Science.gov

Sample records for kev fullerene bombardment

  1. Secondary ion emission under keV carbon cluster bombardment 

    E-print Network

    Locklear, Jay Edward

    2006-10-30

    Secondary ion mass spectrometry (SIMS) is a surface analysis technique capable of providing isotopic and molecular information. SIMS uses keV projectiles to impinge upon a sample resulting in secondary ion emission from nanometric dimensions...

  2. The production and sputtering of S2 by keV ion bombardment

    NASA Technical Reports Server (NTRS)

    Boring, J. W.; Chrisey, D. B.; Oshaughnessy, D. J.; Phipps, J. A.; Zhao, N.

    1986-01-01

    The ion bombardment of S-containing molecules in comets is simulated experimentally. Mass-analyzed 30-keV beams of Ar(+) and He(+) are directed at solid S, H2S, and CS2 targets at temperatures 15 K, and the neutral molecular species produced are ionized and analyzed using a quadrupole mass spectrometer. The dominant species detected are S1 and S2 for the S target, H2S and S2 for the H2S target, and S, CS, S2, and CS2 for the CS2 target. In the latter case, it is found that after about 10 to the 14th He(+) ions/sq cm have struck the target, further sputtering is prevented by formation of a dark brown deposit which is stable at room temperature; the residue forms more slowly when Ar(+) ions are used. These results, indicating relatively efficient S2 production by ion bombardment, are applied to theoretical models of S2 production and/or ejection by solar-wind, solar-flare, or cosmic-ray ions striking comets. It is found that direct solar-wind production of S2 by sputtering is unlikely at realistic bombardment rates, but that H2S-S2 conversion by energetic ions could be significant, with less stringent ice-temperature and irradiation-flux constraints than in the case of S2 production by photons.

  3. Stability of Extraterrestrial Glycine under Energetic Particle Radiation Estimated from 2 keV Electron Bombardment Experiments

    NASA Astrophysics Data System (ADS)

    Maté, B.; Tanarro, I.; Escribano, R.; Moreno, M. A.; Herrero, V. J.

    2015-06-01

    The destruction of solid glycine under irradiation with 2 keV electrons has been investigated by means of IR spectroscopy. Destruction cross sections, radiolysis yields, and half-life doses were determined for samples at 20, 40, 90, and 300 K. The thickness of the irradiated samples was kept below the estimated penetration depth of the electrons. No significant differences were obtained in the experiments below 90 K, but the destruction cross section at 300 K was larger by a factor of 2. The radiolysis yields and half-life doses are in good accordance with recent MeV proton experiments, which confirms that electrons in the keV range can be used to simulate the effects of cosmic rays if the whole sample is effectively irradiated. In the low temperature experiments, electron irradiation leads to the formation of residues. IR absorptions of these residues are assigned to the presence CO2, CO, OCN-, and CN- and possibly to amide bands I to III. The protection of glycine by water ice is also studied. A water ice film of ˜150 nm is found to provide efficient shielding against the bombardment of 2 keV electrons. The results of this study show also that current Monte Carlo predictions provide a good global description of electron penetration depths. The lifetimes estimated in this work for various environments ranging from the diffuse interstellar medium to the inner solar system, show that the survival of hypothetical primeval glycine from the solar nebula in present solar system bodies is not very likely.

  4. Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions.

    SciTech Connect

    Siekhaus, W. J.; Teslich, N. E.; Weber, P. K.

    2014-10-23

    Depleted uranium that included carbide inclusions was sputtered with 30-keV gallium ions or 16-kev cesium ions to depths much greater than the ions’ range, i.e. using steady-state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady-state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U??Ga??, (UC)??Ga?? and U??Cs?, (UC)??Cs??, respectively.

  5. Spectral reflectance change and luminescence of selected salts during 2-10 KeV proton bombardment - Implications for Io

    NASA Technical Reports Server (NTRS)

    Nelson, R. M.; Nash, D. B.

    1979-01-01

    Radiation damage and luminescence caused by magnetospheric charged particles have been suggested by several investigators as mechanisms that are capable of explaining some of the peculiar spectral/albedo features of Io. In the present paper, this possibility is pursued by measuring the UV-visual spectral reflectance and luminescent efficiency of several proposed Io surface constituents during 2 to 10 keV proton irradiation at room and low temperatures. The luminescence efficiencies of pure samples, studied in the laboratory, suggest that charged-particle induced luminescence from Io's surface might be observable by spacecraft such as Voyager when viewing Io's dark side.

  6. Single impacts of keV fullerene ions on free standing graphene: Emission of ions and electrons from confined volume.

    PubMed

    Verkhoturov, Stanislav V; Geng, Sheng; Czerwinski, Bartlomiej; Young, Amanda E; Delcorte, Arnaud; Schweikert, Emile A

    2015-10-28

    We present the first data from individual C60 impacting one to four layer graphene at 25 and 50 keV. Negative secondary ions and electrons emitted in transmission were recorded separately from each impact. The yields for Cn (-) clusters are above 10% for n ? 4, they oscillate with electron affinities and decrease exponentially with n. The result can be explained with the aid of MD simulation as a post-collision process where sufficient vibrational energy is accumulated around the rim of the impact hole for sputtering of carbon clusters. The ionization probability can be estimated by comparing experimental yields of Cn (-) with those of Cn (0) from MD simulation, where it increases exponentially with n. The ionization probability can be approximated with ejecta from a thermally excited (3700 K) rim damped by cluster fragmentation and electron detachment. The experimental electron probability distributions are Poisson-like. On average, three electrons of thermal energies are emitted per impact. The thermal excitation model invoked for Cn (-) emission can also explain the emission of electrons. The interaction of C60 with graphene is fundamentally different from impacts on 3D targets. A key characteristic is the high degree of ionization of the ejecta. PMID:26520508

  7. Single impacts of keV fullerene ions on free standing graphene: Emission of ions and electrons from confined volume

    NASA Astrophysics Data System (ADS)

    Verkhoturov, Stanislav V.; Geng, Sheng; Czerwinski, Bartlomiej; Young, Amanda E.; Delcorte, Arnaud; Schweikert, Emile A.

    2015-10-01

    We present the first data from individual C60 impacting one to four layer graphene at 25 and 50 keV. Negative secondary ions and electrons emitted in transmission were recorded separately from each impact. The yields for Cn- clusters are above 10% for n ? 4, they oscillate with electron affinities and decrease exponentially with n. The result can be explained with the aid of MD simulation as a post-collision process where sufficient vibrational energy is accumulated around the rim of the impact hole for sputtering of carbon clusters. The ionization probability can be estimated by comparing experimental yields of Cn- with those of Cn0 from MD simulation, where it increases exponentially with n. The ionization probability can be approximated with ejecta from a thermally excited (3700 K) rim damped by cluster fragmentation and electron detachment. The experimental electron probability distributions are Poisson-like. On average, three electrons of thermal energies are emitted per impact. The thermal excitation model invoked for Cn- emission can also explain the emission of electrons. The interaction of C60 with graphene is fundamentally different from impacts on 3D targets. A key characteristic is the high degree of ionization of the ejecta.

  8. Fullerene Machines

    NASA Technical Reports Server (NTRS)

    Globus, Al; Saini, Subhash

    1998-01-01

    Recent computational efforts at NASA Ames Research Center and computation and experiment elsewhere suggest that a nanotechnology of machine phase functionalized fullerenes may be synthetically accessible and of great interest. We have computationally demonstrated that molecular gears fashioned from (14,0) single-walled carbon nanotubes and benzyne teeth should operate well at 50-100 gigahertz. Preliminary results suggest that these gears can be cooled by a helium atmosphere and a laser motor can power fullerene gears if a positive and negative charge have been added to form a dipole. In addition, we have unproven concepts based on experimental and computational evidence for support structures, computer control, a system architecture, a variety of components, and manufacture. Combining fullerene machines with the remarkable mechanical properties of carbon nanotubes, there is some reason to believe that a focused effort to develop fullerene nanotechnology could yield materials with tremendous properties.

  9. Fullerene materials

    SciTech Connect

    Malhotra, R.; Ruoff, R.S.; Lorents, D.C.

    1995-04-01

    Fullerenes are all-carbon cage molecules. The most celebrated fullerene is the soccer-ball shaped C{sub 60}, which is composed of twenty hexagons and twelve pentagons. Because its structure is reminiscent of the geodesic domes of architect R. Buckminster Fuller, C{sub 60} is called buckminsterfullerene, and all the materials in the family are designated fullerenes. Huffman and Kraetschmer`s discovery unleashed activity around the world as scientists explored production methods, properties, and potential uses of fullerenes. Within a short period, methods for their production in electric arcs, plasmas, and flames were discovered, and several companies began selling fullerenes to the research market. What is remarkable is that in all these methods, carbon atoms assemble themselves into cage structures. The capability for self-assembly points to some inherent stability of these structures that allows their formation. The unusual structure naturally leads to unusual properties. Among them are ready solubility in solvents and a relatively high vapor pressure for a pure carbon material. The young fullerene field has already produced a surprising array of structures for the development of carbon-base materials having completely new and different properties from any that were previously possible.

  10. Fullerene Machines

    NASA Technical Reports Server (NTRS)

    Globus, Al; Saini, Subhash (Technical Monitor)

    1998-01-01

    Fullerenes possess remarkable properties and many investigators have examined the mechanical, electronic and other characteristics of carbon SP2 systems in some detail. In addition, C-60 can be functionalized with many classes of molecular fragments and we may expect the caps of carbon nanotubes to have a similar chemistry. Finally, carbon nanotubes have been attached to t he end of scanning probe microscope (Spill) tips. Spills can be manipulated with sub-angstrom accuracy. Together, these investigations suggest that complex molecular machines made of fullerenes may someday be created and manipulated with very high accuracy. We have studied some such systems computationally (primarily functionalized carbon nanotube gears and computer components). If such machines can be combined appropriately, a class of materials may be created that can sense their environment, calculate a response, and act. The implications of such hypothetical materials are substantial.

  11. Energetic Ion Bombardment of Ag Surfaces by C60 and Ga Projectiles

    E-print Network

    Wucher, Andreas

    bombardment-induced release of particles from a metal surface is investigated using energetic fullerene] and Au3 [5, 6] ion guns, applications have expanded dramatically. For example, these sources can by either collision cascade theory or by thermal spikes. The spike model has traditionally been employed

  12. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1994-01-01

    A method of forming synthetic diamond on a substrate. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond film thickness on the substrate.

  13. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1993-01-01

    A method of forming synthetic diamond on a substrate is disclosed. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond thickness on the substrate.

  14. Fullerene Nanogears

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Numerical Aerospace Simulation Systems Division (NAS) of the NASA Ames Research Center, Moffett Field, California is conducting research into molecular-sized devices known as Nanotechnology. This photograph depicts two 'Fullerene Nano-gears' with multiple teeth. The hope is that one day, products can be constructed made of thousands of tiny machines that could self-repair and adapt to the environment in which they exist. Researchers have simulated attaching benzyne molecules to the outside of a nanotube to form gear teeth. Nanotubes are molecular-sized pipes made of carbon atoms. To 'drive' the gears, the supercomputer simulated a laser that served as a motor. The laser creates an electric field around the nanotube. A positively charged atom is placed on one side of the nanotube, and a negatively charged atom on the other side. The electric field drags the nanotube around like a shaft turning. Jie Han, Al Globus, Richard Jaffe and Glenn Deardorff are the authors of a technical paper detailing this technology which appears in The Journal of Nanotechnology.

  15. [Fullerenes in biology].

    PubMed

    Krokosz, Anita

    2007-01-01

    Fullerenes are chemical structures made of carbon atoms. The stable form is molecule composed of 60 carbon atoms arranged in a soccer ball-shaped structure. With respect to its electron donor and acceptor capability and photochemical behavior fullerenes can be effective antioxidants and radical scavengers or prooxidants and photosensitizers. These properties of fullerenes have paid attention on their possible biological applications. Results of previous studies point to the great dependance of fullerenes activity upon quality, quantity and geometry of substituents in fullerene derivatives. Some of fullerene derivatives show antiviral and antimicrobial activity, including anti-HIV properties. C60 and its derivatives are able to exhibit cytotoxic and enzyme-inhibiting abilities as well as radical-quenching and antioxidative abilities. Generation of reactive oxygen species under influence of visible light is another ability of fullerene derivetives desired in photodynamic therapy. PMID:17718393

  16. Fullerenes in Allende Meteorite

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bada, J. L.; Winans, R. E.; Bunch, T. E.

    1994-01-01

    The detection of fullerenes in deposits from meteor impacts has led to renewed interest in the possibility that fullerenes are present in meteorites. Although fullerenes have not previously been detected in the Murchison and Allende meteorites, the Allende meteorite is known to contain several well-ordered graphite particles which are remarkably similar in size and appearance to the fullerene-related structures carbon onions and nanotubes. We report that fullerenes are in fact present in trace amounts in the Allende meteorite. In addition to fullerenes, we detected many polycyclic aromatic hydrocarbons (PAHs) in the Allende meteorite, consistent with previous reports. In particular, we detected benzofluoranthene and corannulene (C20H10), five-membered ring structures which have been proposed as precursors to the formation of fullerene synthesis, perhaps within circumstellar envelopes or other sites in the interstellar medium.

  17. Combustion method for producing fullerenes

    DOEpatents

    Howard, J.B.; McKinnon, J.T.

    1993-12-28

    A method for synthesizing fullerenes in flames is provided. Fullerenes are prepared by burning carbon-containing compounds in a flame and collecting the condensable. The condensable contain the desired fullerenes. Fullerene yields can be optimized and fullerene composition can be selectively varied. Fullerene yields and compositions are determined by selectively controlling flame conditions and parameters such as C/O ratio, pressure, temperature, residence time, diluent concentration and gas velocity. 4 figures.

  18. Combustion method for producing fullerenes

    DOEpatents

    Howard, Jack B. (Winchester, MA); McKinnon, J. Thomas (Boulder, CO)

    1993-01-01

    A method for synthesizing fullerenes in flames is provided. Fullerenes are prepared by burning carbon-containing compounds in a flame and collecting the condensibles. The condensibles contain the desired fullerenes. Fullerene yields can be optimized and fullerene composition can be selectively varied. Fullerene yields and compositions are determined by selectively controlling flame conditions and parameters such as C/O ratio, pressure, temperature, residence time, diluent concentration and gas velocity.

  19. Combustion synthesis of fullerenes and fullerenic nanostructures

    E-print Network

    Goel, Anish

    2002-01-01

    Fullerenes are molecules comprised entirely of sp²-bonded carbon atoms arranged in pentagonal and hexagonal rings to form a hollow, closed-cage structure. Buckyballs, a subset which contains C?? and C??, are single-shell ...

  20. Interstellar and circumstellar fullerenes

    E-print Network

    Bernard-Salas, J; Jones, A P; Peeters, E; Micelotta, E R; Otsuka, M; Sloan, G C; Kemper, F; Groenewegen, M

    2014-01-01

    Fullerenes are a particularly stable class of carbon molecules in the shape of a hollow sphere or ellipsoid that might be formed in the outflows of carbon stars. Once injected into the interstellar medium (ISM), these stable species survive and are thus likely to be widespread in the Galaxy where they contribute to interstellar extinction, heating processes, and complex chemical reactions. In recent years, the fullerene species C60 (and to a lesser extent C70) have been detected in a wide variety of circumstellar and interstellar environments showing that when conditions are favourable, fullerenes are formed efficiently. Fullerenes are the first and only large aromatics firmly identified in space. The detection of fullerenes is thus crucial to provide clues as to the key chemical pathways leading to the formation of large complex organic molecules in space, and offers a great diagnostic tool to describe the environment in which they reside. Since fullerenes share many physical properties with PAHs, understand...

