were injected on gestation day (GD) 11 (terminated with fetuses after either 24 h or 8 days), GD15 (terminated after 24 h or 4 days), or GD18 (terminated after 24 h). Lactating rats were injected on postnatal day 8 and terminated after 24 h, 3 or 11 days. The distribution of radioactivity in pregnant dams was influenced by both the state of pregnancy and time of termination after exposure. The percentage of recovered radioactivity in pregnant and lactating rats was highest in the liver and lungs. Radioactivity was quantitated in over 20 tissues. Radioactivity was found in the placenta and in fetuses of pregnant dams, and in the milk of lactating rats and in pups. Elimination of radioactivity was < 2% in urine and feces at each time point. Radioactivity remained in blood circulation up to 11 days after [(14) C(U)]C60 exposure. Biomarkers of inflammation, cardiovascular injury and oxidative stress were measured to study the biological impacts of [(14) C(U)]C60 exposure. Oxidative stress was elevated in female pups of exposed dams. Metabolomics analysis of urine showed that [(14) C(U)]C60 exposure to pregnant rats impacted the pathways of vitamin B, regulation of lipid and sugar metabolism and aminoacyl-tRNA biosynthesis. This study demonstrated that [(14) C(U)]C60 crosses the placenta at all stages of pregnancy examined, and is transferred to pups via milk.

  9. Distribution and Biomarker of Carbon-14 Labeled Fullerene C60 ([14C(U)]C60) in Pregnant and Lactating Rats and their Offspring after Maternal Intravenous Exposure

    PubMed Central

    Snyder, Rodney W.; Fennell, Timothy R.; Wingard, Christopher J.; Mortensen, Ninell P.; Holland, Nathan A.; Shannahan, Jonathan H.; Pathmasiri, Wimal; Lewin, Anita H.; Sumner, Susan C. J.

    2015-01-01

    A comprehensive distribution study was conducted in pregnant and lactating rats exposed to a suspension of uniformly carbon-14 labeled C60 ([14C(U)]C60). Rats were administered [14C(U)]C60 (~0.2 mg [14C(U)]C60/kg body weight) or 5% polyvinylpyrrolidone (PVP)-saline vehicle via a single tail vein injection. Pregnant rats were injected on gestation day (GD) 11 (terminated with fetuses after either 24h or 8d), GD15 (terminated after 24h or 4d), or GD18 (terminated after 24h). Lactating rats were injected on postnatal day 8 and terminated after 24h, 3d or 11d. The distribution of radioactivity in pregnant dams was influenced by both the state of pregnancy and time of termination after exposure. The percentage of recovered radioactivity in pregnant and lactating rats was highest in liver and lungs. Radioactivity was quantitated in over 20 tissues. Radioactivity was found in placenta and in fetuses of pregnant dams, and in the milk of lactating rats and in pups. Elimination of radioactivity was <2% in urine and feces at each time point. Radioactivity remained in blood circulation up to 11 days after [14C(U)]C60 exposure. Biomarkers of inflammation, cardiovascular injury and oxidative stress were measured to study the biological impacts of [14C(U)]C60 exposure. Oxidative stress were elevated in female pups of exposed dams. Metabolomics analysis of urine showed that [14C(U)]C60 exposure to pregnant rats impacted the pathways of vitamin B, regulation of lipid and sugar metabolism and aminoacyl-tRNA biosynthesis. This study demonstrated that [14C(U)]C60 crosses the placenta at all stages of pregnancy examined, and is transferred to pups via milk. PMID:26081520

  10. On the structural distortion in Rb3C60 and K3C60 revealed by 87Rb- and39K- NMR

    NASA Astrophysics Data System (ADS)

    Apostol, M.; Goze, C.; Rachdi, F.; Mehring, M.; Fischer, J. E.

    1996-04-01

    The splitting of the tetrahedral Rb- and K- NMR lines in Rb3C60 and K3C60 is analyzed in terms of the mechanism of alkali-cation vacancies. The calculations indicate the presence of vacancies only in the tetrahedral positions, and the inter-atomic potentials between the alkali cations and the fullerene molecules account satisfactorily for the temperature dependence of the position of the distorted line.

  11. Spatially resolved, substrate-induced rectification in C60 bilayers on copper

    DOE PAGES

    Smerdon, J. A.; Darancet, P.; Guest, J. R.

    2017-02-22

    Here, we demonstrate rectification ratios (RR) of ≳1000 at biases of 1.3 V in bilayers of C60 deposited on copper. Using scanning tunneling spectroscopy and first-principles calculations, we show that the strong coupling between C60 and the Cu(111) surface leads to the metallization of the bottom C60 layer, while the molecular orbitals of the top C60 are essentially unaffected. Due to this substrate-induced symmetry breaking and to a tunneling transport mechanism, the system behaves as a hole-blocking layer, with a spatial dependence of the onset voltage on intra-layer coordination. Together with previous observations of strong electron-blocking character of pentacene/C60 bilayersmore » on Cu(111), this work further demonstrates the potential of strongly hybridized, C60-coated electrodes to harness the electrical functionality of molecular components.« less

  12. Temperature Evolution of Quasi-one-dimensional C60 Nanostructures on Rippled Graphene.

    PubMed

    Chen, Chuanhui; Zheng, Husong; Mills, Adam; Heflin, James R; Tao, Chenggang

    2015-09-22

    We report the preparation of novel quasi-one-dimensional (quasi-1D) C60 nanostructures on rippled graphene. Through careful control of the subtle balance between the linear periodic potential of rippled graphene and the C60 surface mobility, we demonstrate that C60 molecules can be arranged into a quasi-1D C60 chain structure with widths of two to three molecules. At a higher annealing temperature, the quasi-1D chain structure transitions to a more compact hexagonal close packed quasi-1D stripe structure. This first experimental realization of quasi-1D C60 structures on graphene may pave a way for fabricating new C60/graphene hybrid structures for future applications in electronics, spintronics and quantum information.

  13. Temperature Evolution of Quasi-one-dimensional C60 Nanostructures on Rippled Graphene

    PubMed Central

    Chen, Chuanhui; Zheng, Husong; Mills, Adam; Heflin, James R.; Tao, Chenggang

    2015-01-01

    We report the preparation of novel quasi-one-dimensional (quasi-1D) C60 nanostructures on rippled graphene. Through careful control of the subtle balance between the linear periodic potential of rippled graphene and the C60 surface mobility, we demonstrate that C60 molecules can be arranged into a quasi-1D C60 chain structure with widths of two to three molecules. At a higher annealing temperature, the quasi-1D chain structure transitions to a more compact hexagonal close packed quasi-1D stripe structure. This first experimental realization of quasi-1D C60 structures on graphene may pave a way for fabricating new C60/graphene hybrid structures for future applications in electronics, spintronics and quantum information. PMID:26391054

  14. Diels-Alder addition to H2O@C60 an electronic and structural study

    NASA Astrophysics Data System (ADS)

    Reveles, J. Ulises; Govinda, K. C.; Baruah, Tunna; Zope, Rajendra R.

    2017-10-01

    Exohedral reactivity of endohedral fullerenes has aroused a significant interest because of its potential applications. The present letter examines the effect of an entrapped single water molecule on the reactivity of C60. We study the thermodynamics and kinetics of a Diels-Alder reaction occurring at all non-identical bonds of free C60 and H2O@C60. Our calculations show that encapsulation of water does not have a significant effect on H2O@C60 reactivity compared to C60, as attested by the investigation of the reaction under several orientations of H2O inside C60. Reaction and activation energies indicate that [6,6] bonds are the most reactive sites.

  15. 13C-NMR in Iodine and Potassium Intercalated C60 Solid

    NASA Astrophysics Data System (ADS)

    Maniwa, Yutaka; Shibata, Takayuki; Mizoguchi, Kenji; Kume, Kiyoshi; Kikuchi, Koichi; Ikemoto, Isao; Suzuki, Shinzo; Achiba, Yoji

    1992-07-01

    Iodine intercalated C60, I2.29C60, was studied by 13C NMR above 160 K. A sharp NMR signal and a strong temperature-dependent spin-lattice relaxation time, T1, indicated a presence of C60 molecular rotation much higher than 10 kHz at least down to 160 K. No evidence of metallic characteristics was found in the NMR shift (143± 1 ppm) and the T1 (40± 5 sec at room temperature). In K3C60, metallic behavior, T1T˜constant, was observed at the carbon sites between 20 K and 100 K. Electronic density of states at the Fermi level, N(EF), in I2.29C60 was estimated to be smaller than 0.12 of that in K3C60, assuming a relationship between N(EF) and T1T for normal metals.

  16. Uncontrolled variability in the extinction spectra of C60 nanoparticle suspensions.

    PubMed

    Chang, Xiaojun; Vikesland, Peter J

    2013-08-06

    To properly investigate the environmental transport, fate, and impact of fullerene C60 nanoparticles (nC60), it is necessary to reproducibly obtain nC60 suspensions and to accurately determine their concentration ([C60]). The results in the present study, however, clearly illustrate that the production of nC60 via extended mixing and via sonication are highly stochastic top-down processes subject to widely divergent end points. nC60 suspensions exhibit variable characteristics (e.g., [C60], average particle size, size distribution, etc.) that make it challenging, if not impossible, to acquire reproducible UV-vis extinction spectra. The mass extinction coefficient, which is the absorptivity of a suspension with [C60] = 1 mM obtained by normalizing UV-vis spectra by the mass concentration of C60 in the suspension, decreases with a given suspension's hydrodynamic diameter, whereas the particle extinction coefficient, which is the absorptivity of a suspension containing one mole of nC60 nanoparticles with the same size distribution as the target suspension and calculated based upon the suspension nanoparticle size distribution, increases with its number weighted average diameter. Other spectroscopic properties of nC60 (e.g., absorbance bandwidth, position of absorption maximum, and relative extinction intensity) also change with average particle size. As a result of the extant variability between samples, when UV-vis spectra are employed to calculate or represent [C60] for fullerene nanoparticle suspensions, extreme care must be taken and other colloidal properties of this suspension must be measured to obtain an accurate result.

  17. Study of the interaction of C60 fullerene with human serum albumin in aqueous solution

    SciTech Connect

    Li, Song; Zhao, Xiongce; Mo, Yiming; Cummings, Peter T; Heller, William T

    2013-01-01

    Concern about the toxicity of engineered nanoparticles, such as the prototypical nanomaterial C60 fullerene, continues to grow. While evidence continues to mount that C60 and its derivatives may pose health hazards, the specific molecular interactions of these particles with biological macromolecules require further investigation. To better understand the interaction of C60 with proteins, the protein human serum albumin (HSA) was studied in solution with C60 at C60:HSA molar ratios ranging from 1:2 to 4:1. HSA is the major protein component of blood plasma and plays a role in a variety of functions, such as the maintenance of blood pH and pressure. The C60-HSA interaction was probed by a combination of circular dichroism (CD) spectroscopy, small-angle neutron scattering (SANS) and atomistic molecular dynamics (MD) simulations to understand C60-driven changes in the structure of HSA in solution. The CD spectroscopy demonstrates that the secondary structure of the protein decreases in -helical content in response to the presence of C60. Similarly, C60 produces subtle changes in the solution conformation of HSA, as evidenced by the SANS data and MD. The data do not indicate that C60 is causing a change in the oligomerization state of the protein. Taken together results demonstrate that C60 interacts with HSA, but it does not strongly perturb the structure of the protein by unfolding it or inducing aggregation, suggesting a mechanism for transporting C60 throughout the body to accumulate in various tissues.

  18. Hybridization-Induced Carrier Localization at the C60/ZnO Interface

    SciTech Connect

    Kelly, Leah L.; Racke, David A.; Kim, Hyungchul; Ndione, Paul; Sigdel, Ajaya K.; Berry, Joseph J.; Graham, Samuel; Nordlund, Dennis; Monti, Oliver L. A.

    2016-05-25

    Electronic coupling and ground-state charge transfer at the C60/ZnO hybrid interface is shown to localize carriers in the C60 phase. This effect, revealed by resonant X-ray photoemission, arises from interfacial hybridization between C60 and ZnO. Such localization at carrier-selective electrodes and interlayers may lead to severely reduced carrier harvesting efficiencies and increased recombination rates in organic electronic devices.

  19. Low-temperature dynamics and spectroscopy in exohedral rare-gas C60 fullerene complexes

    NASA Astrophysics Data System (ADS)

    Ruiz, A.; Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.

    2001-03-01

    The adatom dynamics in exohedral C60 fullerene complexes of rare-gas atoms are studied with a three degrees of freedom model. The eigenvalue problem of the corresponding quantum Hamiltonian is solved and the electric-dipole spectra for ArC60, NeC60, and HeC60 in the low-temperature range from 5 to 40 K are simulated. The most important spectral features are related to the degree of angular anisotropy in the adatom-C60 interaction. The ArC60 and NeC60 complexes present very simple spectra which can be assigned in terms of three-mode oscillators; the corresponding motion takes place in the deep hexagon wells (also in the pentagon wells for NeC60) of the interaction potential. On the contrary, the HeC60 complex shows more complicated spectra with important tunneling effects due to the smaller angular anisotropy of the interaction. The onset of almost free internal rotation takes place in this complex at rather low energies, and this gives rise to a low-frequency rotational band in the spectra at temperatures above T˜15 K.

  20. Rotational spectra for off-center endohedral atoms at C60 fullerene

    NASA Astrophysics Data System (ADS)

    Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.

    1996-01-01

    Rotational spectra for endohedral Li+@C60 and Na+@C60 are calculated at different temperatures. Most of the features in these spectra are related with the degree of anisotropy in the atom-cage interaction. While the low anisotropy for Na+@C60 results in rather simple spectra with the 2B oscillation typical of a diatomic molecule, the more eccentric and anisotropic Li+@C60 produces complex spectra with rotational and librational bands. Some interesting effects are induced by the cage rotation, which has been incorporated through a semiclassical formalism.

  1. Rock-salt-type crystal of thermally contracted C60 with encapsulated lithium cation.

    PubMed

    Aoyagi, Shinobu; Sado, Yuki; Nishibori, Eiji; Sawa, Hiroshi; Okada, Hiroshi; Tobita, Hiromi; Kasama, Yasuhiko; Kitaura, Ryo; Shinohara, Hisanori

    2012-04-02

    Rock solid: fullerene-encapsulated Li(+) (Li(+)@C(60)) is an alkaline cation owing to the spherical shape and positive charge. Li(+)@C(60) crystallizes as a rock-salt-type crystal in the presence of PF(6)(-). The orientations of C(60) and PF(6)(-) (orange) are perfectly ordered below 370 K, and Li(+) (purple) hops within the cage. At temperatures below 100 K two Li(+) units are localized at two polar positions within each C(60) . Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Thin film engineering for N@C 60 quantum computers: Spin detection and device patterning approaches

    NASA Astrophysics Data System (ADS)

    Schaefer, Sebastian; Huebener, Kati; Harneit, Wolfgang; Boehme, Christoph; Fostiropoulos, Konstantinos; Angermann, Heike; Rappich, Jörg; Behrends, Jan; Lips, Klaus

    2008-10-01

    Using pulsed electrically detected magnetic resonance (p-EDMR), we measured the coherent spin evolution of about 10,000 paramagnetic states in C 60 fullerene thin films, opening a way to study potentially single-qubit read-out mechanisms of N@C 60 molecules. The N@C 60 compatible, low-temperature method of spray-deposition of fullerenes on silicon substrates pre-patterned by local anodic oxidation is shown to yield fullerene structures on the 10 nm scale, still somewhat too coarse for quantum register structures, but suitable for further steps in the application of the p-EDMR method to N@C 60.

  3. Escherichia coli Inactivation by UVC-Irradiated C60: kinetics and mechanisms.

    PubMed

    Cho, Min; Snow, Samuel D; Hughes, Joseph B; Kim, Jae-Hong

    2011-11-15

    Motivated by recent studies that documented changes in fullerene toxicity after chemical transformation, C(60) aggregates (nC(60)) were subject to UVC irradiation at monochromatic 254 nm and subsequently evaluated for antibacterial and bactericidal properties against Escherichia coli. The nC(60) treated with UVC irradiation, referred to herein as UVC-irradiated C(60), did not directly inhibit bacterial growth at concentrations up to 20 mg/L. In the presence of UVA and visible light, however, UVC-irradiated C(60) rapidly inactivated E. coli, suggesting that photochemical production of reactive oxygen species (ROS) was involved. The use of ROS scavengers and probes determined that hydroxyl radicals were the primary ROS responsible for the E. coli inactivation. Results from protein release, lipid peroxidation, cell permeability, and intracellular enzyme assays suggest that the inactivation mechanism involves UVC-irradiated C(60) diffusing through E. coli cell membrane and producing hydroxyl radicals within the cell. Further study on water-soluble C(60) derivatives and possible transformative processes is, therefore, recommended based on the environmental implications of results presented herein that nC(60) exposed to UVC irradiation is more toxic than parent nC(60).

  4. Comparative toxicity of C60 aggregates toward mammalian cells: role of tetrahydrofuran (THF) decomposition.

    PubMed

    Kovochich, Michael; Espinasse, Benjamin; Auffan, Melanie; Hotze, Ernest M; Wessel, Lauren; Xia, Tian; Nel, Andre E; Wiesner, Mark R

    2009-08-15

    C60 fullerene is a promising material because of its unique physiochemical properties. However, previous studies have reported that colloidal aggregates of C60 (nC60) produce toxicity in fish and human cell cultures. The preparation method of nC60 raises questions as to whether the observed effects stem from fullerenes or from the organic solvents used during the preparation of the suspensions. In this paper, we set out to elucidate the mechanism by which tetrahydrofuran (THF) treatment to enhance the preparation of nC60 leads to cytotoxicity in a mouse macrophage cell line. Our results demonstrate that THF/nC60 but not fullerol or aqueous nC60 generates cellular toxicity through a pathway that involves increased intracellular flux and mitochondrial perturbation in RAW 264.7 cells. Interestingly, the supernatant of the THF/n60 suspension rather than the colloidal fullerene aggregates mimics the cytotoxic effects due to the presence of gamma-butyrolactone and formic acid. Thus, the role of nC60 in the cellular responses is likely not due to the direct effect of the nC60 material surface on the cells but is related to the conversion of THF into a toxic byproduct during preparation of the suspension.

  5. Impurity Decoration for Crystal Shape Control: C60 on Ag(111)

    NASA Astrophysics Data System (ADS)

    Stasevich, T. J.; Tao, C. G.; Cullen, W. G.; Williams, E. D.; Einstein, T. L.

    2008-03-01

    The decoration of hexagonal Ag/Ag(111) monolayer islands by chains of C60, observed via STM at 300K, dramatically changes their shape and fluctuations. We tune coverage so that a single C60 chain fully decorates each Ag island boundary.ootnotetextC.G. Tao et al., PRB 73, 125436 (2006); Nano Letters 7, 1495 (2007). The C60-induced rounding appears due to competing energetic and entropic effects.ootnotetextT.J. Stasevich & TLE, (SIAM) Multiscale Model. Simul. 6, 90 (2007) We estimate the Ag - C60 and C60 - C60 attractions as ˜0.13 eV and ˜0.04 eV, respectively.ootnotetextT.J. Stasevich et al., submitted. The edge fluctuations are remarkable: 1) C60 decoration does not notably impede the step-edge diffusion (SED) and 2) while the bare-island fluctuations are driven by SED, the decorated island has the signature of non-conserved dynamics, even though the C60s remain at the island edge. We suggest that rapidly diffusing Ag atoms randomly attracting the nearby C60s. Generalizations of our model show that both spherical and rectangular decorating molecules will similarly lower the energy of highly-kinked boundaries, leading to similar island shape changes.

  6. Mechanism of complexation of the phenothiazine dye methylene blue with fullerene C60

    NASA Astrophysics Data System (ADS)

    Buchelnikov, A. S.; Kostyukov, V. V.; Yevstigneev, M. P.; Prylutskyy, Yu. I.

    2013-04-01

    The complexation of fullerene C60 with the aromatic dye methylene blue (MB) in aqueous solution was studied. Spectrophotometric titration revealed a reasonably strong interaction between C60 and MB molecules with an equilibrium constant K = 2110 L/mol and the binding of up to five dye molecules with the surface of C60. The energy analysis of the MB-C60 system showed that the intermolecular and hydrophobic interactions were dominant in the energy profile of the complexation, and while the electrostatic factor played an insignificant role.

  7. C60(Nd) nanoparticles enhance chemotherapeutic susceptibility of cancer cells by modulation of autophagy

    NASA Astrophysics Data System (ADS)

    Wei, Pengfei; Zhang, Li; Lu, Yang; Man, Na; Wen, Longping

    2010-12-01

    Autophagy, an evolutionally conserved intracellular process degrading cytoplasmic proteins and organelles for recycling, has become one of the most remarkable strategies applied in cancer research. The fullerene C60 nanoparticle (nC60) has been shown to induce autophagy and sensitize chemotherapeutic killing of cancer cells, but the details still remain unknown. Here we show that a water-dispersed nanoparticle solution of derivatized fullerene C60, C60(Nd) nanoparticles (nC60(Nd)), has greater potential in inducing autophagy and sensitizing chemotherapeutic killing of both normal and drug-resistant cancer cells than nC60 does in an autophagy-dependent fashion. Additionally we further demonstrated that autophagy induced by nC60/C60(Nd) and Rapamycin had completely different roles in cancer chemotherapy. Our results, for the first time, revealed a novel and more potent derivative of the C60 nanoparticle in enhancing the cytotoxicity of chemotherapeutic agents and reducing drug resistance through autophagy modulation, which may ultimately lead to novel therapeutic strategies in cancer therapy.

  8. Characterizing photochemical transformation of aqueous nC60 under environmentally relevant conditions.

    PubMed

    Hwang, Yu Sik; Li, Qilin

    2010-04-15

    Engineered nanomaterials may undergo transformation upon interactions with various environmental factors. In this study, photochemical transformation of aqueous nC60 was investigated under UVA irradiation. nC60 underwent photochemical transformation in the presence of dissolved O2, resulting in surface oxygenation and hydroxylation as demonstrated by XPS and ATR-FTIR analyses. The reaction followed a pseudo-first order rate law with the apparent reaction rate constant of 2.2 x 10(-2) h(-1). However, the core of the nanoparticles remained intact over 21 days of irradiation. Although no mineralization or dissolution of nC60 was observed, experiments using fullerol as a reference fullerene derivative suggested likely dissolution and partial mineralization of nC60 under long-term UVA exposure. Aquatic humic acid reduced nC60 transformation kinetics presumably due to scavenging of reactive oxygen species. Results from this study imply that photochemical transformation is an important factor controlling nC60 physical and chemical properties as well as its fate and transport in the natural aqueous environment. In addition, changes in nC60 surface chemistry drastically reduced C60 extraction efficiency by toluene, suggesting that the existing analytical method for C60 may not be applicable to environmental samples.

  9. Behaviour of fullerenes (C60) in the terrestrial environment: potential release from biosolids-amended soils.

    PubMed

    Navarro, Divina A; Kookana, Rai S; Kirby, Jason K; Martin, Sheridan M; Shareef, Ali; Du, Jun; McLaughlin, Mike J

    2013-11-15

    Owing of their wide-range of commercial applications, fullerene (C60) nanoparticles, are likely to reach environments through the application of treated sludge (biosolids) from wastewater treatment plants to soils. We examined the release behaviour of C60 from contaminated biosolids added to soils with varying physicochemical characteristics. Incubation studies were carried out in the dark for up to 24 weeks, by adding biosolids spiked (1.5mg/kg) with three forms of C60 (suspended in water, in humic acid, and precipitated/particulate) to six contrasting soils. Leaching of different biosolids+soil systems showed that only small fractions of C60 (<5% of applied amount) were released, depending on incubation time and soil properties (particularly dissolved organic carbon content). Release of C60 from unamended soils was greater (at least twice as much) than from biosolids-amended soils. The form of C60 used to spike the biosolids had no significant effect on the release of C60 from the different systems. Contact time of C60 in these systems only slightly increased the apparent release up to 8 weeks, followed by a decrease to 24 weeks. Mass balance analysis at the completion of the experiment revealed that 20-60% of the initial C60 applied could not be accounted for in these systems; the reasons for this are discussed. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  10. Mechanical and optical characteristics of Al-doped C 60 films

    NASA Astrophysics Data System (ADS)

    Nishinaga, Jiro; Aihara, Tomoyuki; Yamagata, Hiroshi; Horikoshi, Yoshiji

    2005-05-01

    Al-doped C 60 films are grown on GaAs and quartz glass substrates by solid source molecular beam epitaxy. Mechanical and optical properties of the films are investigated by Vickers hardness test, absorption and reflectance spectra, and photoluminescence measurements. Vickers hardness of 250 HV is confirmed for the Al-doped C 60 films with the molecular ratio of Al to C 60 of 30, and the Al-doped C 60 films are found to be undissolved in organic solvents. The absorption spectra of pure C 60 films show some peaks caused by the electron transition among the C 60 molecular orbitals. These absorption peaks become less pronounced in Al-doped C 60 films, probably due to Al incorporation in C 60 matrix. In addition, new photoluminescence peaks appear around 1.75, 1.85 and 1.95 eV. The energy of 1.95 eV coincides well with the energy difference between HOMO and LUMO states. These results suggest that the parity forbidden transition is relieved by the molecular distortion due to the Al-C 60 bonding.

  11. Photochemistry of Aqueous C60 Clusters: Wavelength Dependency and Product Characterization

    EPA Science Inventory

    To construct accurate risk assessment models for engineered nanomaterials, there is urgent need for information on the reactivity (or conversely, persistence) and transformation pathways of these materials in the natural environment. As an important step toward addressing this is...

  12. Photochemistry of Aqueous C60 Clusters: Wavelength Dependency and Product Characterization

    EPA Science Inventory

    To construct accurate risk assessment models for engineered nanomaterials, there is urgent need for information on the reactivity (or conversely, persistence) and transformation pathways of these materials in the natural environment. As an important step toward addressing this is...

  13. Structure and physical properties of nanoclustered graphene synthesized from C60 fullerene under high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Chernogorova, Olga; Potapova, Iraida; Drozdova, Ekaterina; Sirotinkin, Vladimir; Soldatov, Alexander V.; Vasiliev, Alexander; Ekimov, Evgeny

    2014-01-01

    C60 treatment at 5-8 GPa, ˜1000 °C results in the fullerene cage collapse and transformation to a phase with outstanding mechanical properties. A detailed structural analysis of the phase reveals that it comprised 7-12 layer graphene clusters with lateral dimension of 2-4 nm. Raman spectra of the nanoclustered graphene phase are similar to those of disordered sp2 carbon structure with an admixture of sp3-bonded carbon. The phase is characterized by a high (up to 19 GPa) hardness, relatively low (about 70 GPa) Young modulus and up to 95% elastic recovery, determining excellent wear resistance and good antifriction properties.

  14. Temperature dependence of the electronic properties of K3C60 and K4C60 single-phase films investigated by means of electron spectroscopies

    NASA Astrophysics Data System (ADS)

    Goldoni, A.; Sangaletti, L.; Friedmann, S. L.; Shen, Z.-X.; Peloi, M.; Parmigiani, F.; Comelli, G.; Paolucci, G.

    2000-11-01

    The normal state temperature dependence of a metallic K3C60 phase pure film has been investigated by means of core levels and valence band photoemission, carbon K edge x-ray absorption, and electron energy loss spectroscopies and compared with that of a Mott-Hubbard insulating K4C60 film. The anomalous temperature behavior of K3C60, in the range 30 K-600 K, can be consistently interpreted considering the presence of orientational disorder of the C60 molecules together with the inhomogeneity of the conduction electron distribution at the molecular level. In particular, the changes observed in the photoemission spectra near the Fermi level, are consistent with the behavior predicted for strongly correlated metallic systems in presence of disorder. Also in the case of K4C60 we observe anomalies in the temperature dependence of core levels photoemission data. These anomalies can be explained with the freezing of the molecular motions at low temperature and point to large thermal fluctuations of the alkali atoms around their equilibrium position at high temperature.

  15. Nanostructures of hydrated C60 fullerene (C60HyFn) protect rat brain against alcohol impact and attenuate behavioral impairments of alcoholized animals.

    PubMed

    Tykhomyrov, Artem A; Nedzvetsky, Victor S; Klochkov, Vladimir K; Andrievsky, Grigory V

    2008-04-18

    It is well known that chronic ethyl alcohol (EtOH) consumption is capable to injure brain cells and to cause essential abnormalities in behavioral characteristics of animals addicted to alcohol. In this work we for the first time have shown that administration of aqueous solutions of hydrated C60 fullerenes (C60HyFn) with C60 concentration of 30nM as a drinking water during chronic alcoholization of rats (a) protects the tissues of central nervous system (CNS) from damage caused by oxidative stress with high efficacy, (b) prevents the pathological loss of both astrocytes (the main cells of CNS) and astrocytic marker, glial fibrillary acidic proteins (GFAP) and, as consequence, (c) due to their adaptogenic effects, C60HyFn significantly improves behavioral response and eliminates emotional deficits induced by chronic alcohol uptake. The wide range of beneficial biological effects, zero-toxicity, and efficacy even in super-small doses provide a rationale for the possible application of C60HyFn for the treatment of alcohol-induced encephalopathy as well as alcoholism prophylaxis.

  16. Behavioral and physiological changes in Daphnia magna when exposed to nanoparticle suspensions (titanium dioxide, nano-C60, and C60HxC70Hx).

    PubMed

    Lovern, Sarah B; Strickler, J Rudi; Klaper, Rebecca

    2007-06-15

    Little is known aboutthe impact manufactured nanoparticles will have on aquatic organisms. Previously, we demonstrated that toxicity differs with nanoparticle type and preparation and observed behavioral changes upon exposure to the more lethal nanoparticle suspensions. In this experiment, we quantified these behavioral and physiological responses of Daphnia magna at sublethal nanoparticle concentrations. Titanium dioxide (TiO2) and fullerenes (nano-C60) were chosen for their potential use in technology. Other studies suggest that addition of functional groups to particles can affect their toxicity to cell cultures, but it is unknown if the same is true at the whole organism level. Therefore, a fullerene derivative, C60HxC70Hx, was also used to examine how functional groups affect Daphnia response. Using a high-speed camera, we quantified several behavior and physiological parameters including hopping frequency, feeding appendage and postabdominal curling movement, and heart rate. Nano-C60 was the only suspension to cause a significant change in heart rate. Exposure to both nano-C60 and C60HxC70Hx suspensions caused hopping frequency and appendage movement to increase. These results are associated with increased risk of predation and reproductive decline. They indicate that certain nanoparticle types may have impacts on population and food web dynamics in aquatic systems.

  17. Fullerene C60 Penetration into Leukemic Cells and Its Photoinduced Cytotoxic Effects

    NASA Astrophysics Data System (ADS)

    Franskevych, D.; Palyvoda, K.; Petukhov, D.; Prylutska, S.; Grynyuk, I.; Schuetze, C.; Drobot, L.; Matyshevska, O.; Ritter, U.

    2017-01-01

    Fullerene C60 as a representative of carbon nanocompounds is suggested to be promising agent for application in photodynamic therapy due to its unique physicochemical properties. The goal of this study was to estimate the accumulation of fullerene C60 in leukemic cells and to investigate its phototoxic effect on parental and resistant to cisplatin leukemic cells. Stable homogeneous water colloid solution of pristine C60 with average 50-nm diameter of nanoparticles was used in experiments. Fluorescent labeled C60 was synthesized by covalent conjugation of C60 with rhodamine B isothiocyanate. The results of confocal microscopy showed that leukemic Jurkat cells could effectively uptake fullerene C60 from the medium. Light-emitting diode lamp (100 mW cm-2, λ = 420-700 nm) was used for excitation of accumulated C60. A time-dependent decrease of viability was detected when leukemic Jurkat cells were exposed to combined treatment with C60 and visible light. The cytotoxic effect of photoexcited C60 was comparable with that induced by H2O2, as both agents caused 50% decrease of cell viability at 24 h at concentrations about 50 μM. Using immunoblot analysis, protein phosphotyrosine levels in cells were estimated. Combined action of C60 and visible light was followed by decrease of cellular proteins phosphorylation on tyrosine residues though less intensive as compared with that induced by H2O2 or protein tyrosine kinase inhibitor staurosporine. All tested agents reduced phosphorylation of 55, 70, and 90 kDa proteins while total suppression of 26 kDa protein phosphorylation was specific only for photoexcited C60.

  18. Fullerene C60 exposure elicits an oxidative stress response in embryonic zebrafish

    PubMed Central

    Usenko, Crystal Y.; Harper, Stacey L.; Tanguay, Robert L.

    2008-01-01

    Due to its unique physicochemical and optical properties, C60 has raised interest in commercialization for a variety of products. While several reports have determined this nanomaterial to act as a powerful antioxidant, many other studies have demonstrated a strong oxidative potential through photoactivation. To directly address the oxidative potential of C60, the effects of light and chemical supplementation and depletion of glutathione (GSH) on C60-induced toxicity were evaluated. Embryonic zebrafish were used as a model organism to examine the potential of C60 to elicit oxidative stress responses. Reduced light during C60 exposure significantly decreased mortality and the incidence of fin malformations and pericardial edema at 200 and 300 ppb C60. Embryos co-exposed to the glutathione precursor, N-acetylcysteine (NAC), also showed reduced mortality and pericardial edema; however, fin malformations were not reduced. Conversely, co-exposure to the GSH synthesis inhibitors, butathionine sulfoximine (BSO) and diethyl maleate (DEM), increased the sensitivity of zebrafish to C60 exposure. Co-exposure of C60 or its hydroxylated derivative, C60(OH)24, with H2O2 resulted in increased mortality along the concentration gradient of H2O2 for both materials. Microarrays were used to examine the effects of C60 on the global gene expression at two time points, 36 and 48 hours post fertilization (hpf). At both life stages there were alterations in the expression of several key stress response genes including glutathione-S-transferase, glutamate cysteine ligase, ferritin, α-tocopherol transport protein and heat shock protein 70. These results support the hypothesis that C60 induces oxidative stress in this model system. PMID:18299140

  19. Photodynamic inactivation of bacteria using novel electrogenerated porphyrin-fullerene C60 polymeric films.

    PubMed

    Ballatore, M Belén; Durantini, Javier; Gsponer, Natalia S; Suarez, María B; Gervaldo, Miguel; Otero, Luis; Spesia, Mariana B; Milanesio, M Elisa; Durantini, Edgardo N

    2015-06-16

    A porphyrin-fullerene C60 dyad (TCP-C60) substituted by carbazoyl groups was used to obtain electrogenerated polymeric films on optically transparent indium tin oxide (ITO) electrodes. This approach produced stable and reproducible polymers, holding fullerene units. The properties of this film were compared with those formed by layers of TCP/TCP-C60 and TCP/ZnTCP. Absorption spectra of the films presented the Soret and Q bands of the corresponding porphyrins. The TCP-C60 film produced a high photodecomposition of 2,2-(anthracene-9,10-diyl)bis(methylmalonate), which was used to detect singlet molecular oxygen O2((1)Δg) production in water. In addition, the TCP-C60 film induced the reduction of nitro blue tetrazolium to diformazan in the presence of NADH, indicating the formation of superoxide anion radical. Moreover, photooxidation of L-tryptophan mediated by TCP-C60 films was found in water. In biological media, photoinactivation of Staphylococcus aureus was evaluated depositing a drop with 2.5 × 10(3) cells on the films. After 30 min irradiation, no colony formation was detected using TCP-C60 or TCP/TCP-C60 films. Furthermore, photocytotoxic activity was observed in cell suspensions of S. aureus and Escherichia coli. The irradiated TCP-C60 film produced a 4 log decrease of S. aureus survival after 30 min. Also, a 4 log reduction of E. coli viability was obtained using the TCP-C60 film after 60 min irradiation. Therefore, the TCP-C60 film is an interesting and versatile photodynamic active surface to eradicate bacteria.

  20. Toxicity of an engineered nanoparticle (fullerene, C60) in two aquatic species, Daphnia and fathead minnow.

    PubMed

    Zhu, Shiqian; Oberdörster, Eva; Haasch, Mary L

    2006-07-01

    Water-soluble fullerene (nC60) has been shown to induce lipid peroxidation (LPO) in brain of juvenile largemouth bass (LMB, Micropterus salmoides) [Oberdörster, E., 2004. Manufactured nanomaterials (fullerenes, c60) induce oxidative stress in brain of juvenile largemouth bass. Environ. Health Persp. 112, 1058-1062]; and upregulate genes related to the inflammatory response and metabolism, most notably CYP2K4 [. Nanotoxicology: an emerging discipline evolving from 116 studies of ultrafine particles. Environ. Health Persp. 113, 823-839]. The initial study in LMB was performed using tetrahydrofuran (THF)-solubilized nC60, although C60 can also be solubilized by stirring in water. The current study investigates differences in acute toxicity to Daphnia magna between THF-solubilized and water-stirred-nC60 as a range-find for further assays in adult male fathead minnow (FHM, Pimephales promelas). The daphnia 48-h LC50 for THF-nC60 was at least one order of magnitude less (0.8 ppm) than that for water-stirred-nC60 (> 35 ppm). FHM were dosed with either 0.5 ppm of THF- or water-stirred-nC60 for 48 h. There was 100% mortality in the THF-nC60-exposed fish between 6 and 18 h, while the water-stirred-nC60-exposed fish showed no obvious physical effects after 48 h. Water-stirred-nC60 elevated LPO in brain, significantly increased LPO in gill, and significantly increased expression of CYP2 family isozymes in liver as compared to control fish.