  1. Information Entropy of Fullerenes.

    PubMed

    Sabirov, Denis Sh; ?sawa, Eiji

    2015-08-24

    The reasons for the formation of the highly symmetric C60 molecule under nonequilibrium conditions are widely discussed as it dominates over numerous similar fullerene structures. In such conditions, evolution of structure rather than energy defines the processes. We have first studied the diversity of fullerenes in terms of information entropy. Sorting 2079 structures from An Atlas of Fullerenes [ Fowler , P. W. ; Manolopoulos , D. E. An Atlas of Fullerenes ; Oxford : Clarendon , 1995 . ], we have found that the information entropies of only 14 fullerenes (<1% of the studied structures) lie between the values of C60 and C70, the two most abundant fullerenes. Interestingly, buckminsterfullerene is the only fullerene with zero information entropy, i.e., an exclusive compound among the other members of the fullerene family. Such an efficient sorting demonstrates possible relevance of information entropy to chemical processes. For this reason, we have introduced an algorithm for calculating changes in information entropy at chemical transformations. The preliminary calculations of changes in information entropy at the selected fullerene reactions show good agreement with thermochemical data. PMID:26158238

  2. Medicinal applications of fullerenes

    PubMed Central

    Bakry, Rania; Vallant, Rainer M; Najam-ul-Haq, Muhammad; Rainer, Matthias; Szabo, Zoltan; Huck, Christian W; Bonn, Günther K

    2007-01-01

    Fullerenes have attracted considerable attention in different fields of science since their discovery in 1985. Investigations of physical, chemical and biological properties of fullerenes have yielded promising information. It is inferred that size, hydrophobicity, three-dimensionality and electronic configurations make them an appealing subject in medicinal chemistry. Their unique carbon cage structure coupled with immense scope for derivatization make them a potential therapeutic agent. The study of biological applications has attracted increasing attention despite the low solubility of carbon spheres in physiological media. The fullerene family, and especially C60, has appealing photo, electrochemical and physical properties, which can be exploited in various medical fields. Fullerene is able to fit inside the hydrophobic cavity of HIV proteases, inhibiting the access of substrates to the catalytic site of enzyme. It can be used as radical scavenger and antioxidant. At the same time, if exposed to light, fullerene can produce singlet oxygen in high quantum yields. This action, together with direct electron transfer from excited state of fullerene and DNA bases, can be used to cleave DNA. In addition, fullerenes have been used as a carrier for gene and drug delivery systems. Also they are used for serum protein profiling as MELDI material for biomarker discovery. In this review we report the aspects of medicinal applications of fullerenes. PMID:18203430

  3. The topology of fullerenes

    PubMed Central

    Schwerdtfeger, Peter; Wirz, Lukas N; Avery, James

    2015-01-01

    Fullerenes are carbon molecules that form polyhedral cages. Their bond structures are exactly the planar cubic graphs that have only pentagon and hexagon faces. Strikingly, a number of chemical properties of a fullerene can be derived from its graph structure. A rich mathematics of cubic planar graphs and fullerene graphs has grown since they were studied by Goldberg, Coxeter, and others in the early 20th century, and many mathematical properties of fullerenes have found simple and beautiful solutions. Yet many interesting chemical and mathematical problems in the field remain open. In this paper, we present a general overview of recent topological and graph theoretical developments in fullerene research over the past two decades, describing both solved and open problems. WIREs Comput Mol Sci 2015, 5:96–145. doi: 10.1002/wcms.1207 Conflict of interest: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. PMID:25678935

  4. Fast Atom Bombardment Mass Spectrometry.

    ERIC Educational Resources Information Center

    Rinehart, Kenneth L., Jr.

    1982-01-01

    Discusses reactions and characteristics of fast atom bombardment (FAB) mass spectroscopy in which samples are ionized in a condensed state by bombardment with xenon or argon atoms, yielding positive/negative secondary ions. Includes applications of FAB to structural problems and considers future developments using the technique. (Author/JN)

  5. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    NASA Astrophysics Data System (ADS)

    Semsang, Nuananong; Yu, LiangDeng

    2013-07-01

    Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  6. [Fullerenes in radiobiology].

    PubMed

    Grebowski, Jacek; Krokosz, Anita

    2010-01-01

    Molecule of fullerene, having a spherical or ellipsoidal shape, is made of rings consisting of five or six carbon atoms, combined with conjugated pi bonds. Delocalization of pi electrons in the molecule of fullerene makes it easy to scavenge free radicals. But, despite being the effective antioxidants and radical scavengers fullerenes may be prooxidants by reactive oxygen species generation. Mammalian cells consist mainly of water (about 70%). Thus, the radical and non-radical products of water radiolysis are the basic sources of radiation damage to biomolecules. Reactive oxygen species, such as hydroxyl (HO*) and superoxide (O2-*) radicals and hydrogen peroxide (H2O2), are responsible for radiation-induced damage in aerated systems. Free radical mechanism of radiation damage suggests that scavengers of free radicals should protect cellular structures against damage. Electron donor compounds should also exhibit protective properties towards oxidized functional groups by reducing them. However, the electron transfer from fullerene to oxygen may generate superoxide radical. The shape of fullerenes allows them to act as carriers of radioactive atoms of isotopes used in the therapy and medical diagnostics. Fullerenes and their derivatives due to its properties are new promising chemicals for application in radiobiology. Fullerenes may be radioprotectors, radiosensitizer or auxiliary compounds in diagnostic imaging. What they are depends on the experimental system used. PMID:21473050

  7. Process for fullerene functionalization

    DOEpatents

    Cahill, P.A.; Henderson, C.C.

    1995-12-12

    Di-addended and tetra-addended Buckminster fullerenes are synthesized through the use of novel organoborane intermediates. The C{sub 60}, C{sub 70}, or higher fullerene is reacted with a borane such as BH{sub 3} in a solvent such as toluene to form an organoborane intermediate. Reaction of the organoborane such as hydrolysis with water or alcohol results in the product di-addended and tetra-addended fullerene in up to 30% yields. Dihydrofullerenes and tetrahydrofullerenes are produced by the process of the invention. 7 figs.

  8. Process for fullerene functionalization

    DOEpatents

    Cahill, Paul A. (Albuquerque, NM); Henderson, Craig C. (Dublin, CA)

    1995-01-01

    Di-addended and tetra-addended Buckminster fullerenes are synthesized through the use of novel organoborane intermediates. The C.sub.60, C.sub.70, or higher fullerene is reacted with a borane such as BH.sub.3 in a solvent such as toluene to form an organoborane intermediate. Reaction of the organoborane such as hydrolysis with water or alcohol results in the product di-addended and tetra-addended fullerene in up to 30% yields. Dihydrofullerenes and tetrahydrofullerenes are produced by the process of the invention.

  9. ARXPS analysis of surface compositional change in ? ion bombarded GaAs (100)

    NASA Astrophysics Data System (ADS)

    Pan, J. S.; Wee, A. T. S.; Huan, C. H. A.; Tan, H. S.; Tan, K. L.

    1997-09-01

    Angle-resolved x-ray photoelectron spectroscopy (ARXPS) has been used to study surface compositional changes in GaAs (100) as a consequence of 1 to 5 keV 0022-3727/30/18/004/img3 ion bombardment. Prior to 0022-3727/30/18/004/img3 ion bombardment, the ARXPS measurements showed that neglecting surface contamination, the composition of the GaAs surface was close to its stoichiometric value of 1:1. After 0022-3727/30/18/004/img3 ion bombardment, the oxide layer was efficiently removed. At steady state the altered layers induced by 1 - 5 keV 0022-3727/30/18/004/img3 ion bombardment were, on average, Ga-rich up to the sampling depth of the ARXPS technique. The ARXPS measurements also showed that the depth profile of the altered layer was a function of 0022-3727/30/18/004/img3 ion energy. The altered layer induced by 1 keV 0022-3727/30/18/004/img3 ion bombardment was inhomogeneous as a function of depth and appeared richer in Ga on the surface than in the subsurface region, that by 3 keV 0022-3727/30/18/004/img3 ion bombardment was homogeneous and that by 5 keV 0022-3727/30/18/004/img3 ion bombardment was less Ga-rich on the surface than in the subsurface region. The results are discussed in the context of preferential sputtering, radiation-enhanced diffusion/segregation, and altered layer thickness dependence on 0022-3727/30/18/004/img3 ion energy.

  10. Conversion of fullerenes to diamond

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1994-01-01

    A method of forming synthetic hydrogen defect free diamond or diamond like films on a substrate. The method involves providing vapor containing fullerene molecules with or without an inert gas, providing a device to impart energy to the fullerene molecules, fragmenting at least in part some of the fullerene molecules in the vapor or energizing the molecules to incipient fragmentation, ionizing the fullerene molecules, impinging ionized fullerene molecules on the substrate to assist in causing fullerene fragmentation to obtain a thickness of diamond on the substrate.

  11. Conversion of fullerenes to diamonds

    DOEpatents

    Gruen, Dieter M. (1324 59th St., Downers Grove, IL 60515)

    1995-01-01

    A method of forming synthetic diamond or diamond-like films on a substrate surface. The method involves the steps of providing a vapor selected from the group of fullerene molecules or an inert gas/fullerene molecule mixture, providing energy to the fullerene molecules consisting of carbon-carbon bonds, the energized fullerene molecules breaking down to form fragments of fullerene molecules including C.sub.2 molecules and depositing the energized fullerene molecules with C.sub.2 fragments onto the substrate with farther fragmentation occurring and forming a thickness of diamond or diamond-like films on the substrate surface.

  12. Combustion energy of fullerene soot

    SciTech Connect

    Man, Naoki; Nagano, Yatsuhisa; Kiyobayashi, Tetsu; Sakiyama, Minoru )

    1995-02-23

    The standard energy of combustion of fullerene soot generated in arc discharge was determined to be [minus]36.0 [+-] 0.5 kJ g[sup [minus]1] by oxygen-bomb combustion calorimetry. The value was much closer to those of C[sub 60] and C[sub 70] than that of graphite. This result provides an energetic reason for the remarkable yield of fullerenes in arc discharge and supports the mechanism of fullerene formation, where fullerenes are the lowest energy products. Fullerene onion formation is interpreted in terms of energy relaxation of the fullerene soot. 20 refs., 1 tab.

  13. Photodynamic therapy with fullerenes

    PubMed Central

    Mroz, Pawel; Tegos, George P.; Gali, Hariprasad; Wharton, Tim; Sarna, Tadeusz; Hamblin, Michael R.

    2010-01-01

    Fullerenes are a class of closed-cage nanomaterials made exclusively from carbon atoms. A great deal of attention has been focused on developing medical uses of these unique molecules especially when they are derivatized with functional groups to make them soluble and therefore able to interact with biological systems. Due to their extended ?-conjugation they absorb visible light, have a high triplet yield and can generate reactive oxygen species upon illumination, suggesting a possible role of fullerenes in photodynamic therapy. Depending on the functional groups introduced into the molecule, fullerenes can effectively photoinactivate either or both pathogenic microbial cells and malignant cancer cells. The mechanism appears to involve superoxide anion as well as singlet oxygen, and under the right conditions fullerenes may have advantages over clinically applied photosensitizers for mediating photodynamic therapy of certain diseases. PMID:17973044

  14. Fullerenes formation in flames

    NASA Technical Reports Server (NTRS)

    Howard, Jack B.

    1993-01-01

    Fullerenes are composed of carbon atoms arranged in approximately spherical or ellipsoidal cages resembling the geodesic domes designed by Buckminster Fuller, after whom the molecules were named. The approximately spherical fullerene, which resembles a soccer ball and contains sixty atoms (C60), is called buckminsterfullerene. The fullerene containing seventy carbon atoms (C70) is approximately ellipsoidal, similar to a rugby ball. Fullerenes were first detected in 1985, in carbon vapor produced by laser evaporation of graphite. The closed shell structure, which has no edge atoms vulnerable to reaction, was proposed to explain the observed high stability of certain carbon clusters relative to that of others at high temperatures and in the presence of an oxidizing gas.

  15. Extraterrestrial Helium Trapped in Fullerenes in the Sudbury Impact Structure

    NASA Technical Reports Server (NTRS)

    Becker, Luann; Poreda, Robert J.; Bada, Jeffrey L.

    1996-01-01

    Fullerenes (C60 and C70) in the Sudbury impact structure contain trapped helium with a He-3/He-4 ratio of 5.5 x 10(exp -4) to 5.9 x 10(exp -4). The He-3/He-4 ratio exceeds the accepted solar wind value by 20 to 30 percent and is higher by an order of magnitude than the maximum reported mantle value. Terrestrial nuclear reactions or cosmic-ray bombardment are not sufficient to generate such a high ratio. The He-3/He-4 ratios in the Sudbury fullerenes are similar to those found in meteorites and in some interplanetary dust particles. The implication is that the helium within the C60 molecules at Sudbury is of extraterrestrial origin.

  16. Fullerene formation and annealing

    SciTech Connect

    Mintmire, J.W.

    1996-04-05

    Why does the highly symmetric carbon cluster C{sub 60} form in such profusion under the right conditions? This question was first asked in 1985, when Kroto suggested that the predominance of the C{sub 60} carbon clusters observed in the molecular beam experiments could be explained by the truncated icosahedral (or soccer ball) form. The name given to this cluster, buckminsterfullerene, led to the use of the term fullerenes for the family of hollow-cage carbon clusters made up of even numbers of triply coordinated carbons arranged with 12 pentagonal rings and an almost arbitrary number of hexagonal rings. More than a decade later, we still lack a completely satisfying understanding of the fundamental chemistry that takes place during fullerene formation. Most current models for fullerene formation require a facile mechanism for ring rearrangement in the fullerene structure, but the simplest proposed mechanisms are believed to have unrealistically high activation barriers. In recent research calculations have suggested that atomic carbon in the reaction mixture could act as a catalyst and allow substantially lower activation barriers for fullerene annealing. This article discusses the background for this research and other adjunct research. 14 refs.

  17. Ion bombardment and titanium film growth on polyimide

    SciTech Connect

    Bodoe, P.; Sundgren, J.

    1988-07-01

    The effects of Ar ion bombardment on the polyimide (PI) surface chemistry, Ti film growth, and the Ti/polyimide interface have been studied using x-ray photoelectron spectroscopy (XPS). The Ti films were grown in an ultrahigh vacuum chamber onto spin coated polyimide substrates and then analyzed in situ by XPS. The substrates were, prior to Ti film deposition, exposed to ion doses of 3.8 x and 30 x 10/sup 14/ ions/cm/sup 2/ using 2-keV Ar ions. By monitoring the chemical shifts in the C 1s level arising from the polyimide molecular structure, a preferential bond breaking of imide carbonyl groups and formation of graphitelike carbons were observed as a consequence of the ion bombardment. As Ti was deposited a C 1s peak corresponding to Ti--C formation was observed for both as-prepared and ion bombarded samples. The initial Ti film growth was studied by measuring the decrease in the C 1s level as a function of the amount of deposit. As expected for polymers the film growth is three dimensional in its character where islands of depositing atoms are formed in the initial stages. However, on ion bombarded PI substrates the number of nucleation sites is so large that the Ti film growth is comparable with a calculated layer-by-layer growth.

  18. Fullerenes from a fulgurite

    SciTech Connect

    Daly, T.K.; Buseck, P.R.; Williams, P.; Lewis, C.F. )

    1993-03-12

    Peaks at 720 and 840 atomic mass units were identified by mass spectrometry in a sample extracted from a fulgurite, which is a glassy rock that forms where lightning strikes the ground. The peaks are interpreted as arising from C[sub 60] and C[sub 70] and the associated peaks as produced from other fullerenes. The intense conditions generated by the lightning not only melted the rock it struck and fused the associated soil but also allowed fullerenes to form, presumably from the organic debris in the soil. 29 refs., 3 figs., 1 tab.

  19. Combustion Synthesis of Fullerenes and Fullerenic Nanostructures In Microgravity

    NASA Technical Reports Server (NTRS)

    Howard, Jack B.; Brooker, John E. (Technical Monitor)

    2002-01-01

    The objectives of the proposed research were to determine the effects of gravity on fullerenes formation in flames and, based on the observed effects, to develop fundamental understanding of fullerenes formation and to identify engineering principles for fullerenes production. The research method consisted of the operation of laminar diffusion flames under normal- and reduced-gravity conditions, and the collection from the flames and subsequent analysis of condensables including any fullerenes present, using coupled high performance liquid chromatography/mass spectrometry and high resolution transmission electron microscopy. The focus included fullerene molecules C60 and C70 and fullerenic nanostructures including tubes, spherules and other shapes. The normal-gravity experiments were performed at MIT and complementary reduced-gravity experiments were to have been contributed by NASA. The independent variables of interest are gravity, fuel type, fuel/oxygen ratio, pressure, gas velocity at burner, diluent type and concentration. Given the large number of variables and the absence of data on either fullerene formation in diffusion flames or gravitational effects on fullerene formation in diffusion or premixed flames, the first part of the work was exploratory while the later part involved detailed study of the most interesting mechanisms. Samples of condensable material from laminar low pressure benzene/argon/oxygen diffusion flames were collected and analyzed by high-performance liquid chromatography to determine the yields of fullerenes, and by high-resolution transmission electron microscopy (HRTEM) to characterize the fullerenic material, i.e., curved-layer nanostructures, on and within the soot particles. The highest concentration of fullerenes was always detected just above the visible stoichiometric surface of a flame. The percentage of fullerenes in the condensable material increases with decreasing pressure. The overall highest amount of fullerenes was found for a surprisingly high dilution fuel with argon. The maximum flame temperature seems to be of minor importance in fullerene formation. The HRTEM analysis of the soot showed an increase of the curvature of the carbon layers, and hence increased fullerenic character. After this maximum, the curvature decreases. In addition to the soot, the samples included fullerenic nanostructures, such as tubes and spheroids including highly-ordered multilayered or onion-like structures. The soot itself shows highly ordered regions that appear to have been cells of ongoing fullerenic nanostructure formation.

  20. Geological occurrence of fullerenes

    SciTech Connect

    Buseck, P.R.; Tsipursky, S.J.; Wang, S. ); Hettich, R. )

    1992-01-01

    Using HRTEM imaging, the authors found C[sub 60] and C[sub 70] fullerenes in shungite, a Precambrian carbon-rich rock from Karelia, Russia. Compositionally, shungite represents coals of the meta-anthracite rank, characterized by low ash and sulfur contents, low volatile yields, and high carbon contents. The shungite occurs within metamorphosed sediments. The overlying rocks consist of gray dolomitized sandstones and poorly sorted silts and clays; the underlying rocks are not exposed. The shungite consists of masses containing up to 99% carbon. Diabase is interstratified with shungite-bearing rocks, and the shungite concentration increases with proximity to the diabase. Their sample comes from inclusions in the diabase. In the HRTEM images the fullerenes appear round (presumably roughly spherical in three dimensions), with white rims and black centers, almost identical to images of synthetic C[sub 60] molecules. Following the HRTEM observations, the fullerene identities were confirmed, first by time-of-flight mass spectrometry and then by more precise laser ablation, laser desorption, and thermal desorption ionization plus Fourier transform (FT) mass spectrometry. These measurements verified that the fullerenes were not generated by the laser ionization event. HRTEM images show that locally they occur in ordered arrays that resemble crystals of synthetic C[sub 60]. FT mass spectra show that the C-13/C-12 isotopic ratios for C[sub 60] and C[sub 70] fall within the normal range of terrestrial isotopic values.

  1. Surface composition and erosion yields for CVD TiB/sub 2/ films subjected to low energy deuterium ion bombardment

    SciTech Connect

    Nelson, G.C.; Borders, J.A.

    1980-01-01

    The surface composition and low energy sputter yield of deuterium bombarded CVD TiB/sub 2/ films have been measured. The sputter yield increases with energy up to 1 keV where it reaches a maximum of 0.024 atoms/ion. Above 1 keV the yield decreases due to ion penetration effects. Surface composition measurements using Auger, x-ray photoelectron and secondary ion mass spectroscopies show that a surface layer about 200 A thick is depleted in B during 2 keV deuterium bombardment. This effect is attributed to preferential sputtering. Oxides and deuterides of titanium are also observed on the deuterium bombardment TiB/sub 2/ surface.

  2. Ion bombardment in RF photoguns

    SciTech Connect

    Pozdeyev,E.; Kayran, D.; Litvinenko, V. N.

    2009-05-04

    A linac-ring eRHIC design requires a high-intensity CW source of polarized electrons. An SRF gun is viable option that can deliver the required beam. Numerical simulations presented elsewhere have shown that ion bombardment can occur in an RF gun, possibly limiting lifetime of a NEA GaAs cathode. In this paper, we analytically solve the equations of motion of ions in an RF gun using the ponderomotive potential of the Rf field. We apply the method to the BNL 1/2-cell SRF photogun and demonstrate that a significant portion of ions produced in the gun can reach the cathode if no special precautions are taken. Also, the paper discusses possible mitigation techniques that can reduce the rate of ion bombardment.

  3. Cereal transformation through particle bombardment

    NASA Technical Reports Server (NTRS)

    Casas, A. M.; Kononowicz, A. K.; Bressan, R. A.; Hasegawa, P. M.; Mitchell, C. A. (Principal Investigator)

    1995-01-01

    The review focuses on experiments that lead to stable transformation in cereals using microprojectile bombardment. The discussion of biological factors that affect transformation examines target tissues and vector systems for gene transfer. The vector systems include reporter genes, selectable markers, genes of agronomic interest, and vector constructions. Other topics include physical parameters that affect DNA delivery, selection of stably transformed cells and plant regeneration, and analysis of gene expression and transmission to the progeny.

  4. Ion bombardment in RF guns

    SciTech Connect

    Pozdeyev, E.; Kayran, D.; Litvinenko, V. N.

    2009-08-04

    We use the ponderomotive potential of the RF field to study the motion of ions in an RF gun. We apply this method to the BNL 1/2-cell SRF photogun and demonstrate that a significant portion of the ions produced in the gun can reach the cathode if no special precautions are taken. Also, we propose simple mitigation techniques that can reduce the rate of ion bombardment.

  5. Metal ion bombardment of onion skin cell wall

    SciTech Connect

    Sangyuenyongpipat, S.; Vilaithong, T.; Yu, L.D.; Verdaguer, A.; Ratera, I.; Ogletree, D.F.; Monteiro, O.R.; Brown, I.G.

    2004-05-10

    Ion bombardment of living cellular material is a novel subfield of ion beam surface modification that is receiving growing attention from the ion beam and biological communities. Although it has been demonstrated that the technique is sound, in that an adequate fraction of the living cells can survive both the vacuum environment and energetic ion bombardment, there remains much uncertainty about the process details. Here we report on our observations of onion skin cells that were subjected to ion implantation, and propose some possible physical models that tend to support the experimental results. The ion beams used were metallic (Mg, Ti, Fe, Ni, Cu), mean ion energy was typically 30keV, and the implantation fluence was in the range 1014 1016 ions/cm2. The cells were viewed using Atomic Force Microscopy, revealing the formation of microcrater-like structures due to ion bombardment. The implantation depth profile was measured with Rutherford backscattering spectrometry and compared to the results of the TRIM, T-DYN and PROFILE computer codes.

  6. Characterizing the Early Impact Bombardment

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.

    2005-01-01

    The early bombardment revealed in the larger impact craters and basins on the moon was a major planetary process that affected all bodies in the inner solar system, including the Earth and Mars. Understanding the nature and timing of this bombardment is a fundamental planetary problem. The surface density of lunar impact craters within a given size range on a given lunar surface is a measure of the age of that surface relative to other lunar surfaces. When crater densities are combined with absolute radiometric ages determined on lunar rocks returned to Earth, the flux of large lunar impactors through time can be estimated. These studies suggest that the flux of impactors producing craters greater than 1 km in diameter has been approximately constant over the past approx. 3 Gyr. However, prior to 3.0 - 3.5 Gyr the impactor flux was much larger and defines an early bombardment period. Unfortunately, no lunar surface feature older than approx. 4 Gyr is accurately dated, and the surface density of craters are saturated in most of the lunar highlands. This means that such data cannot define the impactor flux between lunar formation and approx. 4 Gyr ago.

  7. Diamond film growth from fullerene precursors

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Liu, Shengzhong (Woodridge, IL); Krauss, Alan R. (Naperville, IL); Pan, Xianzheng (Woodridge, IL)

    1997-01-01

    A method and system for manufacturing diamond film. The method involves forming a fullerene vapor, providing a noble gas stream and combining the gas with the fullerene vapor, passing the combined fullerene vapor and noble gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the fullerene and deposition of a diamond film on a substrate.

  8. Doped golden fullerene cages.

    PubMed

    Baletto, Francesca; Ferrando, Riccardo

    2015-11-14

    A first-principles investigation of the effect of the doping of golden cages of 32 atoms is proposed. It is shown that Ag and Cu doping affects the geometrical stability of the icosahedral fullerene Au32 cage, where Ag-doping leads to a new, low symmetric, and prolate motif while Cu-doping leads to a lump, incomplete decahedral shape. Most significantly, the HOMO-LUMO gap depends strongly on the cluster geometry while its dependence on the cluster chemical composition seems to be weaker. PMID:25920946

  9. 42nd Bombardment Squadron (Heavy). History of the 42nd Bombardment Squadron (Heavy) 1940 - 1944 

    E-print Network

    United States Army Air Corps; United States Army Air Corps

    1946-01-01

    -1 History of the 42d Bombardment Squadron (H). 1940 ? 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force Historical Association, IRIS No. 44028...

  10. An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

    NASA Astrophysics Data System (ADS)

    Thopan, P.; Prakrajang, K.; Thongkumkoon, P.; Suwannakachorn, D.; Yu, L. D.

    2013-07-01

    Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells.

  11. High depth resolution SIMS analysis using metal cluster complex ion bombardment

    NASA Astrophysics Data System (ADS)

    Tomita, M.; Kinno, T.; Koike, M.; Tanaka, H.; Takeno, S.; Fujiwara, Y.; Kondou, K.; Teranishi, Y.; Nonaka, H.; Fujimoto, T.; Kurokawa, A.; Ichimura, S.

    2008-03-01

    SIMS depth profiles were measured using metal cluster complex ions of Ir4(CO)7+ as a primary ion beam in order to obtain high depth resolution. Depth resolution was evaluated as a function of primary ion species, energy and incident angle using a multiple boron delta-doped silicon sample. The depth resolution obtained using cluster ion bombardment was considerably better than that obtained by oxygen ion bombardment under the same bombardment condition due to reduction of atomic mixing in the depth. The best depth resolution was 0.9 nm under the bombardment condition of 5 keV, 45° with oxygen flooding, which approaches the value measured with state of the art SIMS analyses. However, depth resolution was not improved by decreasing the cluster ion energy (less than 5 keV), even though the roughness of the sputtered surface was suppressed. The limit of depth resolution improvement may be caused by a carbon cover-layer that prevents the formation of surface oxide that buffers atomic mixing. To overcome this issue, it will be necessary to eliminate carbon from the cluster ion.

  12. 30 years of cosmic fullerenes

    E-print Network

    Berne, O; Mulas, G; Joblin, C

    2015-01-01

    In 1985, "During experiments aimed at understanding the mechanisms by which long-chain carbon molecules are formed in interstellar space and circumstellar shells", Harry Kroto and his collaborators serendipitously discovered a new form of carbon: fullerenes. The most emblematic fullerene (i.e. C$_{60}$ "buckminsterfullerene"), contains exactly 60 carbon atoms organized in a cage-like structure similar to a soccer ball. Since their discovery impacted the field of nanotechnologies, Kroto and colleagues received the Nobel prize in 1996. The cage-like structure, common to all fullerene molecules, gives them unique properties, in particular an extraordinary stability. For this reason and since they were discovered in experiments aimed to reproduce conditions in space, fullerenes were sought after by astronomers for over two decades, and it is only recently that they have been firmly identified by spectroscopy, in evolved stars and in the interstellar medium. This identification offers the opportunity to study the ...

  13. Ion Bombardment Experiments Suggesting an Origin for Organic Particles in Pre-Cometary and Cometary Ices

    NASA Astrophysics Data System (ADS)

    Wdowiak, Thomas J.; Robinson, Edward L.; Flickinger, Gregory C.; Boyd, David A.

    1997-12-01

    Simple molecules frozen as mantles of interstellar and circumstellar grains and incorporated into comets are subjected to ion bombardment in the form of cosmic rays, stellar flares, stellar winds, and ions accelerated in stellar wind shocks. The total expected dosage for the variety of situations range from 10 eV/molecule for interplanetary dust subjected to solar flares to 106 eV/molecule for material in the T Tauri environment. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, we have bombarded frozen gases in the temperature range of 10 K to 30 K with 175 keV protons. After irradiation, removal of the ice by sublimation at an elevated temperature in vacuum reveals a fluffy residue. These experiments suggest that processes resulting in the formation of organic particles found in the coma of Comet Halley, "CHON", may have included ion bombardment. Also, the moderate energy (100 keV to 500 keV) shock accelerated ion environment of bipolar outflow of stars in the planetary nebula stage such as the Red Rectangle, could produce complex molecular species which emit the observed unidentified infrared bands at 3.3 micro-m, 6.2 micro-m, 7.7 micro-m, 8.6 micro-m, and 11.3 micro-m.

  14. Ion Bombardment Experiments Suggesting an Origin for Organic Particles in Pre-Cometary and Cometary Ices

    NASA Technical Reports Server (NTRS)

    Wdowiak, Thomas J.; Robinson, Edward L.; Flickinger, Gregory C.; Boyd, David A.

    1997-01-01

    Simple molecules frozen as mantles of interstellar and circumstellar grains and incorporated into comets are subjected to ion bombardment in the form of cosmic rays, stellar flares, stellar winds, and ions accelerated in stellar wind shocks. The total expected dosage for the variety of situations range from 10 eV/molecule for interplanetary dust subjected to solar flares to 10(exp 6) eV/molecule for material in the T Tauri environment. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, we have bombarded frozen gases in the temperature range of 10 K to 30 K with 175 keV protons. After irradiation, removal of the ice by sublimation at an elevated temperature in vacuum reveals a fluffy residue. These experiments suggest that processes resulting in the formation of organic particles found in the coma of Comet Halley, "CHON", may have included ion bombardment. Also, the moderate energy (100 keV to 500 keV) shock accelerated ion environment of bipolar outflow of stars in the planetary nebula stage such as the Red Rectangle, could produce complex molecular species which emit the observed unidentified infrared bands at 3.3 micro-m, 6.2 micro-m, 7.7 micro-m, 8.6 micro-m, and 11.3 micro-m.

  15. Elasticity, internal excitation, fragmentation, and charge transfer during grazing scattering of fast fullerenes from a KCl(001) surface

    NASA Astrophysics Data System (ADS)

    Wethekam, S.; Merck, J.; Busch, M.; Winter, H.

    2011-02-01

    C60+ and C70+ fullerenes with keV energies are scattered under grazing polar angles of incidence from an atomically clean and flat KCl(001) surface. For this model system of molecule surface interactions, the elastic properties of the fullerenes in front of the surface are studied by polar angular distributions. From the analysis of fragment spectra, the internal excitations of scattered molecules are deduced and excitation mechanisms are identified. Charge fractions indicate a kinematically induced neutralization of the fullerenes. Via an analysis of negatively charged fragments, the transition from a “soft” scattering event with intact outgoing fullerenes to postcollision multifragmentation is analyzed. The data are compared to three-dimensional molecular dynamics simulations based on empirical bond-order potentials.

  16. Femtosecond laser studies of fullerenes and nanotubes 

    E-print Network

    Henderson, Gordon George

    2013-06-29

    This work concerns the interaction of intense, ultrashort laser pulses with fullerenes and carbon nanotubes. This includes the excitation and ionisation dynamics of gas phase fullerenes and the response of carbon nanotubes ...

  17. Diamond film growth from fullerene precursors

    DOEpatents

    Gruen, D.M.; Liu, S.; Krauss, A.R.; Pan, X.

    1997-04-15

    A method and system are disclosed for manufacturing diamond film. The method involves forming a fullerene vapor, providing a noble gas stream and combining the gas with the fullerene vapor, passing the combined fullerene vapor and noble gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the fullerene and deposition of a diamond film on a substrate. 10 figs.

  18. Production Of Fullerenic Soot In Flames

    DOEpatents

    Howard, Jack B. (Winchester, MA); Vander Sande, John B. (Newbury, MA); Chowdhury, K. Das (Cambridge, MA)

    2000-12-19

    A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

  19. Production of fullerenic nanostructures in flames

    DOEpatents

    Howard, Jack B. (Winchester, MA); Vander Sande, John B. (Newbury, MA); Chowdhury, K. Das (Cambridge, MA)

    1999-01-01

    A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

  20. Uraninite and Fullerene in Atmospheric Particulates

    E-print Network

    Utsunomiya, Satoshi

    Research Uraninite and Fullerene in Atmospheric Particulates S A T O S H I U T S U N O M I Y A , K in carbonaceous matter (e50 nm) similar to fullerene. We have also identified, for the first time, closely. In this study, we have completed mass spectrometry analysis to detect the presence of fullerene and also

  1. 30 years of cosmic fullerenes

    NASA Astrophysics Data System (ADS)

    Berné, O.; Montillaud, J.; Mulas, G.; Joblin, C.

    2015-12-01

    In 1985, ``During experiments aimed at understanding the mechanisms by which long-chain carbon molecules are formed in interstellar space and circumstellar shells'', Harry Kroto and his collaborators serendipitously discovered a new form of carbon: fullerenes. The most emblematic fullerene (i.e. C_{60} ``buckminsterfullerene''), contains exactly 60 carbon atoms organized in a cage-like structure similar to a soccer ball. Since their discovery impacted the field of nanotechnologies, Kroto and colleagues received the Nobel prize in 1996. The cage-like structure, common to all fullerene molecules, gives them unique properties, in particular an extraordinary stability. For this reason and since they were discovered in experiments aimed to reproduce conditions in space, fullerenes were sought after by astronomers for over two decades, and it is only recently that they have been firmly identified by spectroscopy, in evolved stars and in the interstellar medium. This identification offered the opportunity to study the molecular physics of fullerenes in the unique physical conditions provided by space, and to make the link with other large carbonaceous molecules thought to be present in space : polycyclic aromatic hydrocarbons.

  2. Pseudorotation in fullerene anions

    NASA Astrophysics Data System (ADS)

    Dunn, Janette L.; Hands, Ian D.; Bates, Colin A.