  1. Transport and retention of fullerene (C60) nanoparticles in natural soils

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Li, Y.; Abriola, L. M.; Pennell, K. D.

    2008-12-01

    Although several column studies have investigated the transport and deposition of fullerene (C60) nanoparticles in ideal porous media, such as washed quartz sands and glass beads, far less attention has been directed toward natural soils. To address this issue, a series of column experiments was performed to quantify the transport and retention of C60 nanoparticles in a borosilicate glass column (10 cm length x 2.5 cm dia.) packed with either Appling soil or Webster soil. Introduction of a C60 suspension containing 1 mM calcium chloride as background electrolyte for up to 65 pore volumes resulted in 100 percent retention of injected mass. Retained C60 nanoparticles were concentrated within 6 cm of the column from inlet, with solid phase concentrations approaching 130 μg/g. The presence of Suwannee River humic acid (20 mg/L) in the C60 suspension slightly enhanced mobility of nC60, although effluent breakthrough was not observed. However, when mixed with 1,000 mg/L polyethoxylate (20) sorbitan monooleate (Tween 80), C60 nanoparticles were readily transported through Appling soil, with less than 40 percent of injected mass retained. Retentions profiles of nC60 exhibited gradual ascent and descent, but not symmetrically, with distance from inlet. A mathematic transport model incorporating classical filtration theory, non-linear sorption process, and straining was utilized to capture C60 effluent breakthrough curves and retention profiles observed in the column experiments. These findings indicate that Appling soil and Webster soil exhibit large retention capacity for C60 nanoparticle, and that transport of C60 is greatly enhanced in the presence of stabilizing agents.

  2. Sputtering of octatetraene by 15 keV C60 projectiles: Comparison of reactive interatomic potentials

    NASA Astrophysics Data System (ADS)

    Kanski, Michal; Maciazek, Dawid; Golunski, Mikolaj; Postawa, Zbigniew

    2017-02-01

    Molecular dynamics computer simulations have been used to probe the effect of the AIREBO, ReaxFF and COMB3 interatomic potentials on sputtering of an organic sample composed of octatetraene molecules. The system is bombarded by a 15 keV C60 projectile at normal incidence. The effect of the applied force fields on the total time of simulation, the calculated sputtering yield and the angular distribution of sputtered particles is investigated and discussed. It has been found that caution should be taken when simulating particles ejection from nonhomogeneous systems that undergo significant fragmentation described by the ReaxFF. In this case, the charge state of many particles is improper due to an inadequacy of a procedure used for calculating partial charges on atoms in molecules for conditions present during sputtering. A two-step simulation procedure is proposed to minimize the effect of this deficiency. There is also a possible problem with the COMB3 potential, at least at conditions present during cluster impact, as its results are very different from AIREBO or ReaxFF.

  3. Energy Gain in Collisions of Highly Charged Ions with C_60

    NASA Astrophysics Data System (ADS)

    Thumm, Uwe; Bárány, Anders; Cederquist, Henrik

    1997-04-01

    Within the dynamical classical over--barrier model for charge transfer in soft ion--cluster collisions [1], we have simulated [2] the kinetic energy gain Q of 3.3 q keV Ar^q+ ions in collisions with neutral C_60 targets. Our semi--classical theory allows for the calculation of Q in two different ways, either as difference of electronic binding energies before and after the collision or by integrating the dynamically changing force between the collision partners along the trajectory. A comparison between the two ways provides an intrinsic test of the model calculation. Comparison with recent experimental data [3] shows good agreement in the main features of the energy gain spectra and facilitates their interpretation in terms of the number and final states of transferred electrons. [1] U. Thumm, J. Phys. B27 3515 (1994); Phys. Rev. A55 (Jan.1997). [2] U. Thumm, A. Bárány and H. Cederquist, to be published. [3] N. Selberg et al., Phys. Rev. A 53, 874 (1996). description U.T. is supported by the Division of Chemical Sciences, Basis Energy Sciences, Office of Energy Research, U.S. Department of Energy.

  4. Synthesis of a Crushed Fullerene C60H24 through Sixfold Palladium-Catalyzed Arylation.

    PubMed

    Dorel, Ruth; de Mendoza, Paula; Calleja, Pilar; Pascual, Sergio; González-Cantalapiedra, Esther; Cabello, Noemí; Echavarren, Antonio M

    2016-07-01

    The synthesis of a new C3v -symmetric crushed fullerene C60H24 (5) has been accomplished in three steps from truxene through sixfold palladium-catalyzed intramolecular arylation of a syn-trialkylated truxene precursor. Laser irradiation of 5 induces cyclodehydrogenation processes that result in the formation of C60, as detected by LDI-MS.

  5. Mechanisms of nC60 removal by the alum coagulation-flocculation-sedimentation process.

    PubMed

    Wang, Chao; Shang, Chii; Chen, Guanghao; Zhu, Xiaoshan

    2013-12-01

    This study explored the mechanisms for nC60 removal in pure water and filtered saline wastewater by the alum coagulation-flocculation-sedimentation process through analyzing the hydrolyzed aluminum species and exploring the complexation of nC60 with aluminum hydroxide precipitates. Sweep flocculation (enmeshment and adsorption) with Alc is the most dominant mechanism contributing to the nC60 removal in pure water. In filtered saline wastewater, hetero-precipitation of Alb with nC60, colloids, and dissolved solids also contributes to the nC60 removal. Alkalinity affected the nC60 removal by changing the hydrolyzed aluminum species distributions. XPS, FTIR, and SEM evidences suggest that the enmeshment and adsorption of nC60 onto the aluminum hydroxide precipitates can be described as the inner-sphere complexation. Based on the above observations, conceptual models for nC60 removal by the alum coagulation-flocculation-sedimentation process in the different water matrices are proposed. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Modelling the manipulation of C60 on the Si001 surface performed with NC-AFM.

    PubMed

    Martsinovich, N; Kantorovich, L

    2009-04-01

    We present a theoretical model of manipulation of the C(60) molecule on the Si(001) surface with a non-contact atomic force microscope (NC-AFM). The model relies on the lowering of the energy barrier for the C(60) manipulation due to the interaction of the C(60) with an AFM tip and the subsequent thermal movement of the molecule over this barrier. We performed numerical simulations of these energy barriers for a series of tip positions relative to the molecule to show how the barriers change with the tip position. The values of these barriers are then used in kinetic Monte Carlo simulations to estimate the probability of the C(60) movement for different tip positions and temperatures. Virtual atomic force microscope simulations, which include the kinetic Monte Carlo treatment of the C(60) movement, are then performed to describe in real time the process of movement of the C(60) molecule during an NC-AFM scan. Our results demonstrate that manipulation of the C(60) molecule, which is covalently bound to the surface, is possible with NC-AFM, even though there is no continuous tip-molecule contact, which is known to be a necessary requirement for the C(60) manipulation with scanning tunnelling microscopy. We show that the manipulation event can be identified in real NC-AFM experiments as an abrupt change in the distance of the tip closest approach (topography), and as spikes in the frequency shift and dissipation signals.

  7. Growth of large, defect-free pure C60 single crystals

    NASA Technical Reports Server (NTRS)

    Meng, R. L.; Ramirez, D.; Jiang, X.; Chow, P. C.; Diaz, C.; Matsuishi, K.; Moss, S. C.; Hor, P. H.; Chu, C. W.

    1991-01-01

    Millimeter-sized single crystals of C60 were grown by sublimation of C60 powder in a vacuum for 6-24 h. The crystals had excellent facets, were free of C70 or solvent, and showed face-centered cubic symmetry with a very small mosaic spread down to 0.01 deg.

  8. Complex of C60 Fullerene with Doxorubicin as a Promising Agent in Antitumor Therapy

    NASA Astrophysics Data System (ADS)

    Prylutska, Svitlana V.; Skivka, Larysa M.; Didenko, Gennadiy V.; Prylutskyy, Yuriy I.; Evstigneev, Maxim P.; Potebnya, Grygoriy P.; Panchuk, Rostyslav R.; Stoika, Rostyslav S.; Ritter, Uwe; Scharff, Peter

    2015-12-01

    The main aim of this work was to evaluate the effect of doxorubicin in complex with C60 fullerene (C60 + Dox) on the growth and metastasis of Lewis lung carcinoma in mice and to perform a primary screening of the potential mechanisms of C60 + Dox complex action. We found that volume of tumor from mice treated with the C60 + Dox complex was 1.4 times less than that in control untreated animals. The number of metastatic foci in lungs of animals treated with C60 + Dox complex was two times less than that in control untreated animals. Western blot analysis of tumor lysates revealed a significant decrease in the level of heat-shock protein 70 in animals treated with C60 + Dox complex. Moreover, the treatment of tumor-bearing mice was accompanied by the increase of cytotoxic activity of immune cells. Thus, the potential mechanisms of antitumor effect of C60 + Dox complex include both its direct action on tumor cells by inducing cell death and increasing of stress sensitivity and an immunomodulating effect. The obtained results provide a scientific basis for further application of C60 + Dox nanocomplexes as treatment agents in cancer chemotherapy.

  9. Density functional study of reactivity and regioselectivity of H2O C60

    NASA Astrophysics Data System (ADS)

    KC, Govinda Bahadur

    The exohedral reactivity of endohedral fullerene has aroused significant interest because of its potential applications in biology, medicine and material science. The encapsulation of a single water molecule without any hydrogen bonding to other compounds, inside the hydrophobic environment of C60 is an intriguing topic to study about. In 2011, Kurotobi and Murata successfully synthesized H2O C60 fullerene. The presence of a polar water molecule inside the cage is expected to cause changes in the exohedral reactivity of C60. In order to find out the impact of an entrapped single water molecule on the reactivity of C60 fullerene, we use density functional theory to study the thermodynamics and kinetics of [4+2] Diels-Alder reaction of 1, 3 cis butadiene at all non-identical bonds of free C60 and H2O C60. Our calculations show that the encapsulation of a single water molecule does not have any significant effect on the exohedral reactivity compared to free C60. Moreover, the obtained reaction energies and activation barriers indicate that [6, 6] bond is more reactive than [5, 6] bond and thus cycloaddition is clearly favored at [6, 6] bond. The dipole moment of the H2O C60 is only 0.48 Debye significantly smaller than that of water molecule. The infrared and Raman spectra of the endohedral fullerene are also computed.

  10. Nonlinear optical response of C60 in solvents: picosecond transient grating experiments

    NASA Astrophysics Data System (ADS)

    Khudyakov, Dmitriy V.; Rubtsov, Igor V.; Lobach, Anatolii S.; Nadtochenko, Victor A.

    1996-05-01

    Time-resolved resonant nonlinear optical response of C60 in a chlorobenzene solution was measured for 528 nm excitation and 1055, 528, and 351 nm probing for zzzz and zzyy configurations. The slow part of the signal (8 +/- 2 ps) was attributed to the orientational motion of C60 excited molecules.

  11. Structural Energetics of Yb_2.75C_60: Charge Transfer and Local Distortions

    NASA Astrophysics Data System (ADS)

    Rabe, Karin M.; Citrin, P. H.

    1997-03-01

    The crystal structure of Yb_2.75C_60 is closely related to that of the well-known superconducting K_3C_60, but with an ordered cationic vacancy sublattice and large displacements of the Yb cations from their ideal sites.(E. Ozdas et al., Nature 375), 126 (1995). This structure is unique among known fullerene compounds in that there are crystallographically inequivalent C_60 molecules with distinct nearest-neighbor cation environments. Recent EXAFS measurements(P. H. Citrin et al., unpublished.) indicate that the C_60 molecules are also significantly distorted. Using a simple electrostatic model of Yb^2+ point cations and C_60 anions as classical charged spheres with an average charge of -5.5, we find that the structural energy is minimized by charge transfer among the inequivalent C_60 anions. The result is three different charge states of -6.2, -5.5, and -4.8. Refinements of this simple model, including charge-state- and local-field-induced distortions of the C_60 molecules and covalent bonding to the nearest-neighbor Yb cations, will be discussed. Within the model, the experimental structural data and the reasons for the stability of this structure in the Yb-C_60 system will be analyzed.

  12. Chemical grafting of Co9S8 onto C60 for hydrogen spillover and storage.

    PubMed

    Han, Lu; Qin, Wei; Zhou, Jia; Jian, Jiahuang; Lu, Songtao; Wu, Xiaohong; Fan, Guohua; Gao, Peng; Liu, Boyu

    2017-04-20

    Metal modified C60 is considered to be a potential hydrogen storage medium due to its high theoretical capacity. Research interest is growing in various hybrid inorganic compounds-C60. While the design and synthesis of a novel hybrid inorganic compound-C60 is difficult to attain, it has been theorized that the atomic hydrogen could transfer from the inorganic compound to the adjacent C60 surfaces via spillover and surface diffusion. Here, as a proof of concept experiment, we graft Co9S8 onto C60via a facile high energy ball milling process. The Raman, XPS, XRD, TEM, HTEM and EELS measurements have been conducted to evaluate the composition and structure of the pizza-like hybrid material. In addition, the electrochemical measurements and calculated results demonstrate that the chemical "bridges" (C-S bonds) between these two materials enhance the binding strength and, hence, facilitate the hydriding reaction of C60 during the hydrogen storage process. As a result, an increased hydrogen storage capacity of 4.03 wt% is achieved, along with a favorable cycling stability of ∼80% after 50 cycles. Excluding the direct hydrogen storage contribution from Co9S8 in the hybrid paper, the hydrogen storage ability of C60 was enhanced by 5.9× through the hydriding reaction caused by the Co9S8 modifier. Based on these experimental measurements and theoretical calculations, the unique chemical structure reported here could potentially inspire other C60-based advanced hybrids.

  13. C60 fullerene as promising therapeutic agent for correcting and preventing skeletal muscle fatigue.

    PubMed

    Prylutskyy, Yurij I; Vereshchaka, Inna V; Maznychenko, Andriy V; Bulgakova, Nataliya V; Gonchar, Olga O; Kyzyma, Olena A; Ritter, Uwe; Scharff, Peter; Tomiak, Tomasz; Nozdrenko, Dmytro M; Mishchenko, Iryna V; Kostyukov, Alexander I

    2017-01-13

    Bioactive soluble carbon nanostructures, such as the C60 fullerene can bond with up to six electrons, thus serving by a powerful scavenger of reactive oxygen species similarly to many natural antioxidants, widely used to decrease the muscle fatigue effects. The aim of the study is to define action of the pristine C60 fullerene aqueous colloid solution (C60FAS), on the post-fatigue recovering of m. triceps surae in anaesthetized rats. During fatigue development, we observed decrease in the muscle effort level before C60FAS administration. After the application of C60FAS, a slower effort decrease, followed by the prolonged retention of a certain level, was recorded. An analysis of the metabolic process changes accompanying muscle fatigue showed an increase in the oxidative stress markers H 2 O 2 (hydrogen peroxide) and TBARS (thiobarbituric acid reactive substances) in relation to the intact muscles. After C60FAS administration, the TBARS content and H 2 O 2 level were decreased. The endogenous antioxidant system demonstrated a similar effect because the GSH (reduced glutathione) in the muscles and the CAT (catalase) enzyme activity were increased during fatigue. C60FAS leads to reduction in the recovery time of the muscle contraction force and to increase in the time of active muscle functioning before appearance of steady fatigue effects. Therefore, it is possible that C60FAS affects the prooxidant-antioxidant muscle tissue homeostasis, subsequently increasing muscle endurance.

  14. Interactions between two C60 molecules measured by scanning probe microscopies

    NASA Astrophysics Data System (ADS)

    Hauptmann, Nadine; González, César; Mohn, Fabian; Gross, Leo; Meyer, Gerhard; Berndt, Richard

    2015-11-01

    {{{C}}}60-functionalized tips are used to probe {{{C}}}60 molecules on Cu(111) with scanning tunneling and atomic force microscopy. Distinct and complex intramolecular contrasts are found. Maximal attractive forces are observed when for both molecules a [6,6] bond faces a hexagon of the other molecule. Density functional theory calculations including parameterized van der Waals interactions corroborate the observations.

  15. On the chemical behavior of C60 hosting H2O and other isoelectronic neutral molecules.

    PubMed

    Galano, Annia; Pérez-González, Adriana; del Olmo, Lourdes; Francisco-Marquez, Misaela; León-Carmona, Jorge Rafael

    2014-08-01

    The density functional theory (DFT) was used to investigate the chemical behavior of C60 hosting neutral guest molecules (NGM). The deformed atoms in molecules (DAM) allowed identifying the regions of electron density depletion and accumulation. The studied NGM are CH4, NH3, H2O, and HF. Based on dipole moment and polarizabilities analyses it is predicted that the NGM@C60 should be more soluble in polar solvents than C60. The deformations on the surface electron density of the fullerenes explain this finding, which might be relevant for further applications of these systems. It was found that the intrinsic reactivity of studied NGM@C60 is only moderately higher than that of C60. This trend is supported by the global reactivity indexes and the frontier orbitals analyses. The free radical scavenging activity of the studied systems, via single electron transfer, was found to be strongly dependent on the chemical nature of the reacting free radical. The presence of the studied NGM inside the C60 influences only to some extent the reactivity of C60 toward free radicals. The distortion of the electron density on the C60 cage, caused by the NGM, is directly related to the electron withdrawing capacity of the later.

  16. Spectroscopic studies of the interaction of C 60 and C 70 films with metal substrates

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Chen, Li-Quan; Li, Yu-Xin; Zhao, Tie-Nan; Huang, Yu-Zhen; Zhang, Zhan-Xiang; Wang, Hui-Tian; Ye, Pei-Xian; Zhao, Zhong-Xian

    1994-09-01

    The interaction of fullerenes C 60 and C 70 films with metal substrates Au, Ag, In and Sn has been studied by UV-visible absorption spectra, IR, Raman, photoluminescence and second-order nonlinear optics. The absorption spectra show new bands for films on Au, Ag, In and Sn film substrates. For C 60 on Au and Ag, new bands appear, peaking at 723 and 566 nm, respectively. For C 60 film on Sn, several new bands are found at 975.4, 1218, 1557, 2000 and 3570 nm in the NIR and IR regions. Raman spectra reveal an additional peak at 350 cm-1 for C 60 film on Au and five new peaks at 350, 532, 564, 1692 and 1850 cm-1 for the film on Sn. An enhancement of the Raman peak intensity is observed in the latter case. A peak blue shift of photoluminescence band from 749 to 735 nm for C 60 on Sn has also been found. Moreover, a second-order nonlinear optics study at 1.06,μm yields a ten times greater secondary harmonic generation signal intensity for C 60 films on Ag than that of Ag, while no signal is observed for C 60 film on glass. For C 70 on Sn, UV absorption bands broaden and new bands are found at 747, 984 and 1738 nm. The above results suggest a structural distortion of C 60 and C 70 molecules, induced by charge transfer from these metals to the molecules.

  17. Effects of humic and fulvic acids on aggregation of aqu/nC60 nanoparticles

    EPA Science Inventory

    Aggregation of fullerene nanoparticles (nC60) is a fundamental process influencing its environmental fate and transport, and toxicity. Using time-resolved dynamic light scattering we systematically investigated aggregation kinetics of nC60 generated from extended mixing in water ...

  18. Carboxylic Acid Fullerene (C60) Derivatives Attenuated Neuroinflammatory Responses by Modulating Mitochondrial Dynamics

    NASA Astrophysics Data System (ADS)

    Ye, Shefang; Zhou, Tong; Cheng, Keman; Chen, Mingliang; Wang, Yange; Jiang, Yuanqin; Yang, Peiyan

    2015-05-01

    Fullerene (C60) derivatives, a unique class of compounds with potent antioxidant properties, have been reported to exert a wide variety of biological activities including neuroprotective properties. Mitochondrial dynamics are an important constituent of cellular quality control and function, and an imbalance of the dynamics eventually leads to mitochondria disruption and cell dysfunctions. This study aimed to assess the effects of carboxylic acid C60 derivatives (C60-COOH) on mitochondrial dynamics and elucidate its associated mechanisms in lipopolysaccharide (LPS)-stimulated BV-2 microglial cell model. Using a cell-based functional screening system labeled with DsRed2-mito in BV-2 cells, we showed that LPS stimulation led to excessive mitochondrial fission, increased mitochondrial localization of dynamin-related protein 1 (Drp1), both of which were markedly suppressed by C60-COOH pretreatment. LPS-induced mitochondria reactive oxygen species (ROS) generation and collapse of mitochondrial membrane potential (Δ Ψm) were also significantly inhibited by C60-COOH. Moreover, we also found that C60-COOH pretreatment resulted in the attenuation of LPS-mediated activation of nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling, as well as the production of pro-inflammatory mediators. Taken together, these findings demonstrated that carboxylic acid C60 derivatives may exert neuroprotective effects through regulating mitochondrial dynamics and functions in microglial cells, thus providing novel insights into the mechanisms of the neuroprotective properties of carboxylic acid C60 derivatives.

  19. Effects of humic and fulvic acids on aggregation of aqu/nC60 nanoparticles

    EPA Science Inventory

    Aggregation of fullerene nanoparticles (nC60) is a fundamental process influencing its environmental fate and transport, and toxicity. Using time-resolved dynamic light scattering we systematically investigated aggregation kinetics of nC60 generated from extended mixing in water ...

  20. Surface Energy of C60 and the Interfacial Interactions in Aqueous Systems

    EPA Science Inventory

    The surface free energy components of C60 powder in the form of compressed pellets were determined by sessile drop contact angle measurements. Based on van Oss-Chaudhury-Good model to Young-Dupre equation, the surface energy of C60 and the contributions of the apolar (Lifshitz-v...

  1. Fullerene C60: surface energy and interfacial interactions in aqueous systems.

    PubMed

    Ma, Xin; Wigington, Bethany; Bouchard, Dermont

    2010-07-20

    The underlying mechanisms of fullerene-fullerene, fullerene-water, and fullerene-soil surface interactions in aqueous systems are not well understood. To advance our understanding of these interfacial interactions, the surface properties of Buckminsterfullerene (C60) and quartz surfaces were investigated. From application of the van Oss-Chaudhury-Good model and the Young-Dupre equation, the Lifshitz-van der Waals, acid-base, and the total surface energies of C60 powder and quartz surfaces were calculated from contact angle measurements using the sessile drop technique. C60 powder measurements indicate low to medium energy surfaces of 41.7 mJ/m2 with a dominant Lifshitz-van der Waals component. In aqueous systems, hydrophobic attraction due to the high cohesion of water is the driving force for C60 aggregation. The high free energy of hydration (DeltaG(pw)(total) = -90.5 mJ/m2) indicates the high affinity of C60 particles for water. Hamaker constants of 4.02 x 10(-21) J (A(pwp)) and 2.59 x 10(-21) J (A(pws)) were derived for C60-C60 and C60-quartz interactions in aqueous systems. The results of this study indicate that surface energy is an important physical parameter that should be considered as a basic characterization property of fullerene nanomaterials.

  2. Anion-Dependent Aggregate Formation and Charge Behavior of Colloidal Fullerenes (n-C60)

    EPA Science Inventory

    The fate and transport of colloidal fullerenes (n-C60) in the environment is likely to be guided by electrokinetic and aggregation behavior. In natural water bodies inorganic ions exert significant effects in determining the size and charge of n-C60 nanoparticles. Although the ef...

  3. Enhanced mobility of fullerene (C60) nanoparticles in the presence of stabilizing agents.

    PubMed

    Wang, Yonggang; Li, Yusong; Costanza, Jed; Abriola, Linda M; Pennell, Kurt D

    2012-11-06

    Experimental and mathematical modeling studies were performed to examine the effects of stabilizing agents on the transport and retention of fullerene nanoparticles (nC(60)) in water-saturated quartz sand. Three stabilizing systems were considered: naturally occurring compounds known to stabilize nanoparticles (Suwannee river humic acid (SRHA) and fulvic acid (SRFA)), synthetic additives used to enhance nanoparticle stability (Tween 80, a nonionic surfactant), and residual contaminants resulting from the manufacturing process (tetrahydrofuran (THF)). The results of column experiments demonstrated that the presence of THF, at concentrations up to 44.5 mg/L, did not alter nC(60) transport and retention behavior, whereas addition of SRHA (20 mg C/L), SRFA (20 mg C/L), or Tween 80 (1000 mg/L) to the influent nC(60) suspensions dramatically increased the mobility of nC(60), as demonstrated by coincidental nanoparticle and nonreactive tracer effluent breakthrough curves (BTCs) and minimal nC(60) retention. When columns were preflushed with surfactant, nC(60) transport was significantly enhanced compared to that in the absence of a stabilizing agent. The presence of adsorbed Tween 80 resulted in nC(60) BTCs characterized by a declining plateau and retention profiles that exhibited hyperexponential decay. The observed nC(60) transport and retention behavior was accurately captured by a mathematical model that accounted for coupled surfactant adsorption-desorption dynamics, surfactant-nanoparticle interactions, and particle attachment kinetics.

  4. Enhanced association for C70 over C60 with a metal complex with corannulene derivate ligands.

    PubMed

    Álvarez, Celedonio M; García-Escudero, Luis A; García-Rodríguez, Raúl; Martín-Álvarez, Jose M; Miguel, Daniel; Rayón, Víctor M

    2014-11-14

    The geometry imposed by the coordination sphere around the metal, together with the choice of the "arms" can be advantageously used to build corannulene-based molecular tweezers, which show great affinities for C60 and C70, as revealed by NMR titration experiments, mass spectroscopy, DFT calculations and the single crystal X-ray structural analysis of the compound C60 ⊂1.

  5. Surface Energy of C60 and the Interfacial Interactions in Aqueous Systems

    EPA Science Inventory

    The surface free energy components of C60 powder in the form of compressed pellets were determined by sessile drop contact angle measurements. Based on van Oss-Chaudhury-Good model to Young-Dupre equation, the surface energy of C60 and the contributions of the apolar (Lifshitz-v...

  6. Synthesis of a Crushed Fullerene C60H24 through Sixfold Palladium‐Catalyzed Arylation

    PubMed Central

    Dorel, Ruth; de Mendoza, Paula; Calleja, Pilar; Pascual, Sergio; González‐Cantalapiedra, Esther; Cabello, Noemí

    2016-01-01

    The synthesis of a new C 3v‐symmetric crushed fullerene C60H24 (5) has been accomplished in three steps from truxene through sixfold palladium‐catalyzed intramolecular arylation of a syn‐trialkylated truxene precursor. Laser irradiation of 5 induces cyclodehydrogenation processes that result in the formation of C60, as detected by LDI‐MS. PMID:27774038

  7. Fullerene-C60 and crown ether doped on C60 sensors for high sensitive detection of alkali and alkaline earth cations

    NASA Astrophysics Data System (ADS)

    Zaghmarzi, Fatemeh Alipour; Zahedi, Mansour; Mola, Adeleh; Abedini, Saboora; Arshadi, Sattar; Ahmadzadeh, Saeed; Etminan, Nazanin; Younesi, Omran; Rahmanifar, Elham; Yoosefian, Mehdi

    2017-03-01

    Fullerenes are effective acceptor components with high electron affinity for charge transfer. The significant influences of chemical adsorption of the cations on the electrical sensitivity of pristine C60 and 15-(C2H4O)5/C60 nanocages could be the basis of new generation of electronic sensor design. The density functional theory calculation for alkali and alkaline earth cations detection by pristine C60 and 15-(C2H4O)5/C60 nanocages are considered at B3LYP level of theory with 6-31 G(d) basis set. The quantum theory of atoms in molecules analysis have been performed to understand the nature of intermolecular interactions between the cations and nanocages. Also, the natural bond orbital analysis have been performed to assess the intermolecular interactions in detail. Furthermore, the frontier molecular orbital, energy gap, work function, electronegativity, number of transferred electron (∆N), dipole moment as well as the related chemical hardness and softness are investigated and calculated in this study. The results show that the adsorption of cations (M=Na+, K+, Mg2+ and Ca2+) are exothermic and the binding energy in pristine C60 nanocage and 15-(C2H4O)5/C60 increases with respect to the cations charge. The results also denote a decrease in the energy gap and an increase in the electrical conductivity upon the adsorption process. In order to validate the obtained results, the density of state calculations are employed and presented in the end as well.

  8. Heterostructures based on graphene and MoS2 layers decorated by C60 fullerenes

    NASA Astrophysics Data System (ADS)

    Chernozatonskii, Leonid A.; Kvashnin, Alexander G.; Sorokin, Pavel B.

    2016-09-01

    Here we present a comprehensive investigation of various novel composite structures based on graphene (G) and molybdenum disulphide (MoS2) monolayers decorated by C60 fullerenes, which can be successfully applied in photovoltaics as a solar cell unit. Theoretical studies of the atomic structure, stability and electronic properties of the proposed G/C60, MoS2/C60 and G/MoS2/C60/G nanostructures were carried out. We show that making the G/MoS2/C60/G heterostructure from the 2D films considered here will lead to the appearance of particular properties suitable for application in photovoltaics due to the broad energetic region of high electronic density of states.

  9. High resolution images of single C 60 molecules on gold (111) using scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Howells, Sam; Chen, Ting; Gallagher, Mark; Sarid, Dror; Lichtenberger, Dennis L.; Wright, Laura L.; Ray, Charles D.; Huffman, Donald R.; Lamb, Lowell D.

    1992-07-01

    The electronic interactions of fullerene molecules with metals, with other molecules, and with themselves are important to the chemical and conductive properties of these materials. We demonstrate high resolution scanning tunneling microscopy images of C 60 molecules condensed on epitaxial gold (111) films on mica, in which the C 60 molecules are isolated from each other. The C 60 molecules were locked in position to the gold substrate by an ordered layer of methyl isobutyl ketone. The images of the C 60 molecules exhibit intramolecular contrast indicating a significant electronic interaction with the gold substrate. Current versus voltage measurements show that both the C 60 and the thin film of methyl isobutyl ketone have conductances comparable to that of the gold substrate.

  10. ESR spectroscopy of the C60 cation produced by photoinduced electron transfer

    PubMed

    Dunsch; Ziegs; Siedschlag; Mattay

    2000-10-02

    In this study the existence of the C60 cation produced by photochemically induced electron transfer in the presence of different sensitising molecules is proved for the first time by using ESR spectroscopy. It is demonstrated for triphenylpyryliumtetrafluoroborate (TPP) by this spectroscopic method that the electron transfer from C60 to TPP occurs without an application of a cosensitiser. Furthermore it is shown that the addition of alcohols causes a new radical in the system C60/TPP. The stationary concentration of the C60 cation diminishes even in the presence of a cosensitiser to such a low concentration that it is not detectable by ESR spectrosopy. The spectroscopic study of the sensitiser/C60 system is also extended to the reaction products.

  11. Rotational dynamics of confined C60 from near-infrared Raman studies under high pressure.

    PubMed

    Zou, Yonggang; Liu, Bingbing; Wang, Liancheng; Liu, Dedi; Yu, Shidan; Wang, Peng; Wang, Tianyi; Yao, Mingguang; Li, Quanjun; Zou, Bo; Cui, Tian; Zou, Guangtian; Wågberg, Thomas; Sundqvist, Bertil; Mao, Ho-Kwang

    2009-12-29

    Peapods present a model system for studying the properties of dimensionally constrained crystal structures, whose dynamical properties are very important. We have recently studied the rotational dynamics of C(60) molecules confined inside single walled carbon nanotube (SWNT) by analyzing the intermediate frequency mode lattice vibrations using near-infrared Raman spectroscopy. The rotation of C(60) was tuned to a known state by applying high pressure, at which condition C(60) first forms dimers at low pressure and then forms a single-chain, nonrotating, polymer structure at high pressure. In the latter state the molecules form chains with a 2-fold symmetry. We propose that the C(60) molecules in SWNT exhibit an unusual type of ratcheted rotation due to the interaction between C(60) and SWNT in the "hexagon orientation," and the characteristic vibrations of ratcheted rotation becomes more obvious with decreasing temperature.

  12. Imaging and spectromicroscopy of photocarrier electron dynamics in C60 fullerene thin films

    NASA Astrophysics Data System (ADS)

    Shibuta, Masahiro; Yamagiwa, Kana; Eguchi, Toyoaki; Nakajima, Atsushi

    2016-11-01

    We have employed a two-photon photoelectron emission microscopy (2P-PEEM) to observe the photocarrier electron dynamics in an organic thin film of fullerene (C60) formed on a highly oriented pyrolytic graphite with a spatial resolution of ca. 135 nm. In this approach, photocarrier electrons in C60 single-layer islands generated by the first pump photon are detected by the second probe photon. These spectromicroscopic observations conducted over a 100 × 100 nm2 region of C60 islands consistently reproduced the macroscopic two-photon photoemission spectrum of fully covered C60 monolayer film, where the energy of photocarrier electron in the islands was +0.9 eV relative to the Fermi level. Time-resolved 2P-PEEM revealed that the photocarrier electron decayed from the monolayered C60 islands into the substrate with a time constant of 470 ± 30 fs.

  13. Atomic-scale ultralow friction simulation of superlubricity of C60 molecular bearing

    NASA Astrophysics Data System (ADS)

    Sasaki, Naruo; Itamura, Noriaki; Miura, Kouji

    2007-11-01

    Simulation of superlubricity of C60 molecular bearing is performed based on molecular mechanics. Atomic-scale frictional feature along [10 overline 1 0] direction of the graphite/C60/graphite interface is numerically investigated compared with that of the graphite/graphite/graphite interface. Simulated interlayer distances of about 1.3nm are in good agreement with previous experimental results[1-3]. Atomic-scale friction coefficient of graphite/C60/graphite interface decreases to about 30% of that of the graphite/graphite/graphite interface. It is clarified that three-dimensional degree of freedom of intercalated C60 motion is one of origins of ultralow friction of graphite/C60/graphite interface along [10 overline 1 0] direction.

  14. Density functional theory study on oligosilane-functionalized C60 fullerene

    NASA Astrophysics Data System (ADS)

    Yoshizawa, Saori; Abe, Shigeaki; Mutoh, Mami; Kusaka, Teruo; Nakamura, Mariko; Yoshida, Yasuhiro; Iida, Junichiro; Kawabata, Hiroshi; Tachikawa, Hiroto

    2017-01-01

    Oligosilane-functionalized C60 fullerenes [namely, C60-(SiH2) n -H, n = 1-4] have been investigated by the density functional theory (DFT) method to elucidate the structures and electronic states of oligosilane-radical added fullerene. The DFT calculation showed that oligosilane radicals bind to the carbon atom of C60 in the on-top site, and a strong Si-C heterojunction is formed. The binding energies of oligosilane radicals to C60 were calculated to be 24.6-28.2 kcal/mol at the CAM-B3LYP/6-311G(d,p) level. The electronic states of oligosilane-functionalized fullerenes C60-(SiH2) n -H are discussed on the basis of theoretical results.

  15. Metallic properties of the ternary fullerides ABa2C60 (A=K,Rb,Cs)

    NASA Astrophysics Data System (ADS)

    Thier, K.-F.; Goze, C.; Mehring, M.; Rachdi, F.; Yildirim, T.; Fischer, J. E.

    1999-04-01

    Electronic properties and molecular dynamics of mixed alkali-alkaline earth fullerides ABa2C60 (A=K,Rb,Cs) are investigated by NMR and compared to the isostructural alkali fullerides A3C60. Consistent with previous Raman investigations, our results indicate a fivefold charge transfer to the C60, a charge state that is not found in pure alkali fullerides. 13C NMR experiments reveal a metallic ground state for all compounds with an inhomogeneous charge distribution on the fullerene molecule. The importance of electron-electron correlations is discussed in terms of the Korringa enhancement factor. Correlation effects appear to be somewhat similar to the isostructural superconducting A3C60. Transverse relaxation experiments were performed to probe the reorientational dynamics of the C60 molecules. No dependence of the activation energy of the reorientational motion on the type of alkali ion is found.

  16. Effects of C60 on the Photochemical Formation of Reactive Oxygen Species from Natural Organic Matter.

    PubMed

    Yin, Lijuan; Zhou, Huaxi; Lian, Lushi; Yan, Shuwen; Song, Weihua

    2016-11-01

    Buckminsterfullerenes (C60) are widely used nanomaterials that are present in surface water. The combination of C60 and humic acid (HA) generates reactive oxygen species (ROS) under solar irradiation, but this process is not well understood. Thus, the present study focused on the photochemical formation of singlet oxygen ((1)O2), hydroxyl radical (HO(•))-like species, superoxide radicals (O2(•-)), hydrogen peroxide (H2O2), and triplet excited states ((3)C60*/(3)HA*) in solutions containing both C60 and HA. The quantum yield coefficients of excited triplet states (fTMP) and apparent quantum yields of ROS were measured and compared to the calculated values, which were based on the conservative mixing model. Although C60 proved to have only a slight impact on the (1)O2 formation from HA, C60 played a key role in the inhibition of O2(•-). The photochemical formation of H2O2 followed the conservative mixing model due to the reaction of C60(•-) with HO2(•)/O2(•-), and the biomolecular reaction rate constant has been measured as (7.4 ± 0.6) × 10(6) M(-1) s(-1). The apparent fTMP was significantly lower than the calculated value, indicating that the steric effect of HA was significant in the reaction of (3)C60* with the TMP probe. In contrast, C60 did not have an effect on the photochemical formation of HO(•) from HA, suggesting that HO(•) is elevated from the hydrophilic surface of HA. The aforementioned results may be useful for predicting the photochemical influence of C60 on aqueous environments.