    2007-07-01

    Jahn-Teller (JT) problems are often characterised by an adiabatic potential energy surface (APES) containing either a set of isoenergetic wells or a trough of equivalent-energy points, which may be warped by higher-order coupling terms or anisotropic effects. In all three cases, the JT effect will be dynamic. Either tunnelling between the wells or rotation (of a distortion) around the trough will restore the original symmetry of the system. This motion is referred to as pseudorotation. It should be possible to observe a JT system in a distorted geometry if measurements are made on a sufficiently short timescale. In various cubic systems, this timescale has been calculated to be the order of picoseconds. Such timescales are accessible using modern methods of ultrafast spectroscopy. Measurements of pseudorotation rates can lead to important information on the strength and nature of the JT coupling present. We will present analytical calculations that allow the rate of pseudorotation to be determined in terms of the vibronic coupling parameters. We will show how these results can be applied to E ? e systems and then to the more complicated system applicable to C60- anions. This is of particular interest because of the high icosahedral symmetry of fullerene ions and also because of the many potential uses of materials containing these ions. We conclude by outlining experiments that should be capable of measuring pseudorotation in C 60 anions.

  3. Superconductivity in doped fullerenes

    SciTech Connect

    Hebard, A.F. )

    1992-11-01

    While there is not complete agreement on the microscopic mechanism of superconductivity in alkali-metal-doped C[sub 60], further research may well lead to the production of analogous materials that lose resistance at even higher temperatures. Carbon 60 is a fascinating and arrestingly beautiful molecule. With 12 pentagonal and 20 hexagonal faces symmetrically arrayed in a soccer-ball-like structure that belongs to the icosahedral point group, I[sub h], its high symmetry alone invites special attention. The publication in September 1990 of a simple technique for manufacturing and concentrating macroscopic amounts of this new form of carbon announced to the scientific community that enabling technology had arrived. Macroscopic amounts of C[sub 60] (and the higher fullerenes, such as C[sub 70] and C[sub 84]) can now be made with an apparatus as simple as an arc furnace powered with an arc welding supply. Accordingly, chemists, physicists and materials scientists have joined forces in an explosion of effort to explore the properties of this unusual molecular building block. 23 refs., 6 figs.

  4. Segregation under low-energy oxygen bombardment in the near-surface region

    NASA Astrophysics Data System (ADS)

    Tada, Y.; Suzuki, K.; Kataoka, Y.

    2008-12-01

    We found that a transient region of SIMS profiles was suppressed to less than the native oxide in silicon, with O 2+ bombardment energy of less than 0.2 keV under an incident angle of 0° with respect to the surface normal without oxygen flooding. However, gallium segregated significantly due to oxidation caused by O 2+ bombardment in this condition. We also found that the segregation decreased as the incident angle increased, and that it disappeared at the angle of around 40°, which was verified by comparing SIMS profiles with the HR-RBS profile. These results suggested that the angle of around 40° was the critical angle to prevent segregation. The transient region was almost the same at angles of 0-40°. Therefore, we consider that the energy of 0.2 keV at the angle of around 40° under O 2+ bombardment without oxygen flooding is the optimum SIMS condition for depth profiling in the near-surface region. On the other hand, the profile shift of arsenic depending on the angle was quite different as compared with gallium, but the shift was a minimum at the same critical angle. We expect that more accurate profiles for other impurities can be obtained using this SIMS condition.

  5. Inorganic Fullerenes, Onions, and Tubes

    ERIC Educational Resources Information Center

    York, Andrew P. E.

    2004-01-01

    Buckminsterfullerene, which is in the shape of a soccer-ball was first discovered in 1985, has many applications as a good lubricant, or as a new superconductor. The synthesis of these inorganic fullerenes involves a great deal of interdisciplinary research between physicists, material scientists, engineers and chemists from various fields.

  6. Development of Mass Spectrometric Ionization Methods for Fullerenes and Fullerene Derivatives

    EPA Science Inventory

    Currently investigations into the environmental behavior of fullerenes and fullerene derivatives is hampered by the lack of well characterized standards and by the lack of readily available quantitative analytical methods. Reported herein are investigations into the utility of ma...

  7. Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

    NASA Astrophysics Data System (ADS)

    Prakrajang, K.; Sangwijit, K.; Anuntalabhochai, S.; Wanichapichart, P.; Yu, L. D.

    2012-09-01

    This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 1015 to 1016 ions/cm2. The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

  8. Superabsorbing Fullerenes: Spectral and Kinetic Characterization of Photoinduced Interactions in Perylenediimide-Fullerene-C60 Dyads

    E-print Network

    van Stokkum, Ivo

    Superabsorbing Fullerenes: Spectral and Kinetic Characterization of Photoinduced Interactions in Perylenediimide-Fullerene-C60 Dyads Je´ro^me Baffreau, Ste´phanie Leroy-Lhez, Pie´trick Hudhomme, Michiel M energy transfer to the fullerene unit, as shown with femtosecond transient absorption spectroscopy

  9. Application of fullerenes in nanomedicine: an update.

    PubMed

    Dellinger, Anthony; Zhou, Zhiguo; Connor, James; Madhankumar, A B; Pamujula, Sarala; Sayes, Christie M; Kepley, Christopher L

    2013-07-01

    Fullerenes are carbon spheres presently being pursued globally for a wide range of applications in nanomedicine. These molecules have unique electronic properties that make them attractive candidates for diagnostic, therapeutic and theranostic applications. Herein, the latest research is discussed on developing fullerene-based therapeutics as antioxidants for inflammatory diseases, their potential as antiviral/bacterial agents, utility as a drug delivery device and the promise of endohedral fullerenes as new MRI contrast agents. The recent discovery that certain fullerene derivatives can stabilize immune effector cells to prevent or inhibit the release of proinflammatory mediators makes them potential candidates for several diseases such as asthma, arthritis and multiple sclerosis. Gadolinium-containing endohedral fullerenes are being pursued as diagnostic MRI contrast agents for several diseases. Finally, a new class of fullerene-based theranostics has been developed, which combine therapeutic and diagnostic capabilities to specifically detect and kill cancer cells. PMID:23837857

  10. Ion bombardment and disorder in amorphous silicon

    SciTech Connect

    Sidhu, L.S.; Gaspari, F.; Zukotynski, S.

    1997-07-01

    The effect of ion bombardment during growth on the structural and optical properties of amorphous silicon are presented. Two series of films were deposited under electrically grounded and positively biased substrate conditions. The biased samples displayed lower growth rates and increased hydrogen content relative to grounded counterparts. The film structure was examined using Raman spectroscopy. The transverse optic like phonon band position was used as a parameter to characterize network order. Biased samples displayed an increased order of the amorphous network relative to grounded samples. Furthermore, biased samples exhibited a larger optical gap. These results are correlated and attributed to reduced ion bombardment effects.

  11. Statistical mechanics of fullerene coalescence growth

    NASA Astrophysics Data System (ADS)

    Maul, Jochen; Berg, Thomas; Marosits, Edit; Schönhense, Gerd; Huber, Gerhard

    2006-10-01

    Among the different carbon allotropes fullerenes are exceptionally intriguing for their spheroidal topology out of pentagons and hexagons. However, the dominant formation mode is still ambiguous. Here, we analyze the fullerene formation process by the statistical analysis of fullerene sizes produced in a laser-induced microplasma finding that a simple two-parameter lognormal distribution describes impressively well the cluster frequencies under various conditions. Our findings clearly reveal coalescent growth following a classical collision dynamics and disagree with several earlier assumptions.

  12. C(240)-----The most Chemically Inert Fullerene?

    NASA Technical Reports Server (NTRS)

    Haddon, R. C.; Scuseria, G. E.; Smalley, R. E.

    1997-01-01

    The reactivity of the fullerenes is primarily a function of their strain, as measured by the pyramidalization angle or curvature of the conjugated carbon atoms. The development of faceting in the structure of large icosahedral fullerenes leads to a minimum in the value of the maximum fullerene pyramidalization angle that lies in the vicinity of C-240. On this basis it is argued that C-240 will be the most chemically inert fullerene. This observation explains the production of [10,10] single-walled nanotubes because a C-240 hemisphere is required for the nucleation of such tubes.

  13. Development of Advanced Alloys using Fullerenes

    NASA Technical Reports Server (NTRS)

    Sims, J.; Wasz, M.; O'Brien, J.; Callahan, D. L.; Barrera, E. V.

    1994-01-01

    Development of advanced alloys using fullerenes is currently underway to produce materials for use in the extravehicular mobility unit (EMU). These materials will be directed toward commercial usages as they are continually developed. Fullerenes (of which the most common is C(sub 60)) are lightweight, nanometer size, hollow molecules of carbon which can be dispersed in conventional alloy systems to enhance strength and reduce weight. In this research, fullerene interaction with aluminum is investigated and a fullerene-reinforced aluminum alloy is being developed for possible use on the EMU. The samples were manufactured using standard commercial approaches including powder metallurgy and casting. Alloys have been processed having 1.3, 4.0 and 8.0 volume fractions of fullerenes. It has been observed that fullerene dispersion is related to the processing approach and that they are stable for the processing conditions used in this research. Emphasis will be given to differential thermal analysis and wavelength dispersive analysis of the processed alloys. These two techniques are particularly useful in determining the condition of the fullerenes during and after processing. Some discussion will be given as to electrical properties of fullerene-reinforced materials. Although the aluminum and other advanced alloys with fullerenes are being developed for NASA and the EMU, the properties of these materials will be of interest for commercial applications where specific Dual-Use will be given.

  14. Toxicological Effects of Fullerenes on Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Schomaker, Justin; Snook, Renee; Howell, Carina

    2014-03-01

    The nematode species Caenorhabditis elegans is a useful genetic model organism due to its simplicity and the substantial molecular, genetic, and developmental knowledge about the species. In this study, this species was used to test the toxicological effects of C60 fullerene nanoparticles. In previous studies using rats, a solution of C60 fullerenes in olive oil proved to extend the life of the subjects. The purpose of this experiment was to subject C. elegans to varying concentrations of C60 fullerenes and observe their toxicological effects. Initial findings indicate a link between fullerene exposure and enlargement of the vulva as well as the formation of a small nodule at the base of the tail in some individuals. While the fullerenes are not lethally toxic in C. elegans, results will be presented that pertain to changes in life span and progeny of the nematodes exposed to varying concentrations of fullerenes as well as the mechanisms of toxicity. High magnification imaging via SEM and/or AFM will be used to characterize the fullerene nanoparticles. Testing the toxicity of fullerenes in a wide variety of organisms will lead to a more complete understanding of the effects of fullerenes on living organisms to ultimately understand their effects in humans. This work was supported by National Science Foundation grants DUE-1058829, DMR-0923047, DUE-0806660 and Lock Haven FPDC grants.

  15. FULLERENES AND PROTO-FULLERENES IN INTERSTELLAR CARBON DUST

    SciTech Connect

    Duley, W. W.; Hu Anming

    2012-01-20

    Laboratory spectra of hydrogenated amorphous carbon (HAC) particles prepared under a variety of conditions show spectral features at 7.05, 8.5, 17.4, and 18.9 {mu}m (1418, 1176, 575, and 529 cm{sup -1}) that have been associated with emission from C{sub 60} molecules. These lines occur in the spectra even though C{sub 60} molecules as such are not present in our samples. It appears that these four spectral lines in HAC can instead be associated with precursor molecules or 'proto-fullerenes' (PFs) that subsequently react to yield C{sub 60}. We develop a model tracing the evolution and de-hydrogenation of HAC dust and show that the observation of an emission feature at 16.4 {mu}m (610 cm{sup -1}) in astronomical spectra signals the presence of the pentagonal carbon rings required for the formation of fullerenes. We suggest that the set of four IR emission lines previously identified with C{sub 60} in many objects that also show the 16.4 {mu}m feature and other polycyclic aromatic hydrocarbon bands arise from PFs rather than C{sub 60}. Tc1 is an example of a source in which de-hydrogenation has proceeded to the point where only fullerenes are present.

  16. Effect of concurrent N2 ion bombardment

    E-print Network

    Zexian, Cao

    ; published 9 February 2004 Nitrogen ion beam extracted from low-temperature plasmas consists of both atomic vapor deposition techniques, often a low- temperature nitrogen plasma is rf biased to bombard recognized that in the low temperature (Te on the order of 105 K) plasmas of nitrogen, such as capacitive

  17. Evidence for Ancient Bombardment of Earth

    E-print Network

    Weiss, Benjamin P.

    : The Moon in a New Light Top 10 Cool Moon Facts Comments (30) You must be logged in to leave a comment: Log! Buzz SPACE.com -- Source of Moon's Magnetism Found http://www.space.com/scienceastronomy/090115-moonEvidence for Ancient Bombardment of Earth Moon Holds Earth's Ancient Secrets Images: Lunar Base

  18. Hydrogen defects in proton bombarded KCl.

    NASA Technical Reports Server (NTRS)

    Chu, Y. H.; Friauf, R. J.; Zeller, E. J.

    1972-01-01

    Optical absorption bands are observed in the UV and IR proton bombarded potassium chloride at liquid nitrogen temperature. It is demonstrated that the absorption is due to trapped protons, and the largest UV band has been identified with the U center.

  19. Production of high voltage by ion bombardment 

    E-print Network

    Phinney, Lucas Carter

    2003-01-01

    A beam of He+ ions was used to bombard a conductive target, allowing the target to build up a voltage. The voltage that built up on the target was measured by using a voltage divider circuit. The target was made out of niobium metal...

  20. Sorghum genetic transformation by particle bombardment.

    PubMed

    Liu, Guoquan; Campbell, Bradley C; Godwin, Ian D

    2014-01-01

    Particle bombardment transformation describes the acceleration of high-velocity microparticles coated with exotic genes through the plant-protective cell walls, in order for the introduced genes to be integrated into the host genome. This technique has proven to be an effective and versatile approach towards plant genetic modification in preceding decades. Particle bombardment has been successfully applied to cereals including rice, maize, wheat, barley, and sorghum. Historically, sorghum has been considered as one of the most recalcitrant major crops with regard to successful genetic transformation; however, tremendous progress has been made in recent years. Transformation efficiency by particle bombardment has now improved from approximately 1 % to in excess of 20 % utilizing an optimized tissue culture and DNA delivery system. The protocol described in this chapter routinely generates transformants at 10-25 % efficiency within sorghum genotype Tx430. The process generally takes 11-16 weeks from initiation of immature embryos to planting of transformants. This protocol covers the operation of both the Bio-Rad PDS-1000/He System and particle inflow gun. Three factors are crucial to an efficient particle bombardment transformation system: (1) an efficient tissue culture system, (2) a highly efficient DNA delivery system, and (3) an effective selection strategy. PMID:24243207

  1. HEAO 3 upper limits to the expected 1634 KeV line from SS 483

    NASA Technical Reports Server (NTRS)

    Wheaton, W. A.; Ling, J. C.; Mahoney, W. A.; Jacobson, A. S.

    1985-01-01

    A model based on 24 Mg(1369) was developed as the source of the lines in which refractory grains in the jets, containing Mg and 0, are bombarded, by ambient protons in the local ISM. The narrowness of the features results because the recoil Mg nucleus is stopped in the grain before the 1369 keV excited state decays. A consequence of the 24 Mg interpretation is the expected appearance of other emission lines, due to 20 Ne and 20 Na, which are produced by proton bombardment of 24 Mg at the 33 MeV/nucleon energy corresponding to the velocity of the jets. These lines appear at rest energies of 1634 keV and 1636 keV, respectively, and should have essentially the same total flux as that emited at 1369 keV. The HEAO 3 data are examined to search for the 1634 keV (rest) emission. The observation and analysis, the results, and the implications for the understanding of SS 433 are discussed.

  2. Extraterrestrial Helium (He@C60) Trapped in Fullerenes in the Sudbury Impact Structure

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bada, J. L.; Poreda, R. J.; Bunch, T. E.