  17. Dramatically enhanced oxygen uptake and ionization yield of positive secondary ions with C60+ sputtering.

    PubMed

    Liao, Hua-Yang; Tsai, Meng-Hung; You, Yun-Wen; Chang, Hsun-Yun; Huang, Chih-Chieh; Shyue, Jing-Jong

    2012-04-03

    To explore C(60)(+) sputtering beyond low-damage depth profiling of organic materials, X-ray photoelectron spectrometry (XPS) and secondary ion mass spectrometry (SIMS) were used to examine metallic surfaces during and after C(60)(+) sputtering. During C(60)(+) sputtering, XPS spectra indicated that the degrees of carbon deposition were different for different metallic surfaces. Moreover, for some metals (e.g., Al, W, Ta, Ti, and Mo), the intensity of the O 1s photoelectron increased significantly during C(60)(+) sputtering, even though the instrument was under ultrahigh vacuum (<5 × 10(-7) Pa). This result indicated that the rate of oxygen uptake was greater than the rate of C(60)(+) sputtering. This behavior was not observed with the commonly used Ar(+) sputtering. To measure the oxygen uptake kinetics, pure oxygen was leaked into the chamber to maintain a 5 × 10(-6) Pa oxygen environment. The C(60)(+)-sputtered surface had a clearly increased rate of oxygen uptake than the Ar(+)-sputtered surface, even for moderately reactive metals such as Fe and Ni. For relatively nonreactive metals such as Cu and Au, a small amount of carbon was implanted and no oxygen uptake was observed. High-resolution XPS spectra revealed the formation of metal carbides on these reactive metals, and the carbon deposition and enhanced uptake of oxygen correlated to the carbide formation. Because oxygen enhances the secondary ion yield through surface passivation, the enhanced oxygen uptake due to C(60)(+) sputtering could be beneficial for SIMS analysis. To examine this hypothesis, C(60)(+) and Ar(+) were used as primary ions, and it was found that the intensity enhancement (because of the oxygen flooding at 5 × 10(-6) Pa) was much higher with C(60)(+) than with Ar(+). Therefore, oxygen flooding during C(60)(+) sputtering has a great potential for enhancing the detection limit due to the enhanced oxygen uptake.

  18. Hydrogen absorption and desorption kinetics in fullerite C60 single crystals. Low-temperature micromechanical and structural characteristics of the interstitial solid solution C60(H2)x

    NASA Astrophysics Data System (ADS)

    Fomenko, L. S.; Lubenets, S. V.; Natsik, V. D.; Stetsenko, Yu. E.; Yagotintsev, K. A.; Strzhemechny, M. A.; Prokhvatilov, A. I.; Osipyan, Yu. A.; Izotov, A. N.; Sidorov, N. S.

    2008-01-01

    The microhardness HV and lattice parameter a of C60 single crystals are measured at room temperature as functions of the hydrogen saturation time t for several values of the saturation temperature (250, 300, and 350°C) at a fixed hydrogen pressure p =30atm. According to the measurements of HV and a, the kinetics of hydrogen absorption is described by a simple exponential law with a single, temperature-dependent characteristic time. In highly saturated samples the microhardness is 4 times greater than for the initial C60 crystal, while the lattice parameter is 0.2% larger. The temperature dependence of the microhardness HV and lattice parameter a of C60(H2)x crystals is investigated in the temperature interval 77-300K. The introduction of hydrogen lowers the temperature of the fcc-sc phase transition, and the transition becomes strongly broadened in temperature. The dependence of the microhardness of the saturated sample on the hold time in air at room temperature is described by the sum of two exponentials with different characteristic times. Kinetics of this kind is presumably due to two processes: desorption of hydrogen from the sample, which causes a decrease of the microhardness, and a simultaneous penetration of gaseous impurities into the sample from the surrounding air, which is accompanied by hardening. The influence of the H2 molecules on the characteristic of the intermolecular interaction in fullerite C60 is discussed and the intercalation-induced processes of dislocation slip and microfracture.

  19. The Curators of the University of Missouri Modeling the Infrared Emission of C_60 in Space

    NASA Astrophysics Data System (ADS)

    Li, Aigen

    Fullerenes are cage-like molecules of pure carbon, such as C_60, C_70, C_76, and C_84. C_60, also known as buckminsterfullerene, is the most stable fullerene and has a soccer- ball like structure. The presence of fullerenes in space has been suggested and observationally explored since their first synthesis in the laboratory in 1985 by Harry Kroto and his colleagues which earned them the 1996 Nobel prize in chemistry. C_60 (as well as C_70) has recently been detected in reflection nebulae, post-AGB stars, protoplanetary nebulae, planetary nebulae, Herbig Ae/Be stars, and young stellar objects through their characteristic infrared emission bands. The formation of C_60 in interstellar and circumstellar environments is not firmly established. Experimental studies have shown that C_60 can be made by gas-phase condensation (e.g. through vaporization of graphite) in a hydrogen-poor environment. In view of the simultaneous detection of C_60 and PAHs in hydrogen-rich interstellar and circumstellar regions, it has also been suggested that C_60 could be generated by the decomposition of hydrogenated amorphous carbon, or the destruction of PAHs, both induced by shocks and/or UV photoprocessing. The phase (gas or solid) and excitation mechanism of C_60 in interstellar and circumstellar conditions are also hotly debated in the literature. One model suggests that C_60 is attached to dust and emits in solid-phase at the equilibrium temperature of the dust. Another model suggests that C_60 is stochastically excited by UV photons and emits in the gas-phase. We prefer the latter model as in interstellar and circumstellar conditions the energy content of a C_60 molecule is often smaller than the energy of a single starlight photon and C_60 is expected to undergo stochastical heating. We propose a two-year project to model the vibrational excitation of C_60 and calculate its infrared emission spectra in a wide variety of regions (e.g. reflection nebulae excited by stars of a range of

  20. Probing Exciton Diffusion and Dissociation in Single-Walled Carbon Nanotube-C60 Heterojunctions

    SciTech Connect

    Dowgiallo, Anne-Marie; Mistry, Kevin S.; Johnson, Justin C.; Reid, Obadiah G.; Blackburn, Jeffrey L.

    2016-05-19

    The efficiency of thin-film organic photovoltaic (OPV) devices relies heavily upon the transport of excitons to type-II heterojunction interfaces, where there is sufficient driving force for exciton dissociation and ultimately the formation of charge carriers. Semiconducting single-walled carbon nanotubes (SWCNTs) are strong near-infrared absorbers that form type-II heterojunctions with fullerenes such as C60. Although the efficiencies of SWCNT-fullerene OPV devices have climbed over the past few years, questions remain regarding the fundamental factors that currently limit their performance. In this study, we determine the exciton diffusion length in the C60 layer of SWCNT-C60 bilayer active layers using femtosecond transient absorption measurements. We demonstrate that hole transfer from photoexcited C60 molecules to SWCNTs can be tracked by the growth of narrow spectroscopic signatures of holes in the SWCNT 'reporter layer'. In bilayers with thick C60 layers, the SWCNT charge-related signatures display a slow rise over hundreds of picoseconds, reflecting exciton diffusion through the C60 layer to the interface. A model based on exciton diffusion with a Beer-Lambert excitation profile, as well as Monte Carlo simulations, gives the best fit to the data as a function of C60 layer thickness using an exciton diffusion length of approximately 5 nm.

  1. {{{\\rm{C}}}_{60}}^{+} and the Diffuse Interstellar Bands: An Independent Laboratory Check

    NASA Astrophysics Data System (ADS)

    Spieler, Steffen; Kuhn, Martin; Postler, Johannes; Simpson, Malcolm; Wester, Roland; Scheier, Paul; Ubachs, Wim; Bacalla, Xavier; Bouwman, Jordy; Linnartz, Harold

    2017-09-01

    In 2015, Campbell et al. presented spectroscopic laboratory gas phase data for the fullerene cation, {{{{C}}}60}+, that coincide with the reported astronomical spectra of two diffuse interstellar band (DIB) features at 9633 and 9578 Å. In the following year, additional laboratory spectra were linked to three other and weaker DIBs at 9428, 9366, and 9349 Å. The laboratory data were obtained using wavelength-dependent photodissociation spectroscopy of small (up to three) He-tagged {{{{C}}}60}+{--}{{He}}n ion complexes, yielding rest wavelengths for the bare {{{{C}}}60}+ cation by correcting for the He-induced wavelength shifts. Here we present an alternative approach to derive the rest wavelengths of the four most prominent {{{{C}}}60}+ absorption features, using high-resolution laser dissociation spectroscopy of {{{{C}}}60}+ embedded in ultracold He droplets. Accurate wavelengths of the bare fullerene cation are derived from linear wavelength shifts recorded for {{He}}n {{{{C}}}60}+ species with n up to 32. A careful analysis of all of the available data results in precise rest wavelengths (in air) for the four most prominent {{{{C}}}60}+ bands: 9631.9(1) Å, 9576.7(1) Å, 9427.5(1) Å, and 9364.9(1) Å. The corresponding bandwidths have been derived and the relative band intensity ratios are discussed.

  2. Volume properties and refraction of aqueous solutions of bisadducts of light fullerene C60 and essential amino acids lysine, threonine, and oxyproline (C60(C6H13N2O2)2, C60(C4H8NO3)2, and C60(C5H9NO2)2) at 25°C

    NASA Astrophysics Data System (ADS)

    Semenov, K. N.; Ivanova, N. M.; Charykov, N. A.; Keskinov, V. A.; Kalacheva, S. S.; Duryagina, N. N.; Garamova, P. V.; Kulenova, N. A.; Nabieva, A.

    2017-02-01

    Concentration dependences of the density of aqueous solutions of bisadducts of light fullerene C60 and essential amino acids are studied by pycnometry. Concentration dependences of the average molar volumes and partial volumes of components (H2O and corresponding bisadducts) are calculated for C60(C6H13N2O2)2-H2O, C60(C4H8NO3)2-H2O, and C60(C5H9NO2)2-H2O binary systems at 25°C. Concentration dependences of the indices of refraction of C60(C6H13N2O2)2-H2O, C60(C4H8NO3)2-H2O, and C60(C5H9NO2)2-H2O binary systems are determined at 25°C. The concentration dependences of specific refraction and molar refraction of bisadducts and aqueous solutions of them are calculated.

  3. Poisson-distributed electron-transfer dynamics from single quantum dots to C60 molecules.

    PubMed

    Song, Nianhui; Zhu, Haiming; Jin, Shengye; Zhan, Wei; Lian, Tianquan

    2011-01-25

    Functional quantum dot (QD)-based nanostructures are often constructed through the self-assembly of QDs with binding partners (molecules or other nanoparticles), a process that leads to a statistical distribution of the number of binding partners. Using single QD fluorescence spectroscopy, we probe this distribution and its effect on the function (electron-transfer dynamics) in QD-C60 complexes. Ensemble-averaged transient absorption and fluorescence decay as well as single QD fluorescence decay measurements show that the QD exciton emission was quenched by electron transfer from the QD to C60 molecules and the electron-transfer rate increases with the C60-to-QD ratio. The electron-transfer rate of single QD-C60 complexes fluctuates with time and varies among different QDs. The standard deviation increases linearly with the average of electron-transfer rates of single QD-C60 complexes, and the distributions of both quantities obey Poisson statistics. The observed distributions of single QD-C60 complexes and ensemble-averaged fluorescence decay kinetics can be described by a model that assumes a Poisson distribution of the number of adsorbed C60 molecules per QD. Our findings suggest that, in self-assembled QD nanostructures, the statistical distribution of the number of adsorbed partners can dominate the distributions of the averages and standard deviation of their interfacial dynamical properties.

  4. Competing length scales for the electronic structure of rings of C60

    NASA Astrophysics Data System (ADS)

    Tan, Jerry; Bryant, Garnett

    Recently, rings of C60 have been fabricated. This opens up the possibility of studying the electronic structure of complex nanosystems with competing length scales: here the length scale defined by individual C60 molecules, the length scale defined by moving along the inner edge of the ring of C60s, and the length scale for the outer edge. The effects of such competing length scales could be probed with a magnetic field B. We use a tight-binding model to study these effects theoretically. Noninteracting electrons are considered. B is included with a Peierls transformation. Calculated electronic spectrum for an isolated ring of carbons, here used as a simple model for C60, is compared with spectra for rings of carbon rings. Changes in spectra due to inter-ring hopping are identified. New structure in the density of states is correlated with the spatial distribution of states in rings of rings. A magnetic field is applied to access and couple different length scales. Calculated spectra for rings of full C60 molecules are compared with the model results to highlight the effects of competing length scales in C60 rings. Results are used to suggest possible experiments for rings of C60 molecules.

  5. High-temperature reactions of C 60 with polycyclic aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Martin, Natalia M.; Luzan, Serhiy M.; Talyzin, Alexandr V.

    2010-02-01

    Fullerenes are proposed as a precursor for preparation of nanocarbon materials using controlled collapse of cage structure by high temperature reaction with polycyclic aromatic hydrocarbons. The chemical modification of C 60 by reaction with anthracene and coronene was studied over a broad temperature interval. The products of the reaction were characterized by X-ray diffraction, and Raman and IR spectroscopy. Mono- and multi-adducts of C 60 with anthracene were obtained in the temperature interval 290-400 °C. Above 400 °C the C 60 adducts are not stable and decompose back to C 60 and anthracene. No chemical adducts of C 60 with coronene were found below 500 °C. Above this temperature fullerite structure was found to expand reflecting interaction with coronene melt and vapor. The reactions of C 60 with anthracene and C 60 with coronene at temperatures above 650 °C resulted in fullerene cage collapse and formation of nanocarbons. These nanocarbons were found to store up to 0.45 wt% of hydrogen at ambient temperatures despite negligible surface area.

  6. Molecular dynamics simulations on the interactions of low molecular weight natural organic acids with C60.

    PubMed

    Sun, Qian; Xie, Hong-Bin; Chen, Jingwen; Li, Xuehua; Wang, Zhuang; Sheng, Lianxi

    2013-07-01

    As an important part of dissolved organic matter (DOM), low molecular weight organic acids (LOAs) may play a key role in the process for DOM stabilizing carbon nanomaterials (e.g. C60) suspensions in aquatic environment. In addition, both LOAs and C60 have been detected in the troposphere and therefore have a chance to interact with each other in the gaseous phase. However, the mechanism for LOAs-C60 interactions and their environmental implications need further investigations. In this study, molecular dynamics (MD) simulation was employed to investigate the interactions between both neutral and ionic LOAs with C60 in vacuum and water. The results showed that the adsorptions of all LOAs on C60 in energy are favorable, and the aromatic acids have stronger interactions with C60 than the aliphatic acids in vacuum and water. The interaction energies (Eint) of the LOA anions with C60 were weaker than those of their corresponding neutral LOA molecules. The models were also developed to predict and interpret Eint based on the results from MD simulations. Dispersion, induction and hydrophobic interactions were found to be the dominating factor in Eint. These findings indicate that cost-efficient MD simulation can be employed as an important tool to predict the adsorption behavior of LOAs on carbon nanomaterials.

  7. STM study of C60F18 high dipole moment molecules on Au(111)

    NASA Astrophysics Data System (ADS)

    Bairagi, K.; Bellec, A.; Chumakov, R. G.; Menshikov, K. A.; Lagoute, J.; Chacon, C.; Girard, Y.; Rousset, S.; Repain, V.; Lebedev, A. M.; Sukhanov, L. P.; Svechnikov, N. Yu.; Stankevich, V. G.

    2015-11-01

    Scanning tunneling microscopy and spectroscopy studies of C60F18 molecules deposited on Au(111) are reported and compared to C60 molecules both at liquid helium temperature and room temperature (RT). Whereas adsorption and electronic properties of C60F18 single molecules were studied at low temperature (LT), self-assemblies were investigated at RT. In both cases, the fluorine atoms of the C60F18 molecules are pointed towards the surface. Individual C60F18 molecules on Au(111) have a HOMO-LUMO gap of 2.9 eV. The self-assembled islands exhibit a close-packed hexagonal lattice with amorphous borders. The comparison with C60 molecules clearly demonstrates the influence of the C60F18 electric dipole moment (EDM) on the electronic properties of single molecules and on the thermodynamics of self-assembled islands. Besides, the apparent height value of a separate molecule increases in a self-assembly environment as a result of a depolarization phenomenon.

  8. Vibrational properties of polymer and quenched CsC{60} phases

    NASA Astrophysics Data System (ADS)

    Sauvajol, J.-L.; Anglaret, E.; Chesnel, K.; Palpacuer, M.; Girard, A.; Moreac, A.; Ameline, J.-C.; Delugeard, Y.; Hennion, B.

    1998-06-01

    We report new results on the vibrational dynamics of polymer and quenched CSC{60} phases. Both the splitting and the structure of new activated lines of polymer CsC{60} are in agreement with the lowering of C{60} molecular symmetry from Ih to D{2h}. An inelastic neutron investigation on polymer and quenched CsC{60} is reported. It allows one to identify the vibrational signature of the low-temperature (T < 150 K) ordered monomer phase on quenched CsC{60}. Nous présentons un certain nombre de résultats originaux concernant la dynamique vibrationnelle de la phase polymère et des phases obtenues par trempe du CsC{60}. Les spectres infrarouge de la phase polymère sont interprétés dans le cadre d'un abaissement de la symétrie du monomère C{60} de Ih à D{2h}. Une étude par diffusion neutronique de la phase polymère et des phases obtenues par trempe a été réalisée. Elle a permis en particulier de déterminer la 'signature' vibrationnelle d'une phase ordonnée monomère à très basse température (T < 150 K) dans le CsC{60} trempé.

  9. Molecular dynamics study on the C60 oscillator in a graphene nanoribbon trench

    NASA Astrophysics Data System (ADS)

    Kang, Jeong Won; Lee, Kang Whan

    2014-07-01

    Here, we present a C60 oscillator encapsulated in a graphene nanoribbon (GNR) trench. The mechanisms of the C60/GNR-trench oscillators are the same as those of the multi-walled carbonnanotube (CNT) oscillators. While the array synthesis of these CNT oscillators is very difficult, the same GNR trench array can be implemented by using current nanofabrication processes. The oscillatory behaviors of a C60 oscillator sucked into a GNR trench were investigated in impulse dynamics via classical molecular dynamics simulations. The oscillatory motions of the C60 oscillator in the GNR trench can be controlled by using the length and the width of the trench as structural parameters because the restoring forces acting on the C60 oscillator are related to the width of the GNR trench and the length of the GNR trench is the direct distance of motion of the C60 oscillator during translation. C60/GNR-trench nanostructures have a wide range of applications in nanotechnology, such as shuttle memories and switches, sensors, and oscillators.

  10. Polyamide 12/ fullerene C60 composites: Investigation on their mechanical and dielectric properties

    NASA Astrophysics Data System (ADS)

    Zuev, Vjacheslav V.

    2014-05-01

    The effect of fullerene C60 on mechanical properties of polymer nanocomposites based on PA12 was investigated. The nanocomposites were prepared by in situ polymerization. The Young's modulus and tensile strength of the polymer nanocomposites are improved by about 20% with loading of 0.02-0.08 wt.% the fullerene C60. Dielectric spectroscopy was used to investigate the influence of nanoparticles on the relaxation processes in polymer matrix. The segmental relaxation processes become faster with the fullerene C60 addition, an effect associated with a decrease of the glass transition temperature. In contrast, the secondary or γ relaxation process of PA12/ fullerene C60 nanocomposites was observed to slow down with addition of fullerene C60. These observations indicate that fullerene C60 as filler has an effect opposite to antiplasticizing that slow down the secondary relaxation (stiffening the material) in the glass state, while at the same time reducing the alpha relaxation time associated with cooperative segmental motions. It behaviour can be connected with inclusion complex formation between PA12 and fullerene C60.

  11. First principles study on the electronic transport properties of C60 and B80 molecular bridges

    NASA Astrophysics Data System (ADS)

    Zheng, X. H.; Hao, H.; Lan, J.; Wang, X. L.; Shi, X. Q.; Zeng, Z.

    2014-08-01

    The electronic transport properties of molecular bridges constructed by C60 and B80 molecules which have the same symmetry are investigated by first principles calculations combined with a non-equilibrium Green's function technique. It is found that, like C60, monomer B80 is a good conductor arising from the charge transfer from the leads to the molecule, while the dimer (B80)2 and (C60)2 are both insulators due to the potential barrier formed at the molecule-molecule interface. Our further study shows that, although both the homogeneous dimer (B80)2 and (C60)2 display poor conductivity, the heterogeneous dimer B80C60 shows a very high conductance as a result from the decreased HOMO-LUMO gap and the excess charge redistribution. Finally, we find that the conductivity of both (B80)2 and (C60)2 can be significantly improved by electron doping, for example, by doping C in (B80)2 and doping N in (C60)2.

  12. Bioaccumulation of fullerene (C60) and corresponding catalase elevation in Lumbriculus variegatus.

    PubMed

    Wang, Jiafan; Wages, Mike; Yu, Shuangying; Maul, Jonathan D; Mayer, Greg; Hope-Weeks, Louisa; Cobb, George P

    2014-05-01

    Fullerene (C(60)), with its unique physical properties and nanometer size, has been mass-produced for many applications in recent decades. The increased likelihood of direct release into the environment has raised interest in understanding both the environmental fate and corresponding biological effects of fullerenes to living organisms. Because few studies have emphasized fullerene uptake and resulting biochemical responses by living organisms, a toxicity screening test and a 28-d bioaccumulation test for Lumbriculus variegatus were performed. No mortality was observed in the range of 0.05 mg C(60) /kg dry sediment to 11.33 mg C(60) /kg dry sediment. A biota-sediment accumulation factor of micron-sized fullerene agglomerates (µ-C(60)) was 0.032 ± 0.008 at day 28, which is relatively low compared with pyrene (1.62 ± 0.22). Catalase (CAT) activity, an oxidative stress indicator, was elevated significantly on day 14 for L. variegatus exposed to µ-C(60) (p = 0.034). This peak CAT activity corresponded to the highest body residues observed in the present study, 199 ± 80 µg C(60) /kg dry weight sediment. Additionally, smaller C(60) agglomerate size increased bioaccumulation potential in L. variegatus. The relationship between C(60) body residue and the increased CAT activity followed a linear regression. All results suggest that C(60) has a lower bioaccumulation potential than pyrene but a higher potential to induce oxidative stress in L. variegatus.

  13. Removal of aqueous nC60 fullerene from water by low pressure membrane filtration.

    PubMed

    Floris, R; Nijmeijer, K; Cornelissen, E R

    2016-03-15

    The potential environmental and health risks of engineered nanoparticles such as buckminsterfullerene C60 in water require their removal during the production of drinking water. We present a study focusing on (i) the removal mechanism and (ii) the elucidation of the role of the membrane pore size during removal of nC60 fullerene nanoparticle suspensions in dead-end microfiltration and ultrafiltration mimicking separation in real industrial water treatment plants. Membranes were selected with pore sizes ranging from 18 nm to 500 nm to determine the significance of the nC60 to membrane pore size ratio and the adsorption affinity between nC60 and membrane material during filtration. Experiments were carried out with a dead-end bench-scale system operated at constant flux conditions including a hydraulic backwash cleaning procedure. nC60 nanoparticles can be efficiently removed by low pressure membrane technology with smaller and, unexpectedly, also by mostly similar or larger pores than the particle size, although the nC60 filtration behaviour appeared to be different. The nC60 size to membrane pore size ratio and the ratio of the cake-layer deposition resistance to the clean membrane resistance, both play an important role on the nC60 filtration behaviour and on the efficiency of the backwash procedure recovering the initial membrane filtration conditions. These results become specifically significant in the context of drinking water production, for which they provide relevant information for an accurate selection between membrane processes and operational parameters for the removal of nC60 in the drinking water treatment.

  14. Enhanced brain penetration of hexamethonium in complexes with derivatives of fullerene C60.

    PubMed

    Piotrovskiy, L B; Litasova, E V; Dumpis, M A; Nikolaev, D N; Yakovleva, E E; Dravolina, O A; Bespalov, A Yu

    2016-05-01

    The present report describes development of hexamethonium complexes based on fullerene C60. Hexamethonium has a limited penetration into CNS and therefore can antagonize central effects of nicotine only when given at high doses. In the present studies conducted in laboratory rodents, intraperitoneal administration of hexamethonium-fullerene complexes blocked effects of nicotine (convulsions and locomotor stimulation). When compared to equimolar doses of hexamethonium, complexes of hexamethonium with derivatives of fullerene C60 were 40 times more potent indicating an enhanced ability to interact with central nicotine receptors. Thus, fullerene C60 derivatives should be explored further as potential carrier systems for polar drug delivery into CNS.

  15. Intramolecular features of individual C 60 molecules on Si(100) observed by STM

    NASA Astrophysics Data System (ADS)

    Yao, Xiaowei; Ruskell, Todd G.; Workman, Richard K.; Sarid, Dror; Chen, Dong

    1996-12-01

    Intramolecular features (IMF) of a variety of individual C 60 molecules adsorbed on an Si(100)-(2 × 1) surface have been imaged by scanning tunneling microscopy under ultrahigh vacuum conditions. Features of individual C 60 molecules clearly show the local density of states superimposed on their cage structure. Both physisorbed (pre-annealed) and chemisorbed (post-annealed) species have been imaged on the same surface, exhibiting characteristics that depend on their bonding nature. Intramolecular features of a physisorbed C 60 molecule and of two chemisorbed molecules are presented.

  16. Analysis of C60 insertion into single wall carbon nanotube by molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Ishii, Takafumi; Esfarjani, Keivan; Hashi, Yuichi; Kawazoe, Yoshiyuki; Iijima, Sumio

    2001-10-01

    Classical molecular dynamics is used to simulate the insertion of C60 into a (10, 10) single wall nano tube (SWNT). We propose that the insertion process occurs through the open end of the tube. After insertion, the energy exchange between the C60 and the nanotube causes the kinetic energy of the former to decrease as it moves inside the tube. This kinetic energy loss is due to a "friction force" which we calculated for several insertion conditions. The binding energy of the C60 with the SWNT is due to Van der Waals interaction, and is found to be about 3.5 eV.

  17. Antiferromagnetic resonance in the Mott insulator fcc-Cs3C60.

    PubMed

    Suzuki, Yuta; Shibasaki, Seiji; Kubozono, Yoshihiro; Kambe, Takashi

    2013-09-11

    The magnetic ground state of the fcc phase of the Mott insulator Cs3C60 was studied using a low-temperature electron spin resonance technique, and antiferromagnetic resonance (AFMR) below 1.57 K was directly observed at ambient pressure. The AFMR modes for the fcc phase of Cs3C60 were investigated using a conventional two-sublattice model with uniaxial anisotropy, and the spin-flop field was determined to be 4.7 kOe at 1.57 K. The static magnetic exchange interactions and anisotropy field for fcc-Cs3C60 were also estimated.

  18. Charge-exchange collisions of C 60z+ : a probe of the ion charge distribution

    NASA Astrophysics Data System (ADS)

    Cameron, Douglas B.; Parks, Joel H.

    1997-06-01

    We present Paul trap measurements of charge-exchange collisions of Li, Cs and C 60 with C 60z+ ions ( z = 1-3) at thermal energies. Surprisingly, the measured charge-exchange rates for each neutral species are not proportional to the ion charge z as would be expected for Langevin collisions involving a uniformly charged ion. The relative rates can be reproduced by a model based on a symmetric distribution of point charges that are free to move on the ion surface during the neutral trajectory. Such behavior can be attributed to static and possibly dynamic Jahn-Teller effects in C 60z+ ions.

  19. Is the ground state of A1C60 (A=Rb, Cs) antiferromagnetic?

    NASA Astrophysics Data System (ADS)

    Rahmer, J.; Knorr, S.; Grupp, A.; Mehring, M.; Hone, J.; Zettl, A.

    1999-09-01

    EPR measurements in the metallic and the low-temperature orthorhombic phases of Rb1C60 and Cs1C60 powder samples have been performed at 9, 34, and 94 GHz. Detailed analysis reveals that all line features emerging in the low-temperature phase can be assigned to paramagnetic defects. We conclude that, in contrast to previous interpretations of the data, no signs of antiferromagnetic resonance (AFMR) have been observed. Furthermore we report on 94 GHz measurements of Rb1C60 single crystals which show a clear angular dependence in the metallic regime.

  20. Entrapping of exohedral metallofullerenes in carbon nanotubes: (CsC60)n@SWNT nano-peapods.

    PubMed

    Sun, Bao-Yun; Sato, Yuta; Suenaga, Kazutomo; Okazaki, Toshiya; Kishi, Naoki; Sugai, Toshiki; Bandow, Shunji; Iijima, Sumio; Shinohara, Hisanori

    2005-12-28

    Exohedral C60-based metallofullerenes, CsC60, have been synthesized and successfully encapsulated into single-wall carbon nanotubes (SWNTs) in high yield by reducing C60 molecules into anions. High-resolution transmission electron microscopy (HRTEM) images and in situ electron energy loss spectroscopy (EELS) indicate that Cs atoms and C60 molecules align within SWNTs as CsC60 exohedral metallofullerenes, and that the formal charge state of encaged CsC60 is expressed as Cs+1C60-1. The present peapods with the exohedral metallofullerenes provide a new insight and the possibility to fine-tune the electronic and transport properties of carbon nanotubes.

  1. C60 SIMS with a Hybrid-Quadrupole Orthogonal time-of-flight Mass Spectrometer

    PubMed Central

    Carado, Anthony; Passarelli, M. K.; Kozole, Joseph; Wingate, J. E.; Winograd, Nicholas; Loboda, A. V.

    2009-01-01

    A hybrid quadrupole orthogonal time-of-flight mass spectrometer optimized for MALDI and electrospray ionization has been equipped with a C60 cluster ion source. This configuration is shown to exhibit a number of characteristics that improve the performance of traditional time-of-flight secondary ion mass spectrometry (SIMS) experiments for the analysis of complex organic materials, and potentially, for chemical imaging. Specifically, the primary ion beam is operated as a continuous rather than a pulsed beam, resulting in up to 4 orders of magnitude greater ion fluence on the target. The secondary ions are extracted at very low voltage into 8 millitorr of N2 gas introduced for collisional focusing and cooling purposes. This extraction configuration is shown to yield secondary ions that rapidly lose memory of the mechanism of their birth, yielding tandem mass spectra that are identical for SIMS and MALDI. With implementation of ion trapping, the extraction efficiency is shown to be equivalent to that found in traditional TOF-SIMS machines. Examples are given, for a variety of substrates that illustrate mass resolution of 12,000–15,600 with mass range for inorganic compounds to m/z 40,000. Preliminary chemical mapping experiments show that with added sensitivity, imaging in the MS/MS mode of operation is straightforward. In general, the combination of MALDI and SIMS is shown to add capabilities to each technique, providing a robust platform for TOF-SIMS experiments that already exists in a large number of laboratories. PMID:18844371

  2. The structure of K3C60 and the mechanism of superconductivity.

    PubMed Central

    Pauling, L

    1991-01-01

    Analysis of the interatomic distances in the superconducting substance K3C60 indicates that each of the K atoms in tetrahedral interstices between C60 spheres accepts three electrons from C60, thus becoming quadricovalent; its four bonds resonate among the 24 adjacent carbon atoms to give a strong framework in which the negative charges are localized on these K atoms. The electric current is carried by the motion of positive charges (holes) through the network of C60 spheres and the K atoms in octahedral holes. Superconductivity is favored by the localization of the negative charges on the tetrahedral K atoms and their noninvolvement in valence-bond resonance, decreasing the rate of mutual extinction of electrons and holes. PMID:11607222

  3. High pressure infrared spectroscopy study on C60∗CS2 solvates

    NASA Astrophysics Data System (ADS)

    Du, Mingrun; Zhou, Miao; Yao, Mingguang; Ge, Peng; Chen, Shuanglong; Yang, Xigui; Liu, Ran; Liu, Bo; Cui, Tian; Sundqvist, Bertil; Liu, Bingbing

    2017-02-01

    High pressure IR study has been carried out on C60∗CS2 solvates up to 34.8 GPa. It is found that the intercalated CS2 molecules significantly affect the transformations of C60 molecules under pressure. As a probe, the intercalated CS2 molecules can well detect the orientational ordering transition and deformation of C60 molecules under pressure. The chemical stability of CS2 molecules under pressure is also dramatically enhanced due to the spacial shielding effet from C60 molecules around in the solvated crystal. These results provide new insight into the effect of interactions between intercalants and fullerenes on the transformations in fullerene solvates under pressure.

  4. Azafullerene C 59N, a stable free radical substituent in crystalline C 60

    NASA Astrophysics Data System (ADS)

    Fülöp, Ferenc; Rockenbauer, Antal; Simon, Ferenc; Pekker, Sándor; Korecz, László; Garaj, Slaven; Jánossy, András

    2001-02-01

    Solid solutions of C 59N azafullerene in C 60 with concentrations of 10 -5 to 10 -4 were produced in large quantities in an electric gas discharge tube. C 59N is a stable monomeric substituent molecule in crystalline C 60. The isotropic 14N and 13C hyperfine coupling constants measured by electron spin resonance (ESR) are characteristic of the extent of delocalization of the charge over the cage and are a sensitive test of electronic structure calculations. The C 59N reorientational activation energy measured below the face centered cubic (fcc) to simple cubic (sc) transition is 2300 K. This value is similar to that of the matrix C 60 molecules, indicating that C 59N-C 60 intermolecular interactions are weak.

  5. Rotational reorientation dynamics of C60 in various solvents. Picosecond transient grating experiments

    NASA Astrophysics Data System (ADS)

    Rubtsov, I. V.; Khudiakov, D. V.; Nadtochenko, V. A.; Lobach, A. S.; Moravskii, A. P.

    1994-11-01

    The picosecond transient grating technique has been used to study the rotational reorientation of C60 in various solvents: in toluene 7 +/- 1.5 ps, o-dichlorobenzene 10.3 +/- 1.5 ps, o-xylene 13 +/- 2 ps and in decalin 3.5 +/- 1.5 ps. The data obtained cannot be described by hydrodynamic Debye theory. Rough-sphere fluid theory predicts the correct values for C60 rotation in toluene, o-dichlorobenzene and in decalin. The deviations for o-xylene are probably connected with the specifics of the local solvent structure or with the stronger interaction of C60 with solvent molecules. The rotation of C60 in decalin is rapid and approaches the rotation in the gas phase determined by inertia.

  6. Attosecond study of confinement in photoionization of xenon caged in C60

    NASA Astrophysics Data System (ADS)

    Magrakvelidze, Maia; Dixit, Gopal; Madjet, Mohamed; Chakraborty, Himadri

    2015-05-01

    Effects of atom-fullerene orbital hybridization and C60 cavity on the attosecond time delay of the photoionization of Xe in the Xe@C60 endohedral molecule are investigated using time dependent local density approximation (TDLDA) augmented by the Leeuwen and Baerends exchange-correlation functional. TDLDA Wigner-Smith delay is found to modify via three distinct mechanisms: (i) Screening (or anti-screening) of the atomic valence emission due to the plasmonic motions of C60 charge cloud; (ii) dynamical interactions between Xe Cooper minima and C60 cavity minima; and (iii) confinement oscillations in the photoionization of inner 4d shell of Xe from the resonant formation of standing waves inside the cavity. The effects may be experimentally accessible by the so called RABITT metrology. This work was supported by the U.S. National Science Foundation.

  7. Thermodynamic properties of solid face centered cubic Rb3C60 at high temperature and pressure

    NASA Astrophysics Data System (ADS)

    Yang, W.; Sun, J. X.; Liu, H.; Yan, G. F.

    2014-03-01

    Analytic equation of state and thermodynamic quantities of solid fcc Rb3C60 are derived by using an analytic mean field potential method. For intermolecular forces, the double-exponential potential is utilized. Four potential parameters are determined by fitting experimental compression data of Rb3C60 up to 14 GPa at 296 K. Various physical quantities including isothermals, thermal expansion, isochoric heat capacity, Helmholtz free energy and internal energy are calculated and analyzed. Calculated results are consistent with available experimental data in literature. Furthermore, spinodal temperature for Rb3C60 is found to be 2,860 K. Results verify that analytic mean field potential method is a useful approach to consider the anharmonic effect at high temperatures. Numerous reasonable predictions and the change trend of the properties for Rb3C60 at high temperature and pressure have been given.