    1997-01-01

    Fullerenes (C60 and C70) have recently been identified in a shock-produced breccia (Onaping Formation) associated with the 1.85-Ga Sudbury Impact Crater. The presence of parts-per-million levels of fullerenes in this impact structure raises interesting questions about the processes that led to the formation of fullerenes and the potential for delivery of intact organic material to the Earth by a large bolide (e.g., asteroid or comet). Two possible scenarios for the presence of fullerenes in the Sudbury impact deposits are that (1) fullerenes are synthesized within the impact plume from the C contained in the bolide; or (2) fullerenes are already present in the bolide and survived the impact event. The correlation of C and trapped noble gas atoms in meteorites is well established. Primitive meteorites contain several trapped noble gas components that have anomalous isotopic compositions, some of which may have a presolar origin. Several C-bearing phases, including SiC, graphite, and diamond, have been recognized as carriers of trapped noble gases. It has also been suggested that fullerenes (C60 and C70) might be a carrier of noble gas components in carbonaceous chondrites. Recently, fullerenes have been detected in separate samples in the Allende meteorite. Carbon-60 is large enough to enclose the noble gases He, Ne, Ar, Kr, and Xe, but it is too small to contain diatomic gases such as N2 or triatomic gases such as CO2. Recent experimental work has demonstrated that noble gases of a specific isotopic composition can be introduced into synthetic fullerenes at high temperatures and pressures; these encapsulated gases can then be released by the breaking of one or more C bonds during step-heating under vacuum. These thermal-release patterns for He encapsulated within the C60 molecule (He@C60) are similar to the patterns for acid residues of carbonaceous chondrites, suggesting that fullerenes could be an additional carrier of trapped noble gases in acid residues of meteorites. Analysis and Results: In order to characterize the noble gas compositions of the Sudbury fullerenes, we undertook a systematic study of acid-resistant residues throughout the C-rich layer (Black member) of the Onaping Formation. Samples were demineralized and extracted using standard techniques. The Onaping extracts were analyzed using several techniques, including UV-Vis adsorption, electro spray mass spectrometry, and laser desorption (linear and reflectron) time-of-flight (TOF) mass spectrometry (LDMS). The Sudbury fullerenes were then separated and purified using HPLC coupled with a photo diode array detector. The HPLC extracts containing the purified fullerenes were loaded into a metal tube furnace within a glove box under a N atmosphere in preparation for noble gas analyses. The 3-He and 4-He content of the fullerene extracts was measured using previously reported standard techniques . Discussion: Fullerenes (C60 and C70) in the Sudbury Impact Structure have been found to contain trapped He with a 3-He/4-He ratio greater than 5 x 10(exp -4). The 3-He/4-He ratio exceeds the accepted solar value by more than 30% and is more than 10x higher than the maximum reported mantle value. Terrestrial nuclear reactions or cosmic-my bombardment are not sufficient to generate such a high ratio. The 3-He/4-He ratios in the Sudbury fullerenes are similar to those determined for interplanetary dust particles. The greater-than-solar ratios of 3-He/4-He in the Sudbury fullerenes may indicate a presolar origin, although alternative mechanisms occurring in the ISM to explain these high ratios (e.g., spallation reactions, selective He implantation, etc.) cannot be entirely ruled out. We are currently attempting to isolate enough fullerene material to measure anomalous Ne (or Kr or Xe) contained within the C60 (e.g., the "pure" 22-Ne component) and thus determine whether the Sudbury fullerenes are indeed presolar in origin.

  3. Fullerene polymers from solid precursors

    SciTech Connect

    Fischer, J.E. National Institute of Standards and Technology, Gaithersburg, MD )

    1994-06-10

    One of the many speculations that quickly followed on the heels of the Kraetschmer-Huffman process for producing large quantities of C[sub 60] buckminsterfullerene was the possibility of stitching the molecules together to create a linear chain polymer, a [open quotes]pearl necklace[close quotes] of buckyballs. In addition to being chemically elegant and intrinsically beautiful, such a material might be expected to exhibit interesting electronic and nonlinear optical properties. Traditional solution-phase routes to fullerene polymerization have thus far resulted only in mixtures of incompletely characterized species with a high degree of cross-linking. This article reviews experiments that show that this goal might be achieved by starting from a fullerene solid precursor.

  4. Functionalized Fullerenes in Photodynamic Therapy

    PubMed Central

    Huang, Ying-Ying; Sharma, Sulbha K.; Yin, Rui; Agrawal, Tanupriya; Chiang, Long Y.; Hamblin, Michael R.

    2014-01-01

    Since the discovery of C60 fullerene in 1985, scientists have been searching for biomedical applications of this most fascinating of molecules. The unique photophysical and photochemical properties of C60 suggested that the molecule would function well as a photosensitizer in photodynamic therapy (PDT). PDT uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that kill unwanted cells. However the extreme insolubility and hydrophobicity of pristine C60, mandated that the cage be functionalized with chemical groups that provided water solubility and biological targeting ability. It has been found that cationic quaternary ammonium groups provide both these features, and this review covers work on the use of cationic fullerenes to mediate destruction of cancer cells and pathogenic microorganisms in vitro and describes the treatment of tumors and microbial infections in mouse models. The design, synthesis, and use of simple pyrrolidinium salts, more complex decacationic chains, and light-harvesting antennae that can be attached to C60, C70 and C84 cages are covered. In the case of bacterial wound infections mice can be saved from certain death by fullerene-mediated PDT. PMID:25544837

  5. The quest for inorganic fullerenes

    NASA Astrophysics Data System (ADS)

    Pietsch, Susanne; Dollinger, Andreas; Strobel, Christoph H.; Park, Eun Ji; Ganteför, Gerd; Seo, Hyun Ook; Kim, Young Dok; Idrobo, Juan-Carlos; Pennycook, Stephen J.

    2015-10-01

    Experimental results of the search for inorganic fullerenes are presented. MonSm- and WnSm- clusters are generated with a pulsed arc cluster ion source equipped with an annealing stage. This is known to enhance fullerene formation in the case of carbon. Analogous to carbon, the mass spectra of the metal chalcogenide clusters produced in this way exhibit a bimodal structure. The species in the first maximum at low mass are known to be platelets. Here, the structure of the species in the second maximum is studied by anion photoelectron spectroscopy, scanning transmission electron microscopy, and scanning tunneling microcopy. All experimental results indicate a two-dimensional structure of these species and disagree with a three-dimensional fullerene-like geometry. A possible explanation for this preference of two-dimensional structures is the ability of a two-element material to saturate the dangling bonds at the edges of a platelet by excess atoms of one element. A platelet consisting of a single element only cannot do this. Accordingly, graphite and boron might be the only materials forming nano-spheres because they are the only single element materials assuming two-dimensional structures.

  6. Functionalized fullerenes in photodynamic therapy.

    PubMed

    Huang, Ying-Ying; Sharma, Sulbha K; Yin, Rui; Agrawal, Tanupriya; Chiang, Long Y; Hamblin, Michael R

    2014-09-01

    Since the discovery of C60 fullerene in 1985, scientists have been searching for biomedical applications of this most fascinating of molecules. The unique photophysical and photochemical properties of C60 suggested that the molecule would function well as a photosensitizer in photodynamic therapy (PDT). PDT uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that kill unwanted cells. However the extreme insolubility and hydrophobicity of pristine CO60, mandated that the cage be functionalized with chemical groups that provided water solubility and biological targeting ability. It has been found that cationic quaternary ammonium groups provide both these features, and this review covers work on the use of cationic fullerenes to mediate destruction of cancer cells and pathogenic microorganisms in vitro and describes the treatment of tumors and microbial infections in mouse models. The design, synthesis, and use of simple pyrrolidinium salts, more complex decacationic chains, and light-harvesting antennae that can be attached to C60, C70 and C84 cages are covered. In the case of bacterial wound infections mice can be saved from certain death by fullerene-mediated PDT. PMID:25544837

  7. Symmetry, Fullerenes, Nanotechnology and Other Stuff Virginia Tech

    E-print Network

    Zhigilei, Leonid V.

    Symmetry, Fullerenes, Nanotechnology and Other Stuff H. C. Dorn Virginia Tech Alpha helix Protein, and Curl (1984-5) Large Fullerenes Laser Apparatus C60, Fullerenes, BuckyBalls! 0.2 m 0.7 nm #12;Dr. Richard Smalley, Nobel Laureate,1996 Leukemia Victim, October 2005 Fullerenes (Buckyballs) Icosahedral (Ih

  8. Fullerenic structures and such structures tethered to carbon materials

    DOEpatents

    Goel, Anish; Howard, Jack B.; Vander Sande, John B.

    2010-01-05

    The fullerenic structures include fullerenes having molecular weights less than that of C.sub.60 with the exception of C.sub.36 and fullerenes having molecular weights greater than C.sub.60. Examples include fullerenes C.sub.50, C.sub.58, C.sub.130, and C.sub.176. Fullerenic structure chemically bonded to a carbon surface is also disclosed along with a method for tethering fullerenes to a carbon material. The method includes adding functionalized fullerene to a liquid suspension containing carbon material, drying the suspension to produce a powder, and heat treating the powder.

  9. Fullerenic structures and such structures tethered to carbon materials

    DOEpatents

    Goel, Anish; Howard, Jack B.; Vander Sande, John B.

    2012-10-09

    The fullerenic structures include fullerenes having molecular weights less than that of C.sub.60 with the exception of C.sub.36 and fullerenes having molecular weights greater than C.sub.60. Examples include fullerenes C.sub.50, C.sub.58, C.sub.130, and C.sub.176. Fullerenic structure chemically bonded to a carbon surface is also disclosed along with a method for tethering fullerenes to a carbon material. The method includes adding functionalized fullerene to a liquid suspension containing carbon material, drying the suspension to produce a powder, and heat treating the powder.

  10. Gas storage using fullerene based adsorbents

    NASA Technical Reports Server (NTRS)

    Loutfy, Raouf O. (Inventor); Lu, Xiao-Chun (Inventor); Li, Weijiong (Inventor); Mikhael, Michael G. (Inventor)

    2000-01-01

    This invention is directed to the synthesis of high bulk density high gas absorption capacity adsorbents for gas storage applications. Specifically, this invention is concerned with novel gas absorbents with high gravimetric and volumetric gas adsorption capacities which are made from fullerene-based materials. By pressing fullerene powder into pellet form using a conventional press, then polymerizing it by subjecting the fullerene to high temperature and high inert gas pressure, the resulting fullerene-based materials have high bulk densities and high gas adsorption capacities. By pre-chemical modification or post-polymerization activation processes, the gas adsorption capacities of the fullerene-based adsorbents can be further enhanced. These materials are suitable for low pressure gas storage applications, such as oxygen storage for home oxygen therapy uses or on-board vehicle natural gas storage. They are also suitable for storing gases and vapors such as hydrogen, nitrogen, carbon dioxide, and water vapor.

  11. Interstellar Fullerene Compounds and Diffuse Interstellar Bands

    E-print Network

    Omont, Alain

    2015-01-01

    Recently, the presence of fullerenes in the interstellar medium (ISM) has been confirmed, especially with the first confirmed identification of two strong diffuse interstellar bands (DIBs) with C60+. This justifies reassesing the importance of interstellar fullerenes of various sizes with endohedral or exohedral inclusions and heterofullerenes (EEHFs). The phenomenology of fullerenes is complex. In addition to formation in shock shattering, fully dehydrogenated PAHs in diffuse interstellar (IS) clouds could perhaps efficiently transform into fullerenes including EEHFs. But it is extremely difficult to assess their expected abundance, composition and size distribution, except for C60+. As often suggested, EEHFs share many properties with C60, as regards stability, formation/destruction, chemical processes and many basic spectral features. We address the importance of various EEHFs as possible DIB carriers. Specifically, we discuss IS properties and the contributions of fullerenes of various sizes and charge su...

  12. Fullerene–biomolecule conjugates and their biomedicinal applications

    PubMed Central

    Yang, Xinlin; Ebrahimi, Ali; Li, Jie; Cui, Quanjun

    2014-01-01

    Fullerenes are among the strongest antioxidants and are characterized as “radical sponges.” The research on biomedicinal applications of fullerenes has achieved significant progress since the landmark publication by Friedman et al in 1993. Fullerene–biomolecule conjugates have become an important area of research during the past 2 decades. By a thorough literature search, we attempt to update the information about the synthesis of different types of fullerene–biomolecule conjugates, including fullerene-containing amino acids and peptides, oligonucleotides, sugars, and esters. Moreover, we also discuss in this review recently reported data on the biological and pharmaceutical utilities of these compounds and some other fullerene derivatives of biomedical importance. While within the fullerene–biomolecule conjugates, in which fullerene may act as both an antioxidant and a carrier, specific targeting biomolecules conjugated to fullerene will undoubtedly strengthen the delivery of functional fullerenes to sites of clinical interest. PMID:24379667

  13. Production of Endohedral Fullerenes by Ion Implantation

    SciTech Connect

    Diener, M.D.; Alford, J. M.; Mirzadeh, S.

    2007-05-31

    The empty interior cavity of fullerenes has long been touted for containment of radionuclides during in vivo transport, during radioimmunotherapy (RIT) and radioimaging for example. As the chemistry required to open a hole in fullerene is complex and exceedingly unlikely to occur in vivo, and conformational stability of the fullerene cage is absolute, atoms trapped within fullerenes can only be released during extremely energetic events. Encapsulating radionuclides in fullerenes could therefore potentially eliminate undesired toxicity resulting from leakage and catabolism of radionuclides administered with other techniques. At the start of this project however, methods for production of transition metal and p-electron metal endohedral fullerenes were completely unknown, and only one method for production of endohedral radiofullerenes was known. They therefore investigated three different methods for the production of therapeutically useful endohedral metallofullerenes: (1) implantation of ions using the high intensity ion beam at the Oak Ridge National Laboratory (ORNL) Surface Modification and Characterization Research Center (SMAC) and fullerenes as the target; (2) implantation of ions using the recoil energy following alpha decay; and (3) implantation of ions using the recoil energy following neutron capture, using ORNL's High Flux Isotope Reactor (HFIR) as a thermal neutron source. While they were unable to obtain evidence of successful implantation using the ion beam at SMAC, recoil following alpha decay and neutron capture were both found to be economically viable methods for the production of therapeutically useful radiofullerenes. In this report, the procedures for preparing fullerenes containing the isotopes {sup 212}Pb, {sup 212}Bi, {sup 213}Bi, and {sup 177}Lu are described. None of these endohedral fullerenes had ever previously been prepared, and all of these radioisotopes are actively under investigation for RIT. Additionally, the chemistry for derivatizing the radiofullerenes for water-solubility and a method for removing exohedral radionuclides are reported. The methods and chemistry developed during this CRADA are the crucial first steps for the development of fullerenes as a method superior to existing technologies for in vivo transport of radionuclides.

  14. Inhibition of Inflammatory Arthritis Using Fullerene Nanomaterials

    PubMed Central

    Dellinger, Anthony L.; Cunin, Pierre; Lee, David; Kung, Andrew L.; Brooks, D. Bradford; Zhou, Zhiguo; Nigrovic, Peter A.; Kepley, Christopher L.

    2015-01-01

    Inflammatory arthritis (e.g. rheumatoid arthritis; RA) is a complex disease driven by the interplay of multiple cellular lineages. Fullerene derivatives have previously been shown to have anti-inflammatory capabilities mediated, in part, by their ability to prevent inflammatory mediator release by mast cells (MC). Recognizing that MC can serve as a cellular link between autoantibodies, soluble mediators, and other effector populations in inflammatory arthritis, it was hypothesized that fullerene derivatives might be used to target this inflammatory disease. A panel of fullerene derivatives was tested for their ability to affect the function of human skin-derived MC as well as other lineages implicated in arthritis, synovial fibroblasts and osteoclasts. It is shown that certain fullerene derivatives blocked Fc?R- and TNF-?-induced mediator release from MC; TNF-?-induced mediator release from RA synovial fibroblasts; and maturation of human osteoclasts. MC inhibition by fullerene derivatives was mediated through the reduction of mitochondrial membrane potential and Fc?R-mediated increases in cellular reactive oxygen species and NF-?B activation. Based on these in vitro data, two fullerene derivatives (ALM and TGA) were selected for in vivo studies using K/BxN serum transfer arthritis in C57BL/6 mice and collagen-induced arthritis (CIA) in DBA/1 mice. Dye-conjugated fullerenes confirmed localization to affected joints in arthritic animals but not in healthy controls. In the K/BxN moldel, fullerenes attenuated arthritis, an effect accompanied by reduced histologic inflammation, cartilage/bone erosion, and serum levels of TNF-?. Fullerenes remained capable of attenuating K/BxN arthritis in mast cell-deficient mice Cre-Master mice, suggesting that lineages beyond the MC represent relevant targets in this system. These studies suggest that fullerene derivatives may hold promise both as an assessment tool and as anti-inflammatory therapy of arthritis. PMID:25879437

  15. Nanocone formation on ion-bombarded InP surfaces

    NASA Astrophysics Data System (ADS)

    Kramczynski, Detlef; Gnaser, Hubert

    2015-11-01

    Surfaces of InP(1 0 0) were bombarded by 2.1 keV Ar+ ions under normal incidence. The total accumulated ion fluence the samples were exposed to was varied roughly from 1 × 1017 cm-2 to 3 × 1018 cm-2 while ion fluxes in the range of (0.1-2) × 1014 cm-2 s-1 were used. The surface morphology resulting from these ion irradiations was examined by scanning electron microscopy (SEM). For a specific range of ion fluxes and fluences, regular closely-spaced nanocone arrays are found to form, with the cones having typical base diameters of about 100 nm. Around their outer peripheries, they commonly exhibit rather distinct protrusions, an observation not reported in previous investigations. The inspection of the initial stages of nanocone formation indicates that the growth of adatom islands, first on the pristine surface and later on previously formed islands, may lead to these 3D nanostructures. This finding would imply that surface diffusion processes of adatoms constitute an important mechanism in the evolution of the observed topography.

  16. Machine Phase Fullerene Nanotechnology: 1996

    NASA Technical Reports Server (NTRS)

    Globus, Al; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    NASA has used exotic materials for spacecraft and experimental aircraft to good effect for many decades. In spite of many advances, transportation to space still costs about $10,000 per pound. Drexler has proposed a hypothetical nanotechnology based on diamond and investigated the properties of such molecular systems. These studies and others suggest enormous potential for aerospace systems. Unfortunately, methods to realize diamonoid nanotechnology are at best highly speculative. Recent computational efforts at NASA Ames Research Center and computation and experiment elsewhere suggest that a nanotechnology of machine phase functionalized fullerenes may be synthetically relatively accessible and of great aerospace interest. Machine phase materials are (hypothetical) materials consisting entirely or in large part of microscopic machines. In a sense, most living matter fits this definition. To begin investigation of fullerene nanotechnology, we used molecular dynamics to study the properties of carbon nanotube based gears and gear/shaft configurations. Experiments on C60 and quantum calculations suggest that benzyne may react with carbon nanotubes to form gear teeth. Han has computationally demonstrated that molecular gears fashioned from (14,0) single-walled carbon nanotubes and benzyne teeth should operate well at 50-100 gigahertz. Results suggest that rotation can be converted to rotating or linear motion, and linear motion may be converted into rotation. Preliminary results suggest that these mechanical systems can be cooled by a helium atmosphere. Furthermore, Deepak has successfully simulated using helical electric fields generated by a laser to power fullerene gears once a positive and negative charge have been added to form a dipole. Even with mechanical motion, cooling, and power; creating a viable nanotechnology requires support structures, computer control, a system architecture, a variety of components, and some approach to manufacture. Additional information is contained within the original extended abstract.

  17. Observation of an all-boron fullerene

    NASA Astrophysics Data System (ADS)

    Zhai, Hua-Jin; Zhao, Ya-Fan; Li, Wei-Li; Chen, Qiang; Bai, Hui; Hu, Han-Shi; Piazza, Zachary A.; Tian, Wen-Juan; Lu, Hai-Gang; Wu, Yan-Bo; Mu, Yue-Wen; Wei, Guang-Feng; Liu, Zhi-Pan; Li, Jun; Li, Si-Dian; Wang, Lai-Sheng

    2014-08-01

    After the discovery of fullerene-C60, it took almost two decades for the possibility of boron-based fullerene structures to be considered. So far, there has been no experimental evidence for these nanostructures, in spite of the progress made in theoretical investigations of their structure and bonding. Here we report the observation, by photoelectron spectroscopy, of an all-boron fullerene-like cage cluster at B40- with an extremely low electron-binding energy. Theoretical calculations show that this arises from a cage structure with a large energy gap, but that a quasi-planar isomer of B40- with two adjacent hexagonal holes is slightly more stable than the fullerene structure. In contrast, for neutral B40 the fullerene-like cage is calculated to be the most stable structure. The surface of the all-boron fullerene, bonded uniformly via delocalized ? and ? bonds, is not perfectly smooth and exhibits unusual heptagonal faces, in contrast to C60 fullerene.

  18. Metallosupramolecular receptors for fullerene binding and release.

    PubMed

    García-Simón, Cristina; Costas, Miquel; Ribas, Xavi

    2015-12-22

    Fullerene extracts are easily available from fullerene soot, but finding an efficient strategy to obtain them in pure form remains elusive, especially for higher fullerenes (Cx, x > 70). The properties of the latter remain unclear and their potential application to multiple research fields has not been developed mainly due to their purification difficulties. In this Tutorial Review we cover the use of molecular receptors for the separation of fullerenes by means of host-guest interactions. This strategy allows gaining selectivity, no specialized equipment is required and, ideally, recyclable systems can be designed. We focus on the metallosupramolecular receptors using the metal-ligand coordination approach, which offers a controlled and versatile strategy to design fullerene hosts, and the latest strategies to release the fullerene guest will be described. The field is probably in its beginnings but it is rapidly evolving and we are confident that this tutorial review will help researchers to rapidly gain a general overview of the main works and concepts that are leading this promising strategy and that may lead towards a useful methodology to purify fullerenes. PMID:26456881

  19. Ion bombardment experiments suggesting an origin for organic particles in pre-cometary and cometary ices

    NASA Technical Reports Server (NTRS)

    Wdowiak, Thomas J.; Robinson, Edward L.; Flickinger, Gregory C.; Boyd, David A.

    1989-01-01

    During the Giotto and Vega encounters with Comet Halley both organic particles called CHON and energetic ions were detected. The acceleration of ions to hundreds of keV in the vicinity of the bow shock and near the nucleus may be a demonstration of a situation occurring in the early solar system (perhaps during the T Tauri stage) that led to the formation of organic particles only now released. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, frozen gases were bombarded at 10 K with 175 keV protons with the result that fluffy solid material remains after sublimation of the ice. Initial experiments were carried out with a gas mixture in parts of 170 carbon monoxide, 170 argon, 25 water, 20 nitrogen, and 15 methane formulated to reflect an interstellar composition in experiments involving the freezing out of the products of a plasma. The plasma experiments resulted in a varnish-like film residue that exhibited luminescence when excited with ultraviolet radiation, while the ion bombardment created particulate material that was not luminescent.

  20. Fusion mechanism in fullerene-fullerene collisions -- The deciding role of giant oblate-prolate motion

    E-print Network

    Handt, Jan

    2015-01-01

    We provide answers to long-lasting questions in the puzzling behavior of fullerene-fullerene fusion: Why are the fusion barriers so exceptionally high and the fusion cross sections so extremely small? An ab initio nonadiabatic quantum molecular dynamics (NA-QMD) analysis of C$_{60}$+C$_{60}$ collisions reveals that the dominant excitation of an exceptionally "giant" oblate-prolate H$_g(1)$ mode plays the key role in answering both questions. From these microscopic calculations, a macroscopic collision model is derived, which reproduces the NA-QMD results. Moreover, it predicts analytically fusion barriers for different fullerene-fullerene combinations in excellent agreement with experiments.

  1. Fusion mechanism in fullerene-fullerene collisions -- The deciding role of giant oblate-prolate motion

    E-print Network

    Jan Handt; Ruediger Schmidt

    2015-03-09

    We provide answers to long-lasting questions in the puzzling behavior of fullerene-fullerene fusion: Why are the fusion barriers so exceptionally high and the fusion cross sections so extremely small? An ab initio nonadiabatic quantum molecular dynamics (NA-QMD) analysis of C$_{60}$+C$_{60}$ collisions reveals that the dominant excitation of an exceptionally "giant" oblate-prolate H$_g(1)$ mode plays the key role in answering both questions. From these microscopic calculations, a macroscopic collision model is derived, which reproduces the NA-QMD results. Moreover, it predicts analytically fusion barriers for different fullerene-fullerene combinations in excellent agreement with experiments.

  2. Ease of formation of nested fullerenes

    NASA Astrophysics Data System (ADS)

    Dodziuk, Helena; Dolgonos, Grigory; Lukin, Oleg

    2000-10-01

    Molecular mechanics calculations using CVFF force field for isolated fullerenes C60, C240, C540, C960 and the nested ones they form indicate that the process of buckyonion formation is cooperative and driven by nonbonded interactions. The calculations for the nested fullerenes involving all isomers of C70, C76 and C 80 satisfying isolated pentagon rule indicate that the complex formation with these guests is less efficient than that with the C 60. Molecular dynamics simulations for C60, C240, C540, C960 and for the quaternary complex C 60@C 240@C 540@C 960 support the cooperativity of the process of nested fullerenes formation.

  3. Applications of Functionalized Fullerenes in Tumor Theranostics

    PubMed Central

    Chen, Zhiyun; Ma, Lijing; Liu, Ying; Chen, Chunying

    2012-01-01

    Functionalized fullerenes with specific physicochemical properties have been developed for cancer diagnosis and therapy. Notably, metallofullerene is a new class of magnetic resonance imaging (MRI) contrast-enhancing agent, and may have promising applications for clinical diagnosis. Polyhydroxylated and carboxyl fullerenes have been applied to photoacoustic imaging. Moreover, in recent years, functionalized fullerenes have shown potential in tumor therapies, such as photodynamic therapy, photothermal treatment, radiotherapy and chemotherapeutics. Their antitumor effects may be associated with the modulation of oxidative stress, anti-angiogenesis, and immunostimulatory activity. While various types of novel nanoparticle agents have been exploited in tumor theranostics, their distribution, metabolism and toxicity in organisms have also been a source of concern among researchers. The present review summarizes the potential of fullerenes as tumor theranostics agents and their possible underlying mechanisms are discussed. PMID:22509193

  4. Synthesis and properties of novel fullerene derivatives

    SciTech Connect

    Da Ros, T.; Prato, M.; Guldi, D.; Alessio, E.; Valli, L.; Carano, M.; Paolucci, F.; Ceroni, P.; Roffia, S.

    1998-08-01

    Synthesis and chemical properties of a novel fullerene-porphyrin dyad is reported. Energy/electron transfer is studied based on cyclic voltametry and UV-visible spectroscopy. {copyright} {ital 1998 American Institute of Physics.}

  5. Recent advances in fullerene science (Invited)

    SciTech Connect

    Dunk, P. W.; Marshall, A. G.; Mulet-Gas, M.; Rodriguez-Fortea, A.; Poblet, J. M.

    2014-12-09

    The development of very high resolution FT-ICR mass spectrometers (Marshall et al, 1998) has made a wide range of new measurements possible and by combining this new technology with laser vaporization supersonic beam methods of producing carbon species (chains, rings and fullerenes), new advances in understanding of the fullerene creation mechanisms and their reactivity have been possible. In this overview, new understanding has been developed with regard to: a) closed-network growth of fullerenes (Dunk et al, 2012a); b) small endohedral species such as M?C{sub 28} (Dunk et al., 2012b); c) metallofullerene and fullerene formation under conditions in stellar outflows with relevance to stardust (Dunk et al., 2013a) and d) The formation of heterofullerenes by direct exposure of C{sub 60} toboron vapor (Dunk et al., 2013b)

  6. Mechanochemistry of fullerenes and related materials.

    PubMed

    Zhu, San-E; Li, Fei; Wang, Guan-Wu

    2013-09-21

    The low or lack of solubility of fullerenes, carbon nanotubes and graphene/graphite in organic solvents and water severely hampers the study of their chemical functionalizations and practical applications. Covalent and noncovalent functionalizations of fullerenes and related materials via mechanochemistry seem appealing to tackle these problems. In this review article, we provide a comprehensive coverage on the mechanochemical reactions of fullerenes, carbon nanotubes and graphite, including dimerizations and trimerizations, nucleophilic additions, 1,3-dipolar cycloadditions, Diels-Alder reactions, [2 + 1] cycloadditions of carbenes and nitrenes, radical additions, oxidations, etc. It is intriguing to find that some reactions of fullerenes can only proceed under solvent-free conditions or undergo different reaction pathways from those of the liquid-phase counterparts to generate completely different products. We also present the application of the mechanical milling technique to complex formation, nanocomposite formation and enhanced hydrogen storage of carbon-related materials. PMID:23677148

  7. Characterizing Fullerene Nanoparticles in Aqueous Suspensions

    EPA Science Inventory

    Studies have indicated that fullerenes can form stable colloidal suspensions in water when introduced to the aqueous phase through solvent exchange, sonication, or extended mixing. The colloidal suspensions created using these techniques have effective aqueous phase concentratio...

  8. Photoionization of fullerens and atoms confined in fullerenes

    NASA Astrophysics Data System (ADS)

    Hadighehjavani, Mohammad

    The photoionization cross sections of small fullerenes (C28, C32, C40, C44, and C50), and the outer and near-outer shells of atoms (noble gases, alkaline earth) confined endohedrally inside a C60 molecule are calculated employing a time-dependent local density approximation formulation. Plasmon and confinement resonances are found to be a general feature of these cross sections, and dramatic interchannel coupling effects, significantly increasing the atomic cross sections, are exhibited in all cases in the vicinity of the C60 plasmons. Hybridization effects, the mixing of the atomic and cage bound state wave functions, are also found, but no systematics of the hybridization present themselves. Also, in the case of Ar C60, Inter-atomic Columbic decay (ICD) has been found and studied.

  9. Adsorption of amino acids by fullerenes and fullerene nanowhiskers

    NASA Astrophysics Data System (ADS)

    Hashizume, Hideo; Hirata, Chika; Fujii, Kazuko; Miyazawa, Kun’ichi

    2015-12-01

    We have investigated the adsorption of some amino acids and an oligopeptide by fullerene (C60) and fullerene nanowhiskers (FNWs). C60 and FNWs hardly adsorbed amino acids. Most of the amino acids used have a hydrophobic side chain. Ala and Val, with an alkyl chain, were not adsorbed by the C60 or FNWs. Trp, Phe and Pro, with a cyclic structure, were not adsorbed by them either. The aromatic group of C60 did not interact with the side chain. The carboxyl or amino group, with the frame structure of an amino acid, has a positive or negative charge in solution. It is likely that the C60 and FNWs would not prefer the charged carboxyl or amino group. Tri-Ala was adsorbed slightly by the C60 and FNWs. The carboxyl or amino group is not close to the center of the methyl group of Tri-Ala. One of the methyl groups in Tri-Ala would interact with the aromatic structure of the C60 and FNWs. We compared our results with the theoretical interaction of 20 bio-amino acids with C60. The theoretical simulations showed the bonding distance between C60 and an amino acid and the dissociation energy. The dissociation energy was shown to increase in the order, Val < Phe < Pro < Asp < Ala < Trp < Tyr < Arg < Leu. However, the simulation was not consistent with our experimental results. The adsorption of albumin (a protein) by C60 showed the effect on the side chains of Try and Trp. The structure of albumin was changed a little by C60. In our study Try and Tyr were hardly adsorbed by C60 and FNWs. These amino acids did not show a different adsorption behavior compared with other amino acids. The adsorptive behavior of mono-amino acids might be different from that of polypeptides.

  10. Self-assembly of the fullerenes

    SciTech Connect

    Smalley, R.E. )

    1992-03-01

    The account deals with a central mystery of the fullerene story: How are they made How can the fullerenes in general, and C[sub 60] in particular, possibly, be made spontaneously in high yield simply by condensing carbon vapor in a special way The mystery of how this happens in the case of carbon is still by no means fully resolved. Theories of this process are discussed.

  11. Calculation of the cross section for charge transfer in fullerene-fullerene collisions

    SciTech Connect

    Iroshnikov, G. S.

    2006-11-15

    An expression for the charge transfer cross section in fullerene-fullerene collisions is derived by using an instanton approximation for the tunnel splitting of energy levels. The expression is valid in the adiabatic approximation and provides an accurate description of available experimental data.

  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. Fullerene surfactants and their use in polymer solar cells

    DOEpatents

    Jen, Kwan-Yue; Yip, Hin-Lap; Li, Chang-Zhi

    2015-12-15

    Fullerene surfactant compounds useful as interfacial layer in polymer solar cells to enhance solar cell efficiency. Polymer solar cell including a fullerene surfactant-containing interfacial layer intermediate cathode and active layer.

  14. Modelling the structure of ion bombarded binary alloys

    SciTech Connect

    Ossi, P.M.

    1995-09-01

    An atomistic model of phase formation in ion bombarded thin binary metallic films is discussed. Compositional changes occur at the interface between collision cascades and crystal matrix. Relaxation arises via elementary charge transfer reactions, with formation of dimers of an effective alloys, a set of conditions specific to vitrification and respectively to crystal formation under ion bombardment is obtained.

  15. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 1 May 1946 - 31 July 1946 

    E-print Network

    United States Army Air Corps; United States Army Air Corps

    1946-01-01

    -1 42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents 1 May 1946 ? 31 July 1946. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943...

  16. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, April 1944 - November 1944 

    E-print Network

    United States Army Air Corps

    1946-01-01

    -1 42nd Bombardment Squadron (H) Monthly Squadron Histories April 1944 ? November 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force...

  17. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, December 1944 - January 1945 

    E-print Network

    United States Army Air Corps

    1946-01-01

    -1 42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents December 1944 ? January 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943...

  18. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 20 May 1943 - 5 March 1944 

    E-print Network

    United States Army Air Corps

    1946-01-01

    -1 42nd Bombardment Squadron (H) Missions: 20 May 1943 ? 5 March 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force Historical Association...

  19. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 5 March 1944 - 18 August 1944 

    E-print Network

    United States Army Air Corps

    1946-01-01

    =ISO-8859-1 42nd Bombardment Squadron (H) Missions: 5 March 1944 ? 18 August 1944. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air...

  20. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, February 1944 - March 1945 

    E-print Network

    United States Army Air Corps

    1946-01-01

    -1 42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents February 1944 ? March 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943...

  1. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, April 1945 - November 1945 

    E-print Network

    United States Army Air Corps

    1946-01-01

    -1 42nd Bombardment Squadron (H) Monthly Squadron Histories and Documents April 1945 ? November 1945. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943...