  8. Structural transitions of SWNT filled with C60 under high pressure

    NASA Astrophysics Data System (ADS)

    Yong-gang, Zou; Li, Xu; Kun, Tian; He, Zhang; Xiao-hui, Ma; Ming-guang, Yao

    2016-05-01

    Raman spectra of C60 filled single-walled carbon nanotubes (C60@SWNTs) with diameters of 1.3-1.5 nm have been studied under high pressure. A plateau in the pressure dependence of the G-band frequency at around 10 GPa was observed in both experiments with 514 nm and 830 nm excitation lasers, which is similar to the high pressure behaviors of pristine SWNTs. This structural transition has been assigned to the transformation into a peanut-like structure of the nanotubes. At pressure below 2 GPa, no obvious Raman signature related to the structural transition of nanotubes was observed, unlike what has been reported for C70 filled nanotubes. We discussed this point in terms of the arrangement differences of C60 and C70 molecules inside the nanotubes. At higher pressure up to 15 GPa, a graphite-like pressure evolution was observed in our C60@SWNTs.

  9. Spectromicroscopy of C60 and azafullerene C59N: Identifying surface adsorbed water.

    PubMed

    Erbahar, Dogan; Susi, Toma; Rocquefelte, Xavier; Bittencourt, Carla; Scardamaglia, Mattia; Blaha, Peter; Guttmann, Peter; Rotas, Georgios; Tagmatarchis, Nikos; Zhu, Xiaohui; Hitchcock, Adam P; Ewels, Chris P

    2016-10-17

    C60 fullerene crystals may serve as important catalysts for interstellar organic chemistry. To explore this possibility, the electronic structures of free-standing powders of C60 and (C59N)2 azafullerenes are characterized using X-ray microscopy with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, closely coupled with density functional theory (DFT) calculations. This is supported with X-ray photoelectron spectroscopy (XPS) measurements and associated core-level shift DFT calculations. We compare the oxygen 1s spectra from oxygen impurities in C60 and C59N, and calculate a range of possible oxidized and hydroxylated structures and associated formation barriers. These results allow us to propose a model for the oxygen present in these samples, notably the importance of water surface adsorption and possible ice formation. Water adsorption on C60 crystal surfaces may prove important for astrobiological studies of interstellar amino acid formation.

  10. Spectromicroscopy of C60 and azafullerene C59N: Identifying surface adsorbed water

    PubMed Central

    Erbahar, Dogan; Susi, Toma; Rocquefelte, Xavier; Bittencourt, Carla; Scardamaglia, Mattia; Blaha, Peter; Guttmann, Peter; Rotas, Georgios; Tagmatarchis, Nikos; Zhu, Xiaohui; Hitchcock, Adam P.; Ewels, Chris P.

    2016-01-01

    C60 fullerene crystals may serve as important catalysts for interstellar organic chemistry. To explore this possibility, the electronic structures of free-standing powders of C60 and (C59N)2 azafullerenes are characterized using X-ray microscopy with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, closely coupled with density functional theory (DFT) calculations. This is supported with X-ray photoelectron spectroscopy (XPS) measurements and associated core-level shift DFT calculations. We compare the oxygen 1s spectra from oxygen impurities in C60 and C59N, and calculate a range of possible oxidized and hydroxylated structures and associated formation barriers. These results allow us to propose a model for the oxygen present in these samples, notably the importance of water surface adsorption and possible ice formation. Water adsorption on C60 crystal surfaces may prove important for astrobiological studies of interstellar amino acid formation. PMID:27748425

  11. High-efficiency palladium catalysts supported on ppy-modified C60 for formic acid oxidation.

    PubMed

    Bai, Zhengyu; Yang, Lin; Guo, Yuming; Zheng, Zhi; Hu, Chuangang; Xu, Pengle

    2011-02-14

    A facile preparation of polypyrrole-modified fullerene supported Pd nanoparticles catalyst is introduced; electrochemical measurements demonstrate that the obtained Pd/ppy-C(60) catalyst shows a good electrocatalytic activity and stability for the oxidation of formic acid.

  12. Spectromicroscopy of C60 and azafullerene C59N: Identifying surface adsorbed water

    NASA Astrophysics Data System (ADS)

    Erbahar, Dogan; Susi, Toma; Rocquefelte, Xavier; Bittencourt, Carla; Scardamaglia, Mattia; Blaha, Peter; Guttmann, Peter; Rotas, Georgios; Tagmatarchis, Nikos; Zhu, Xiaohui; Hitchcock, Adam P.; Ewels, Chris P.

    2016-10-01

    C60 fullerene crystals may serve as important catalysts for interstellar organic chemistry. To explore this possibility, the electronic structures of free-standing powders of C60 and (C59N)2 azafullerenes are characterized using X-ray microscopy with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, closely coupled with density functional theory (DFT) calculations. This is supported with X-ray photoelectron spectroscopy (XPS) measurements and associated core-level shift DFT calculations. We compare the oxygen 1s spectra from oxygen impurities in C60 and C59N, and calculate a range of possible oxidized and hydroxylated structures and associated formation barriers. These results allow us to propose a model for the oxygen present in these samples, notably the importance of water surface adsorption and possible ice formation. Water adsorption on C60 crystal surfaces may prove important for astrobiological studies of interstellar amino acid formation.

  13. Orientational order in the stable buckminster fullerene solvate C60·2CBr2H2

    NASA Astrophysics Data System (ADS)

    Ye, J.; Barrio, M.; Negrier, Ph.; Qureshi, N.; Rietveld, I. B.; Céolin, R.; Tamarit, J. Ll.

    2017-04-01

    Crystals of the solvate C60·2CBr2H2 (monoclinic C2/ m), which is stable in air, were grown by slow evaporation of solutions of C60 in CBr2H2 at room temperature. The high enthalpy change for the complete desolvation process, 54.9 kJ mol-1 of solvent, as well as the relatively large negative excess volume of -49.6 Å3 indicate the presence of strong intermolecular interactions between C60 and CBr2H2. The strong intermolecular interactions are consistent with an overall orientational order for the C60 and the CBr2H2 molecules in the solvate as found by the Rietveld refinement of its crystal structure.

  14. Spectroscopic study on the interaction of pristine C60 and serum albumins in solution

    NASA Astrophysics Data System (ADS)

    Liu, Shufang; Sui, Yu; Guo, Kai; Yin, Zhijuan; Gao, Xibao

    2012-08-01

    The interaction of nanomaterials with biological macromolecules is an important foundation of the design and the biological safety assessments of nanomaterials. This work aims to investigate the interaction between pristine C60 and serum albumins (human serum albumin and bovine serum albumin) in solution. Stable aqueous dispersion of C60 was prepared by simple direct ultrasonic method and characterized by UV-vis spectrophotometry, transmission electronic microscopy and dynamic light scattering techniques, and spectroscopic methods (fluorescence spectroscopy, synchronous fluorescence spectroscopy and circular dichroism spectroscopy) were utilized for the investigation. It was found that the fluorescence of serum albumins could be quenched by C60 nanoparticles in a substantially similar way. Slight changes of the surrounding microenvironment of amino residues were observed, while little effects on the protein secondary structure occurred. The different effects of dispersion methods on the interaction of C60 nanoparticles with serum protein were also compared and discussed.

  15. Preparation and surface enhanced Raman scattering behavior of Ag-coated C60 nanoclusters

    NASA Astrophysics Data System (ADS)

    Kang, Shi-Zhao; Yin, Die-er; Li, Xiangqing; Mu, Jin

    2013-12-01

    Ag-coated C60 nanoclusters were prepared and characterized with X-ray diffraction, transmission electron microscopy and nitrogen adsorption-desorption isotherm measurement. The Ag-coated C60 nanoclusters were assembled on the glass substrate to form a thin film using the layer-by-layer technique. Meanwhile, the surface enhanced Raman scattering (SERS) of musk xylene adsorbed on the film of Ag-coated C60 nanoclusters was explored. The results indicated that the film of Ag-coated C60 nanoclusters was a unique SERS-active substrate with a detection limit of 10-9 mol L-1 for musk xylene. Furthermore, the surface enhanced mechanisms were discussed preliminarily.

  16. Polymorphism control of superconductivity and magnetism in Cs(3)C(60) close to the Mott transition.

    PubMed

    Ganin, Alexey Y; Takabayashi, Yasuhiro; Jeglic, Peter; Arcon, Denis; Potocnik, Anton; Baker, Peter J; Ohishi, Yasuo; McDonald, Martin T; Tzirakis, Manolis D; McLennan, Alec; Darling, George R; Takata, Masaki; Rosseinsky, Matthew J; Prassides, Kosmas

    2010-07-08

    The crystal structure of a solid controls the interactions between the electronically active units and thus its electronic properties. In the high-temperature superconducting copper oxides, only one spatial arrangement of the electronically active Cu(2+) units-a two-dimensional square lattice-is available to study the competition between the cooperative electronic states of magnetic order and superconductivity. Crystals of the spherical molecular C(60)(3-) anion support both superconductivity and magnetism but can consist of fundamentally distinct three-dimensional arrangements of the anions. Superconductivity in the A(3)C(60) (A = alkali metal) fullerides has been exclusively associated with face-centred cubic (f.c.c.) packing of C(60)(3-) (refs 2, 3), but recently the most expanded (and thus having the highest superconducting transition temperature, T(c); ref. 4) composition Cs(3)C(60) has been isolated as a body-centred cubic (b.c.c.) packing, which supports both superconductivity and magnetic order. Here we isolate the f.c.c. polymorph of Cs(3)C(60) to show how the spatial arrangement of the electronically active units controls the competing superconducting and magnetic electronic ground states. Unlike all the other f.c.c. A(3)C(60) fullerides, f.c.c. Cs(3)C(60) is not a superconductor but a magnetic insulator at ambient pressure, and becomes superconducting under pressure. The magnetic ordering occurs at an order of magnitude lower temperature in the geometrically frustrated f.c.c. polymorph (Néel temperature T(N) = 2.2 K) than in the b.c.c.-based packing (T(N) = 46 K). The different lattice packings of C(60)(3-) change T(c) from 38 K in b.c.c. Cs(3)C(60) to 35 K in f.c.c. Cs(3)C(60) (the highest found in the f.c.c. A(3)C(60) family). The existence of two superconducting packings of the same electronically active unit reveals that T(c) scales universally in a structure-independent dome-like relationship with proximity to the Mott metal-insulator transition

  17. Depth profiling of taxol-loaded poly(styrene- b-isobutylene- b-styrene) using Ga + and C 60+ ion beams

    NASA Astrophysics Data System (ADS)

    Braun, R. M.; Cheng, J.; Parsonage, E. E.; Moeller, J.; Winograd, N.

    2006-07-01

    The surface of a triblock copolymer, containing a solid-phase drug, was investigated using 15 keV Ga + and 20 keV C 60+ ion beams. Overall, the results illustrate the successful use of a cluster ion beam for greatly enhancing the molecular ion and high-mass fragment ion intensities from the surface and bulk of the polymer system. The use of C 60+ also established the ability to see through common overlayers like poly(dimethyl siloxane) which was not possible using atomic ion sources. Moreover, the use of C 60+ allowed depth profiles to be obtained using primary ion dose densities in excess of 6 × 10 14 C 60+/cm 2. Resulting sputter craters possess relatively flat bottoms without the need for sample rotation and reached depths of ca. 2 μm. AFM results illustrate the more gentile removal of surface species using cluster ions. Specifically, phase contrast and topographic images suggest the relatively high ion doses do not significantly alter the phase distribution or surface topography of the polymer. However, a slight increase in rms roughness was noticed.

  18. Gas-phase Absorptions of C60+: A New Comparison with Astronomical Measurements

    NASA Astrophysics Data System (ADS)

    Walker, G. A. H.; Campbell, E. K.; Maier, J. P.; Bohlender, D.; Malo, L.

    2016-11-01

    Campbell et al. recently revised, by a few tenths of an Å, the wavelengths for their low-temperature laboratory measurements of fullerene {{{C}}}60+ bands. This accounts for the perturbation caused by the He atom to the {{{C}}}60+{--}{He} spectrum. Here, we demonstrate that the revised laboratory wavelengths improve coincidence with the 9632, 9577, 9428, 9365, and 9348 diffuse interstellar bands detected towards the stars HD 46711, HD 169454, and HD 183143.

  19. Prominent Charge-Transfer State at α-Sexithiophene/C60 Interface

    NASA Astrophysics Data System (ADS)

    Takahashi, Yousuke; Yonezawa, Kouhei; Kamioka, Hayato; Yasuda, Takeshi; Han, Liyuan; Moritomo, Yutaka

    2013-06-01

    We performed femtosecond time-resolved spectroscopy in α-sexithiophene (6T)/C60 bilayer and mixed films. We observed sharp and intense photoinduced absorption (PIA) at 1.2 eV and ascribed it to the charge-transfer (CT) state. The spectral features are interpreted in terms of homogenous molecular stacking at 6T/C60 interface and quantum confinement effect in 6T.

  20. Biodistribution and tumor uptake of C60(OH) x in mice

    NASA Astrophysics Data System (ADS)

    Ji, Zhi Qiang; Sun, Hongfang; Wang, Haifang; Xie, Qunying; Liu, Yuangfang; Wang, Zheng

    2006-02-01

    Radiolabeling of fullerol, 125I-C60(OH) x , was performed by the traditional chloramine-T method. The C-I covalent bond in I-C60(OH) x was characterized by X-ray photoelectron spectroscopy (XPS) that was sufficiently stable for in vivo study. Laser light scattering spectroscopy clearly showed that C60(OH) x aggregated to large nanoparticle clumps with a wide range of distribution. The clumps formed were also visualized by transmission electron microscope (TEM). We examined the biodistribution and tumor uptake of C60(OH) x in five mouse bearing tumor models, including mouse H22 hepatocarcinoma, human lung giantcellcarcinoma PD, human colon cancer HCT-8, human gastric cancer MGC803, and human OS732 osteosarcoma. The accumulation ratios of 125I-C60(OH) x in mouse H22 hepatocarcinoma to that in normal muscle tissue (T/N) and blood (T/B) at 1, 6, 24 and 72 h, reveal that 125I-C60(OH) x gradually accumulates in H22 tumor, and retains for a quite long period (e.g., T/N 3.41, T/B 3.94 at 24 h). For the other four tumor models, the T/N ratio at 24 h ranges within 1.21-6.26, while the T/B ratio ranges between 1.23 and 4.73. The accumulation of C60(OH) x in tumor is mostly due to the enhanced permeability and retention effect (EPR) and the phagocytosis of mononuclear phagocytes. Hence, C60(OH) x might serve as a photosensitizer in the photodynamic therapy of some kinds of tumor.

  1. Multichromophoric Perylenediimide-Silicon Phthalocyanine-C60 System as an Artificial Photosynthetic Analogue.

    PubMed

    Martín-Gomis, Luis; Peralta-Ruiz, Francisco; Thomas, Michael B; Fernández-Lázaro, Fernando; D'Souza, Francis; Sastre-Santos, Ángela

    2017-03-17

    Sequential photoinduced energy transfer followed by electron transfer and the formation of charge-separated states, which are primary events of natural photosynthesis, have been demonstrated in a newly synthesized multichromophoric covalently linked triad, PDI-SiPc-C60 . The triad comprises a perylenediimide (PDI), which primarily fulfils antenna and electron-acceptor functionalities, silicon phthalocyanine (SiPc) as an electron donor, and fulleropyrrolidine (C60 ) as a second electron acceptor. The multi-step convergent synthetic procedure developed here produced good yields of the triad and control dyads, PDI-SiPc and SiPc-C60 . The structures and geometries of the newly synthesized donor-acceptor systems have been established from spectral, computational, and electrochemical studies with reference to appropriate control compounds. Ultrafast energy transfer from (1) PDI* to SiPc in the case of PDI-SiPc and PDI-SiPc-C60 was witnessed. An energy-level diagram established from spectral and electrochemical data suggested the formation of two types of charge-separated states, that is, PDI-SiPc(.+) -C60(.-) and PDI(.-) -SiPc(.+) -C60 from the (1) SiPc* in the triad, with generation of the latter being energetically more favorable. However, photochemical studies involving femtosecond transient spectroscopy revealed the formation of PDI-SiPc(.+) -C60(.-) as a major charge-separated product. This observation may be rationalized in terms of the closer spatial proximity to SiPc of C60 compared to PDI in the triad. The charge-separated state persisted for a few nanoseconds prior to populating the (3) SiPc* state during charge recombination.

  2. Energy-level alignment at interfaces between manganese phthalocyanine and C60.

    PubMed

    Waas, Daniel; Rückerl, Florian; Knupfer, Martin; Büchner, Bernd

    2017-01-01

    We have used photoelectron spectroscopy to determine the energy-level alignment at organic heterojunctions made of manganese phthalocyanine (MnPc) and the fullerene C60. We show that this energy-level alignment depends upon the preparation sequence, which is explained by different molecular orientations. Moreover, our results demonstrate that MnPc/C60 interfaces are hardly suited for application in organic photovoltaic devices, since the energy difference of the two lowest unoccupied molecular orbitals (LUMOs) is rather small.

  3. Evidence for sp3 carbon atoms in the RbC60 dimer phase

    NASA Astrophysics Data System (ADS)

    Thier, K.-F.; Mehring, M.; Rachdi, F.

    1997-01-01

    High resolution 13C NMR experiments prove the existence of sp3 carbon atoms which are assigned to the dimer bonds in the quenched phase of RbC60. The relative intensities of the sp3 lines support a model where the C60 monomers are connected via a single bond. Spin-lattice relaxation measurements and 13C spectral changes reveal the transition to the polymer phase above 200 K.

  4. Effects of light energy and reducing agents on C60-mediated photosensitizing reactions.

    PubMed

    Quinones, Michael; Zhang, Yazhou; Riascos, Penelope; Hwang, Huey-Min; Aker, Winfred G; He, Xiaojia; Gao, Ruomei

    2014-01-01

    Many biomolecules contain photoactive reducing agents, such as reduced nicotinamide adenine dinucleotide (NADH) and 6-thioguanine (6-TG) incorporated into DNA through drug metabolism. These reducing agents may produce reactive oxygen species under UVA irradiation or act as electron donors in various media. The interactions of C60 fullerenes with biological reductants and light energy, especially via the Type-I electron-transfer mechanism, are not fully understood although these factors are often involved in toxicity assessments. The two reductants employed in this work were NADH for aqueous solutions and 6-TG for organic solvents. Using steady-state photolysis and electrochemical techniques, we showed that under visible light irradiation, the presence of reducing agents enhanced C60 -mediated Type-I reactions that generate superoxide anion (O2(.-)) at the expense of singlet oxygen ((1)O2) production. The quantum yield of O2(.-) production upon visible light irradiation of C60 is estimated below 0.2 in dipolar aprotic media, indicating that the majority of triplet C60 deactivate via Type-II pathway. Upon UVA irradiation, however, both C60 and NADH undergo photochemical reactions to produce O2(.-), which could lead to a possible synergistic toxicity effects. C60 photosensitization via Type-I pathway is not observed in the absence of reducing agents. © 2013 The American Society of Photobiology.

  5. C60 aminofullerene immobilized on silica as a visible-light-activated photocatalyst.

    PubMed

    Lee, Jaesang; Mackeyev, Yuri; Cho, Min; Wilson, Lon J; Kim, Jae-Hong; Alvarez, Pedro J J

    2010-12-15

    A new strategy is described to immobilize photoactive C(60) aminofullerene on silica gel (3-(2-succinic anhydride)propyl functionalized silica), thus enabling facile separation of the photocatalyst for recycling and repeated use. An organic linker moiety containing an amide group was used to anchor C(60) aminofullerene to the functionalized silica support. The linker moiety prevents aqueous C(60) aggregation/agglomeration (shown by TEM images), resulting in a remarkable enhancement of photochemical (1)O(2) production under visible light irradiation. With no loss in efficacy of (1)O(2) production plus insignificant chemical modification of the aminoC(60)/silica photocatalyst after multiple cycling, the system offers a promising new visible-light-activated photocatalyst. Under visible-light irradiation, the aminoC(60)/silica photocatalyst is capable of effective and kinetically enhanced oxidation of Ranitidine and Cimetidine (pharmaceutical pollutants) and inactivation of MS-2 bacteriophage compared to aqueous solutions of the C(60) aminofullerene alone. Thus, this photocatalyst could enable water treatment in less developed areas by alleviating dependence on major infrastructure, including the need for electricity.

  6. Differential photoactivity of aqueous [C60] and [C70] fullerene aggregates.

    PubMed

    Moor, Kyle J; Snow, Samuel D; Kim, Jae-Hong

    2015-05-19

    Many past studies have focused on the aqueous photochemical properties of colloidal suspensions of C60 and various [C60] fullerene derivatives, yet few have investigated the photochemistry of other larger cage fullerene species (e.g., C70, C74, C84, etc.) in water. This is a critical knowledge gap because these larger fullerenes may exhibit different properties compared to C60, including increased visible light absorption, altered energy level structures, and variable cage geometries, which may greatly affect aggregate properties and resulting aqueous photoactivity. Herein, we take the first steps toward a detailed investigation of the aqueous photochemistry of larger cage fullerene species, by focusing on [C70] fullerene. We find that aqueous suspensions of C60 and C70, nC60 and nC70, respectively, exhibit many similar physicochemical properties, yet nC70 appears to be significantly more photoactive than nC60. Studies are conducted to elucidate the mechanism behind nC70's superior (1)O2 generation, including the measurement of (1)O2 production as a function of incident excitation wavelength, analysis of X-ray diffraction data to determine crystal packing arrangements, and the excited state dynamics of aggregate fullerene species via transient absorption spectroscopy.

  7. Non-detection of C60 fullerene at two mass extinction horizons

    NASA Astrophysics Data System (ADS)

    Carrasquillo, Anthony J.; Cao, Changqun; Erwin, Douglas H.; Summons, Roger E.

    2016-03-01

    Fullerene (C60) have been reported in a number of geologic samples and, in some cases, attributed to carbonaceous materials delivered during bolide impact events. The extraction and detection of C60 poses significant analytical challenges, and some studies have been called into question due to the possibility of C60 forming in situ. Here, we extracted samples taken from the Permian-Triassic boundary section in Meishan, South China and the Cretaceous-Paleogene boundary exposed at Stevns Klint, Denmark, and analyzed the residues using a fast and reliable method for quantifying C60. Extraction of both whole rock and completely demineralized samples were completed under conditions that previously yielded C60 as well as using an optimized approach based on recent literature reports. These extracts were analyzed using mass spectrometry with the soft-ionization techniques, atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI), which have not been shown to form fullerenes in-situ. In no case were we able to detect C60, nor could we corroborate previous reports of its occurrence in these sediments, thereby challenging the utility of fullerene as a proxy for bolide impacts or mass extinction events.

  8. Preparation of C60 Nanowhiskers-SnO2 Nanocomposites and Photocatalytic Degradation of Organic Dyes.

    PubMed

    Park, Hae Soo; Ko, Weon Bae

    2015-10-01

    C60 nanowhiskers were prepared using a liquid-liquid interfacial precipitation (LLIP) method. Tin oxide (SnO2) nanoparticles were synthesized by a reaction of tin (IV) chloride pentahydrate with ammonium nitrate in an electric furnace. The C60 nanowhiskers-SnO2 nanocomposites were calcined in an electric furnace at 700 °C under an inert argon gas atmosphere for 2 h. The crystallinity, morphology and optical properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and UV-vis spectrophotometry. The photocatalytic activity of the C60 nanowhiskers-SnO2 nanocomposites in the degradation of the organic dyes, such as methylene blue, methyl orange, rhodamine B, and brilliant green, under ultraviolet light at 254 nm by UV-vis spectrophotometry was evaluated and compared with that of C60 nanowhiskers and SnO2 nanoparticles. The experimental results showed that C60 nanowhiskers-SnO2 nanocomposites exhibited remarkably higher photocatalytic degradation of organic dyes compared to C60 nanowhiskers and SnO2 nanoparticles.

  9. Potential Suppressive Effects of Two C60 Fullerene Derivatives on Acquired Immunity

    NASA Astrophysics Data System (ADS)

    Hirai, Toshiro; Yoshioka, Yasuo; Udaka, Asako; Uemura, Eiichiro; Ohe, Tomoyuki; Aoshima, Hisae; Gao, Jian-Qing; Kokubo, Ken; Oshima, Takumi; Nagano, Kazuya; Higashisaka, Kazuma; Mashino, Tadahiko; Tsutsumi, Yasuo

    2016-10-01

    The therapeutic effects of fullerene derivatives on many models of inflammatory disease have been demonstrated. The anti-inflammatory mechanisms of these nanoparticles remain to be elucidated, though their beneficial roles in allergy and autoimmune diseases suggest their suppressive potential in acquired immunity. Here, we evaluated the effects of C60 pyrrolidine tris-acid (C60-P) and polyhydroxylated fullerene (C60(OH)36) on the acquired immune response in vitro and in vivo. In vitro, both C60 derivatives had dose-dependent suppressive effects on T cell receptor-mediated activation of T cells and antibody production by B cells under anti-CD40/IL-4 stimulation, similar to the actions of the antioxidant N-acetylcysteine. In addition, C60-P suppressed ovalbumin-specific antibody production and ovalbumin-specific T cell responses in vivo, although T cell-independent antibodies responses were not affected by C60-P. Together, our data suggest that fullerene derivatives can suppress acquired immune responses that require T cells.

  10. C_60/Ferromagnet Composites: Observation of a Temperature-Dependent Crossover from Negative to Positive Magnetoresistance

    NASA Astrophysics Data System (ADS)

    Hudspeth, Q. M.; Arnason, S. B.; Hebard, A. F.

    2001-03-01

    In this work we report on the fabrication and characterization of composite thin films (M_xC_60) of C_60 with ferromagnetic metals (M). Magnetoresistance (MR) measurements will be presented for Ni_xC_60 samples with x in the range 20 - 90. A change in MR from negative (characteristic of pure Ni) at high temperatures to positive at low temperatures is observed as the sample temperature is decreased from 300 to 2 K. This crossover from negative to positive MR is similar to that seen below 1 K in phosphorous-doped silicon[1], and more recently at higher temperatures in Fe_1-yCo_ySi[2] and is attributed to quantum interference effects in the presence of Coulomb interactions with spin splitting. This interpretation can be tested for the M_xC_60 composites by comparing the MR of M_xC_60 (M= Fe, Co, Ni) with Gd_xC_60. In the Gd composite we would expect the positive MR to be absent since magnetism in Gd arises from local moments and the carriers are no longer responsible for both magnetism and conduction as they are in Fe_1-yCo_ySi. [1] T. F. Rosenbaum et al., Phys. Rev. Lett. 47, 1758 (1981). [2] N. Manyala, et al., Nature 404, 581 (2000).

  11. Fabrication of filamentary potassium-doped C 60 superconductors by suspension spinning method

    NASA Astrophysics Data System (ADS)

    Goto, T.; Maezawa, M.

    2004-10-01

    This paper describes the preparation of filamentary potassium-doped C 60 superconductors prepared by the suspension spinning method. Commercial C 60 powder was suspended in mixed poly(vinyl alcohol) solution of dimethyl sulfoxide and hexamethylphosphoric triamide (sample A). The viscous suspension was extruded as a filament into a precipitating medium of methyl alcohol and coiled on a drum. The filamentary sample was also prepared by the suspension spinning by using polyacrylonitrile solution of N, N-dimethylformamide (sample B). The samples were pyrolyzed to remove volatile components. Doping of potassium for the samples was prepared as following: At first, powder samples of nominal composition K 6C 60 was prepared by reaction of C 60 with excess potassium. The K 6C 60 powder and filamentary sample with stoichiometric ratio of K 3C 60 were placed in Pyrex glass tubes and vacuum-sealed and heated at 250 °C for 36 h. SQUID measurement shows the superconductivity of sample B with Tc=18 K. On the other hand, the superconductivity more than 2 K was not detected for sample A.

  12. The applications of buckminsterfullerene C60 and derivatives in orthopaedic research

    PubMed Central

    Liu, Qihai; Cui, Quanjun; Li, Xudong Joshua; Jin, Li

    2014-01-01

    Buckminsterfullerene C60 and derivatives have been extensively explored in biomedical research due to their unique structure and unparalleled physicochemical properties. C60 is characterized as a “free radical sponge” with an anti-oxidant efficacy several hundred-fold higher than conventional anti-oxidants. Also, the C60 core has a strong electron-attracting ability and numerous functional compounds with widely different properties can be added to this fullerene cage. This review focused on the applications of C60 and derivatives in orthopaedic research, such as the treatment of cartilage degeneration, bone destruction, intervertebral disc degeneration (IVDD), vertebral bone marrow disorder, radiculopathy, etc., as well as their toxicity in vitro and in vivo. We suggest that C60 and derivatives, especially the C60 cores coupled with functional groups presenting new biological and pharmacological activities, are advantageous in orthopaedic research and will be promising in clinical performance for musculoskeletal disorders treatment; however, the pharmacokinetics and toxicology of these agents as local/systemic administration need to be carefully determined. PMID:24409811

  13. Exploration and characterization of new synthesis methods for C60 colloidal suspensions in water

    NASA Astrophysics Data System (ADS)

    Hilburn, Martha E.

    Buckminsterfullerene, C60, has been used in the production of several commercial products from badminton racquets and lubricants for their mechanical properties to cosmetics and even dietary supplements for their "antioxidant" properties. Multi-ton production of C60 began in 2003 encouraging serious consideration of its fate in the environment in the case of an accidental release or improper disposal. Although C60 is practically insoluble in water, it readily forms stable aqueous colloidal suspensions (termed nC60) through solvent exchange methods or long-term vigorous stirring in water. Two new solvent exchange methods for synthesizing nC60 are presented. These methods combine key advantages of multiple existing synthesis methods including high yield, narrow particle size distribution, short synthesis time, and an absence of solvents such as tetrahydrofuran that have historically caused problems in laboratory synthesized aggregates. The resulting samples are attractive candidates for use in controlled environmental impact, biological, and toxicity studies. An improved method for quantifying residual solvents in nC60 samples utilizing solid phase micro extraction gas chromatography mass spectrometry (SPME-GC-MS) is also discussed.

  14. Caging effects in the low-temperature rotational spectra of endohedral diatomic molecules at C60 fullerene

    NASA Astrophysics Data System (ADS)

    Hernández-Rojas, J.; Bretón, J.; Gomez Llorente, J. M.

    1996-04-01

    Caging effects in the low-temperature (T=50 K) rotational spectra of CO@C60, LiF@C60, and LiH@C60 are investigated by first deriving an effective Hamiltonian to describe the coupled rotation of both, cage and confined molecule. Our results prove the close connection between the degree of anisotropy of the molecule-cage interaction and the features in the rotational spectra. If the anisotropy is weak, as in CO@C60, the spectra are dominated by the free rotation of the confined molecule. The stronger anisotropy in LiF@C60 and LiH@C60 produces more complex spectra dominated by librational motions and hindered rotations. The cage rotation plays a fundamental role in the spectral features, enhancing the CO free rotation in CO@C60, and broadening the librational bands in LiF@C60 and LiH@C60.

  15. Interaction of porphine and its metal complexes with C60 fullerene: a DFT study.

    PubMed

    Basiuk, Vladimir A

    2005-04-28

    We performed DFT calculations (BLYP general-gradient approximation in conjunction with a double numerical basis set) for the interaction of free porphine ligand and a number of its metal complexes with C60 molecule to analyze how the nature of a central metal ion influences the geometry and electronic characteristics (electrostatic potential and spin density distribution and highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) structure). We found that the presence of a central metal ion is crucial for a strong interaction. The energy of interaction between H2P and C60 is -0.3 kcal mol(-1) only, whereas the formation energies for the metal complexes vary from -27.3 kcal mol(-1) for MnClP.C60 to -45.8 kcal mol(-1) for MnP.C60. As a rule, the formation energy correlates with the separations between porphinate and fullerene molecules; the Mn and Fe complexes exhibit the closest approach of ca. 2.2 A between the metal ion and carbon atoms of C60. In most porphine-C60 complexes studied, the two closest contacts of central metal ion or H are those with carbon atoms of the (6,6) bond; VOP.C60 is the only exception, where the closest V...C contacts involve the (5,6) bond. The macrocycle geometry changes, and the magnitude of the effect depends on the central atom, being especially dramatic for Mn, MnCl, and Fe complexes. The shape of LUMOs in most complexes with C60 is not affected notably as compared to the LUMO of the isolated C60 molecule. In the case of Fe, the HOMO extends from the central atom to two opposite pyrrol rings. At the same time, the HOMO-LUMO gap energy decreases drastically in most cases, by ca. 20-30 kcal mol(-1). For electrostatic potential distribution, we systematically observed that the negative lobe contacting C60 shrinks, whereas the opposite one becomes notably bigger. In the case of paramagnetic complexes of VO, Mn, FeCl, Co, and Cu, spin density distribution was analyzed as well.

  16. Molecular dynamics simulations of sputtering of Langmuir-Blodgett multilayers by keV C60 projectiles

    PubMed Central

    Paruch, R.; Rzeznik, L.; Czerwinski, B.; Garrison, B. J.; Winograd, N.; Postawa, Z.

    2009-01-01

    Coarse-grained molecular dynamics computer simulations are applied to investigate fundamental processes induced by an impact of keV C60 projectile at an organic overlayer composed of long, well-organized linear molecules. The energy transfer pathways, sputtering yields, and the damage induced in the irradiated system, represented by a Langmuir-Blodgett (LB) multilayers composed from molecules of bariated arachidic acid, are investigated as a function of the kinetic energy and impact angle of the projectile and the thickness of the organic system. In particular, the unique challenges of depth profiling through a LB film vs. a more isotropic solid are discussed. The results indicate that the trajectories of projectile fragments and, consequently, the primary energy can be channeled by the geometrical structure of the overlayer. Although, a similar process is known from sputtering of single crystals by atomic projectiles, it has not been anticipated to occur during C60 bombardment due to the large size of the projectile. An open and ordered molecular structure of LB films is responsible for such behavior. Both the extent of damage and the efficiency of sputtering depend on the kinetic energy, the impact angle, and the layer thickness. The results indicate that the best depth profiling conditions can be achieved with low-energy cluster projectiles irradiating the organic overlayer at large off-normal angles. PMID:20174461

  17. Effects of humic and fulvic acids on aggregation of aqu/nC60 nanoparticles.

    PubMed

    Zhang, Wei; Rattanaudompol, U-Sa; Li, Hui; Bouchard, Dermont

    2013-04-01

    Aggregation of fullerene nanoparticles (nC(60)) is a fundamental process influencing its environmental fate and transport, and toxicity. Using time-resolved dynamic light scattering we systematically investigated aggregation kinetics of nC(60) generated from extended mixing in water (termed as aqu/nC(60)) in a range of symmetrical monovalent (NaCl) or divalent (MgSO(4)) electrolyte concentrations with the presence/absence of model natural organic matter (NOM), i.e., Suwannee River humic acid (SRHA) and fulvic acid (SRFA), at three pH levels (4, 7.8, 9.8). Electrophoretic mobility (EPM) data were interpreted according to the Ohshima's soft particle theory to obtain average characteristics of the adsorbed NOM layers, which was then used to explain the observed aggregation profiles. Results indicate that the presence of NOM stabilized aqu/nC(60), and SRHA was more effective than SRFA in suppressing aqu/nC(60) aggregation. The stabilization effect of NOM in the presence of NaCl was less pronounced than in the presence of MgSO(4), likely as a result of high aggregation potential of aqu/nC(60) in the presence of MgSO(4) due to effective charge screening and neutralization. The differential stabilization capacity between SRHA and SRFA could be explained by the structural and conformational characteristics of the adsorbed NOM layers by invoking steric repulsion, as determined by both the adsorbed layer thickness and the NOM affinity to aqu/nC(60). While this was true under most conditions, the discrepancy observed in the presence of MgSO(4) at pH 9.8 may be attributed to inter-particle aggregation through Mg(2+) binding with SRFA that is not included in steric repulsion theory. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Carbon fullerenes (C60s) can induce inflammatory responses in the lung of mice

    SciTech Connect

    Park, Eun-Jung; Kim, Hero; Kim, Younghun; Yi, Jongheop; Choi, Kyunghee; Park, Kwangsik

    2010-04-15

    Fullerenes (C60s) occur in the environment due to natural and anthropogenic sources such as volcanic eruptions, forest fires, and the combustion of carbon-based materials. Recently, production and application of engineered C60s have also rapidly increased in diverse industrial fields and biomedicine due to C60' unique physico-chemical properties, so toxicity assessment on environmental and human health is being evaluated as a valuable work. However, data related to the toxicity of C60s have not been abundant up to now. In this study, we studied the immunotoxic mechanism and change of gene expression caused by the instillation of C60s. As a result, C60s induced an increase in sub G1 and G1 arrest in BAL cells, an increase in pro-inflammatory cytokines such as IL-1, TNF-alpha, and IL-6, and an increase of Th1 cytokines such as IL-12 and IFN-r in BAL fluid. In addition, IgE reached the maximum at 1 day after treatment in both BAL fluid and the blood, and decreased in a time-dependent manner. Gene expression of the MHC class II (H2-Eb1) molecule was stronger than that of the MHC class I (H2-T23), and an increase in T cell distribution was also observed during the experiment period. Furthermore, cell infiltration and expression of tissue damage related genes in lung tissue were constantly observed during the experiment period. Based on this, C60s may induce inflammatory responses in the lung of mice.