  2. Effects of fullerene C60 nanocomposites on human platelet aggregation.

    PubMed

    Vaschenko, V I; Samonin, V V; Popov, V A; Antonenkova, E V; Nikonova, V J; Vilyaninov, V N; Podvjaznikov, M L; Kidalov, V N; Titulova, T B; Vaschenko, T N

    2012-03-01

    The effects of fullerene C(60) nanocomposites on human platelet aggregation induced by ADP, ristocetin, and collagen were studied. The nanocomposite containing fullerene C(60) in polyvinyl pyrrolidone solution did not change platelet aggregation, while fullerene C(60) in crown ether and Twin-80 solutions inhibited ADP-induced platelet aggregation by 20 and 30%, respectively. PMID:22803150

  3. Antibacterial Activity of Fullerene Water Suspensions: Effects of

    E-print Network

    Alvarez, Pedro J.

    Antibacterial Activity of Fullerene Water Suspensions: Effects of Preparation Method and Particle and Department of Chemistry, Rice University, Houston, Texas 77005 Fullerene research in biological systems has to aggregate, forming stable fullerene water suspensions (FWS) whose properties differ from those of bulk solid

  4. The Differential Cytotoxicity of Water-Soluble Fullerenes

    E-print Network

    Natelson, Douglas

    The Differential Cytotoxicity of Water-Soluble Fullerenes Christie M. Sayes, John D. Fortner, Wenh, 2004 ABSTRACT We show that the cytotoxicity of water-soluble fullerene species is a sensitive function of surface derivatization; in two different human cell lines, the lethal dose of fullerene changed over 7

  5. Wiener Dimension: Fundamental Properties and (5,0)-Nanotubical Fullerenes

    E-print Network

    Klavzar, Sandi

    Wiener Dimension: Fundamental Properties and (5,0)-Nanotubical Fullerenes Yaser Alizadeha , Vesna of dimension 1 is 2-connected. It is shown that the (5, 0)-nanotubical fullerene graph on 10k (k 3) vertices has Wiener dimension k. As a consequence the Wiener index of these fullerenes is obtained. 1

  6. Generating Fullerenes at Random Bor Plestenjak and Tomaz Pisanski

    E-print Network

    Plestenjak, Bor

    Generating Fullerenes at Random Bor Plestenjak and Tomaz Pisanski IMFM/TCS, University of Ljubljana, POB 1016, Croatia. Received: 1 #12;Abstract In the present paper a method for generating fullerenes;1. INTRODUCTION Fullerenes and other pure carbon cages remain a subject of active re- search. The mechanism

  7. Computer simulation study of fullerene translocation through lipid membranes

    E-print Network

    Wong-Ekkabut, Jirasak

    Computer simulation study of fullerene translocation through lipid membranes JIRASAK WONG-EKKABUT1 aggregates of fullerene molecules can enter cells and alter their functions, and also cross the blood­brain barrier. However, the mechanisms by which fullerenes penetrate and disrupt cell membranes are still poorly

  8. Microscopic mechanism of fullerene fusion Seungwu Han,1

    E-print Network

    Tománek, David

    Microscopic mechanism of fullerene fusion Seungwu Han,1 Mina Yoon,2 Savas Berber,2 Noejung Park,3 calculations with a search of phase space, we investigate the microscopic fusion mechanism of C60 fullerenes. We find that the 2+2 cycloaddition reaction, a necessary precursor for fullerene fusion, may

  9. A FULLERENE FORMATION MODEL PROPOSED FROM MOLECULAR DYNAMICS SIMULATIONS

    E-print Network

    Maruyama, Shigeo

    A FULLERENE FORMATION MODEL PROPOSED FROM MOLECULAR DYNAMICS SIMULATIONS Yasutaka Yamaguchi distributed carbon atoms was simulated. A C60 imperfect fullerene obtained in the simulation was kept at 2500 in the clustering simulation. Through successive pentagon-migration transformations, the perfect fullerene structure

  10. New Structural Parameters and Permanents of Adjacency Matrices of Fullerenes

    E-print Network

    Bai, Fengshan

    New Structural Parameters and Permanents of Adjacency Matrices of Fullerenes Shan Jiang Heng Liang.R.CHINA. (Received November 25, 2004) Abstract The permanent of the adjacency matrix of a fullerene Cn is related. The stepwise regression model is used to predict the permanents of adjacency matrices of fullerenes

  11. The minimal non-fullerene Voronoi polyhedra Bor Plestenjak

    E-print Network

    Plestenjak, Bor

    The minimal non-fullerene Voronoi polyhedra Bor Plestenjak Department of Theoretical Computer their associated Voronoi regions de ne a polyhedron that is for most n a fullerene. In this paper the exceptional minimal non-fullerene polyhedra are dis- cussed. In this paper we study uniform distributions of points

  12. Graph-Theoretic Independence as a Predictor of Fullerene Stability

    E-print Network

    Larson, Craig E.

    Graph-Theoretic Independence as a Predictor of Fullerene Stability S. Fajtlowicz a, C. E. Larson b of a fullerene, the size of the largest set of vertices such that no two are adjacent (corresponding in identifying stable fullerene isomers. The experimentally characterized isomers with 60, 70 and 76 atoms

  13. Asymptotic Shape of a Fullerene Ball T. A. Witten*

    E-print Network

    Witten, Thomas A.

    Asymptotic Shape of a Fullerene Ball T. A. Witten* and Hao Li James Franck Institute, University-enclosing elas- tic sheet such as a large fullerene ball of linear dimension R. Stretching deformation is crucial in determining the optimal shape, in conjunc- tion with bending. The asymptotic shape of a symmetrical fullerene

  14. Constructing I[subscript h] Symmetrical Fullerenes from Pentagons

    ERIC Educational Resources Information Center

    Gan, Li-Hua

    2008-01-01

    Twelve pentagons are sufficient and necessary to form a fullerene cage. According to this structural feature of fullerenes, we propose a simple and efficient method for the construction of I[subscript h] symmetrical fullerenes from pentagons. This method does not require complicated mathematical knowledge; yet it provides an excellent paradigm for…

  15. FORMATION PROCESS OF EMPTY AND METAL-CONTAINING FULLERENE

    E-print Network

    Maruyama, Shigeo

    FORMATION PROCESS OF EMPTY AND METAL-CONTAINING FULLERENE MOLECULAR DYNAMICS AND FT-ICR STUDIES mechanism of empty and metal-containing fullerene was studied through MD (molecular dynamics) simulations compared with empty fullerene formation simulation. FT-ICR mass spectrometer directly connected

  16. Photoconductivity in Donor-Acceptor Polyferrocenylsilane-Fullerene Composite Films

    E-print Network

    Sargent, Edward H. "Ted"

    Photoconductivity in Donor-Acceptor Polyferrocenylsilane-Fullerene Composite Films Paul W. Cyr) and fullerenes as the active layers were fabricated. Buckminsterfullerene C60 and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) fullerene derivative were investigated as electron acceptors in the devices

  17. Wiener Dimension: Fundamental Properties and (5,0)Nanotubical Fullerenes

    E-print Network

    Klavzar, Sandi

    Wiener Dimension: Fundamental Properties and (5,0)­Nanotubical Fullerenes Yaser Alizadeh a , Vesna and it is proved that a graph of dimension 1 is 2­connected. It is shown that the (5, 0)­nanotubical fullerene of these fullerenes is obtained. 1 Corresponding author #12; 1 Introduction The distance considered in this paper

  18. INFRARED STUDY OF FULLERENE PLANETARY NEBULAE

    SciTech Connect

    Garcia-Hernandez, D. A.; Acosta-Pulido, J. A.; Manchado, A.; Garcia-Lario, P.; Stanghellini, L.; Shaw, R. A.; Cataldo, F. E-mail: amt@iac.es E-mail: Pedro.Garcia-Lario@sciops.esa.int E-mail: letizia@noao.edu

    2012-12-01

    We present a study of 16 planetary nebulae (PNe) where fullerenes have been detected in their Spitzer Space Telescope spectra. This large sample of objects offers a unique opportunity to test conditions of fullerene formation and survival under different metallicity environments because we are analyzing five sources in our own Galaxy, four in the Large Magellanic Cloud (LMC), and seven in the Small Magellanic Cloud (SMC). Among the 16 PNe studied, we present the first detection of C{sub 60} (and possibly also C{sub 70}) fullerenes in the PN M 1-60 as well as of the unusual {approx}6.6, 9.8, and 20 {mu}m features (attributed to possible planar C{sub 24}) in the PN K 3-54. Although selection effects in the original samples of PNe observed with Spitzer may play a potentially significant role in the statistics, we find that the detection rate of fullerenes in C-rich PNe increases with decreasing metallicity ({approx}5% in the Galaxy, {approx}20% in the LMC, and {approx}44% in the SMC) and we interpret this as a possible consequence of the limited dust processing occurring in Magellanic Cloud (MC) PNe. CLOUDY photoionization modeling matches the observed IR fluxes with central stars that display a rather narrow range in effective temperature ({approx}30,000-45,000 K), suggesting a common evolutionary status of the objects and similar fullerene formation conditions. Furthermore, the data suggest that fullerene PNe likely evolve from low-mass progenitors and are usually of low excitation. We do not find a metallicity dependence on the estimated fullerene abundances. The observed C{sub 60} intensity ratios in the Galactic sources confirm our previous finding in the MCs that the fullerene emission is not excited by the UV radiation from the central star. CLOUDY models also show that line- and wind-blanketed model atmospheres can explain many of the observed [Ne III]/[Ne II] ratios using photoionization, suggesting that possibly the UV radiation from the central star, and not shocks, is triggering the decomposition of the circumstellar dust grains. With the data at hand, we suggest that the most likely explanation for the formation of fullerenes and graphene precursors in PNe is that these molecular species are built from the photochemical processing of a carbonaceous compound with a mixture of aromatic and aliphatic structures similar to that of hydrogenated amorphous carbon dust.

  19. Synthesis of Fullerene-Fused Dioxanes/Dioxepanes: Ferric Perchlorate-Mediated One-Step Reaction of [60]Fullerene with Diols.

    PubMed

    Zhang, Xiao-Feng; Li, Fa-Bao; Wu, Jun; Shi, Ji-Long; Liu, Zhan; Liu, Li

    2015-06-19

    The facile one-step reaction of [60]fullerene with various diols in the presence of ferric perchlorate afforded a series of rare fullerene-fused dioxanes/dioxepanes. Nevertheless, the reaction of [60]fullerene with diethylene glycol, triethylene glycol, and tripropylene glycol promoted by ferric perchlorate unexpectedly generated fullerene-fused dioxanes instead of the anticipated fullerene-fused crown ethers. A plausible reaction mechanism is proposed to explain the formation of fullerene-fused dioxane/dioxepane products. PMID:25996442

  20. Energetics of water permeation through fullerene membrane

    PubMed Central

    Isobe, Hiroyuki; Homma, Tatsuya; Nakamura, Eiichi

    2007-01-01

    Lipid bilayer membranes are important as fundamental structures in biology and possess characteristic water-permeability, stability, and mechanical properties. Water permeation through a lipid bilayer membrane occurs readily, and more readily at higher temperature, which is largely due to an enthalpy cost of the liquid-to-gas phase transition of water. A fullerene bilayer membrane formed by dissolution of a water-soluble fullerene, Ph5C60K, has now been shown to possess properties entirely different from those of the lipid membranes. The fullerene membrane is several orders of magnitude less permeable to water than a lipid membrane, and the permeability decreases at higher temperature. Water permeation is burdened by a very large entropy loss and may be favored slightly by an enthalpy gain, which is contrary to the energetics observed for the lipid membrane. We ascribe this energetics to favorable interactions of water molecules to the surface of the fullerene molecules as they pass through the clefts of the rigid fullerene bilayer. The findings provide possibilities of membrane design in science and technology. PMID:17846427

  1. 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.

  2. Spacecraft charging investigation for the CTS project. [electric insulator surface tests by electron bombardment for Communications Technology Satellite

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.; Lovell, R. R.; Gore, V.

    1975-01-01

    Results to date are presented for a program of analytical and experimental investigations to assess the impact of discharge pulses from spacecraft surfaces in the joint Canadian-American Communications Technology Satellite (CTS). All insulator surfaces tested experienced visible discharges when subjected to an electron beam with energy greater than 10 keV. Discharge rate was found to be a function of current flux. The deployable solar array sample experienced discharges under bombardment from the cell or kapton side. There was no measurable cell performance degradation due to the discharges.

  3. Materials science: C66 fullerene encaging a scandium dimer

    NASA Astrophysics Data System (ADS)

    Wang, Chun-Ru; Kai, Tsutomu; Tomiyama, Tetsuo; Yoshida, Takuya; Kobayashi, Yuji; Nishibori, Eiji; Takata, Masaki; Sakata, Makoto; Shinohara, Hisanori

    2000-11-01

    The geometry of carbon cages (fullerenes) is governed by the isolated-pentagon rule (IPR), which states that the most stable fullerenes are those in which all pentagons are surrounded by five hexagons. Although this rule has been verified experimentally, it is impossible for fullerenes in the range C60 to C70 to obey it. Here we describe the production and characterization of an IPR-violating metallofullerene, Sc2@C66, a C66 fullerene encaging a scandium dimer. Our results indicate that encapsulation of the metal dimer significantly stabilizes this otherwise extremely unstable C66 fullerene.

  4. Production of fullerenes using concentrated solar flux

    DOEpatents

    Fields, Clark L. (Greeley, CO); Pitts, John Roland (Lakewood, CO); King, David E. (Lakewood, CO); Hale, Mary Jane (Golden, CO); Bingham, Carl E. (Denver, CO); Lewandowski, Allan A. (Evergreen, CO)

    2000-01-01

    A method of producing soot containing high amounts of fullerenes comprising: providing a primary concentrator capable of impingement of a concentrated beam of sunlight onto a carbon source to cause vaporization of carbon and subsequent formation of fullerenes, or providing a solar furnace having a primary concentrator with a focal point that concentrates a solar beam of sunlight; providing a reflective secondary concentrator having an entrance aperture and an exit aperture at the focal point of the solar furnace; providing a carbon source at the exit aperture of the secondary concentrator; supplying an inert gas over the carbon source to keep the secondary concentrator free from vaporized carbon; and impinging a concentrated beam of sunlight from the secondary concentrator on the carbon source to vaporize the carbon source into a soot containing high amounts of fullerenes.

  5. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions

    NASA Astrophysics Data System (ADS)

    Zope, Rajendra R.; Bhusal, Shusil; Basurto, Luis; Baruah, Tunna; Jackson, Koblar

    2015-08-01

    We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C60@C240 and C60@C180 onions shows that, compared to the polarizability of isolated C60 fullerene, the encapsulation of the C60 in C240 and C180 fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C60 in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability.

  6. Fullerenes in an impact crater on the LDEF spacecraft

    NASA Technical Reports Server (NTRS)

    Radicati di Brozolo, F.; Bunch, T. E.; Fleming, R. H.; Macklin, J.

    1994-01-01

    The fullerenes C60 and C70 have been found to occur naturally on Earth and have also been invoked to explain features in the absorption spectra of interstellar clouds. But no definitive spectroscopic evidence exists for fullerenes in space and attempts to find fullerenes in carbonaceous chondrites have been unsuccessful. Here we report the observation of fullerenes associated with carbonaceous impact residue in a crater on the Long Duration Exposure Facility (LDEF) spacecraft. Laser ionization mass spectrometry and Raman spectroscopy indicate the presence of fullerenes in the crater and in adjacent ejecta. Man-made fullerenes survive experimental hypervelocity (approximately 6.1 km s-1) impacts into aluminium targets, suggesting that space fullerenes contained in a carbonaceous micrometeorite could have survived the LDEF impact at velocities towards the lower end of the natural particle encounter range (<13 km s-1). We also demonstrate that the fullerenes were unlikely to have formed as instrumental artefacts, nor are they present as contaminants. Although we cannot specify the origin of the fullerenes with certainty, the most plausible source is the chondritic impactor. If, alternatively, the impact produced the fullerenes in situ on LDEF, then this suggests a viable mechanism for fullerene production in space.

  7. Site specific atomic polarizabilities in endohedral fullerenes and carbon onions.

    PubMed

    Zope, Rajendra R; Bhusal, Shusil; Basurto, Luis; Baruah, Tunna; Jackson, Koblar

    2015-08-28

    We investigate the polarizability of trimetallic nitride endohedral fullerenes by partitioning the total polarizability into site specific components. This analysis indicates that the polarizability of the endohedral fullerene is essentially due to the outer fullerene cage and has insignificant contribution from the encapsulated unit. Thus, the outer fullerene cages effectively shield the encapsulated clusters and behave like Faraday cages. The polarizability of endohedral fullerenes is slightly smaller than the polarizability of the corresponding bare carbon fullerenes. The application of the site specific polarizabilities to C60@C240 and C60@C180 onions shows that, compared to the polarizability of isolated C60 fullerene, the encapsulation of the C60 in C240 and C180 fullerenes reduces its polarizability by 75% and 83%, respectively. The differences in the polarizability of C60 in the two onions is a result of differences in the bonding (intershell electron transfer), fullerene shell relaxations, and intershell separations. The site specific analysis further shows that the outer atoms in a fullerene shell contribute most to the fullerene polarizability. PMID:26328842

  8. Hydride formation in zirconium and titanium as a result of low energy ion bombardment

    NASA Astrophysics Data System (ADS)

    Jackman, J. A.; Carpenter, G. J. C.; McCaffrey, J.