  19. Metal-oxide-semiconductor diodes containing C60 fullerenes for non-volatile memory applications

    NASA Astrophysics Data System (ADS)

    Beckmeier, Daniel; Baumgärtner, Hermann

    2013-01-01

    For non-volatile memories, silicon-oxide-nitride-oxide-silicon or floating gate structures are used to store information by charging and discharging electronic states reversibly. In this article, we propose to replace the floating gate by C60 molecules. This would allow more defined programming voltages because of the discrete molecular energy levels and a higher resistance to tunneling oxide defects because of the weak electrical connection between the single molecules. Such C60 MOS diode structures are produced and their electrical properties are analyzed regarding current transport and charging mechanism of the molecules. To create the MOS structures, C60 molecules (5% of a monolayer) are evaporated onto a part of a clean silicon wafer and covered by amorphous silicon in situ in an ultra high vacuum system. Then the wafer is oxidized in wet atmosphere at just 710 °C through the C60 layer. The goal is to produce a clean oxide above and under the molecules without destroying them. Aluminum gate contacts are defined on top of these layers to perform complementary capacitance voltage (CV) and current voltage (IV) measurements. First, the gate voltage is swept to analyze the injection current, then CV measurements are performed after each sweep to analyze the charge state of the C60 layer and the oxide quality. Reference diodes without C60 on the same wafer show an identical Fowler-Nordheim (FN) tunneling behavior for currents injected from silicon or from aluminum, respectively. In the CV curves, no pronounced flatband voltage shift is observable. In diodes with C60, for negative gate voltages, a classical FN tunneling is observed and compared to theory. The electron injection from silicon shows a different tunneling current behavior. It starts at a lower electric field and has a smaller slope then a FN current would have. It is identified as a trap-assisted tunneling (TAT) current caused by oxidation-induced traps under the C60 layer. It is modeled by an

  20. Influence of biofilm on the transport of fullerene (C60) nanoparticles in porous media.

    PubMed

    Tong, Meiping; Ding, Jiali; Shen, Yun; Zhu, Pingting

    2010-02-01

    The significance of biofilm on fullerene C(60) nanoparticles transport and deposition were examined both in porous media and quartz crystal microbalance with dissipation (QCM-D) systems under a variety of environmentally relevant ionic strength (1-25 mM in NaCl and 0.1-5 mM in CaCl(2)) and flow conditions (4-8 m day(-1)). The magnitudes of deposition rate coefficients (k(d)) were compared between porous media with and without biofilm extracellular polymeric substances (EPS) coating under equivalent fluid velocities and solution chemistries. The observed k(d) were greater in porous media with biofilm EPS coating relative to those without biofilm EPS coating across the entire solution ionic strengths and fluid velocities examined, demonstrating that the enhancement of C(60) deposition by the biofilm EPS coating is relevant to a wide range of environmental conditions. This greater deposition was also observed on silica surfaces with biofilm EPS coating in QCM-D system. The results clearly showed that biofilm EPS have a great influence on C(60) deposition. Derjaguin-Landau-Verwey-Overbeek (DLVO) theory could not explain the enhanced C(60) deposition by biofilm EPS. Biochemical and physical characteristics of biofilm EPS were responsible for the increased C(60) deposition. Copyright 2009 Elsevier Ltd. All rights reserved.

  1. Between Crystal and Glass: Thermal Transport in C60 Molecular Crystals

    NASA Astrophysics Data System (ADS)

    Lu, Simon; Kumar, Sushant; McGaughey, Alan

    Molecular crystals of the fullerene C60 and its derivatives [e.g., phenyl-C61-butyric acid methyl ester (PCBM)] are candidate materials for use in photovoltaics and thermoelectrics. In thermoelectrics, their usefulness is due in part to their exceptionally low thermal conductivities (0.4 W/m-K for C60 and 0.05 W/m-K for PCBM) at room temperature. Little is known regarding the microscopic physics underlying these low thermal conductivities. An important question is whether thermal transport in the C60 molecular crystal is (i) crystal-like, where energy is transported as collective vibrations of the centers of mass of the molecules, or (ii) amorphous-like, where energy diffuses from molecule to molecule. We use molecular dynamics (MD) simulations and the Green-Kubo method to probe this question by predicting the relative contributions of crystal-like and amorphous-like transport to the thermal conductivity of the C60 molecular crystal. To isolate crystal-like transport, we perform simulations on C60 crystals where molecular rotations and intra-molecular vibrations are prohibited. To isolate amorphous-like transport, we fix the centers of mass of the molecules. We compare the MD results to predictions from a fully diffusive network resistance model. This work is supported by the National Science Foundation (Grant DMR-1507325).

  2. nC60 deposition kinetics: the complex contribution of humic acid, ion concentration, and valence.

    PubMed

    McNew, Coy P; LeBoeuf, Eugene J

    2016-07-01

    The demonstrated toxicity coupled with inevitable environmental release of nC60 raise serious concerns about its environmental fate and transport, therefore it is crucial to understand how nC60 will interact with subsurface materials including attached phase soil and sediment organic matter (AP-SOM). This study investigated the attachment of nC60 onto a Harpeth humic acid (HHA) coated silica surface under various solution conditions using a quartz crystal microbalance with dissipation monitoring. The HHA coating greatly enhanced nC60 attachment at low ion concentrations while hindering attachment at high ion concentrations in the presence of both mono and divalent cations. At low ion concentrations, the HHA greatly reduced the surface potential of the silica, enhancing nC60 deposition through reduction in the electrostatic repulsion. At high ion concentrations however, the reduced surface potential became less important due to the near zero energy barrier to deposition and therefore non-DLVO forces dominated, induced by compaction of the HHA layer, and leading to hindered attachment. In this manner, observed contributions from the HHA layer were more complex than previously reported and by monitoring surface charge and calculated DLVO interaction energy alongside attachment experiments, this study advances the mechanistic understanding of the variable attachment contributions from the humic acid layer.

  3. First Production of C60 Nanoparticle Plasma Jet for Study of Disruption Mitigation for ITER

    NASA Astrophysics Data System (ADS)

    Bogatu, I. N.; Thompson, J. R.; Galkin, S. A.; Kim, J. S.; Brockington, S.; Case, A.; Messer, S. J.; Witherspoon, F. D.

    2012-10-01

    Unique fast response and large mass-velocity delivery of nanoparticle plasma jets (NPPJs) provide a novel application for ITER disruption mitigation, runaway electrons diagnostics and deep fueling. NPPJs carry a much larger mass than usual gases. An electromagnetic plasma gun provides a very high injection velocity (many km/s). NPPJ has much higher ram pressure than any standard gas injection method and penetrates the tokamak confining magnetic field. Assimilation is enhanced due to the NP large surface-to-volume ratio. Radially expanding NPPJs help achieving toroidal uniformity of radiation power. FAR-TECH's NPPJ system was successfully tested: a coaxial plasma gun prototype (˜35 cm length, 96 kJ energy) using a solid state TiH2/C60 pulsed power cartridge injector produced a hyper-velocity (>4 km/s), high-density (>10^23 m-3), C60 plasma jet in ˜0.5 ms, with ˜1-2 ms overall response-delivery time. We present the TiH2/C60 cartridge injector output characterization (˜180 mg of sublimated C60 gas) and first production results of a high momentum C60 plasma jet (˜0.6 g.km/s).

  4. Electron-Phonon Interactions in Field-Effect Doped Layers of Crystalline C_60

    NASA Astrophysics Data System (ADS)

    Romero, Nichols A.; Kim, Jeongnim; Martin, Richard M.

    2002-03-01

    Recent developments [1] have shown that MOS-FET devices can induce 2-D metallic layers in C_60 with a high carrier density. For 2-4 holes per C_60, superconductivity has been observed with transition temperatures Tc as high as 52 K in pure C_60 [1a] and 117 K in intercalated C_60 [1b], the highest Tc reported for any non-copper-oxide superconductor. Density functional calculations [2] have shown that the carriers are confined to 2-D bands, with states that are highly distorted due to the field and 2-D Fermi surfaces that are very sensitive to the orientational order. In this work we study the electron-phonon interactions for the metallic interface states, motivated by the evidence that superconductivity in the bulk is electron-phonon mediated. Calculations are performed with the SIESTA local orbital DFT code [3] for a range of electron and hole densities in various ordered C_60 layers. *Supported by NSF DMR 99-76550 and DOE DEFG-96-ER45439. [1] [a]J. H. Schön, Ch. Kloc and B. Batlogg, Nature 408, 549 (2000); [b] Science 293, 2432 (2001). [2] J. L. Mozos, P. Ordejón and R. Martin, to be published. [3] P. Ordejón E. Artacho, and J. M. Soler, Phys. Rev. B 53, R10441 (1996).

  5. Observation of Ground- and Excited-State Charge Transfer at the C60/Graphene Interface.

    PubMed

    Jnawali, Giriraj; Rao, Yi; Beck, Jonathan H; Petrone, Nicholas; Kymissis, Ioannis; Hone, James; Heinz, Tony F

    2015-07-28

    We examine charge transfer interactions in the hybrid system of a film of C60 molecules deposited on single-layer graphene using Raman spectroscopy and Terahertz (THz) time-domain spectroscopy. In the absence of photoexcitation, we find that the C60 molecules in the deposited film act as electron acceptors for graphene, yielding increased hole doping in the graphene layer. Hole doping of the graphene film by a uniform C60 film at a level of 5.6 × 10(12)/cm(2) or 0.04 holes per interfacial C60 molecule was determined by the use of both Raman and THz spectroscopy. We also investigate transient charge transfer occurring upon photoexcitation by femtosecond laser pulses with a photon energy of 3.1 eV. The C60/graphene hybrid exhibits a short-lived (ps) decrease in THz conductivity, followed by a long-lived increase in conductivity. The initial negative photoconductivity transient, which decays within 2 ps, reflects the intrinsic photoresponse of graphene. The longer-lived positive conductivity transient, with a lifetime on the order of 100 ps, is attributed to photoinduced hole doping of graphene by interfacial charge transfer. We discuss possible microscopic pathways for hot carrier processes in the hybrid system.

  6. Depth profiling of cells and tissues by using C 60+ and SF 5+ as sputter ions

    NASA Astrophysics Data System (ADS)

    Malmberg, Per; Kriegeskotte, Christian; Arlinghaus, Heinrich F.; Hagenhoff, Birgit; Holmgren, Jan; Nilsson, Mikael; Nygren, Håkan

    2008-12-01

    In the present study, SF 5+ and C 60+ were used as primary ions for sputtering and Bi 3+ was used as primary ions for analysis. The depth profiling procedure was utilized to make 3D images of the chemistry of single cultured cells and tissue samples of intact intestinal epithelium. The results show sputtering of organic material from cells and tissue with both SF 5+ and C 60+ sources. Cholesterol fragments were found in the superficial layers when sputtering with C 60+. Spectra were collected revealing the change in yield along the z-axis of the sample. 3D images of the localization of Na, K, phosphocholine and cholesterol were constructed with both ion sources for single cell cultures and the mouse intestine. Cryostate sections of mouse intestine were analysed in 2D and the results were compared with the 3D image of the intestine. The localization of cholesterol and phosphocholine was found to be similar in cryostate sections analysed in two dimensions and the sputtered, freeze-dried intestine analysed in 3D. The comparison of 2D and 3D images suggest that the phosphocholine signal faded with C 60+ sputtering. In conclusion, both C 60+ and SF 5+ can be used as primary ion sources for sputtering of organic material from cells and tissues. Consecutive analysis with a Bi 3+ source can be used to obtain image stacks that could be used for reconstruction of 3D images.

  7. Topochemical 3D polymerization of C60 under high pressure at elevated temperatures.

    PubMed

    Yamanaka, Shoji; Kini, Nagesh S; Kubo, Akira; Jida, Saeko; Kuramoto, Hideaki

    2008-04-02

    Fullerene C60 monomer crystals were compressed to a face-centered cubic (fcc) phase with a lattice parameter of a = 11.93(5) A and a micro-Vickers hardness of 4500 kg/mm2 using high-pressure and high-temperature conditions of 15 GPa at 500-600 degrees C. The hardness is compatible with that of cubic boron nitride (c-BN), suggesting the formation of a 3D C60 polymer. The single-crystal X-ray structural analysis revealed that each C60 molecule in the polymer was linked to the 12 nearest neighbors by [2+2] cycloaddition between the common pentagon-hexagon (56) edges. However, ab initio geometry optimization and molecular dynamics calculations suggested that the 3D polymer should have a rhombohedral structure with the space group of R containing [3+3] cycloaddition between the pentagons of C60 molecules within the plane perpendicular to the 3-fold axis. The higher apparent symmetry of fcc was observed as an averaged structure of different orientations of the rhombohedral structure. The R structure can be derived by only a slight rotation of each C60 unit in the (111) plane of the fcc structure. The band-structure calculation suggested that the 3D polymer (R) was a semiconductor; the activation energy for the electrical conductivity was experimentally determined to be 0.25 eV at 550 K.

  8. Computational study of enantioselective interaction between C60 fullerene and its derivatives with L-histidine.

    PubMed

    Lal, Bhajan

    2007-04-01

    The mechanism of the enantioselective binding of L-histidine with C(60) fullerene and its derivatives, (1,2-methanofullerene C(60))-61-carboxylic acid, diethyl (1,2-methanofullerene C(60))-61-61-dicarboxylate and tert-butyl (1,2-methanofullerene C(60))-61-carboxylate based chiral selectors was studied by quantum chemical calculations. All the molecules were fully optimized at RHF/6-31G* basis set. Relative energies between the different complexes were subsequently estimated with single-point electronic energies computed using Møller-Plesset perturbation theory (MP2). Stability and feasibility of all the generated structures were supported by their respective energy minima and fundamental frequencies. It was observed that interaction of fullerene derivatives with L-histidine is due to the existence of hydrogen bonding forces during the complex formation. The intermolecular forces, flow of atomic charges, binding energy, hardness, dipole moment and localization of electrostatic potential are in agreement with enantioselective interaction of L-histidine with C(60) fullerene and its derivatives. It is found that theoretical evaluation to be consistent with the experimental data.

  9. C60+ - looking for the bucky-ball in interstellar space

    NASA Astrophysics Data System (ADS)

    Galazutdinov, G. A.; Shimansky, V. V.; Bondar, A.; Valyavin, G.; Krełowski, J.

    2017-03-01

    The laboratory gas-phase spectrum recently published by Campbell et al. has reinvigorated attempts to confirm the presence of the C_{60}^+ cation in the interstellar medium, through an analysis of the spectra of hot, reddened stars. This search is hindered by at least two issues that need to be addressed: (i) the wavelength range of interest is severely polluted by strong water-vapour lines coming from the Earth's atmosphere; (ii) one of the major bands attributed to C_{60}^+, at 9633 Å, is blended with the stellar Mg II line, which is susceptible to non-local thermodynamic equilibrium effects in hot stellar atmospheres. Both these issues are carefully considered here for the first time, based on high-resolution and high signal-to-noise ratio echellé spectra for 19 lines of sight. The result is that the presence of C_{60}^+ in interstellar clouds is brought into question.

  10. Secondary ion mass spectrometry with C60+ and Au4004+ projectiles

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Verkhoturov, Stanislav V.; Locklear, Jay E.; Schweikert, Emile A.

    2008-01-01

    Alternating nanometric thin layer films made from poly(diallyldimethylammonium chloride), poly(styrene sulfonate) and montmorillonite clay were analyzed with 26 keV C60+ (433 eV/atom) and 136 keV Au4004+ (340 eV/atom). Secondary ion (SI) emission depth from such thin films was determined to be ~6-9 nm with C60+ bombardment. Similar depth of emission was also reported with Au4004+ projectile impacts [Z. Li, S.V. Verkhoturov, E.A. Schweikert, Anal. Chem. 78 (2006) 7410]. The SI spectra contain recoiled C60 projectile constituents (m/z = 12, 13, 36). They track the compositional variation of the assembled thin layers except for C- and CH- whose abundances appear to correlate with the presence of metal atoms in the topmost layer.

  11. Low-temperature infrared spectroscopy of H2 in solid C60

    NASA Astrophysics Data System (ADS)

    Churchill, Hugh

    2007-03-01

    Diffuse reflectance infrared spectroscopy was used to probe the quantum dynamics of H2 trapped in a C60 lattice. Because free H2 is infrared inactive, features of the infrared spectra are induced solely through interactions with the host material and as such provide detailed information about the potential at the binding site. The design and construction of a cryogenic apparatus allowed the extension of previous room temperature measurements to temperatures as low as 10 K at pressures as high as 100 atm. The low temperature spectra contained much sharper peaks and a rich fine structure, enabling more precise determination of the details of the C60-H2 interaction potential. These studies of H2 in C60 inform hydrogen storage materials research in a broader context, as illustrated by the diffuse reflectance spectra of H2 in MOF-5.

  12. Infrared spectroscopy of endohedral HD and D2 in C60

    NASA Astrophysics Data System (ADS)

    Ge, Min; Nagel, U.; Hüvonen, D.; Rõõm, T.; Mamone, S.; Levitt, M. H.; Carravetta, M.; Murata, Y.; Komatsu, K.; Lei, Xuegong; Turro, N. J.

    2011-09-01

    We report on the dynamics of two hydrogen isotopomers, D2 and HD, trapped in the molecular cages of a fullerene C60 molecule. We measured the infrared spectra and analyzed them using a spherical potential for a vibrating rotor. The potential, vibration-rotation Hamiltonian, and dipole moment parameters are compared with previously studied H2@C60 parameters [M. Ge, U. Nagel, D. Hüvonen, T. Rõõm, S. Mamone, M. H. Levitt, M. Carravetta, Y. Murata, K. Komatsu, J. Y.-C. Chen, and N. J. Turro, J. Chem. Phys. 134, 054507 (2011), 10.1063/1.3535598]. The isotropic part of the potential is similar for all three isotopomers. In HD@C60, we observe mixing of the rotational states and an interference effect of the dipole moment terms due to the displacement of the HD rotation center from the fullerene cage center.

  13. Nanofibers of fullerene C60 through interplay of ball-and-socket supermolecules.

    PubMed

    Hubble, Lee J; Raston, Colin L

    2007-01-01

    Mixing solutions of p-tBu-calix[5]arene and C(60) in toluene results in a 1:1 complex (C(60)) intersection(p-tBu-calix[5]arene), which precipitates as nanofibers. The principle structural unit is based on a host-guest ball-and-socket nanostructure of the two components, with an extended structure comprising zigzag/helical arrays of fullerenes (powder X-ray diffraction data coupled with molecular modeling). Under argon at temperatures above 309 degrees C, the fibers undergo selective volatilization of the calixarenes to afford C(60)-core nanostructures encapsulated in a graphitic material sheath, which exhibits a dramatic increase in surface area. Above 650 degrees C the material exhibits an ohmic conductance response, due to the encapsulation process.

  14. Electrical properties of a two-dimensionally hexagonal C60 photopolymer

    NASA Astrophysics Data System (ADS)

    Onoe, J.; Nakayama, T.; Aono, M.; Hara, T.

    2004-07-01

    We investigated the electrical properties of a two-dimensionally (2D) hexagonal C60 photopolymer, using four-probe measurements in air at room temperature. The current-voltage curve shows that the photopolymer exhibits nondoped semiconducting behavior. This behavior is consistent with the theoretical prediction that a 2D hexagonal C60 polymer with a crosslinkage of a [2+2] cycloadditional four-member ring between adjacent C60 molecules is semiconducting [S. Okada and S. Saito, Phys. Rev. B 59, 1930 (1999)]. The origin of these semiconducting properties is discussed on the basis of density-functional calculations for the valence molecular orbitals of the dumbbell C120, which is regarded as a basic unit of the [2+2] crosslinkage of the 2D photopolymer.

  15. Spin frustration and magnetic ordering in the Mott insulating fcc-Cs3C60

    NASA Astrophysics Data System (ADS)

    Kasahara, Yuichi; Takeuchi, Yuki; Itou, Tatsuaki; Iwasa, Yoshihiro; Arcon, Denis; Rosseinsky, Matthew; Prassides, Kosmas

    2014-03-01

    The low-temperature magnetic state at ambient pressure has been investigated by specific heat and nuclear magnetic resonance (NMR) measurements in face-centered-cubic (fcc-) Cs3C60, which is characterized by a Mott insulating state with S = 1 / 2 spins in C603- anions and a geometrical spin frustration inherent in the fcc lattice. Specific heat exhibited no sharp anomaly down to 0.4 K, but both magnetic specific heat and NMR relaxation rate revealed a broad peak around 2.5 K, indicating that the reported antiferromagnetic ordering is accompanied by a gradual freezing of electronic spins with distributed transition temperatures. These results are unexpected in the conventional fcc antiferromagnets. Interplay of geometrical frustration, orientational disorder of C60 molecules, and weak Mottness gives rise to the unique magnetic ground state in fcc-Cs3C60.

  16. Direct detection of density of gap states in C60 single crystals by photoemission spectroscopy

    NASA Astrophysics Data System (ADS)

    Bussolotti, Fabio; Yang, Janpeng; Hiramoto, Masahiro; Kaji, Toshihiko; Kera, Satoshi; Ueno, Nobuo

    2015-09-01

    We report on the direct and quantitative evaluation of density of gap states (DOGS) in large-size C60 single crystals by using ultralow-background, high-sensitivity ultraviolet photoemission spectroscopy. The charging of the crystals during photoionization was overcome using photoconduction induced by simultaneous laser irradiation. By comparison with the spectra of as-deposited and gas exposed C60 thin films the following results were found: (i) The DOGS near the highest occupied molecular orbital edge in the C60 single crystals (1019-1021states e V-1c m-3) mainly originates from the exposure to inert and ambient gas atmosphere during the sample preparation, storage, and transfer; (ii) the contribution of other sources of gap states such as structural imperfections at grain boundaries is negligible (<1018states e V-1c m-3) .

  17. Electronic Pair-Binding and Hund's Rule Violations in Doped C60

    NASA Astrophysics Data System (ADS)

    Jiang, Hong-Chen; Kivelson, Steven

    We calculate the electronic properties of the t-J model on a C60 molecule using the density-matrix renormalization group and show that Hund's first rule is violated and that for an average of three added electron per molecule, an effective attraction (pair-binding) arises for intermediate values of t=J. Specifically, it is energetically favorable to put four electrons on one C60 and two on a second rather than putting three on each. Our results show that a dominantly electronic mechanism of superconductivity is possible in doped C60. HCJ and SAK were supported by the Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract DE-AC02-76SF00515.

  18. In situ electrical resistance and activation energy of solid C60 under high pressure

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Liu, Cai-Long; Gao, Chun-Xiao

    2013-09-01

    The in situ electrical resistance and transport activation energies of solid C60 fullerene have been measured under high pressure up to 25 GPa in the temperature range of 300-423 K by using a designed diamond anvil cell. In the experiment, four parts of boron-doped diamond films fabricated on one anvil were used as electrical measurement probes and a W—Ta thin film thermocouple which was integrated on the other diamond anvil was used to measure the temperature. The current results indicate that the measured high-pressure resistances are bigger than those reported before at the same pressure and there is no pressure-independent resistance increase before 8 GPa. From the temperature dependence of the resistivity, the C60 behaviors as a semiconductor and the activation energies of the cubic C60 fullerene are 0.49, 0.43, and 0.36 eV at 13, 15, and 19 GPa, respectively.

  19. Role of buffer in organic solar cells using C60 as an acceptor

    NASA Astrophysics Data System (ADS)

    Song, Q. L.; Li, C. M.; Wang, M. L.; Sun, X. Y.; Hou, X. Y.

    2007-02-01

    A thin buffer layer is indispensable for a high power conversion efficiency in an organic solar cell with fullerene (C60) as the acceptor. In present work, the authors proposed that the role of the buffer layer in an organic solar cell is to prohibit the electron transfer from metal to C60, and thus a desired built-in electric field can promote the free carrier collection. The built-in electric field in different organic solar cells with and without the thin C60 layer was studied by the transient photovoltage technique. The experimental results supported our proposal and indicated that the exciton blocking effect reported in the literature might not be the role of the buffer layer.

  20. Confinement and cavity effects in time-domain photoionization and recombination of Kr@C60

    NASA Astrophysics Data System (ADS)

    Magrakvelidze, Maia; Dixit, Gopal; Madjet, Mohamed; Chakraborty, Himadri

    2014-05-01

    Photoionization (PI) and radiative recombination (RR) of the endofullerene molecule, Kr@C60, are studied in a framework of time-dependent local density approximation (TDLDA) augmented by the Leeuwen and Baerends exchange-correlation functional. Phases of the dipole matrix elements corresponding to transitions to (PI) and from (RR) the continuum, involving atomic-type, fullerene-type and atom-fullerene hybrid levels of the molecule, are considered. Associated Wigner-Smith time-delays are extracted. Effects of the confinement on the phase and time-delay at Kr Cooper minima, and that of the C60 cavity at C60 cross section minima have been examined. Further, intercoulombic decay (ICD) and hybrid Auger-ICD resonances, direct results of the confinement, are found to considerably enrich the time-domain response of the molecule. This work was supported by the National Science Foundation.

  1. Interfacial and intermolecular interactions determining the rotational orientation of C60 adsorbed on Au(111)

    NASA Astrophysics Data System (ADS)

    Paßens, Michael; Karthäuser, Silvia

    2015-12-01

    Close-packed monolayers of fullerenes on metallic substrates are very rich systems with respect to their rotational degrees of freedom and possible interactions with different adsorption sites or next neighbours. In this connection, we report in detail on the (2√3 × 2√3)R30°-superstructure of C60 with respect to the Au(111)-surface. We use molecular orbital imaging in systematic UHV-STM studies to reveal the delicate balance of interfacial and intermolecular interactions in this system. Thus, bright C60-molecules in 5:6-top and 6:6-top geometries are observed depending on the respective next neighbours. Moreover, tiny changes in the appearance of the unoccupied molecular orbitals of dim C60-molecules in hex-vac positions are identified which are caused by the respective interaction with the facets surrounding the Au-vacancy.

  2. Photocatalytic C60-amorphous TiO2 composites prepared by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Justh, Nóra; Firkala, Tamás; László, Krisztina; Lábár, János; Szilágyi, Imre Miklós

    2017-10-01

    Nanocomposites of TiO2 and single fullerene (C60) molecule are prepared by atomic layer deposition (ALD). To create nucleation sites for the ALD reaction, the bare fullerene is functionalized by H2SO4/HNO3 treatment, which results in C60-SO3H. After a NaOH washing step the intermediate hydrolyzes into C60sbnd OH. This process and the consecutive ALD growth of TiO2 are monitored with FTIR, TG/DTA-MS, EDX, Raman, FTIR, XRD, and TEM measurements. Although the TiO2 grown by ALD at 80 and 160 °C onto fullerol is amorphous it enhances the decomposition of methyl orange under UV exposure. This study proves that amorphous TiO2 grown by low temperature ALD has photocatalytic activity, and it can be used e.g. as self-cleaning coatings also on heat sensitive substrates.

  3. The bonding nature of individual C60 molecules to Si(100) surfaces

    NASA Astrophysics Data System (ADS)

    Yao, X.; Workman, R. K.; Peterson, C. A.; Chen, D.; Sarid, D.

    It is demonstrated that bonding-dependent local density of states and energy levels of individual C60 molecules, adsorbed on Si(100)-(2×1) surfaces under ultra-high-vacuum conditions, can be obtained using scanning tunneling microscopy and spectroscopy. High-resolution images of individual C60 molecules, physisorbed (preannealed) and chemisorbed (postannealed) on different sites on the same sample, reveal clear intramolecular features superimposed on the molecules' cage structure that are consistent with their bonding nature. Spectroscopic measurements of individual C60 molecules chemisorbed at these sites yield energy levels that exhibit a transition of their electronic structure from that of a near-free adsorbate to that of SiC. The spectroscopic data corresponds to the observed changes in local density of states. These results demonstrate the power of scanning tunneling microscopy to determine the electronic structure and bonding characteristics of individual molecules.

  4. Valence photoelectron spectra of an electron-beam-irradiated C60 film

    NASA Astrophysics Data System (ADS)

    Onoe, Jun; Nakao, Aiko; Hida, Akira

    2004-10-01

    Valence photoelectron spectra of an electron-beam (EB) irradiated C60 film, which exhibited metallic electron-transport properties in air at room temperature, are presented. The electronic structure of the C60 film became closer to that of graphite as the EB-irradiation time increased, and its density of states around the Fermi level was eventually greater than for the graphite. This suggests that the electronic structure of the C60 film changed from a semiconductor to a semimetal and/or metal by EB irradiation. Interestingly, the electronic structure remained metallic even after five days of air exposure, which is the reason for the metallic electron-transport property in our previous report [Appl. Phys. Lett. 82, 595 (2003)].

  5. Langmuir-Blodgett film and nonlinear optical property of C 60-glycine ester derivative

    NASA Astrophysics Data System (ADS)

    Zhou, Dejian; Gan, Liangbing; Luo, Chuping; Tan, Haisong; Huang, Chunhui; Liu, Zhongfan; Wu, Zhongyun; Zhao, Xinsheng; Xia, Xiaohua; Zhang, Songbin; Sun, Fengqing; Xia, Zongju; Zou, Yinghua

    1995-03-01

    Both the Langmuir and Langmuir-Blodgett films of two C 60-glycine ester derivatives, C 60(C 6H 9NO 4) ( 1) and C 60(C 8H 13NO 4) ( 2), have been prepared at the air/water interface. The Langmuir films can be readily transferred onto hydrophilic quartz substrates in Z type to form LB films. The LB film of 1 has good vertical homogeneity as indicated by UV-VIS spectra and a SHG study. The second- and third-order molecular hyperpolarizabilities β and γ have been determined to be (2.3 ± 1.0) × 10 -29, 3.4 × 10 -31 esu for 1 and (1.9 ± 0.8) × 10 -29, 3.3 × 10 -31 esu for 2, respectively.

  6. Preparation of (99m)Tc-C(60)(OH)(x) and its biodistribution studies.

    PubMed

    Qingnuan, Li; yan, Xiu; Xiaodong, Zhang; Ruili, Liu; qieqie, Du; Xiaoguang, Shun; Shaoliang, Chen; Wenxin, Li

    2002-08-01

    The biological behavior of fullerene derivatives shows their considerable potential for medical applications. In order to provide a C(60) derivative for biodistriburtion studies, the (99m)Tc-labeling of C(60)(OH)(x) was optimized. Gamma counting and single photon emission computed tomography (SPECT) were used to assess the biodistribution of the (99m)Tc-labeled compound in mice and rabbits. Biodistribution studies in mice and imaging of rabbits indicated that (99m)Tc-C(60)(OH)(x) was widely distributed in all tissues. A significant percentage of total activity was retained for 48 h, particularly in the kidneys, bone, spleen, and liver. All tissues displayed a slow clearance over 48 h, except for bone, which showed slightly increasing localization within 24 h.

  7. Substrate effects on the analysis of biomolecular layers using Au +, Au 3+ and C 60+ bombardments

    NASA Astrophysics Data System (ADS)

    Kordys, Jeanette; Fletcher, John S.; Lockyer, Nicholas P.; Vickerman, John C.

    2008-12-01

    Effects of platinum silicon, graphite and PET substrates on the secondary ion yield of sub-monolayer and multilayer samples of Cyclosporin A following 20 keV Au +, Au 3+and C 60+ impacts have been investigated. The obtained results of sub-monolayer samples show that platinum enhances the yield of the pseudo-molecular ion following Au + and Au 3+ impacts due to the high density of the substrate that enables the energy of the primary ions to be deposited near the surface. C 60+ impacts on sub-monolayer samples are less effective, but there is an enhancement on PET substrates. Impacts of 20 keV Au + and Au 3+ are not very efficient on multilayer samples. 20 keV C 60+ impacts enhance the yields significantly, especially for the relatively high molecular weight [M+H] + ion.

  8. Simulation of Scan-Directional Dependence of Superlubricity of C60 Molecular Bearings and Graphite

    NASA Astrophysics Data System (ADS)

    Itamura, Noriaki; Miura, Kouji; Sasaki, Naruo

    2009-06-01

    The scan-directional dependence of the superlubricity of a C60 molecular bearing system (graphite/C60/graphite interface) is studied and compared with that of a graphite system (graphite/graphite/graphite interface) by molecular mechanics simulation. The mean lateral force reaches a maximum within a narrow region approximately in the [1010] direction. For other regions, has a nearly constant value of less than 1 pN. In particular, in the [1230] direction, reaches a minimum of nearly zero. It is clarified that reflects the following types of C60 motion: sliding above the carbon bond and a discrete slip to the neighboring AB-stacking position. The load dependence of also exhibits marked anisotropy. The orders of magnitude of the simulated friction coefficients are comparable to those obtained in our previous experiments.

  9. Interceptor effect of C60 fullerene on the in vitro action of aromatic drug molecules.

    PubMed

    Skamrova, Galyna B; Laponogov, Ivan; Buchelnikov, Anatoly S; Shckorbatov, Yuriy G; Prylutska, Svitlana V; Ritter, Uwe; Prylutskyy, Yuriy I; Evstigneev, Maxim P

    2014-07-01

    C60 fullerenes are spherical molecules composed purely of carbon atoms. They inspire a particularly strong scientific interest because of their specific physico-chemical properties and potential medical and nanotechnological applications. In this work we are focusing on studying the influence of the pristine C60 fullerene on biological activity of some aromatic drug molecules in human buccal epithelial cells. Assessment of the heterochromatin structure in the cell nucleus as well as the barrier function of the cell membrane was performed. The methods of cell microelectrophoresis and atomic force microscopy were also applied. A concentration-dependent restoration of the functional activity of the cellular nucleus after exposure to DNA-binding drugs (doxorubicin, proflavine and ethidium bromide) has been observed in human buccal epithelial cells upon addition of C60 fullerene at a concentration of ~10(-5 )M. The results were shown to follow the framework of interceptor/protector action theory, assuming that non-covalent complexation between C60 fullerene and the drugs (i.e., hetero-association) is the major process responsible for the observed biological effects. An independent confirmation of this hypothesis was obtained via investigation of the cellular response of buccal epithelium to the coadministration of the aromatic drugs and caffeine, and it is based on the well-established role of hetero-association in drug-caffeine systems. The results indicate that C60 fullerene may reverse the effects caused by the aromatic drugs, thereby pointing out the potential possibility of the use of aromatic drugs in combination with C60 fullerene for regulation of their medico-biological action.

  10. Nonthermal decomposition of C60 polymers induced by tunneling electron injection

    NASA Astrophysics Data System (ADS)

    Nakamura, Yoshiaki; Kagawa, Fumitaka; Kasai, Koichi; Mera, Yutaka; Maeda, Koji

    2004-11-01

    Scanning tunneling microscopic (STM) studies of C60 films deposited on highly oriented pyrolytic graphite substrates revealed that the electron injection from the STM tip induces the decomposition (isomerization) of the C60 molecules that have been polymerized also by the electron injection into the films. Both reaction rates were characterized by a linear dependence on the injected tunneling current and a common threshold around 2 V in the sample bias dependence. We discuss two nonthermal mechanisms for the polymerization and decomposition reactions: electronic excitation mechanism by Auger decay and a hypothetical ionic reaction model.

  11. Effect of C60 adducts on the dynamic structure of aromatic solvation shells

    NASA Astrophysics Data System (ADS)

    Peerless, James S.; Bowers, G. Hunter; Kwansa, Albert L.; Yingling, Yaroslava G.

    2017-06-01

    We report herein on the use of all-atom molecular dynamics simulations to investigate the solvation environment of C60 and four C60-derived fullerenes immersed in a variety of aromatic solvents. Utilizing a recently developed solvation shell analysis technique that quantifies the spatial relationships between fullerenes and solvent on a molecular level, we show that the number of fullerene substituents and solvent chemistry are crucial determinants of the solvation shell structure and thus fullerene solvation behavior. Specifically, it is shown for the derivatives investigated that the number of fullerene substituents is more critical to solvation behavior than the substituent chemistry.

  12. Photon, Electron and Secondary Ion Emission from Single C60 keV Impacts

    PubMed Central

    Fernandez-Lima, F. A.; Eller, M. J.; Verkhoturov, S. V.; Della-Negra, S.; Schweikert, E. A.

    2010-01-01

    This paper presents the first observation of coincidental emission of photons, electrons and secondary ions from individual C60 keV impacts. An increase in photon, electron and secondary ion yields is observed as a function of C60 projectile energy. The effect of target structure/composition on photon and electron emissions at the nanometer level is shown for a CsI target. The time-resolved photon emission may be characterized by a fast component emission in the UV-Vis range with a short decay time, while the electron and secondary ion emission follow a Poisson distribution. PMID:21218166

  13. Energy-level alignment at interfaces between manganese phthalocyanine and C60

    PubMed Central

    Rückerl, Florian; Büchner, Bernd

    2017-01-01

    We have used photoelectron spectroscopy to determine the energy-level alignment at organic heterojunctions made of manganese phthalocyanine (MnPc) and the fullerene C60. We show that this energy-level alignment depends upon the preparation sequence, which is explained by different molecular orientations. Moreover, our results demonstrate that MnPc/C60 interfaces are hardly suited for application in organic photovoltaic devices, since the energy difference of the two lowest unoccupied molecular orbitals (LUMOs) is rather small. PMID:28546887

  14. High-resolution 13C NMR investigation in Cs4C60

    NASA Astrophysics Data System (ADS)

    Goze, C.; Rachdi, F.; Mehring, M.

    1996-08-01

    Four inequivalent carbons were identified by using high-resolution magic angle spinning 13C NMR spectroscopy in Cs4C60. The room temperature NMR spectrum consists of four lines at 214 ppm, 189 ppm, 164 ppm, and 159 ppm, which collapse into a single line at 183 ppm when the sample is heated above 350 K. The intensity of the latter is the sum of the four line intensities. The observed behavior is interpreted in terms of a nonuniform charge and spin distribution on the C60 molecules combined with molecular dynamics.

  15. Ferromagnetic resonance and high field ESR in a TDAE-C60 single crystal

    NASA Astrophysics Data System (ADS)

    Arčon, D.; Cevc, P.; Omerzu, A.; Blinc, R.; Mehring, M.; Knorr, S.; Grupp, A.; Barra, A.-L.; Chouteau, G.

    1998-08-01

    Frequency variable ESR measurements have been performed on well annealed TDAE-C60 single crystals between 40 MHz and 245 GHz. A non-linear variation of the electron resonance frequency with the magnetic field has been observed below TC=16 K in the radio-frequency region. The observed ferromagnetic resonance data are characteristic for a three-dimensional Heisenberg ferromagnet with a small positive uniaxial anisotropy field. The easy axis coincides with the crystal c-direction which is the direction of closest approach of the C60- ions.

  16. High resolution NMR studies of one and two dimensional polymerized C60

    NASA Astrophysics Data System (ADS)

    Rachdi, F.; Goze, C.; Hajji, L.; Thier, K. F.; Zimmer, G.; Mehring, M.; Núñez-Regueiro, M.

    We present NMR data of the polymeric phase of em{emvar{A}C_{60}} with em{emvar{A}}=em{K}, em{Rb}, em{Cs}. From the temperature dependent \\isotope{13}{C} line shift of em{RbC_{60}} we have extracted information about the electron density distribution on the em{C_{60}} molecules. The data also support the existence of an \\orbital{sp}{3}{} like bonding type between the molecules. The magnetic phase transition observed at low temperature in em{RbC_{60}} and em{CsC_{60}} is monitored by an increase of the second moment as well as an increase of the spin lattice relaxation rates of the \\isotope{13}{C} and alkali nuclei. The results are compared to \\isotope{13}{C} NMR data of em{KC_{60}} where no signs of a magnetic ordering are found. The magnetically ordered phases are discussed in terms of antiferromagnetic spin density wave. We also report on \\isotope{13}{C} NMR measurements of orthorhombic one dimensional and rhombohedral two dimensional polymers of em{C_{60}} obtained under high pressure. By spinning the samples up to ǎlunit{12}{kHz}, we are able to identify two resonances at ǎlunit{146}{ppm} and ǎlunit{73.5}{ppm} for the orthorhombic polymer and six resonances at ǎlunit*{149.1}{ppm}, ǎlunit*{147.9}{ppm}, ǎlunit*{145.2}{ppm}, ǎlunit*{139.6}{ppm}, ǎlunit*{134.8}{ppm} and ǎlunit{73.5}{ppm} for the rhombohedral one. The static distortion of the em{C_{60}} molecules induced by the transformation under pressure must be at the origin of the observed inequivalent carbons in both systems. The \\isotope{13}{C} NMR lineshape simulations of the obtained spectra are compatible with the suggested polymeric structures where the em{C_{60}} molecules are connected by [2+2] cycloadditions.

  17. Temporal Changes in Aqu/C60 Physical-Chemical, Deposition, and Transport Characteristics in Aqueous Systems

    EPA Science Inventory

    Little is known about how temporal changes in the physical–chemical properties of C60 aggregates formed in aqueous systems (termed aqu/C60) can impact transport pathways contributing to ecological exposures. In this study three aqu/C60 suspensions of short-term (100 days), interm...

  18. Temporal Changes in Aqu/C60 Physical-Chemical, Deposition, and Transport Characteristics in Aqueous Systems

    EPA Science Inventory

    Little is known about how temporal changes in the physical–chemical properties of C60 aggregates formed in aqueous systems (termed aqu/C60) can impact transport pathways contributing to ecological exposures. In this study three aqu/C60 suspensions of short-term (100 days), interm...

  19. Geometrical effects of ( 14N@C 60) 2, 14N@C 60 and C 59N endohedral fullerenes within single-walled carbon nanotube as peapods on electronic structure and magnetic properties

    NASA Astrophysics Data System (ADS)

    Suzuki, Atsushi; Oku, Takeo

    2011-09-01

    Design of spin labels inside for possible molecular spintronics, which contains of 1D spin chain filling single-walled carbon nanotube (SWCNT) with magnetic endohedral fullerenes of ( 14N@C 60) 2, 14N@C 60 and C 59N has been proposed. Electronic structure and magnetic properties of ( 14N@C 60) 2-SWCNT, 14N@C 60-SWCNT, 14N@C 60 and C 59N were characterized. Geometrical effect of ( 14N@C 60) 2, 14N@C 60 and C 59N within SWCNT on chemical shift of 13C, principal g-tensor, A-tensor in hfc of nitrogen atom and excited state transition was investigated by ab-initio density functional theory. The magnetic properties would be originated in the spin density distribution with π-electron interaction between encapsulated fullerenes and inner surface on SWCNT and extent of charge transfer.

  20. A new way to synthesize superconducting metal-intercalated C60 and FeSe

    PubMed Central

    Takahei, Yuuki; Tomita, Keitaro; Itoh, Yugo; Ashida, Keishi; Lee, Ji-Hyun; Nishimoto, Naoki; Kimura, Takumi; Kudo, Kazutaka; Nohara, Minoru; Kubozono, Yoshihiro; Kambe, Takashi

    2016-01-01

    Doping with the optimum concentration of carriers (electrons or holes) can modify the physical properties of materials. Therefore, improved ways to achieve carrier doping have been pursued extensively for more than 50 years. Metal-intercalation is one of the most important techniques for electron doping of organic / inorganic solids, and has produced superconductors from insulators and metallic solids. The most successful examples are metal-intercalated graphite and C60 superconductors. Metal intercalation has been performed using solid-reaction and liquid solvent techniques. However, precise control of the quantity of intercalants in the target solids can be difficult to achieve using these methods, as that quantity depends largely on the initial conditions. Here we report an electrochemical method for metal-intercalation, and demonstrate the preparation of superconductors using organic and inorganic materials (C60 and FeSe). The metal atoms are effectively intercalated into the spaces in C60 and FeSe solids by supplying an electric current between electrodes in a solvent that includes electrolytes. The recorded superconducting transition temperatures, Tc’s, were the same as those of metal-intercalated C60 and FeSe prepared using solid-reaction or liquid solvent techniques. This technique may open a new avenue in the search for organic / inorganic superconductors. PMID:26732250

  1. A new way to synthesize superconducting metal-intercalated C60 and FeSe.

    PubMed

    Takahei, Yuuki; Tomita, Keitaro; Itoh, Yugo; Ashida, Keishi; Lee, Ji-Hyun; Nishimoto, Naoki; Kimura, Takumi; Kudo, Kazutaka; Nohara, Minoru; Kubozono, Yoshihiro; Kambe, Takashi

    2016-01-06

    Doping with the optimum concentration of carriers (electrons or holes) can modify the physical properties of materials. Therefore, improved ways to achieve carrier doping have been pursued extensively for more than 50 years. Metal-intercalation is one of the most important techniques for electron doping of organic / inorganic solids, and has produced superconductors from insulators and metallic solids. The most successful examples are metal-intercalated graphite and C60 superconductors. Metal intercalation has been performed using solid-reaction and liquid solvent techniques. However, precise control of the quantity of intercalants in the target solids can be difficult to achieve using these methods, as that quantity depends largely on the initial conditions. Here we report an electrochemical method for metal-intercalation, and demonstrate the preparation of superconductors using organic and inorganic materials (C60 and FeSe). The metal atoms are effectively intercalated into the spaces in C60 and FeSe solids by supplying an electric current between electrodes in a solvent that includes electrolytes. The recorded superconducting transition temperatures, Tc's, were the same as those of metal-intercalated C60 and FeSe prepared using solid-reaction or liquid solvent techniques. This technique may open a new avenue in the search for organic / inorganic superconductors.

  2. Conformational, IR spectroscopic and electronic properties of conium alkaloids and their adducts with C60 fullerene

    NASA Astrophysics Data System (ADS)

    Zabolotnyi, M. A.; Prylutskyy, Yu I.; Poluyan, N. A.; Evstigneev, M. P.; Dovbeshko, G. I.

    2016-08-01

    Conformational, IR spectroscopic and electronic properties of the components of Conium alkaloids (Conium maculatum) in aqueous environment were determined by model calculations and experiment. With the help of FT-IR spectroscopy the possibility of formation of an adduct between γ-coniceine alkaloid and C60 fullerene was demonstrated, which is important for further application of conium analogues in biomedical purposes.

  3. Detection of fullerenes (C60 and C70) in commercial cosmetics

    PubMed Central

    Benn, Troy M.; Westerhoff, Paul; Herckes, Pierre

    2013-01-01

    Detection methods are necessary to quantify fullerenes in commercial applications to provide potential exposure levels for future risk assessments of fullerene technologies. The fullerene concentrations of five cosmetic products were evaluated using liquid chromatography with mass spectrometry to separate and specifically detect C60 and C70 from interfering cosmetic substances (e.g., castor oil). A cosmetic formulation was characterized with transmission electron microscopy, which confirmed that polyvinylpyrrolidone encapsulated C60. Liquid-liquid extraction of fullerenes from control samples approached 100% while solid-phase and sonication in toluene extractions yielded recoveries of 27–42%. C60 was detected in four commercial cosmetics ranging from 0.04 to 1.1 μg/g, and C70 was qualitatively detected in two samples. A single-use quantity of cosmetic (0.5 g) may contain up to 0.6 μg of C60, demonstrating a pathway for human exposure. Steady-state modeling of fullerene adsorption to biosolids is used to discuss potential environmental releases from wastewater treatment systems. PMID:21300421

  4. Suspension and Characterization of Aqueous C60 Nanomaterials in Natural and Engineered Waters

    EPA Science Inventory

    Many current studies on the aqueous suspension of fullerene (aqu/C60) have used deionized water or simple salt solutions, and as a result little is know about the suspension of fullerene nanomatierals under environmentally relevant conditions, such as solutions that contain organ...

  5. Modified denatured lysozyme effectively solubilizes fullerene c60 nanoparticles in water

    NASA Astrophysics Data System (ADS)

    Siepi, Marialuisa; Politi, Jane; Dardano, Principia; Amoresano, Angela; De Stefano, Luca; Monti, Daria Maria; Notomista, Eugenio

    2017-08-01

    Fullerenes, allotropic forms of carbon, have very interesting pharmacological effects and engineering applications. However, a very low solubility both in organic solvents and water hinders their use. Fullerene C60, the most studied among fullerenes, can be dissolved in water only in the form of nanoparticles of variable dimensions and limited stability. Here the effect on the production of C60 nanoparticles by a native and denatured hen egg white lysozyme, a highly basic protein, has been systematically studied. In order to obtain a denatured, yet soluble, lysozyme derivative, the four disulfides of the native protein were reduced and exposed cysteines were alkylated by 3-bromopropylamine, thus introducing eight additional positive charges. The C60 solubilizing properties of the modified denatured lysozyme proved to be superior to those of the native protein, allowing the preparation of biocompatible highly homogeneous and stable C60 nanoparticles using lower amounts of protein, as demonstrated by dynamic light scattering, transmission electron microscopy and atomic force microscopy studies. This lysozyme derivative could represent an effective tool for the solubilization of other carbon allotropes.

  6. Fullerene C60: Surface Energy and Interfacial Interactions in Aqueous Systems

    EPA Science Inventory

    The underlying mechanisms of fullerene−fullerene, fullerene−water, and fullerene−soil surface interactions in aqueous systems are not well understood. To advance our understanding of these interfacial interactions, the surface properties of Buckminsterfullerene (C60) and quartz s...

  7. Non-aqueous capillary electrophoresis separation of fullerenes and C60 fullerene derivatives.

    PubMed

    Astefanei, Alina; Núñez, Oscar; Galceran, M Teresa

    2012-08-01

    As the interest in the use of fullerene compounds in biomedical and cosmetic applications increases, so too does the need to develop methods for their determination and quantitation in such complex matrices. In this work, we studied the behavior of C60 and C70 fullerenes in non-aqueous capillary electrophoresis, as well as two C60 fullerene derivatives not previously reported by any electrophoretic method, N-methyl-fulleropyrrolidine and (1,2-methanofullerene C60)-61-carboxylic acid. The separation was performed using fused-silica capillaries with an I.D. of 50 μm and tetraalkylammonium salts, namely tetra-n-decylammonium bromide (200 mM) and tetraethylammonium bromide (40 mM), in a solvent mixture containing 6 % methanol and 10 % acetic acid in acetonitrile/chlorobenzene (1:1 v/v) as the background electrolyte. Detection limits, based on a signal-to-noise ratio of 3:1, were calculated, and values between 1 and 3.7 mg/L were obtained. Good run-to-run and day-to-day precisions on concentration were achieved with relative standard deviation lower than 15 %. For the first time, an electrophoretic technique has been applied for the analysis of C60 fullerene in a commercial cosmetic cream. A standard addition method was used for quantitation, and the result was compared with that obtained by analyzing the same cream by liquid chromatography coupled to mass spectrometry.

  8. Effect of Humic Acid and Sunlight on the Generation of aqu/C60

    EPA Science Inventory

    Little is known about the effect of sunlight and natural organic matter, such as humic acid, on the aqueous suspension of fullerene C60. This knowledge gap limits our ability to determine the environmental impact of potential environmental releases of these materials. Aqueous sus...

  9. Morphological phase diagrams of C60 and C70 films on graphite

    NASA Astrophysics Data System (ADS)

    Sato, Kazuma; Tanaka, Tomoyasu; Akaike, Kouki; Kanai, Kaname

    2017-10-01

    The morphologies of C60 and C70 fullerene films vacuum-deposited onto graphite at various deposition rates and grown at several temperatures were investigated using atomic force microscopy. These fullerene films on graphite are model systems of physisorption of organic molecules that likely exhibit little chemical interaction with the graphite's surface. The morphologies of C60 and C70 films grown on graphite can be understood well from growth models previously reported. Comparison of the morphological phase diagrams obtained for C60 and C70 indicate that the diffusion properties of the adsorbed molecule are key in determining the morphology of the obtained film. The low diffusion rate of C70 resulted in various film morphologies for all deposition conditions tested. Also, the obtained phase diagrams can be understood by the results of fractal dimension analysis on the C60 and C70 islands. The fundamental understanding of film growth obtained using these ideal physisorption systems will aid in understanding film growth by other molecular adsorption systems.

  10. Suspension and Characterization of Aqueous C60 Nanomaterials in Natural and Engineered Waters

    EPA Science Inventory

    Many current studies on the aqueous suspension of fullerene (aqu/C60) have used deionized water or simple salt solutions, and as a result little is know about the suspension of fullerene nanomatierals under environmentally relevant conditions, such as solutions that contain organ...

  11. UV Irradiation and Humic Acid Mediate Aggregation of Aqueous Fullerene (nC60) Nanoparticles

    EPA Science Inventory

    The transport and fate of engineered nanomaterials is affected by multiple environmental factors, including sunlight and natural organic matter. In this study, the initial aggregation kinetics of aqueous fullerene (nC60) nanoparticles before and after UVA irradiation was investig...

  12. Modified denatured lysozyme effectively solubilizes fullerene c60 nanoparticles in water.

    PubMed

    Siepi, Marialuisa; Politi, Jane; Dardano, Principia; Amoresano, Angela; De Stefano, Luca; Maria Monti, Daria; Notomista, Eugenio

    2017-08-18

    Fullerenes, allotropic forms of carbon, have very interesting pharmacological effects and engineering applications. However, a very low solubility both in organic solvents and water hinders their use. Fullerene C60, the most studied among fullerenes, can be dissolved in water only in the form of nanoparticles of variable dimensions and limited stability. Here the effect on the production of C60 nanoparticles by a native and denatured hen egg white lysozyme, a highly basic protein, has been systematically studied. In order to obtain a denatured, yet soluble, lysozyme derivative, the four disulfides of the native protein were reduced and exposed cysteines were alkylated by 3-bromopropylamine, thus introducing eight additional positive charges. The C60 solubilizing properties of the modified denatured lysozyme proved to be superior to those of the native protein, allowing the preparation of biocompatible highly homogeneous and stable C60 nanoparticles using lower amounts of protein, as demonstrated by dynamic light scattering, transmission electron microscopy and atomic force microscopy studies. This lysozyme derivative could represent an effective tool for the solubilization of other carbon allotropes.

  13. UV Irradiation and Humic Acid Mediate Aggregation of Aqueous Fullerene (nC60) Nanoparticles

    EPA Science Inventory

    The transport and fate of engineered nanomaterials is affected by multiple environmental factors, including sunlight and natural organic matter. In this study, the initial aggregation kinetics of aqueous fullerene (nC60) nanoparticles before and after UVA irradiation was investig...

  14. Ultrahigh Performance C60 Nanorod Large Area Flexible Photoconductor Devices via Ultralow Organic and Inorganic Photodoping

    PubMed Central

    Saran, Rinku; Stolojan, Vlad; Curry, Richard J.

    2014-01-01

    One dimensional single-crystal nanorods of C60 possess unique optoelectronic properties including high electron mobility, high photosensitivity and an excellent electron accepting nature. In addition, their rapid large scale synthesis at room temperature makes these organic semiconducting nanorods highly attractive for advanced optoelectronic device applications. Here, we report low-cost large-area flexible photoconductor devices fabricated using C60 nanorods. We demonstrate that the photosensitivity of the C60 nanorods can be enhanced ~400-fold via an ultralow photodoping mechanism. The photodoped devices offer broadband UV-vis-NIR spectral tuneability, exhibit a detectivitiy >109 Jones, an external quantum efficiency of ~100%, a linear dynamic range of 80 dB, a rise time 60 µs and the ability to measure ac signals up to ~250 kHz. These figures of merit combined are among the highest reported for one dimensional organic and inorganic large-area planar photoconductors and are competitive with commercially available inorganic photoconductors and photoconductive cells. With the additional processing benefits providing compatibility with large-area flexible platforms, these devices represent significant advances and make C60 nanorods a promising candidate for advanced photodetector technologies. PMID:24853479

  15. Conjugated Porphyrin Dimers: Cooperative Effects and Electronic Communication in Supramolecular Ensembles with C60.

    PubMed

    Moreira, Luis; Calbo, Joaquín; Aragó, Juan; Illescas, Beatriz M; Nierengarten, Iwona; Delavaux-Nicot, Béatrice; Ortí, Enrique; Martín, Nazario; Nierengarten, Jean-François

    2016-11-30

    Two new conjugated porphyrin-based systems (dimers 3 and 4) endowed with suitable crown ethers have been synthesized as receptors for a fullerene-ammonium salt derivative (1). Association constants in solution have been determined by UV-vis titration experiments in CH2Cl2 at room temperature. The designed hosts are able to associate up to two fullerene-based guest molecules and present association constants as high as ∼5 × 10(8) M(-1). Calculation of the allosteric cooperative factor α for supramolecular complexes [3·12] and [4·12] showed a negative cooperative effect in both cases. The interactions accounting for the formation of the associates are based, first, on the complementary ammonium-crown ether interaction and, second, on the π-π interactions between the porphyrin rings and the C60 moieties. Theoretical calculations have evidenced a significant decrease of the electron density in the porphyrin dimers 3 and 4 upon complexation of the first C60 molecule, in good agreement with the negative cooperativity found in these systems. This negative effect is partially compensated by the stabilizing C60-C60 interactions that take place in the more stable syn-disposition of [4·12].

  16. Density functional investigation of CO and NO adsorption on TM-decorated C60 fullerene

    NASA Astrophysics Data System (ADS)

    El Mahdy, A. M.

    2016-10-01

    We have analysed the adsorptions of CO and NO molecules on pristine, TM (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn) in TM-doped fullerene C60 by using density functional theory (DFT) calculations at B3LYP/6-31g(d) theoretical level. This work revealed that the transition metal doped fullerenes were more highly sensitive to CO and NO adsorption than that of pure fullerene C60. The Fe-doped fullerenes C60 displayed the strongest interaction with C and N atoms of CO and NO molecules respectively. The nature of charge transfer between the d-orbitals of TM, and the π* orbital of the nearby C and N of CO and NO are clarified. Natural bond orbital (NBO) analysis reveals that the electronic configuration of the doped TM metal represents a qualitative change with respect to that of the free-metal. The binding of CO and NO precursor is mostly dominated by the metal E (i) (XO ..TM) pairwise additive contributions, and the role of the C60 is not restricted to supporting the metal.

  17. A BPTTF-based self-assembled electron-donating triangle capable of C60 binding.

    PubMed

    Goeb, Sébastien; Bivaud, Sébastien; Dron, Paul Ionut; Balandier, Jean-Yves; Chas, Marcos; Sallé, Marc

    2012-03-25

    A kinetically stable self-assembled redox-active triangle is isolated. The resulting electron-donating cavity, which incorporates three BPTTF units, exhibits a remarkable binding ability for electron-deficient C(60), supported by a favorable combination of structural and electronic features.

  18. C60 Recognition from Extended Tetrathiafulvalene Bis-acetylide Platinum(II) Complexes.

    PubMed

    Bastien, Guillaume; Dron, Paul I; Vincent, Manon; Canevet, David; Allain, Magali; Goeb, Sébastien; Sallé, Marc

    2016-11-18

    The favorable spatial organization imposed by the square planar 4,4'-di(tert-butyl)-2,2'-bipyridine (dbbpy) platinum(II) complex associated with the electronic and shape complementarity of π-extended tetrathiafulvalene derivatives (exTTF) toward fullerenes is usefully exploited to construct molecular tweezers, which display good affinities for C60.

  19. The effect of incident angle on the C 60+ bombardment of molecular solids

    NASA Astrophysics Data System (ADS)

    Kozole, Joseph; Willingham, David; Winograd, Nicholas

    2008-12-01

    The effect of incident angle on the quality of SIMS molecular depth profiling using C 60+ was investigated. Cholesterol films of ˜300 nm thickness on Si were employed as a model and were eroded using 40 keV C 60+ at an incident angle of 40° and 73° with respect to the surface normal. The erosion process was characterized by determining at each angle the relative amount of chemical damage, the total sputtering yield of cholesterol molecules, and the interface width between the film and the Si substrate. The results show that there is less molecule damage at an angle of incidence of 73° and that the total sputtering yield is largest at an angle of incidence of 40°. The measurements suggest reduced damage is not necessarily dependent upon enhanced yields and that depositing the incident energy nearer the surface by using glancing angles is most important. The interface width parameter supports this idea by indicating that at the 73° incident angle, C 60+ produces a smaller altered layer depth. Overall, the results show that 73° incidence is the better angle for molecular depth profiling using 40 keV C 60+.

  20. Relative partial cross sections for single, double, and triple photoionization of C60 and C70.

    PubMed

    Mitsuke, Koichiro; Katayanagi, Hideki; Kafle, Bhim P; Huang, Chaoqun; Yagi, Hajime; Prodhan, Md Serajul I; Kubozono, Yoshihiro

    2007-08-30

    Partial cross sections for the photoion formation from C(60) and C(70) were determined from the yields of singly, doubly, and triply charged ions which were measured by mass spectrometry combined with tunable synchrotron radiation at hnu = 25-120 eV. The dependence of the detection efficiencies on the mass-to-charge ratio was evaluated by using the formula proposed by Twerenbold et al. Corrections of the detection efficiency were found to be critical for obtaining accurate partial cross sections for photoionization of fullerenes. Revisions were made of the partial cross-section curves for single and double photoionization of C(60) and C(70). The curve for triple photoionization of C(70) was newly proposed. The ratios between the cross sections for double and single photoionization increase with hnu and reach saturated values of 0.78 at 85 eV for C(60) and approximately 1.3 at 100 eV for C(70). In contrast, the ratios at 120 eV between the cross sections for triple and single photoionization of C(60) and C(70) amount to 0.14 and approximately 0.38, respectively. The formation mechanism of multiply charged fullerene ions was discussed in terms of valence-electron excitation to antibonding unoccupied orbitals and/or spherical standing waves inside the cavity of a fullerene. This excitation could be followed by Spectator Auger processes and transmission of the excess electronic energy among numerous vibrational degrees of freedom.

  1. Fullerene C60: Surface Energy and Interfacial Interactions in Aqueous Systems

    EPA Science Inventory

    The underlying mechanisms of fullerene−fullerene, fullerene−water, and fullerene−soil surface interactions in aqueous systems are not well understood. To advance our understanding of these interfacial interactions, the surface properties of Buckminsterfullerene (C60) and quartz s...

  2. Effect of Humic Acid and Sunlight on the Generation of aqu/C60

    EPA Science Inventory

    Little is known about the effect of sunlight and natural organic matter, such as humic acid, on the aqueous suspension of fullerene C60. This knowledge gap limits our ability to determine the environmental impact of potential environmental releases of these materials. Aqueous sus...

  3. Conjugated Porphyrin Dimers: Cooperative Effects and Electronic Communication in Supramolecular Ensembles with C60

    PubMed Central

    2016-01-01

    Two new conjugated porphyrin-based systems (dimers 3 and 4) endowed with suitable crown ethers have been synthesized as receptors for a fullerene-ammonium salt derivative (1). Association constants in solution have been determined by UV–vis titration experiments in CH2Cl2 at room temperature. The designed hosts are able to associate up to two fullerene-based guest molecules and present association constants as high as ∼5 × 108 M–1. Calculation of the allosteric cooperative factor α for supramolecular complexes [3·12] and [4·12] showed a negative cooperative effect in both cases. The interactions accounting for the formation of the associates are based, first, on the complementary ammonium-crown ether interaction and, second, on the π–π interactions between the porphyrin rings and the C60 moieties. Theoretical calculations have evidenced a significant decrease of the electron density in the porphyrin dimers 3 and 4 upon complexation of the first C60 molecule, in good agreement with the negative cooperativity found in these systems. This negative effect is partially compensated by the stabilizing C60C60 interactions that take place in the more stable syn-disposition of [4·12]. PMID:27640915

  4. Charge carrier dynamics at the pentacene-C60 interface (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Döring, Robin Carl; Karthäuser, Andrea; Breuer, Tobias; Witte, Gregor; Chatterjee, Sangam

    2017-02-01

    Organic molecular solids feature various properties considered advantageous for next-generation photovoltaic devices such as mechanical flexibility and ease of fabrication by, e.g., large-scale and large volume printing. Additionally, Singlet-Exciton Fission may allow surpassing the Shockley-Queisser limit. Here, one photoexcited singlet-type exciton decays into two triplet-type excitons, effectively doubling the number of excited charge carriers. Hence, above-unity quantum efficiencies may be achieved in photovoltaics and have been reported in for example, pentacene (PEN) -C60 heterojunctions. Here, we study the carrier dynamics at well-defined PEN-C60 interface model systems by time-resolved photoluminescence spectroscopy experiments for different excitation photon energies. Thereby, we disentangle charge transfer and excitation dynamics, i.e., injection, transport, dissociation, and extraction. The photoluminescence spectra reveal two distinct transition energies associated with charge-transfer (CT) states expected from photoelectron spectroscopy experiments. These long-lived transitions show a clear dependence on excitation energy, corroborating the proposed CT transitions and revealing the fact that carriers need to be created in both individual constituents for CT transitions to be observable. Additionally, the C60 photoluminescence efficiency strongly quenches for increasing PEN coverage while the lifetime is drastically enhanced yielding strong evidence for an electron transfer between the PEN ground state and C60 when only the latter is photoexcited.

  5. Anisotropic electronic structure of orthorhombic RbC60: A high-field ESR investigation

    NASA Astrophysics Data System (ADS)

    Rahmer, J.; Grupp, A.; Mehring, M.; Hone, J.; Zettl, A.

    2001-02-01

    The full anisotropy of the electronic g tensor of a RbC60 single crystal was determined by applying high-field ESR. The principal values of the g tensor gxx=2.0014, gyy=2.0012, and gzz=2.0019 reflect the orthorhombic symmetry and 3D nature of this polymeric phase.

  6. Vortex dynamics in Rb3C60 observed by 87Rb and 13C NMR

    NASA Astrophysics Data System (ADS)

    Zimmer, G.; Mehring, M.; Rachdi, F.; Fischer, J. E.

    1996-08-01

    The vortex dynamics in Rb3C60 is investigated by 87Rb and 13C NMR. It is shown that spin-spin relaxation as well as two-dimensional exchange experiments allow an estimation of the time scale of vortex fluctuations. The effective pinning potential is deduced from the temperature dependence of the NMR parameters.

  7. Fullerene (C60)/CdS nanocomposite with enhanced photocatalytic activity and stability

    NASA Astrophysics Data System (ADS)

    Cai, Qiang; Hu, Zhuofeng; Zhang, Qian; Li, Boyuan; Shen, Zhurui

    2017-05-01

    Herein, the fullerene (C60)/CdS nanocomposite has been fabricated by a facile one-pot hydrothermal method. Its photocatatlytic hydrogen (H2) evolution rate and degradation efficiency of Rhodamine B (Rh B) are evaluated under visible light irradiation (λ ≥ 420 nm). The content of C60 has been changed from 0.4 wt% to 8 wt%, and the optimal value for photocatalytic activity is determined to be 0.4 wt%. The H2 evolution rate over this optimal sample reaches 1.73 mmol h-1 g-1 and its apparent degradation rate of Rh B is 0.089 min-1 (degradation efficiency of 97% within 40 min), which is 2.3 times and 1.5 times compared to that of pure CdS reference. Moreover, the photocorrosion of CdS in composite is effectively suppressed, and its photocatalytic activity can be well maintained after three recycles (97.8% retaining for composite vs. 84.4% retaining for CdS). Then, the enhanced photocatalytic activity and stability of C60/CdS nanocomposite are further studied by spectroscopic and electrochemical methods. Results show that the C60 species covering on the surface of CdS can efficiently accelerate the separation and transfer of photoexcited charge carriers, which can improve its activity, and reduce the photocorrosion of CdS.

  8. Single-crystalline C60 nanostructures by sonophysical preparation: tuning hollow nanobowls as catalyst supports for methanol oxidation.

    PubMed

    Zhang, Yang; Jiang, Lang; Li, Hui; Fan, Louzhen; Hu, Wenping; Wang, Chunru; Li, Yongfang; Yang, Shihe

    2011-04-18

    Large-scale single-crystalline hollow nanobowls of pure C(60) were prepared by applying a sonophysical strategy in a binary organic solution. Through the simple adjustment of the concentration of the C(60) /m-xylene solution and the volume ratio of m-xylene to acetonitrile, C(60) nanorings, nanoplates, nanorods, and nanowires were also selectively synthesized. The promise of the C(60) hollow structures as Pt catalyst supports is heightened by the significantly enhanced catalytic activity toward methanol oxidation for a given amount of C(60) used, which demonstrates their potential application in fuel cells.

  9. Incubation of solid state C60 fullerene under UV irradiation mimicking environmentally relevant conditions.

    PubMed

    Carboni, Andrea; Helmus, Rick; Parsons, John R; Kalbitz, Karsten; de Voogt, Pim

    2017-05-01

    Carbon-based nanomaterials, such as C60 fullerenes, are expected to accumulate in soil due to direct release and deposition from the atmosphere. However, little is known about the environmental fate of these nanoparticles which may be susceptible to photochemical and microbial degradation. In the present work, C60 was incubated for a period of 28 days and irradiated with UVA light. Three experiments were carried out where the fullerenes were either spiked onto a glass surface or added to quartz sand or sandy soil samples. At specific time intervals the samples were extracted and analysed by liquid chromatography coupled to UV or high resolution mass spectrometric (HRMS) detection. The fullerenes were degraded in all the treatments and the decay followed a pseudo-first-order rate law. In absence of a solid matrix, the half-life (t1⁄2) of the C60 was 13.1 days, with an overall degradation of 45.1% that was accompanied by the formation of functionalized C60-like structures. Furthermore, mass spectrometric analysis highlighted the presence of a large number of transformation products that were not directly related to the irradiation and presented opened cage and oxidized structures. When C60 was spiked into solid matrices the degradation occurred at a faster rate (t1⁄2 of 4.5 and 0.8 days for quartz sand and sandy soil, respectively). Minor but consistent losses were found in the non-irradiated samples, presumably due to biotic or chemical processes occurring in these samples. The results of this study suggest that light-mediated transformation of the fullerenes will occur in the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. NMR Study of the Superconducting Gap Variation near the Mott Transition in Cs3C60

    NASA Astrophysics Data System (ADS)

    Wzietek, P.; Mito, T.; Alloul, H.; Pontiroli, D.; Aramini, M.; Riccò, M.

    2014-02-01

    Former extensive studies of superconductivity in the A3C60 compounds, where A is an alkali metal, have led one to consider that Bardeen-Cooper-Schrieffer electron-phonon pairing prevails in those compounds, though the incidence of electronic Coulomb repulsion has been highly debated. The discovery of two isomeric fulleride compounds Cs3C60 which exhibit a transition with pressure from a Mott insulator (MI) to a superconducting (SC) state clearly reopens that question. Using pressure (p) as a single control parameter of the C60 balls lattice spacing, one can now study the progressive evolution of the SC properties when the electronic correlations are increased towards the critical pressure pc of the Mott transition. We have used C13 and Cs133 NMR measurements on the cubic phase A15-Cs3C60 just above pc=5.0(3) kbar, where the SC transition temperature Tc displays a dome shape with decreasing cell volume. From the T dependence below Tc of the nuclear spin lattice relaxation rate (T1)-1 we determine the electronic excitations in the SC state, that is 2Δ, the gap value. The latter is found to be largely enhanced with respect to the Bardeen-Cooper-Schrieffer value established in the case of dense A3C60 compounds. It even increases slightly with decreasing p towards pc, where Tc decreases on the SC dome, so that 2Δ /kBTc increases regularly upon approaching the Mott transition. These results bring clear evidence that the increasing correlations near the Mott transition are not significantly detrimental to superconductivity. They rather suggest that repulsive electron interactions might even reinforce elecron-phonon superconductivity, being then partly responsible for the large Tc values, as proposed by theoretical models taking the electronic correlations as a key ingredient.

  11. Mechanism for doping induced p type C60 using thermally evaporated molybdenum trioxide (MoO3) as a dopant

    NASA Astrophysics Data System (ADS)

    Yang, Jin-Peng; Wang, Wen-Qing; Cheng, Li-Wen; Li, Yan-Qing; Tang, Jian-Xin; Kera, Satoshi; Ueno, Nobuo; Zeng, Xiang-hua

    2016-05-01

    Thermally evaporated molybdenum trioxide (MoO3) doped C60 films, which could change n type features of pristine C60 to form a p type mixed C60 layer, are investigated by x-ray and ultraviolet photoelectron spectroscopy. It is found that C60 HOMO progressively shifts closer to the Fermi level after increased MoO3 doping concentration, and final onset of C60 HOMO is pinned at binding energy of 0.20 eV, indicating the formation of p type C60 films. It is proposed that in charge transfer induced p type C60 formation, due to large electron affinity of MoO3 (6.37 eV), electrons from HOMO of C60 could easily transfer to MoO3 to form cations and therefore increase hole concentration, which could gradually push C60 HOMO to the Fermi level and finally form p type C60 films. Moreover, clear different types of C60 species have been confirmed from UPS spectra in highly doped films.

  12. On the Electronic and Magnetic Properties of the ionic superatomic solid Ni9Te6(PEt3)8 C60

    NASA Astrophysics Data System (ADS)

    Chauhan, Vikas; Sahoo, Sanjubala; Khanna, Shiv; Physics Department VCU Collaboration

    We have carried out first principles electronic structure studies to examine the atomic structure, stability, and electronic and magnetic properties of the recently synthesized Ni9Te6(PEt3)8 C60 ionic material consisting of Ni9Te6(PEt3)8 superatoms and C60. It is shown that the PEt3 ligands result in an internal coulomb well that lifts the quantum states of the Ni9Te6 cluster lowering its ionization potential to 3.39 eV thus creating a superatomic alkali motif. The metallic core has a spin magnetic moment of 5.3 µb in agreement with experiment. The clusters are marked by low magnetic anisotropy energy (MAE) of 2.72 meV and a larger intra-exchange coupling exceeding 0.2 eV indicating that the observed paramagnetic behavior around 10K is due to superparamagnetic relaxations. The magnetic motifs separated by C60 experience a weak superexchange that stabilizes a ferromagnetic ground state as observed around 2K. The calculated MAE is sensitive to the charged state that could account for the observed change in magnetic transition temperature with size of the ligands or anion. We gratefully acknowledge funding support from the Department of Energy under Award Number DE-SC0006420.

  13. Computer simulations of material ejection during C60 and Arm bombardment of octane and β-carotene

    NASA Astrophysics Data System (ADS)

    Palka, G.; Kanski, M.; Maciazek, D.; Garrison, B. J.; Postawa, Z.

    2015-06-01

    Molecular dynamics (MD) computer simulations are used to investigate material ejection and fragment formation during keV C60 and Arm (m = 60, 101, 205, 366, 872 and 2953) bombardment of organic solids composed from octane and β-carotene molecules at 0° and 45° impact angle. Both systems are found to sputter efficiently. For the octane system, material removal occurs predominantly by ejection of intact molecules, while fragment emission is a significant ejection channel for β-carotene. A difference in the molecular dimensions is proposed to explain this observation. It has been shown that the dependence of the sputtering yield Y on the primary kinetic energy E and the cluster size n can be expressed in a simplified form if represented in reduced units. A linear and nonlinear dependence of the Y/n on the E/n are identified and the position of the transition point from the linear to nonlinear regions depends on the size of the cluster projectile. The impact angle has a minor influence on the shape of the simplified representation.

  14. Analysis of C60-fullerene derivatives and pristine fullerenes in environmental samples by ultrahigh performance liquid chromatography-atmospheric pressure photoionization-mass spectrometry.

    PubMed

    Astefanei, Alina; Núñez, Oscar; Galceran, Maria Teresa

    2014-10-24

    In this work, a method is proposed for the simultaneous analysis of several pristine fullerenes (C60, C70, C76, C78, and C84) and three C60-fullerene derivatives (N-methyl fulleropyrrolidine, [6,6]-phenyl C61 butyric acid methyl ester and [6,6]-phenyl C61 butyric acid butyl ester) in environmental samples. The method involves the use of ultrahigh performance liquid chromatography coupled to atmospheric pressure photoionization mass spectrometry (UHPLC-APPI-MS) and allowed the chromatographic separation in less than 4.5min. The product ions from tandem mass spectrometry studies of fullerene derivatives were characterized and the most abundant one (m/z 720), corresponding to [C60](-), was selected for quantitation. Selected reaction monitoring (SRM at 0.7m/z FWHM) by acquiring two transitions using both isotopic cluster ions [M](-) and [M+1](-) as precursor ions was proposed for quantitation and confirmation purposes. For pristine fullerenes, highly selective selected ion monitoring (H-SIM) acquisition mode by monitoring the isotopic cluster ions [M](-) and [M+1](-) was used. Pressurized solvent extraction conditions were optimized in order to improve recoveries of the studied fullerene compounds from sediment samples. Values up to 87-92% for C60-fullerene derivatives and lower but still acceptable, 70-80%, for pristine fullerenes were obtained. Method limits of quantitation (MLOQs) ranging from 1.5pgL(-1) to 5.5ngL(-1) in water samples and from 0.1ngkg(-1) to 523ngkg(-1) in sediments were obtained with good precision (relative standard deviations always lower than 13%). The applicability of the developed method was evaluated by analyzing several environmental samples such as sediments and pond water and the detected levels for C60-fullerene derivatives were of 0.1-2.7ngkg(-1) and 1.5-8.5pgL(-1), respectively. C60 and C70 were the only pristine fullerenes detected in the analyzed samples (0.1-7.2ngkg(-1) in sediments and 9-330pgL(-1) in water pond samples). Copyright

  15. Controlling the Electronic and Structural Coupling of C60 Nano Films on Fe(001) through Oxygen Adsorption at the Interface.

    PubMed

    Picone, Andrea; Giannotti, Dario; Riva, Michele; Calloni, Alberto; Bussetti, Gianlorenzo; Berti, Giulia; Duò, Lamberto; Ciccacci, Franco; Finazzi, Marco; Brambilla, Alberto

    2016-10-05

    C60 molecules coupled to metals form hybrid systems exploited in a broad range of emerging fields, such as nanoelectronics, spintronics, and photovoltaic solar cells. The electronic coupling at the C60/metal interface plays a crucial role in determining the charge and spin transport in C60-based devices; therefore, a detailed understanding of the interface electronic structure is a prerequisite to engineering the device functionalities. Here, we compare the electronic and structural properties of C60 monolayers interfaced with Fe(001) and oxygen-passivated Fe(001)-p(1 × 1)O substrates. By combining scanning tunneling microscopy and spectroscopy, Auger electron spectroscopy, photoemission and inverse photoemission spectroscopies, we are able to elucidate the striking effect of oxygen on the interaction between Fe(001) and C60. Upon C60 deposition on the oxygen-passivated surface, the oxygen layer remains buried at the C60/Fe(001)-p(1 × 1)O interface, efficiently decoupling the fullerene film from the metallic substrate. Tunneling and photoemission spectroscopies reveal the presence of well-defined molecular resonances for the C60/Fe(001)-p(1 × 1)O system, with a large HOMO-LUMO gap of about 3.4 eV. On the other hand, for the C60/Fe(001) interface, a strong hybridization between the substrate states and the C60 orbitals occurs, resulting in broader molecular resonances.

  16. Investigation of hydrogen induced fluorescence in C60 and its potential use in luminescence down shifting applications.

    PubMed

    Teprovich, J A; Washington, A L; Dixon, J; Ward, P A; Christian, J H; Peters, B; Zhou, J; Giri, S; Sharp, D N; Velten, J A; Compton, R N; Jena, P; Zidan, R

    2016-11-10

    Herein the photophysical properties of hydrogenated fullerenes (fulleranes) synthesized by direct hydrogenation utilizing hydrogen pressure (100 bar) and elevated temperatures (350 °C) are compared to the fulleranes C60H18 and C60H36 synthesized by amine reduction and the Birch reduction, respectively. Through spectroscopic measurements and density functional theory (DFT) calculations of the HOMO-LUMO gaps of C60Hx (0 ≤ x ≤ 60), we show that hydrogenation significantly affects the electronic structure of C60 by decreasing conjugation and increasing sp(3) hybridization. This results in a blue shift of the emission maximum as the number of hydrogen atoms attached to C60 increases. Correlations in the emission spectra of C60Hx produced by direct hydrogenation and by chemical methods also support the hypothesis of the formation of C60H18 and C60H36 during direct hydrogenation with emission maxima of 435 and 550 nm respectively. We also demonstrate that photophysical tunability, stability, and solubility of C60Hx in a variety of organic solvents make them easily adaptable for application as luminescent down-shifters in heads-up displays, light-emitting diodes, and luminescent solar concentrators. The utilizization of carbon based materials in these applications can potentially offer advantages over commonly utilized transition metal based quantum dot chromophores. We therefore propose that the controlled modification of C60 provides an excellent platform for evaluating how individual chemical and structural changes affect the photophysical properties of a well-defined carbon nanostructure.

  17. The adsorption of C 60 and the co-adsorption of C 60 and H 2O on α-Al 2O 3 (1 overline102)-(2 × 1)

    NASA Astrophysics Data System (ADS)

    Hamza, A. V.; Balooch, M.

    1992-10-01

    Binding of submonolayer coverages of C 60 to α-Al 2O 3(1 overline102)-(2 × 1) is observed by temperature-programmed desorption with peak temperatures for desorption between 430 and 460 K. Estimated first-order activation energy and pre-exponential factor are 25 ± 6 kcal/mol and 6.3 × 10 11 s -1. Multilayer desorption of C 60 behaves similarly to that observed previously from the (0001) surface. Exposure of C 60 to a water pre-dosed surface did not displace the adsorbed surface hydroxyls. Concomitant desorption of C 60 and water is observed from a water pre-dosed surface subsequently exposed to C 60 multilayers, whereas water post-dosed onto a C 60-covered surface has a sticking probability less than 4 × 10 -3.

  18. Recent Advances in Electrochemical Biosensors Based on Fullerene-C60 Nano-Structured Platforms.

    PubMed

    Pilehvar, Sanaz; De Wael, Karolien

    2015-11-23

    Nanotechnology is becoming increasingly important in the field of (bio)sensors. The performance and sensitivity of biosensors is greatly improved with the integration of nanomaterials into their construction. Since its first discovery, fullerene-C60 has been the object of extensive research. Its unique and favorable characteristics of easy chemical modification, conductivity, and electrochemical properties has led to its tremendous use in (bio)sensor applications. This paper provides a concise review of advances in fullerene-C60 research and its use as a nanomaterial for the development of biosensors. We examine the research work reported in the literature on the synthesis, functionalization, approaches to nanostructuring electrodes with fullerene, and outline some of the exciting applications in the field of (bio)sensing.

  19. Diffusion and self-assembly of C60 molecules on monolayer graphyne sheets

    PubMed Central

    Ozmaian, Masoumeh; Fathizadeh, Arman; Jalalvand, Morteza; Ejtehadi, Mohammad Reza; Allaei, S. Mehdi Vaez

    2016-01-01

    The motion of a fullerene (C60) on 5 different types of graphyne is studied by all-atom molecular dynamics simulations and compared with former studies on the motion of C60 on graphene. The motion shows a diffusive behavior which consists of either a continuous motion or discrete movements between trapping sites depending on the type of the graphyne sheet. For graphyne-4 and graphyne-5, fullerenes could detach from the surface of the graphyne sheet at room temperature which was not reported for similar cases on graphene sheets. Collective motion of a group of fullerenes interacting with a graphyne studied and it is shown that fullerenes exhibit stable assemblies. Depending on the type of graphyne, these assemblies can have either single or double layers. The mobility of the assembled structures is also dependent on the type of the graphyne sheet. The observed properties of the motion suggests novel applications for the complexes of fullerene and monolayer graphynes. PMID:26912386

  20. Recent Advances in Electrochemical Biosensors Based on Fullerene-C60 Nano-Structured Platforms

    PubMed Central

    Pilehvar, Sanaz; De Wael, Karolien

    2015-01-01

    Nanotechnology is becoming increasingly important in the field of (bio)sensors. The performance and sensitivity of biosensors is greatly improved with the integration of nanomaterials into their construction. Since its first discovery, fullerene-C60 has been the object of extensive research. Its unique and favorable characteristics of easy chemical modification, conductivity, and electrochemical properties has led to its tremendous use in (bio)sensor applications. This paper provides a concise review of advances in fullerene-C60 research and its use as a nanomaterial for the development of biosensors. We examine the research work reported in the literature on the synthesis, functionalization, approaches to nanostructuring electrodes with fullerene, and outline some of the exciting applications in the field of (bio)sensing. PMID:26610583

  1. Photodegradation of the electronic structure of PCBM and C60 films in air

    NASA Astrophysics Data System (ADS)

    Anselmo, Ana S.; Dzwilewski, Andrzej; Svensson, Krister; Moons, Ellen

    2016-05-01

    Fullerenes are common electron acceptors in organic solar cells. Here the photostability in air of the electronic structures of spin-coated PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) and evaporated C60 films are studied using ultraviolet photoelectron spectroscopy (UPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. After exposing these materials in air to simulated sunlight, the filled and empty molecular orbitals are strongly altered, indicating that the conjugated π-system of the C60-cage has degraded. Even a few minutes in normal lab light induces changes. These results stress the importance of protecting fullerene-based films from light and air during processing, operation, and storage.

  2. Unravelling the multilayer growth of the fullerene C60 in real time

    NASA Astrophysics Data System (ADS)

    Bommel, S.; Kleppmann, N.; Weber, C.; Spranger, H.; Schäfer, P.; Novak, J.; Roth, S. V.; Schreiber, F.; Klapp, S. H. L.; Kowarik, S.

    2014-11-01

    Molecular semiconductors are increasingly used in devices, but understanding of elementary nanoscopic processes in molecular film growth is in its infancy. Here we use real-time in situ specular and diffuse X-ray scattering in combination with kinetic Monte Carlo simulations to study C60 nucleation and multilayer growth. We determine a self-consistent set of energy parameters describing both intra- and interlayer diffusion processes in C60 growth. This approach yields an effective Ehrlich-Schwoebel barrier of EES=110 meV, diffusion barrier of ED=540 meV and binding energy of EB=130 meV. Analysing the particle-resolved dynamics, we find that the lateral diffusion is similar to colloids, but characterized by an atom-like Schwoebel barrier. Our results contribute to a fundamental understanding of molecular growth processes in a system, which forms an important intermediate case between atoms and colloids.

  3. MAPLE preparation and characterization of mixed arylenevinylene based oligomers:C60 layers

    NASA Astrophysics Data System (ADS)

    Stanculescu, A.; Socol, G.; Vacareanu, L.; Socol, M.; Rasoga, O.; Breazu, C.; Girtan, M.; Stanculescu, F.

    2016-06-01

    This paper presents some studies about the preparation by matrix-assisted pulsed laser evaporation (MAPLE) of mixed layers based on two arylenevinylene oligomers, 1,4-bis [4-(N,N‧-diphenylamino)phenylvinyl] benzene (L78) and 3,3‧-bis(N-hexylcarbazole)vinylbenzene (L13) as donor and buckminsterfullerene (C60) as acceptor, blended in three different weight ratios: 1:1, 1:2 and 1:3. The optical, morphological, structural and electrical properties of these mixed layers have been investigated emphasizing the effect of the layer composition and of the significant degree of disorder. I-V characteristics have revealed typically solar cell behaviour for the heterostructures prepared with mixed layers containing L78 (L13) and fullerene blended in a weight ratio of 1:2. The solar cell structure glass/ITO/L13:C60/Al has shown the best parameters.

  4. Novel facile method for obtaining CdSe/polyaniline/C60 composite materials.

    PubMed

    Rusen, Edina; Diacon, Aurel; Mocanu, Alexandra; Nistor, Leona Cristina

    2016-08-30

    This study presents a novel method for the oxidative polymerization of aniline (ANI) by employing fullerene C60/cadmium selenide (CdSe) quantum dots, as promoting agent of the polymerization system. The polymerization initiation mechanism is based on the difference between the HOMO-LUMO energy levels of the components which permits the formation of a continuous donor-acceptor exchange. Both the polymerization reaction evolution and the molecular weights of the obtained polymers have been characterized. The novelty of the paper consists in the synthesis of a novel nano-composite material through a novel polymerization technique. The resulting material containing PANI, CdSe quantum dots and C60 has been characterized by UV-Vis, NIR, fluorescence, TEM and GPC analyses.

  5. (CH3Br⋯NH3)@C60: The effect of nanoconfinement on halogen bonding

    NASA Astrophysics Data System (ADS)

    Srivastava, Ambrish Kumar; Pandey, Sarvesh Kumar; Misra, Neeraj

    2016-10-01

    Halogen bonds resemble hydrogen bonds in many aspects. How do the properties of halogen bonds change when confined to nanoregion? In order to explore this, we have encapsulated a halogen bonded complex, CH3Br⋯NH3 inside C60 fullerene and studied their properties using density functional theory and quantum theory of atoms in molecule. Our findings show that the geometry of CH3Br⋯NH3 complex is appreciably bent inside C60, interaction becomes covalent with larger interaction energy, unlike free CH3Br⋯NH3 complex, which is linear with closed shell interaction. Thus, the halogen bonded complexes show quite different properties at nanoscale.

  6. Crystallinity of the epitaxial heterojunction of C60 on single crystal pentacene

    NASA Astrophysics Data System (ADS)

    Tsuruta, Ryohei; Mizuno, Yuta; Hosokai, Takuya; Koganezawa, Tomoyuki; Ishii, Hisao; Nakayama, Yasuo

    2017-06-01

    The structure of pn heterojunctions is an important subject in the field of organic semiconductor devices. In this work, the crystallinity of an epitaxial pn heterojunction of C60 on single crystal pentacene is investigated by non-contact mode atomic force microscopy and high-resolution grazing incidence x-ray diffraction. Analysis shows that the C60 molecules assemble into grains consisting of single crystallites on the pentacene single crystal surface. The in-plane mean crystallite size exceeds 0.1 μm, which is at least five time larger than the size of crystallites deposited onto polycrystalline pentacene thin films grown on SiO2. The results indicate that improvement in the crystal quality of the underlying molecular substrate leads to drastic promotion of the crystallinity at the organic semiconductor heterojunction.

  7. Novel facile method for obtaining CdSe/polyaniline/C60 composite materials

    NASA Astrophysics Data System (ADS)

    Rusen, Edina; Diacon, Aurel; Mocanu, Alexandra; Nistor, Leona Cristina

    2016-08-01

    This study presents a novel method for the oxidative polymerization of aniline (ANI) by employing fullerene C60/cadmium selenide (CdSe) quantum dots, as promoting agent of the polymerization system. The polymerization initiation mechanism is based on the difference between the HOMO-LUMO energy levels of the components which permits the formation of a continuous donor-acceptor exchange. Both the polymerization reaction evolution and the molecular weights of the obtained polymers have been characterized. The novelty of the paper consists in the synthesis of a novel nano-composite material through a novel polymerization technique. The resulting material containing PANI, CdSe quantum dots and C60 has been characterized by UV-Vis, NIR, fluorescence, TEM and GPC analyses.

  8. Relative Photoionization Cross Sections of Super-Atom Molecular Orbitals (SAMOs) in C60.

    PubMed

    Bohl, Elvira; Sokół, Katarzyna P; Mignolet, Benoit; Thompson, James O F; Johansson, J Olof; Remacle, Francoise; Campbell, Eleanor E B

    2015-11-25

    The electronic structure and photoinduced dynamics of fullerenes, especially C60, is of great interest because these molecules are model systems for more complex molecules and nanomaterials. In this work we have used Rydberg Fingerprint Spectroscopy to determine the relative ionization intensities from excited SAMO (Rydberg-like) states in C60 as a function of laser wavelength. The relative ionization intensities are then compared to the ratio of the photoionization widths of the Rydberg-like states, computed in time-dependent density functional theory (TD-DFT). The agreement is remarkably good when the same photon order is required to energetically access the excited states. This illustrates the predictive potential of quantum chemistry for studying photoionization of large, complex molecules as well as confirming the assumption that is often made concerning the multiphoton excitation and rapid energy redistribution in the fullerenes.

  9. Scaling of size distributions of C60 and C70 fullerene surface islands

    NASA Astrophysics Data System (ADS)

    Dubrovskii, V. G.; Berdnikov, Y.; Olyanich, D. A.; Mararov, V. V.; Utas, T. V.; Zotov, A. V.; Saranin, A. A.

    2017-06-01

    We present experimental data and a theoretical analysis for the size distributions of C60 and C70 surface islands deposited onto In-modified Si(111)√3 × √3-Au surface under different conditions. We show that both fullerene islands feature an analytic Vicsek-Family scaling shape where the scaled size distributions are given by a power law times an incomplete beta-function with the required normalization. The power exponent in this distribution corresponds to the fractal shape of two-dimensional islands, confirmed by the experimentally observed morphologies. Quite interestingly, we do not see any significant difference between C60 and C70 fullerenes in terms of either scaling parameters or temperature dependence of the diffusion constants. In particular, we deduce the activation energy for surface diffusion of ED = 140 ± 10 meV for both types of fullerenes.

  10. First-principles calculations of the electronic structure of one-dimensional C60 polymers

    NASA Astrophysics Data System (ADS)

    Beu, Titus A.; Onoe, Jun; Hida, Akira

    2005-10-01

    The geometrical and electronic properties of two dimers (one with C2h symmetry) from the Stone-Wales rearrangement sequence of C60 dimers [described by E. Osawa and K. Honda, Full Sci. Technol. 4, 939 (1996)] are investigated by density functional and tight-binding calculations. The trimer and the infinite periodic polymer derived from the C2h symmetry dimer are shown to continue a decreasing trend of the energy gap between the highest occupied (HOMO) and the lowest unoccupied (LUMO) molecular orbitals to values smaller than 0.1 eV. The very small energy gap, in conjunction with the extension of the HOMO orbital over the whole cross-linkage region, provides an explanation for the observed conducting properties of electron beam irradiated C60 films.

  11. Novel facile method for obtaining CdSe/polyaniline/C60 composite materials

    PubMed Central

    Rusen, Edina; Diacon, Aurel; Mocanu, Alexandra; Nistor, Leona Cristina

    2016-01-01

    This study presents a novel method for the oxidative polymerization of aniline (ANI) by employing fullerene C60/cadmium selenide (CdSe) quantum dots, as promoting agent of the polymerization system. The polymerization initiation mechanism is based on the difference between the HOMO-LUMO energy levels of the components which permits the formation of a continuous donor-acceptor exchange. Both the polymerization reaction evolution and the molecular weights of the obtained polymers have been characterized. The novelty of the paper consists in the synthesis of a novel nano-composite material through a novel polymerization technique. The resulting material containing PANI, CdSe quantum dots and C60 has been characterized by UV-Vis, NIR, fluorescence, TEM and GPC analyses. PMID:27572228

  12. Thermopower of benzenedithiol and C60 molecular junctions with Ni and Au electrodes.

    PubMed

    Lee, See Kei; Ohto, Tatsuhiko; Yamada, Ryo; Tada, Hirokazu

    2014-09-10

    We have performed thermoelectric measurements of benzenedithiol (BDT) and C60 molecules with Ni and Au electrodes using a home-built scanning tunneling microscope. The thermopower of C60 was negative for both Ni and Au electrodes, indicating the transport of carriers through the lowest unoccupied molecular orbital in both cases, as was expected from the work functions. On the other hand, the Ni-BDT-Ni junctions exhibited a negative thermopower, whereas the Au-BDT-Au junctions exhibited a positive thermopower. First-principle calculations revealed that the negative thermopower of Ni-BDT-Ni junctions is due to the spin-split hybridized states generated by the highest occupied molecular orbital of BDT coupled with s- and d-states of the Ni electrode.

  13. Monolayer of Hydrazine Facilitates the Direct Covalent Attachment of C60 Fullerene to a Silicon Surface.

    PubMed

    Gao, Fei; Teplyakov, Andrew V

    2017-02-13

    The development of oxygen-free organic-inorganic interfaces has led to new schemes for the functionalization of silicon surfaces with nitrogen-based chemical groups. However, building layers of large structures directly on this functionalized surface has remained elusive. This work confirms the path to form a stable interface between silicon and buckminsterfullerene C60 based on covalent chemical bonds. The starting point for this modification is the hydrazine-reacted Si(111) surface with the diamine functionality, which is further reacted directly with the C60 molecules. The chemistry of this process is confirmed spectroscopically and microscopically and can be used to form organic-inorganic interfaces separated by a single layer of nitrogen.

  14. Unravelling the multilayer growth of the fullerene C60 in real time

    PubMed Central

    Bommel, S.; Kleppmann, N.; Weber, C.; Spranger, H.; Schäfer, P.; Novak, J.; Roth, S.V.; Schreiber, F.; Klapp, S.H.L.; Kowarik, S.

    2014-01-01

    Molecular semiconductors are increasingly used in devices, but understanding of elementary nanoscopic processes in molecular film growth is in its infancy. Here we use real-time in situ specular and diffuse X-ray scattering in combination with kinetic Monte Carlo simulations to study C60 nucleation and multilayer growth. We determine a self-consistent set of energy parameters describing both intra- and interlayer diffusion processes in C60 growth. This approach yields an effective Ehrlich–Schwoebel barrier of EES=110 meV, diffusion barrier of ED=540 meV and binding energy of EB=130 meV. Analysing the particle-resolved dynamics, we find that the lateral diffusion is similar to colloids, but characterized by an atom-like Schwoebel barrier. Our results contribute to a fundamental understanding of molecular growth processes in a system, which forms an important intermediate case between atoms and colloids. PMID:25369851

  15. Optical modeling of organic solar cells based on CuPc and C60.

    PubMed

    Monestier, Florent; Simon, Jean-Jacques; Torchio, Philippe; Escoubas, Ludovic; Ratier, Bernard; Hojeij, Wassim; Lucas, Bruno; Moliton, André; Cathelinaud, Michel; Defranoux, Christophe; Flory, François

    2008-05-01

    We have investigated the influence of the poly(3,4-ethylenedioxythiophene)-blend-poly(styrene-sulfonate) (PEDOT:PSS) layer on the short-circuit current density (J(sc)) of single planar heterojunction organic solar cells based on a copper phthalocyanine (CuPc)-buckminsterfullerene (C(60)) active layer. Complete optical and electrical modeling of the cell has been performed taking into account optical interferences and exciton diffusion. Comparison of experimental and simulated external quantum efficiency has allowed us to estimate the exciton diffusion length to be 37 nm for the CuPc and 19 nm for the C(60). The dependence of short-circuit current densities versus the thickness of the PEDOT:PSS layer is analyzed and compared with experimental data. It is found that the variation in short-circuit current densities could be explained by optical interferences.

  16. Prediction of ordered phases of encapsulated C60, C70, and C78 inside carbon nanotubes.

    PubMed

    Troche, Karla S; Coluci, Vitor R; Braga, Scheila F; Chinellato, David D; Sato, Fernando; Legoas, Sergio B; Rurali, Riccardo; Galvão, Douglas S

    2005-02-01

    We report the first detailed fully atomistic molecular dynamics study of the encapsulation of symmetric (C(60)) and asymmetric fullerenes (C(70) and C(78)) inside single-walled carbon nanotubes of different diameters. Different ordered phases have been found and shown to be tube diameter dependent. Rotational structural disorder significantly affecting the volume fraction of the packing was observed for the molecular arrangements of asymmetric fullerenes. Although these effects make more difficult the existence of ordered phases, our results showed that complex packing arrangements (very similar to the ones obtained for C(60)) are also possible for C(70) and C(78). Comparisons with results from continuum and hard-sphere models, ab initio electronic structure calculations, and simulations of the high-resolution transmission electron microscopy images of the obtained fullerene packing phases are also presented.

  17. Formation of an interstitially alloyed phase in Mg/C60 composite

    NASA Astrophysics Data System (ADS)

    Shin, Jaehyuck; Yoon, Sock-yeon; Choi, Hyunjoo; Shin, Seeun; Bae, Donghyun

    2013-07-01

    The formation of an interstitially alloyed phase and its effects on mechanical properties are investigated for a magnesium-based composite containing fullerene (Mg/C60). The Mg/C60 composite was fabricated using the ball milling method followed by hot rolling and then the composite sheet was annealed at 425°C for up to 37 h. The fullerene was dispersed during the ball milling process and it was decomposed. The carbon atoms from the decomposed fullerene diffused into the magnesium matrix, which increasingly occupied the octahedral sites of the magnesium as the annealing continued. The formed interstitially alloyed phase expanded as the annealing time increased, and magnesium carbide was formed after 37 h. Vickers hardness value increased as the interstitially alloyed phase continuously formed and it decreased when the magnesium carbide was formed, because the carbon atoms at the magnesium interstices may interact with moving dislocations, resulting in an increase in the hardness of the magnesium.

  18. Epitaxial Growth of an Organic p-n Heterojunction: C60 on Single-Crystal Pentacene.

    PubMed

    Nakayama, Yasuo; Mizuno, Yuta; Hosokai, Takuya; Koganezawa, Tomoyuki; Tsuruta, Ryohei; Hinderhofer, Alexander; Gerlach, Alexander; Broch, Katharina; Belova, Valentina; Frank, Heiko; Yamamoto, Masayuki; Niederhausen, Jens; Glowatzki, Hendrik; Rabe, Jürgen P; Koch, Norbert; Ishii, Hisao; Schreiber, Frank; Ueno, Nobuo

    2016-06-01

    Designing molecular p-n heterojunction structures, i.e., electron donor-acceptor contacts, is one of the central challenges for further development of organic electronic devices. In the present study, a well-defined p-n heterojunction of two representative molecular semiconductors, pentacene and C60, formed on the single-crystal surface of pentacene is precisely investigated in terms of its growth behavior and crystallographic structure. C60 assembles into a (111)-oriented face-centered-cubic crystal structure with a specific epitaxial orientation on the (001) surface of the pentacene single crystal. The present experimental findings provide molecular scale insights into the formation mechanisms of the organic p-n heterojunction through an accurate structural analysis of the single-crystalline molecular contact.

  19. Frequency-dependent spin-lattice relaxation in 15NatC60

    NASA Astrophysics Data System (ADS)

    Knorr, S.; Grupp, A.; Mehring, M.; Waiblinger, M.; Weidinger, A.

    2001-11-01

    We report on pulsed electron-spin-resonance (ESR) investigations of endohedral 15N@C60. In order to study the spin-lattice relaxation and its underlying mechanisms, we performed saturation-recovery experiments both in X band (9.5 GHz) and W band (94 GHz). We find recovery signals with a non-exponential time behavior which are due to several relaxation pathways. The temperature dependence of the relaxation rate can be understood by assuming that fluctuations of the finestructure and hyperfine interaction play the dominant role for the relaxation. These fluctuations are due to the damped quantum oscillator of the nitrogen atom inside C60. In our model, the observed differences in X band and W band are ascribed to an overdamped motion of this oscillator.

  20. Phonon Drag and Carrier Diffusion Contributions in Thermoelectric Power of K3C60 Fullerides

    NASA Astrophysics Data System (ADS)

    Varshney, Dinesh; Jain, Rajendra; Singh, Namita

    2012-01-01

    The thermoelectric power (S) of K3C60 fullerides is theoretically analyzed. Mott expression within parabolic band approximation is used to reveal the electron diffusive thermoelectric power (Scdiff) following Fermi energy as electron parameter, Scdiff show linear temperature dependence. S infers a change in slope above transition temperature and become almost linear above 70 K. The phonon drag thermoelectric power (Sphdrag) is computed within relaxation time approximation when thermoelectric power is limited by scattering of phonons from defects, grain boundaries, phonons and electrons as carriers. The Sphdrag of K3C60 is anomalous and it is an artifact of strong phonon-electron and phonon scattering mechanism. The thermoelectric power within relaxation time approximation has been taken into account ignoring a possible energy dependence of the scattering rates. Behaviour of S(T) is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between carrier diffusion and phonon drag contributions.

  1. Microscopic dynamics of an amorphous C60 x /C70(1 - x) fullerene mixture

    NASA Astrophysics Data System (ADS)

    Khusnutdinoff, R. M.; Mokshin, A. V.; Takhaviev, I. D.

    2015-02-01

    This paper presents the results of investigation of the propagation mechanism of collective excitations in amorphous C60 x /C70(1 - x) fullerene mixtures (with equimolar concentration x = 0.50), which were obtained using molecular dynamics simulation. The critical glass-transition temperature of the system T c = 1548 K was determined from the change in the behavior of the Wendt-Abraham parameter. Spectral densities of the time correlation functions of the longitudinal and transverse currents for a wide region of wave numbers at temperatures below the glass-transition temperature were calculated. It was found that the dynamics of density fluctuations in amorphous C60 x /C70(1 - x) fullerene mixtures is characterized by two dispersion acoustic-like branches of the longitudinal and transverse polarizations. The influence of poly-dispersity and form factor of the molecule of the mixture component on the microscopic dynamics of the density fluctuation in multicomponent systems was established.

  2. Band structure and Fermi surface of electron-doped C60 monolayers.

    PubMed

    Yang, W L; Brouet, V; Zhou, X J; Choi, Hyoung J; Louie, Steven G; Cohen, Marvin L; Kellar, S A; Bogdanov, P V; Lanzara, A; Goldoni, A; Parmigiani, F; Hussain, Z; Shen, Z-X

    2003-04-11

    C60 fullerides are challenging systems because both the electron-phonon and electron-electron interactions are large on the energy scale of the expected narrow band width. We report angle-resolved photoemission data on the band dispersion for an alkali-doped C60 monolayer and a detailed comparison with theory. Compared to the maximum bare theoretical band width of 170 meV, the observed 100-meV dispersion is within the range of renormalization by electron-phonon coupling. This dispersion is only a fraction of the integrated peak width, revealing the importance of many-body effects. Additionally, measurements on the Fermi surface indicate the robustness of the Luttinger theorem even for materials with strong interactions.

  3. Atomic-scale mechanical properties of orientated C60 molecules revealed by noncontact atomic force microscopy.

    PubMed

    Pawlak, Rémy; Kawai, Shigeki; Fremy, Sweetlana; Glatzel, Thilo; Meyer, Ernst

    2011-08-23

    In this work, the mechanical properties of C(60) molecules adsorbed on Cu(111) are measured by tuning-fork-based noncontact atomic force microscopy (nc-AFM) and spectroscopy at cryogenic conditions. Site-specific tip-sample force variations are detected above the buckyball structure. Moreover, high-resolution images obtained by nc-AFM show the chemical structure of this molecule and describes unambiguously its orientations on the surface.

  4. Synthesis and Characterization of Conducting Elastomers Based on Interpenetrated C60-Derived Polymer Networks

    DTIC Science & Technology

    2007-11-02

    CHARACTERIZATION OF CONDUCTING ELASTOMERS BASED ON INTERPENETRATED C 60-DERIVED POLYMER NETWORKS" 6. AUTHOR( S ) PROFESSOR LONG Y. CHIANG PROFESSOR LEE Y. WANG 7...PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) IHE FOUNDATION OF CONDENSED MATTER SCIENCES NATIONAL TAIWAN UNIVERSITY 1 ROOSEVELT ROAD TAIPEI...TAIWAN 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) ASIAN OFFICE OF AEROSPACE RESEARCH AND DEVELOPMENT (AOARD) UNIT 45002 f\\P0 AP 96337

  5. Spectroscopic observations of the displacement dynamics of physically adsorbed molecules-CO on C60

    NASA Astrophysics Data System (ADS)

    Yuan, Chunqing; Yates, John T.

    2016-10-01

    In this paper, we observed physically adsorbed CO molecules on C60 surface being displaced by impinging noble gas atoms (He, Ne, Ar, Kr), either through a dynamic displacement process or an exothermic replacement process, depending on their adsorption energies. This displacement mechanism could shift from one to the other depending on the surface coverage and temperature. Furthermore, rotational energy of the impinging molecules may also contribute to the dynamic displacement process by supplying additional energy.

  6. Growth mechanism of silicon carbide films on silicon substrates using C 60 carbonization

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Workman, Richard; Sarid, Dror

    1995-12-01

    Silicon carbide films were grown on silicon substrates using C 60 molecules as a carbon source. The grown films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and infrared spectroscopy (IRS). Also, using SiO 2 as a mask on the Si substrate, a patterned SiC film was grown. Growth and defect mechanisms are discussed and compared with conventional CVD carbidizing methods.

  7. Phase diagrams of model C60 and C70 fullerenes from short-range attractive potentials.

    PubMed

    Orea, Pedro

    2009-03-14

    We report a computer-simulation study of six model fluids interacting through short-range attractive potentials in order to calculate the vapor-liquid (VL) diagrams using canonical Monte Carlo simulation. It is found that the binodal curves of these systems correctly reproduce those reported in the literature for C(60) and C(70) Girifalco potentials. Besides, we found that all coexistence curves collapse into a master curve when we rescale with their respective critical points.

  8. Zero-field-splitting in the lowest triplet state of C 60

    NASA Astrophysics Data System (ADS)

    Surján, P. R.; Németh, K.; Bennati, M.; Grupp, A.; Mehring, M.

    1996-03-01

    Zero-field-splitting parameters D and E for the fullerene C 60 in its Jahn-Teller distorted triplet state were calculated and compared to recent experimental results. The E value vanishes due to symmetry, while we obtained a non-zero D value of D = -0.009 cm -1 in the D 5d distorted lowest triplet state. The absolute value of D is in good agreement with experimental data, which suggests that the sign of D is negative.

  9. Pseudoentanglement of Spin States in the Multilevel 15N@C60 System

    NASA Astrophysics Data System (ADS)

    Mehring, M.; Scherer, W.; Weidinger, A.

    2004-11-01

    We have prepared combined electron and nuclear spin pseudoentangled states Ψ±27 and Φ±18 out of the total number of eight quantum states in the multilevel quantum system of a nitrogen atom with electron spin 3/2 and nuclear spin 1/2 encaged in the endohedral fullerene 15N@C60. Density matrix tomography was applied to verify the degree of entanglement.

  10. Symmetry of C60 and a Force Constant Model for Vibrational Modes

    NASA Astrophysics Data System (ADS)

    Koç, Ramazan; Tütüncüler, Hayriye

    1998-02-01

    A force-constant model for the vibrational modes in C60 is presented. The Keating type potential is adopted for calculating the dynamical matrix. Using symmetries of the molecule, the dynamical matrix which yields the vibrational modes is block-diagonalized. We summarize the role of group theory in specifying the vibrational modes. The results are in excellent agreement with experiments. The effect of bond-stretching force constants on the vibrational modes will be presented.

  11. Superconductivity of Rb 3 C 60 : breakdown of the Migdal-Eliashberg theory

    NASA Astrophysics Data System (ADS)

    Cappelluti, E.; Grimaldi, C.; Pietronero, L.; Strässler, S.; Ummarino, G. A.

    2001-06-01

    In this paper, through an exhaustive analysis within the Migdal-Eliashberg theory, we show the incompatibility of experimental data of Rb3C60 with the basic assumptions of the standard theory of superconductivity. For different models of the electron-phonon spectral function α2F(Ω) we solve numerically the Eliashberg equations to find which values of the electron-phonon coupling λ, of the logarithmic phonon frequency and of the Coulomb pseudopotential μ* reproduce the experimental data of Rb3C60. We find that the solutions are essentially independent of the particular shape of α2F(Ω) and that, to explain the experimental data of Rb3C60, one has to resort to extremely large couplings: λ = 3.0+/-0.8. This results differs from the usual partial analyses reported up to now and we claim that this value exceeds the maximum allowed λ compatible with the crystal lattice stability. Moreover, we show quantitatively that the obtained values of λ and strongly violate Migdal's theorem and consequently are incompatible with the Migdal-Eliashberg theory. One has therefore to consider the generalization of the theory of superconductivity in the nonadiabatic regime to account for the experimental properties of fullerides.

  12. Intensity-resolved IR multiple photon ionization and fragmentation of C60.

    PubMed

    Bakker, Joost M; Lapoutre, Vivike J F; Redlich, Britta; Oomens, Jos; Sartakov, Boris G; Fielicke, André; von Helden, Gert; Meijer, Gerard; van der Meer, Alexander F G

    2010-02-21

    The sequential absorption of multiple infrared (IR) photons by isolated gas-phase species can lead to their dissociation and/or ionization. Using the newly constructed "Free-Electron Laser for IntraCavity Experiments" (FELICE) beam line at the FELIX facility, neutral C(60) molecules have been exposed to an extremely high number (approximately 10(23)) of photons/cm(2) for a total time duration of up to 5 micros. At wavelengths around 20 microm, resonant with allowed IR transitions of C(60), ionization and extensive fragmentation of the fullerenes are observed. The resulting photofragment distributions are attributed to absorption in fragmentation products formed once C(60) is excited to internal energies at which fragmentation or ionization takes place within the duration of the laser pulse. The high IR intensities available combined with the large interaction volume permit spatially resolved detection of the ions inside the laser beam, thereby disentangling the contributions from different IR intensities. The use of spatial imaging reveals intensity dependent mass distributions that are substantially narrower than what has been observed previously, indicating rather narrow energy distributions. A simple rate-equation modeling of the excitation process supports the experimental observations.

  13. Morphology Change of C60 Islands on Organic Crystals Observed by Atomic Force Microscopy.

    PubMed

    Freund, Sara; Hinaut, Antoine; Pawlak, Rémy; Liu, Shi-Xia; Decurtins, Silvio; Meyer, Ernst; Glatzel, Thilo

    2016-06-28

    Organic-organic heterojunctions are nowadays highly regarded materials for light-emitting diodes, field-effect transistors, and photovoltaic cells with the prospect of designing low-cost, flexible, and efficient electronic devices.1-3 However, the key parameter of optimized heterojunctions relies on the choice of the molecular compounds as well as on the morphology of the organic-organic interface,4 which thus requires fundamental studies. In this work, we investigated the deposition of C60 molecules at room temperature on an organic layer compound, the salt bis(benzylammonium)bis(oxalato)cupurate(II), by means of noncontact atomic force microscopy. Three-dimensional molecular islands of C60 having either triangular or hexagonal shapes are formed on the substrate following a "Volmer-Weber" type of growth. We demonstrate the dynamical reshaping of those C60 nanostructures under the local action of the AFM tip at room temperature. The dissipated energy is about 75 meV and can be interpreted as the activation energy required for this migration process.

  14. Energy level alignment at C60/DTDCTB/PEDOT:PSS interfaces in organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Yoo, Jisu; Jung, Kwanwook; Jeong, Junkyeong; Hyun, Gyeongho; Lee, Hyunbok; Yi, Yeonjin

    2017-04-01

    The electronic structure of a narrow band gap small molecule ditolylaminothienyl-benzothiadiazole-dicyanovinylene (DTDCTB), possessing a donor-acceptor-acceptor configuration, was investigated with regard to its application as an efficient donor material in organic photovoltaics (OPVs). The interfacial orbital alignment of C60/DTDCTB/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was determined using in situ ultraviolet photoelectron and inverse photoelectron spectroscopic methods. The ionization energy and electron affinity values of DTDCTB were measured to be 5.27 eV and 3.65 eV, respectively, and thus a very small transport gap of 1.62 eV was evaluated. Large band bending of DTDCTB on PEDOT:PSS was observed, resulting in a low hole extraction barrier. Additionally, the photovoltaic gap between the highest occupied molecular orbital level of the DTDCTB donor and the lowest unoccupied molecular orbital level of the C60 acceptor was estimated to be 1.30 eV, which is known to be the theoretical maximum open-circuit voltage in OPVs employing the C60/DTDCTB active layer. The unique electronic structures of DTDCTB contributed toward the recently reported excellent power conversion efficiencies of OPVs containing a DTDCTB donor material.

  15. Possible light-induced superconductivity in K3C60 at high temperature.

    PubMed

    Mitrano, M; Cantaluppi, A; Nicoletti, D; Kaiser, S; Perucchi, A; Lupi, S; Di Pietro, P; Pontiroli, D; Riccò, M; Clark, S R; Jaksch, D; Cavalleri, A

    2016-02-25

    The non-equilibrium control of emergent phenomena in solids is an important research frontier, encompassing effects such as the optical enhancement of superconductivity. Nonlinear excitation of certain phonons in bilayer copper oxides was recently shown to induce superconducting-like optical properties at temperatures far greater than the superconducting transition temperature, Tc (refs 4-6). This effect was accompanied by the disruption of competing charge-density-wave correlations, which explained some but not all of the experimental results. Here we report a similar phenomenon in a very different compound, K3C60. By exciting metallic K3C60 with mid-infrared optical pulses, we induce a large increase in carrier mobility, accompanied by the opening of a gap in the optical conductivity. These same signatures are observed at equilibrium when cooling metallic K3C60 below Tc (20 kelvin). Although optical techniques alone cannot unequivocally identify non-equilibrium high-temperature superconductivity, we propose this as a possible explanation of our results.

  16. Functionalization of silicon dioxide surface with 3-aminopropyltrimethoxysilane for fullerene C60 immobilization.

    PubMed

    Delafosse, Grégory; Patrone, Lionel; Goguenheim, Didier

    2011-10-01

    Formation of self-assembled monolayers (SAM) of 3-aminopropyltrimethoxysilane (APTMS), chemically bonded to silicon dioxide surface, using a new solvent free process, has been studied by contact angle measurements, ellipsometry, ATR-FTIR spectroscopy and AFM imaging. The possibility of using as-obtained APTMS SAMs for anchoring functional molecular moieties is then studied with fullerene C60. In a first part we have analyzed the grafting kinetics of APTMS SAMs in order to control the formation of a single monolayer. Results show that about four hours are needed to obtain a complete APTMS single monolayer. In parallel, the ordering kinetics of the SAM has been monitored by ATR-FTIR spectroscopy, showing that the monolayer reaches its final order before grafting. We show that those APTMS SAMs can be used to graft C60 molecules deposited from a solution and forming about one monolayer anchored on amine terminal moieties. Such results could help paving the way to the preparation of hybrid C60-based molecular devices on silicon through a bottom-up approach.

  17. Spin-based diagnostic of nanostructure in copper phthalocyanine-C60 solar cell blends.

    PubMed

    Warner, Marc; Mauthoor, Soumaya; Felton, Solveig; Wu, Wei; Gardener, Jules A; Din, Salahud; Klose, Daniel; Morley, Gavin W; Stoneham, A Marshall; Fisher, Andrew J; Aeppli, Gabriel; Kay, Christopher W M; Heutz, Sandrine

    2012-12-21

    Nanostructure and molecular orientation play a crucial role in determining the functionality of organic thin films. In practical devices, such as organic solar cells consisting of donor-acceptor mixtures, crystallinity is poor and these qualities cannot be readily determined by conventional diffraction techniques, while common microscopy only reveals surface morphology. Using a simple nondestructive technique, namely, continuous-wave electron paramagnetic resonance spectroscopy, which exploits the well-understood angular dependence of the g-factor and hyperfine tensors, we show that in the solar cell blend of C(60) and copper phthalocyanine (CuPc)-for which X-ray diffraction gives no information-the CuPc, and by implication the C(60), molecules form nanoclusters, with the planes of the CuPc molecules oriented perpendicular to the film surface. This information demonstrates that the current nanostructure in CuPc:C(60) solar cells is far from optimal and suggests that their efficiency could be considerably increased by alternative film growth algorithms.

  18. The 9577 and 9632 Å Diffuse Interstellar Bands: {{\\rm{C}}}_{60}^{+} as Carrier

    NASA Astrophysics Data System (ADS)

    Walker, G. A. H.; Campbell, E. K.; Maier, J. P.; Bohlender, D.

    2017-07-01

    Galazutdinov et al. (2017) recently claimed that the relative strengths of the 9577 and 9632 Å diffuse interstellar bands (DIBs) are too poorly correlated to be caused by a single source, the {{{C}}}60+ ion. Their conclusion is based on theoretical modeling of contaminating stellar Mg ii lines at 9631.9 and 9632.4 Å and UVES spectra. This contradicts their earlier result and those of several others that the two DIBs are closely correlated and, within the errors and effects of stellar blends, exhibit an intensity ratio consistent with that found in the 6 K laboratory spectrum of {{{C}}}60+. We consider the use of close spectral standards to be superior to model atmosphere calculations in correcting for contamination by the Mg ii lines. We have examined some of the same UVES spectra and demonstrate that a lack of suitably observed telluric standards makes it impossible to adequately correct for telluric water vapor contamination, leading to unreliable continuum levels. The possible effects of higher temperatures, in the 30-100 K range, on the {{{C}}}60+ electronic absorption band profiles, and their relative intensities, are also considered.

  19. Hydrodynamic model of the collective electron resonances in C60 fullerene

    NASA Astrophysics Data System (ADS)

    Gildenburtg, V. B.; Pavlichenko, I. A.

    2017-08-01

    The polarization-response spectrum of the fullerene C60 modeled as a homogeneous spherical plasma shell is calculated in the framework of the hydrodynamic approach, allowing for the spatial dispersion caused by the Fermi-distributed valence electrons. The dipole eigenoscillation spectrum of the shell is found to contain a series of plasmons distinguished by the frequency and the radial structure. The first two of them (whose structures for C60 are the subject of discussion up to now) pass to the lower and higher surface plasmons of the plasma shell if its thickness is much larger than the Tomas-Fermi length. However, under parameter values corresponding to the C60 molecule, when these lengths are of the same order, both these plasmons (providing the main contribution to the fullerene absorption spectrum) are found to be actually volume ones in their spatial structure, and the frequency of the higher of them becomes larger than the plasma frequency (as with all the higher volume plasmons). The resonance curve of the fullerene absorption cross-section calculated on the basis of the developed model with allowance for the surface losses caused by the reflection of electrons at the shell boundaries agrees well with the experimental data.

  20. White-Rot Basidiomycete-mediated Decomposition of C60 Fullerol

    PubMed Central

    Schreiner, Kathryn M.; Filley, Timothy R.; Blanchette, Robert A.; Bowen, Brenda Beitler; Bolskar, Robert D.; Hockaday, William C.; Masiello, Caroline A.; Raebiger, James W.

    2009-01-01

    Industrially produced carbon-based nanomaterials (CNM), including fullerenes and nanotubes, will be introduced into the environment in increasing amounts in the next decades. One likely environmental chemical transformation of C60 is oxidation to C60 fullerol through both abiotic- and biotic-mediated means. Unfortunately, knowledge of the environmental fate of oxidized CNM is lacking. This study used bulk and compound specific 13C stable isotope ratio mass spectrometry techniques and spectroradiometry analysis to examine the ability of two white rot basidiomycete fungi (Phlebia tremellosa and Trametes versicolor) to metabolize and degrade an oxygenated CNM, C60 fullerol. After 32 weeks of decay, both fungi were able to bleach and oxidize fullerol to CO2. Additionally, the fungi incorporated minor amounts of the fullerol carbon into lipid biomass. These findings are significant in that they represent the first report of direct biodegradation and utilization of any fullerene derivative and provide valuable information about the possible environmental fates of other CNM. PMID:19534129

  1. Synergistic mitotoxicity of chloromethanes and fullerene C60 nanoaggregates in Daphnia magna midgut epithelial cells.

    PubMed

    Seke, Mariana; Markelic, Milica; Morina, Arian; Jovic, Danica; Korac, Aleksandra; Milicic, Dragana; Djordjevic, Aleksandar

    2016-12-03

    Adsorption of non-polar compounds by suspended fullerene nanoaggregates (nC60) may enhance their toxicity and affect the fate, transformation, and transport of non-polar compounds in the environment. The potential of stable fullerene nanoaggregates as contaminant carriers in aqueous systems and the influence of chloromethanes (trichloromethane and dichloromethane) were studied on the midgut epithelial cells of Daphnia magna by light and electron microscopy. The size and shape of fullerene nanoaggregates were observed and measured using dynamic light scattering, transmission electron microscopy, and low vacuum scanning electron microscopy. The nC60 in suspension appeared as a bulk of aggregates of irregular shape with a surface consisting of small clumps 20-30 nm in diameter. The presence of nC60 aggregates was confirmed in midgut lumen and epithelial cells of D. magna. After in vivo acute exposure to chloromethane, light and electron microscopy revealed an extensive cytoplasmic vacuolization with disruption and loss of specific structures of D. magna midgut epithelium (mitochondria, endoplasmic reticulum, microvilli, peritrophic membrane) and increased appearance of necrotic cells. The degree of observed changes depended on the type of treatment: trichloromethane (TCM) induced the most notable changes, whereas fullerene nanoaggregates alone had no negative effects. Transmission electron microscopy also indicated increased lysosomal degradation and severe peroxidative damages of enterocyte mitochondria following combined exposure to chloromethane and fullerene nanoaggregates. In conclusion, the adsorption of chloromethane by fullerene nanoaggregates enhances their toxicity and induces peroxidative mitochondrial damage in midgut enterocytes.

  2. Degradation and Microbial Uptake of C60 Fullerols in Contrasting Agricultural Soils.

    PubMed

    Berry, Timothy D; Filley, Timothy R; Clavijo, Andrea P; Bischoff Gray, Marianne; Turco, Ronald

    2017-02-07

    The environmental fate of functionalized carbon nanomaterials (CNM) remains poorly understood. Using (13)C-labeled nanomaterial we present the results of a study investigating the mineralization and microbial uptake of surface-functionalized C60 (fullerols) in agricultural soils with contrasting properties. Soil microcosms rapidly mineralized fullerol C, as determined by (13)C-content in the respired CO2, with higher fullerol mineralization in an organic, clay-rich soil versus a silty, low C soil (∼56.3% vs ∼30.9% fullerol C mineralized over 65 days). By tracking the enriched (13)C from fullerol into microbial phospholipid fatty acids (PLFA) we also report, for the first time, the incorporation of nanomaterial-derived C into soil microbial biomass, primarily by fungi and Gram-negative bacteria. While more fullerol C was incorporated into PLFA in the organic C-rich soil (0.77% vs 0.19% of PLFA C), this soil incorporated fullerol C into biomass less efficiently than the silty, low C soil (0.13% and 0.84% of assimilated fullerol C, respectively). These results demonstrate that, in contrast to pristine C60, surface functionalized C60 are unlikely to accumulate in surface soils and are readily mineralized by a range of soil microorganisms.

  3. Transformation-deformation bands in C60 after the treatment in a shear diamond anvil cell

    NASA Astrophysics Data System (ADS)

    Kulnitskiy, B. A.; Blank, V. D.; Levitas, V. I.; Perezhogin, I. A.; Popov, M. Yu; Kirichenko, A. N.; Tyukalova, E. V.

    2016-04-01

    The C60 fullerene has been investigated by high-resolution transmission electron microscopy and electron energy loss spectroscopy in a shear diamond anvil cell after applying pressure and shear deformation treatment of fcc phase. Shear transformation-deformation bands are revealed consisting of shear-strain-induced nanocrystals of linearly polymerized fullerene and polytypes, the triclinic, monoclinic, and hcp C60, fragments of amorphous structures, and voids. Consequently, after pressure release, the plastic strain retains five high pressure phases, which is potentially important for their engineering applications. Localized shear deformation initially seems contradictory because high pressure phases of C60 are stronger than the initial low pressure phase. However, this was explained by transformation-induced plasticity during localized phase transformations. It occurs due to a combination of applied stresses and internal stresses from a volume reduction during phase transformations. Localized phase transformations and plastic shear deformation promote each other, which produce positive mechanochemical feedback and cascading transformation-deformation processes. Since the plastic shear in a band is much larger than is expected based on the torsion angle, five phase transformations occur in the same region with no transformation outside the band. The results demonstrate that transformation kinetics cannot be analyzed in terms of prescribed shear, and methods to measure local shear should be developed.

  4. Effect of Orbital Hybridization on Spin-Polarized Tunneling across Co/C60 Interfaces.

    PubMed

    Wang, Kai; Strambini, Elia; Sanderink, Johnny G M; Bolhuis, Thijs; van der Wiel, Wilfred G; de Jong, Michel P

    2016-09-26

    The interaction between ferromagnetic surfaces and organic semiconductors leads to the formation of hybrid interfacial states. As a consequence, the local magnetic moment is altered, a hybrid interfacial density of states (DOS) is formed, and spin-dependent shifts of energy levels occur. Here, we show that this hybridization affects spin transport across the interface significantly. We report spin-dependent electronic transport measurements for tunnel junctions comprising C60 molecular thin films grown on top of face-centered-cubic (fcc) epitaxial Co electrodes, an AlOx tunnel barrier, and an Al counter electrode. Since only one ferromagnetic electrode (Co) is present, spin-polarized transport is due to tunneling anisotropic magnetoresistance (TAMR). An in-plane TAMR ratio of approximately 0.7% has been measured at 5 K under application of a magnetic field of 800 mT. The magnetic switching behavior shows some remarkable features, which are attributed to the rotation of interfacial magnetic moments. This behavior can be ascribed to the magnetic coupling between the Co thin films and the newly formed Co/C60 hybridized interfacial states. Using the Tedrow-Meservey technique, the tunnel spin polarization of the Co/C60 interface was found to be 43%.

  5. Multi-dimensional Modeling of Fullerene (C60) Nanoparticle Transport in the Subsurface Environment

    NASA Astrophysics Data System (ADS)

    Bai, C.; Li, Y.

    2011-12-01

    The escalating production and consumption of engineered nanomaterials may lead to increased release into groundwater. A number of studies have revealed the potential human health effects and aquatic toxicity of nanomaterials. Understanding the fate and transport of engineered nanomaterials is very important for evaluating their potential risks to human and ecological health. While a lot of efforts have been put forward in this area, limited work has been conducted to evaluate engineered nanomaterial transport in multi-dimension and at field scale. In this work, we simulate the transport of fullerene aggregates (nC60), a widely used engineered nanomaterial, in a multi-dimensional environment. A Modular Three-Dimensional Multispecies Transport Model (MT3DMS) was modified to incorporate the transport and retention of nC60. The modified MT3DMS was validated by comparing with analytical solutions and one-dimensional numerical simulation results. The validated simulator was then used to simulate nC60 transport in two- and three-dimensional field sites. Hypothetical scenarios for nanomaterial entering the subsurface environment, including entering from an injection well and releasing from a waste site were investigated. Influences of injection rate, groundwater velocity, ground water recharge rate, subsurface heterogeneity, and nanomaterial size and surface property were evaluated. Insights gained from this work will be discussed.

  6. Theoretical study of C60 as catalyst for dehydrogenation in LiBH4

    NASA Astrophysics Data System (ADS)

    Scheicher, Ralph H.; Li, Sa; Moyses Araujo, C.; Blomqvist, Andreas; Ahuja, Rajeev; Jena, Puru

    2011-08-01

    Complex light metal hydrides possess many properties which make them attractive as a storage medium for hydrogen, but typically catalysts are required to lower the hydrogen desorption temperature and to facilitate hydrogen uptake in the form of a reversible reaction. The overwhelming focus in the search for catalysing agents has been on compounds containing titanium, but the precise mechanism of their actions remains somewhat obscure. A recent experiment has now shown that fullerenes (C60) can also act as catalysts for both hydrogen uptake and release in lithium borohydride (LiBH4). In an effort to understand the involved mechanism, we have employed density functional theory to carry out a detailed study of the interaction between this complex metal hydride and the carbon nanomaterial. Considering a stepwise reduction of the hydrogen content in LiBH4, we find that the presence of C60 can lead to a substantial reduction of the involved H-removal energies. This effect is explained as a consequence of the interaction between the BHx - complex and the C60 entity.

  7. 13C NMR of molecular configurations leading to ferromagnetic exchange in TDAE-C60

    NASA Astrophysics Data System (ADS)

    Blinc, R.; Millia, F.; Apih, T.; Arcon, D.; Jeglic, P.; Mihailovic, D.; Omerzu, A.

    2001-11-01

    The temperature dependence of the 13C NMR spectra of a 40% 13C enriched well annealed TDAE-C60 sample has been measured at a Larmor frequency vL=95.57 MHz in a field of 9 T between 300 K and 7 K. Three transitions are found: the motional transition around 150 K, the ferromagnetic transition which occurs in a field of 9 T at Tc=24 K, and a transition to an inhomogeneous ferromagnetic phase around 9 K. The 13C spectra are dominated by the Fermi contact interaction between the unpaired electron and the 13C nuclei as well as by the electron-nuclear dipolar interactions. The temperature dependence of the observed lineshapes can be understood by a superposition of uniaxial rotations of the C60- ions around their 3-fold axes plus a flipping of the axes of rotation. The flipping starts to freeze out below the motional transition at 150 K whereas uniaxial rotational jumps seem to persist down to the lowest temperature studied. The results are compatible with the C60- orientational disorder proposed by Narymbetov et al. maximizing the ferromagnetic exchange interactions.

  8. Ferromagnetism in C60 polymers: pure carbon or contamination with metallic impurities?

    PubMed

    Talyzin, A V; Dzwilewski, A

    2007-01-01

    A review of ferromagnetism in C60 polymeric materials synthesized by high pressure high temperature (HPHT) treatment is presented. Analysis of published data proves that the reported ferromagnetism cannot be assigned to polymeric structure in either perfect or defect states. Most recent experimental studies have not confirmed previously reported levels of magnetization in polymeric samples while it appears that ferromagnetism of "magnetic carbon" is preserved above the depolymerization point of any C60 polymer. Identical ferromagnetic properties in some samples of fullerene polymer and graphite like hard carbon phase also show that the effect is most likely not connected to fullerenes at all. Most of the data published previously as an evidence of ferromagnetism in C60 polymers synthesized at HPHT conditions can be explained by contamination with magnetic impurities. Formation of iron carbide (Fe3C) due to reaction of metallic iron with fullerene molecules allows to explain observed Curie temperature of approximately 500 K and levels of magnetization reported for "magnetic carbon".

  9. Thermoelectric power of K3C60 fullerides: Phonon drag and carrier diffusion contributions

    NASA Astrophysics Data System (ADS)

    Choudhary, K. K.; Kaurav, N.; Varshney, Dinesh

    2009-03-01

    The thermoelectric power (S) in normal state of superconducting K3C60 fullerides is theoretically estimated. S infers a change in slope ahove transition temperature and become almost linear above 70 K. Mott expression is used to generate the electron diffusive thermoelectric power (Scdiff.) using Fermi energy as electron free parameter, Scdiff. shows linear temperature dependence. Later on, the phonon drag thermoelectric power (Sphdrag) is calculated within the relaxation time approximation when thermoelectric power is limited by the scattering of phonons from defects, grain boundaries, phonons and electrons as carriers. The Sphdrag in normal state of K3C60 is anomalous and it is an artifact of strong phonon-electron and -phonon scattering mechanism. The thermoelectric power within the relaxation time approximation has been taken into account ignoring a possible energy dependence of the scattering rates. Further, the behaviour of the S (T) is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between carrier diffusion and phonon drag contributions. The numerical analysis of thermoelectric power in the metallic phase of K3C60 has been compared wit experimental results and shows good agreement.

  10. Unique Separation Behavior of a C60 Fullerene-Bonded Silica Monolith Prepared by an Effective Thermal Coupling Agent.

    PubMed

    Kubo, Takuya; Murakami, Yoshiki; Tsuzuki, Madoka; Kobayashi, Hiroshi; Naito, Toyohiro; Sano, Tomoharu; Yan, Mingdi; Otsuka, Koji

    2015-12-07

    Herein, we report a newly developed C60 fullerene-bonded silica monolith in a capillary with unique retention behavior due to the structure of C60 fullerene. N-Hydroxysuccinimide (NHS)-conjugated C60 fullerene was successfully synthesized by a thermal coupling agent, perfluorophenyl azide (PFPA), and assigned by spectroscopic analyses. Then, NHS-PFPA-C60 fullerene was attached onto the surface of a silica monolith in a capillary. The capillary provided specific separation ability for polycyclic aromatic hydrocarbons in liquid chromatography by an effective π-π interaction. Furthermore, corannulene, which has a hemispherical structure, was selectively retained in the capillary based on the specific structural recognition due to the spherical C60 fullerene. This is the first report revealing the spherical recognition ability by C60 fullerene in liquid chromatographic separation.

  11. C60 Fullerene as Promising Therapeutic Agent for the Prevention and Correction of Skeletal Muscle Functioning at Ischemic Injury

    NASA Astrophysics Data System (ADS)

    Nozdrenko, D. M.; Zavodovskyi, D. O.; Matvienko, T. Yu.; Zay, S. Yu.; Bogutska, K. I.; Prylutskyy, Yu. I.; Ritter, U.; Scharff, P.

    2017-02-01

    The therapeutic effect of pristine C60 fullerene aqueous colloid solution (C60FAS) on the functioning of the rat soleus muscle at ischemic injury depending on the time of the general pathogenesis of muscular system and method of administration C60FAS in vivo was investigated. It was found that intravenous administration of C60FAS is the optimal for correction of speed macroparameters of contraction for ischemic muscle damage. At the same time, intramuscular administration of C60FAS shows pronounced protective effect in movements associated with the generation of maximum force responses or prolonged contractions, which increase the muscle fatigue level. Analysis of content concentration of creatine phosphokinase and lactate dehydrogenase enzymes in the blood of experimental animals indicates directly that C60FAS may be a promising therapeutic agent for the prevention and correction of ischemic-damaged skeletal muscle function.

  12. Electronic absorption spectra of C60+ -L (L = He, Ne, Ar, Kr, H2, D2, N2) complexes

    NASA Astrophysics Data System (ADS)

    Holz, Mathias; Campbell, Ewen Kyle; Rice, Corey Allen; Maier, John Paul

    2017-02-01

    Electronic spectra in the near infrared of C60+ with He, Ne, Ar, Kr, H2, D2 and N2 attached have been recorded below 10 K in a cryogenic radio frequency ion trap. Additional absorption bands are observed compared to the spectrum of C60+ -He. In the case of C60+ -N2, the strongest one of these shifts to lower energies by 21.3 cm-1 compared to the origin band of C60+ -He at 10378.5 cm-1. The pattern in the spectrum is dependent on the attached ligand. The gas-phase observations on C60+ -Ne allow a rationalization of the relative intensities of the absorptions of C60+ in a neon matrix.

  13. Molecular orientation and lattice ordering of C60 molecules on the polar FeO/Pt(111) surface.

    PubMed

    Qin, Zhihui; Liu, Cunding; Chen, Jian; Guo, Qinmin; Yu, Yinghui; Cao, Gengyu

    2012-01-14

    C(60) molecules assemble into close packing layer under the domination of the intermolecular interaction when deposited onto Pt(111)-supported FeO layer kept at 400 K. From corresponding high resolution scanning tunneling microscopy (STM) image, a kind of C(60) molecular orientational ordering stabilized by the intermolecular interaction is revealed as C(60)/FeO(111)-(√133 × √133) R17.5° structure and determined from the commensurability between the C(60) nearest-neighbor distance and the lattice of the underlying oxygen layer. Moreover, due to the inhomogeneously distributed work function of the underlying FeO layer, the C(60) molecular electronic state is periodically modulated resulting in a bright-dim STM contrast. In addition, one coincidence lattice ordering is determined as 8 × 8 superstructure with respect to the C(60) primitive cell, which overlays a 3 × 3 moiré cell of the underlying FeO layer.

  14. Molecular orientation and lattice ordering of C60 molecules on the polar FeO/Pt(111) surface

    NASA Astrophysics Data System (ADS)

    Qin, Zhihui; Liu, Cunding; Chen, Jian; Guo, Qinmin; Yu, Yinghui; Cao, Gengyu

    2012-01-01

    C60 molecules assemble into close packing layer under the domination of the intermolecular interaction when deposited onto Pt(111)-supported FeO layer kept at 400 K. From corresponding high resolution scanning tunneling microscopy (STM) image, a kind of C60 molecular orientational ordering stabilized by the intermolecular interaction is revealed as C60/FeO(111)-(√133 × √133) R17.5° structure and determined from the commensurability between the C60 nearest-neighbor distance and the lattice of the underlying oxygen layer. Moreover, due to the inhomogeneously distributed work function of the underlying FeO layer, the C60 molecular electronic state is periodically modulated resulting in a bright-dim STM contrast. In addition, one coincidence lattice ordering is determined as 8 × 8 superstructure with respect to the C60 primitive cell, which overlays a 3 × 3 moiré cell of the underlying FeO layer.

  15. The effect of fullerene C60 on the mechanical and dielectrical behavior of epoxy resins at low loading

    NASA Astrophysics Data System (ADS)

    Pikhurov, D. V.; Zuev, Vjacheslav V.

    2014-05-01

    Fullerene C60 / epoxy polymers nanocomposites with different C60 loading have (0.01-0.12 wt.%) been prepared. Mechanical testing shows that compared with neat epoxy, mechanical and toughning properties of composites are greatly improved. The addition of fullerene C60 increased the modulus of the epoxy (up to 20%), but the glass transition temperature was unaffected. The measured impact strength was also increased, from 38 to to 115 kJ/m2 with the addition of 0.12wt.% of fullerene C60. The toughning mechanism has been discussed. Dielectric spectroscopy was used to investigate the influence of nanoparticles on the relaxation processes in polymer matrix.

  16. Analyses of the Binding between Water Soluble C60 Derivatives and Potential Drug Targets through a Molecular Docking Approach

    PubMed Central

    Liu, Junjun; Zhang, Houjin

    2016-01-01

    Fullerene C60, a unique sphere-shaped molecule consisting of carbon, has been proved to have inhibitory effects on many diseases. However, the applications of C60 in medicine have been severely hindered by its complete insolubility in water and low solubility in almost all organic solvents. In this study, the water-soluble C60 derivatives and the C60 binding protein’s structures were collected from the literature. The selected proteins fall into several groups, including acetylcholinesterase, glutamate racemase, inosine monophosphate dehydrogenase, lumazine synthase, human estrogen receptor alpha, dihydrofolate reductase and N-myristoyltransferase. The C60 derivatives were docked into the binding sites in the proteins. The binding affinities of the C60 derivatives were calculated. The bindings between proteins and their known inhibitors or native ligands were also characterized in the same way. The results show that C60 derivatives form good interactions with the binding sites of different protein targets. In many cases, the binding affinities of C60 derivatives are better than those of known inhibitors and native ligands. This study demonstrates the interaction patterns of C60 derivatives and their binding partners, which will have good impact on the fullerene-based drug discovery. PMID:26829126

  17. Electron Spin Density Distribution in the Polymer Phase of CsC60: Assignment of the NMR Spectrum

    NASA Astrophysics Data System (ADS)

    de Swiet, T. M.; Yarger, J. L.; Wagberg, T.; Hone, J.; Gross, B. J.; Tomaselli, M.; Titman, J. J.; Zettl, A.; Mehring, M.

    2000-01-01

    We present high resolution 133Cs-13C double resonance NMR data and 13C-13C NMR correlation spectra of 13C enriched samples of the polymeric phase of CsC60. These data lead to a partial assignment of the lines in the 13C NMR spectrum of CsC60 to the carbon positions on the C60 molecule. A plausible completion of the assignment can be made on the basis of an ab initio calculation. The data support the view that the conduction electron density is concentrated at the C60 ``equator,'' away from the interfullerene bonds.

  18. New type of redox nanoprobe: C60-based nanomaterial and its application in electrochemical immunoassay for doping detection.

    PubMed

    Han, Jing; Zhuo, Ying; Chai, Ya-Qin; Xiang, Yun; Yuan, Ruo

    2015-02-03

    Carbon nanomaterials were usually exploited as nanocarriers in an electrochemical immunosensor but rarely acted as redox nanoprobes. Herein, our motivation is to adequately utilize the inner redox activity of fullerene (C60) to obtain a new type of redox nanoprobe based on a hydrophilic C60 nanomaterial. First, C60 nanoparticles (C60NPs) were prepared by phase-transfer method and functionalized with amino-terminated polyamidoamine (PAMAM) to obtain the PAMAM decorated C60NPs (PAMAM-C60NPs) which have better hydrophilicity compared to that of unmodified C60NPs and possesses abundant amine groups for further modification. Following that, gold nanoparticles (nano-Au) were absorbed on the PAMAM-C60NPs surface, and the resultant Au-PAMAM-C60NPs were employed as a new type of redox nanoprobe and nanocarrier to label detection antibodies (Ab2). Doping control has become the biggest problem facing international sport. Erythropoietin (EPO) as a blood doping agent has been a hotspot in doping control. After sandwich-type immunoreaction between EPO (as a model) and Ab2-labeled Au-PAMAM-C60NPs, the resultant immunosensor was further incubated with a drop of tetraoctylammonium bromide (TOAB) which acts as booster to arouse the inner redox activity of Au-PAMAM-C60NPs, thus a pair of reversible redox peaks is observed. As a result, the proposed immunosensor shows a wide linear range and a relatively low detection limit for EPO. This strategy paves a new avenue for exploring the redox nanoprobe based on carbon nanomaterials in the electrochemical biosensor field.

  19. Molecular dynamic-secondary ion mass spectrometry (D-SIMS) ionized by co-sputtering with C60+ and Ar+.

    PubMed

    You, Yun-Wen; Chang, Hsun-Yun; Lin, Wei-Chun; Kuo, Che-Hung; Lee, Szu-Hsian; Kao, Wei-Lun; Yen, Guo-Ji; Chang, Chi-Jen; Liu, Chi-Ping; Huang, Chih-Chieh; Liao, Hua-Yang; Shyue, Jing-Jong

    2011-10-15

    Dynamic secondary ion mass spectrometry (D-SIMS) analysis of poly(ethylene terephthalate) (PET) and poly(methyl methacrylate) (PMMA) was conducted using a quadrupole mass analyzer with various combinations of continuous C(60)(+) and Ar(+) ion sputtering. Individually, the Ar(+) beam failed to generate fragments above m/z 200, and the C(60)(+) beam generated molecular fragments of m/z ~1000. By combining the two beams, the auxiliary Ar(+) beam, which is proposed to suppress carbon deposition due to C(60)(+) bombardment and/or remove graphitized polymer, the sputtering range of the C(60)(+) beam is extended. Another advantage of this technique is that the high sputtering rate and associated high molecular ion intensity of the C(60)(+) beam generate adequate high-mass fragments that mask the damage from the Ar(+) beam. As a result, fragments at m/z ~900 can be clearly observed. As a depth-profiling tool, the single C(60)(+) beam cannot reach a steady state for either PET or PMMA at high ion fluence, and the intensity of the molecular fragments produced by the beam decreases with increasing C(60)(+) fluence. As a result, the single C(60)(+) beam is suitable for profiling surface layers with limited thickness. With C(60)(+)-Ar(+) co-sputtering, although the initial drop in intensity is more significant than with single C(60)(+) ionization because of the damage introduced by the auxiliary Ar(+), the intensity levels indicate that a more steady-state process can be achieved. In addition, the secondary ion intensity at high fluence is higher with co-sputtering. As a result, the sputtered depth is enhanced with co-sputtering and the technique is suitable for profiling thick layers. Furthermore, co-sputtering yields a smoother surface than single C(60)(+) sputtering.

  20. Continuum modeling investigation of gigahertz oscillators based on a C60 fullerene inside cyclic peptide nanotubes

    NASA Astrophysics Data System (ADS)

    Sadeghi, F.; Ansari, R.; Darvizeh, M.

    2016-02-01

    Research concerning the fabrication of nano-oscillators with operating frequency in the gigahertz (GHz) range has become a focal point in recent years. In this paper, a new type of GHz oscillators is introduced based on a C60 fullerene inside a cyclic peptide nanotube (CPN). To study the dynamic behavior of such nano-oscillators, using the continuum approximation in conjunction with the 6-12 Lennard-Jones (LJ) potential function, analytical expressions are derived to determine the van der Waals (vdW) potential energy and interaction force between the two interacting molecules. Employing Newton's second law, the equation of motion is solved numerically to arrive at the telescopic oscillatory motion of a C60 fullerene inside CPNs. It is shown that the fullerene molecule exhibits different kinds of oscillation inside peptide nanotubes which are sensitive to the system parameters. Furthermore, for the precise evaluation of the oscillation frequency, a novel semi-analytical expression is proposed based on the conservation of the mechanical energy principle. Numerical results are presented to comprehensively study the effects of the number of peptide units and initial conditions (initial separation distance and velocity) on the oscillatory behavior of C60 -CPN oscillators. It is found out that for peptide nanotubes comprised of one unit, the maximum achievable frequency is obtained when the inner core oscillates with respect to its preferred positions located outside the tube, while for other numbers of peptide units, such frequency is obtained when the inner core oscillates with respect to the preferred positions situated in the space between the two first or the two last units. It is further found out that four peptide units are sufficient to obtain the optimal frequency.