    1993-06-01

    Parallel energy loss spectroscopy (PEELS), convergent beam microdiffraction and secondary ion mass spectrometry (SIMS) have revealed that extensive hydride formation can occur in Zr and Ti6A14V as a direct consequence of low energy (a few keV) Ar ion bombardment in a typical ion thinning unit. Pure hydride films several microns thick could be formed on bulk samples in a few hours of sputtering under conditions which are frequently used to prepare samples for transmission electron microscopy. This effect was largely independent of the presence of contaminating hydrogen introduced in the form of water vapour in the sputter chamber, or hydrogen contamination in the incident Ar beam. However, hydride formation could be strongly influenced by controlling the presence of hydrocarbons arising from the evaporation of pump oil. Details of the degree of hydride formation as a result of experimental conditions are presented.

  9. Biomedical applications of functionalized fullerene-based nanomaterials

    PubMed Central

    Partha, Ranga; Conyers, Jodie L

    2009-01-01

    Since their discovery in 1985, fullerenes have been investigated extensively due to their unique physical and chemical properties. In recent years, studies on functionalized fullerenes for various applications in the field of biomedical sciences have seen a significant increase. The ultimate goal is towards employing these functionalized fullerenes in the diagnosis and therapy of human diseases. Functionalized fullerenes are one of the many different classes of compounds that are currently being investigated in the rapidly emerging field of nanomedicine. In this review, the focus is on the three categories of drug delivery, reactive oxygen species quenching, and targeted imaging for which functionalized fullerenes have been studied in depth. In addition, an exhaustive list of the different classes of functionalized fullerenes along with their applications is provided. We will also discuss and summarize the unique approaches, mechanisms, advantages, and the aspect of toxicity behind utilizing functionalized fullerenes for biomedical applications. PMID:20011243

  10. A Highly-Ordered 3D Covalent Fullerene Framework**

    PubMed Central

    Minar, Norma K; Hou, Kun; Westermeier, Christian; Döblinger, Markus; Schuster, Jörg; Hanusch, Fabian C; Nickel, Bert; Ozin, Geoffrey A; Bein, Thomas

    2015-01-01

    A highly-ordered 3D covalent fullerene framework is presented with a structure based on octahedrally functionalized fullerene building blocks in which every fullerene is separated from the next by six functional groups and whose mesoporosity is controlled by cooperative self-assembly with a liquid-crystalline block copolymer. The new fullerene-framework material was obtained in the form of supported films by spin coating the synthesis solution directly on glass or silicon substrates, followed by a heat treatment. The fullerene building blocks coassemble with a liquid-crystalline block copolymer to produce a highly ordered covalent fullerene framework with orthorhombic Fmmm symmetry, accessible 7.5?nm pores, and high surface area, as revealed by gas adsorption, NMR spectroscopy, small-angle X-ray scattering (SAXS), and TEM. We also note that the 3D covalent fullerene framework exhibits a dielectric constant significantly lower than that of the nonporous precursor material. PMID:25958846

  11. Distributed curvature and stability of fullerenes.

    PubMed

    Fowler, Patrick W; Nikoli?, Sonja; De Los Reyes, Rasthy; Myrvold, Wendy

    2015-09-21

    Energies of non-planar conjugated ? systems are typically described qualitatively in terms of the balance of ? stabilisation and the steric strain associated with geometric curvature. Curvature also has a purely graph-theoretical description: combinatorial curvature at a vertex of a polyhedral graph is defined as one minus half the vertex degree plus the sum of reciprocal sizes of the faces meeting at that vertex. Prisms and antiprisms have positive combinatorial vertex curvature at every vertex. Excluding these two infinite families, we call any other polyhedron with everywhere positive combinatorial curvature a PCC polyhedron. Cubic PCC polyhedra are initially common, but must eventually die out with increasing vertex count; the largest example constructed so far has 132 vertices. The fullerenes Cn have cubic polyhedral molecular graphs with n vertices, 12 pentagonal and (n/2 - 10) hexagonal faces. We show that there are exactly 39 PCC fullerenes, all in the range 20 ?n? 60. In this range, there is only partial correlation between PCC status and stability as defined by minimum pentagon adjacency. The sum of vertex curvatures is 2 for any polyhedron; for fullerenes the sum of squared vertex curvatures is linearly related to the number of pentagon adjacencies and hence is a direct measure of relative stability of the lower (n? 60) fullerenes. For n? 62, non-PCC fullerenes with a minimum number of pentagon adjacencies minimise mean-square curvature. For n? 70, minimum mean-square curvature implies isolation of pentagons, which is the strongest indicator of stability for a bare fullerene. PMID:26283188

  12. Modification of Polymer Materials by Ion Bombardment: Case Studies

    SciTech Connect

    Bielinski, D. M.; Jagielski, J.; Piatkowska, A.

    2009-03-10

    The paper discusses possibility of application of ion beam bombardment for modification of polymers. Changes to composition, structure and morphology of the surface layer produced by the treatment and their influence on engineering and functional properties of wide range of polymer materials are presented. Special attention has been devoted to modification of tribological properties. Ion bombardment results in significant reduction of friction, which can be explained by increase of hardness and wettability of polymer materials. Hard but thin enough skin does not result in cracking but improves their abrasion resistance. Contrary to conventional chemical treatment ion beam bombardment works even for polymers hardly susceptible to modification like silicone rubber or polyolefines.

  13. Laser controlled magnetism in hydrogenated fullerene films

    SciTech Connect

    Makarova, Tatiana L.; Shelankov, Andrei L.; Kvyatkovskii, Oleg E.; Zakharova, Irina B.; Buga, Sergei G.; Volkov, Aleksandr P.

    2011-04-15

    Room temperature ferromagnetic-like behavior in fullerene photopolymerized films treated with monatomic hydrogen is reported. The hydrogen treatment controllably varies the paramagnetic spin concentration and laser induced polymerization transforms the paramagnetic phase to a ferromagnetic-like one. Excess laser irradiation destroys magnetic ordering, presumably due to structural changes, which was continuously monitored by Raman spectroscopy. We suggest an interpretation of the data based on first-principles density-functional spin-unrestricted calculations which show that the excess spin from mono-atomic hydrogen is delocalized within the host fullerene and the laser-induced polymerization promotes spin exchange interaction and spin alignment in the polymerized phase.

  14. Transgenic sorghum plants via microprojectile bombardment.

    PubMed Central

    Casas, A M; Kononowicz, A K; Zehr, U B; Tomes, D T; Axtell, J D; Butler, L G; Bressan, R A; Hasegawa, P M

    1993-01-01

    Transgenic sorghum plants have been obtained after microprojectile bombardment of immature zygotic embryos of a drought-resistant sorghum cultivar, P898012. DNA delivery parameters were optimized based on transient expression of R and C1 maize anthocyanin regulatory elements in scutellar cells. The protocol for obtaining transgenic plants consists of the delivery of the bar gene to immature zygotic embryos and the imposition of bialaphos selection pressure at various stages during culture, from induction of somatic embryogenesis to rooting of regenerated plantlets. One in about every 350 embryos produced embryogenic tissues that survived bialaphos treatment; six transformed callus lines were obtained from three of the eight sorghum cultivars used in this research. Transgenic (T0) plants were obtained from cultivar P898012 (two independent transformation events). The presence of the bar and uidA genes in the T0 plants was confirmed by Southern blot analysis of genomic DNA. Phosphinothricin acetyltransferase activity was detected in extracts of the T0 plants. These plants were resistant to local application of the herbicide Ignite/Basta, and the resistance was inherited in T1 plants as a single dominant locus. Images Fig. 1 Fig. 2 Fig. 4 Fig. 5 PMID:8248230

  15. Genetic transformation of wheat via particle bombardment.

    PubMed

    Sparks, Caroline A; Jones, Huw D

    2014-01-01

    Since its first invention in the late 1980s the particle gun has evolved from a basic gunpowder driven machine firing tungsten particles to one more refined which uses helium gas as the propellant to launch alternative heavy metal particles such as gold and silver. The simple principle is that DNA-coated microscopic particles (microcarriers) are accelerated at high speed by helium gas within a vacuum and travel at such a velocity as to penetrate target cells. However, the process itself involves a range of parameters which are open to variation: microparticle type and size, gun settings (rupture pressure, target distance, vacuum drawn, etc.), preparation of components (e.g., gold coating), and preparation of plant tissues. Here is presented a method optimized for transformation of wheat immature embryos using the Bio-Rad PDS-1000/He particle gun to deliver gold particles coated with a gene of interest and the selectable marker gene bar at 650 psi rupture pressure. Following bombardment, various tissue culture phases are used to encourage embryogenic callus formation and regeneration of plantlets and subsequent selection using glufosinate ammonium causes suppression of non-transformed tissues, thus assisting the detection of transformed plants. This protocol has been used successfully to generate transgenic plants for a wide range of wheat varieties, both spring and winter bread wheats (T. aestivum L.) and durum wheats (T. turgidum L.). PMID:24243206

  16. Production of Mg and Al Auger electrons by noble gas ion bombardment of Mg and Al surfaces

    NASA Technical Reports Server (NTRS)

    Ferrante, J.; Pepper, S. V.

    1976-01-01

    Relative production efficiencies of Mg and Al Auger electrons by He, Ne, Ar, Kr, and Xe ion bombardment are reported as a function of ion energy for energies not exceeding 3 keV. The experimental apparatus employed consisted of a LEED-Auger system equipped with an ion gun and a four-grid retarding-potential analyzer. It is found that: (1) the shape of the ion-excited Auger signal was independent of the rare gas and quite symmetric; (2) the Al signal was about an order of magnitude smaller than the Mg signal for a given bombarding species and ion-gun voltage; (3) no signal was observed for He(+) bombardment under any of the experimental conditions; (4) signal strengths were independent of temperature and ion dose; (5) the Auger production efficiencies differed by no more than a factor of two among the different gases - except for He(+) - on a given metal; (6) all the signal strengths increased with increasing ion-gun voltage, with no maximum exhibited; and (7) the apparent threshold energy for the Al signal was higher than that for the Mg signal. The differences between the results for the two metals are attributed to the fact that the Al 2p orbital lies deeper in energy and closer to the nucleus than the corresponding Mg orbital.

  17. Effects of spherical fullerene nanoparticles on a dipalmitoyl phosphatidylcholine lipid monolayer: a coarse grain molecular dynamics

    E-print Network

    Nielsen, Steven O.

    Effects of spherical fullerene nanoparticles on a dipalmitoyl phosphatidylcholine lipid monolayer. Here, we use coarse grain molecular dynamics simulations to study spherical fullerene molecules show that all the tested fullerene molecules can spontaneously diffuse into both a lipid bilayer

  18. Monitoring of Aqueous Fullerene Dispersions by Thermal-Lens Spectrometry

    NASA Astrophysics Data System (ADS)

    Mikheev, I. V.; Volkov, D. S.; Proskurnin, M. A.; Korobov, M. V.

    2015-06-01

    Aqueous fullerene solutions (dispersions) are very promising materials of biomedicine and biotechnology. Of importance are the traceability of their production and characterization of their optical and colloidal properties. Thermal-lens spectrometry, as a method suitable for both optical and thermophysical studies, was used to elucidate the forms of non-modified fullerenes in their aqueous dispersions and to determine low concentrations of and fullerenes. It was shown that the residual amounts of toluene in aqueous fullerene dispersions made according to the solvent-exchange protocol could be detected by thermal lensing. As a result, the technique for the production of aqueous fullerene dispersions was improved compared to the existing data providing higher fullerene concentrations. The limits of detection of and fullerenes are approximately , which are 20-fold lower compared to conventional spectrophotometry. The distinction between aqueous fullerene dispersions in comparison with organic solutions of fullerenes caused by the formation of large clusters is shown by the comparison of transient and steady-state calibration curves for aqueous and organic fullerene solutions and model reference systems under various thermal-lens excitation conditions. The advantages of thermal lensing for such colloidal systems are discussed.

  19. Inorganic nanotubes and fullerene-like nanoparticles.

    PubMed

    Tenne, R

    2006-11-01

    Although graphite, with its anisotropic two-dimensional lattice, is the stable form of carbon under ambient conditions, on nanometre length scales it forms zero- and one-dimensional structures, namely fullerenes and nanotubes, respectively. This virtue is not limited to carbon and, in recent years, fullerene-like structures and nanotubes have been made from numerous compounds with layered two-dimensional structures. Furthermore, crystalline and polycrystalline nanotubes of pure elements and compounds with quasi-isotropic (three-dimensional) unit cells have also been synthesized, usually by making use of solid templates. These findings open up vast opportunities for the synthesis and study of new kinds of nanostructures with properties that may differ significantly from the corresponding bulk materials. Various potential applications have been proposed for the inorganic nanotubes and the fullerene-like phases. Fullerene-like nanoparticles have been shown to exhibit excellent solid lubrication behaviour, suggesting many applications in, for example, the automotive and aerospace industries, home appliances, and recently for medical technology. Various other potential applications, in catalysis, rechargeable batteries, drug delivery, solar cells and electronics have also been proposed. PMID:18654160

  20. 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.

  1. Search for fullerenes in stone meteorites

    NASA Astrophysics Data System (ADS)

    Oester, M. Y.; Kuechl, D.; Sipiera, P. P.; Welch, C. J.

    1994-07-01

    The possibility of identifying fullerenes in stony meteorites became apparent from a paper given by Radicati de Brozolo. In this paper it was reported that fullerenes were present in the debris resulting from a collision between a micrometeoroid and an orbiting satellite. This fact generated sufficient curiosity to initiate a search for the presence of fullerenes in various stone meteorites. In the present study seven ordinary chondrites (al-Ghanim L6 (find), Dimmitt H4 (find), Lazbuddie LL5 (find), New Concord H5 (fall), Silverton H4 (find), Springlake L6 (find), and Umbarger L3/6 (find)). Four carbonaceous chondrites (ALH 83100 C2 (find), ALH 83108 C30 (find), Allende CV3 (fall), and Murchison CM2 (fall), and one achondrite (Monticello How (find)) were analyzed for the presence of fullerenes. The analytical procedure employed was as follows: 100 mg of meteorite was ground up with a mortar and pestle; 10 mL of toluene was then added and the mixture was refluxed for 90 min; this mixture was then filtered through a short column of silica; a 50 microliter sample was then analyzed by high pressure liquid chromatography (HPLC) using a Buckyclutcher I column with a mobile phase consisting of equal volumes of toluene and hexane at a flow rate of 1.00 mg per minute, with detection at 330 and 600 nm. Three of the meteorites, Allende, Murchison, and al-Ghanim, gave HPLC traces containing peaks with similar retention times to the HPLC trace of an authentic fullerene C60. However, further analysis using an HPLC instrument equipped with a diode-array detector failed to confirm any of the substances detected in the three meteorites as C60. Additional analyses will be conducted to identify what the HPLC traces actually represent.

  2. Surface roughening and erosion rate change at low energy SIMS depth profiling of silicon during oblique O bombardment

    NASA Astrophysics Data System (ADS)

    Fares, B.; Gautier, B.; Holliger, Ph.; Baboux, N.; Prudon, G.; Dupuy, J.-Cl.

    2006-12-01

    Surface roughening of boron ?-doped Si samples under low energy (0.5 keV/ O, 44 ° and 54 °, and 1.0 keV/ O, 48 °) O bombardment at oblique incidence with and without oxygen flooding was studied with atomic force microscopy (AFM) and secondary ion mass spectrometry (SIMS). The erosion rate, the surface topography and the depth resolution as a function of depth have been measured. Changes in secondary ion yields have been correlated with changes in surface topography. It is found that the surface roughness depends on impact energy and incidence angle without flooding. The roughness decreases with decreasing impact energy. For the same energy (0.5 keV/ O), the wavelength increases slightly with increasing angle of incidence and the roughness increases with increasing angle of incidence. With flooding, the roughness can be efficiently avoided. The best conditions to avoid roughness when analysing ultra shallow profiles with our magnetic sector instrument is 0.5 keV/ O, 44 ° with flooding. A procedure for the depth calibration of the profiles revealed that surface roughness causes an erosion rate change as measured using the shift of the position of the measured B peaks with and without flooding. The consequences of the roughness in terms of depth resolution of the profiles are analysed with and without flooding. Moreover, we show that the value of the Gaussian broadening parameter of the depth resolution function is closely related to the final dispersion of the heights in the crater bottom.

  3. Study of endohedral doped C60 fullerene using model potentials

    NASA Astrophysics Data System (ADS)

    Umran, N. M.; Kaur, Narinder; Seema, K.; Kumar, Ranjan

    2015-05-01

    In this paper, we present a study of Si, Ge, Au and Tl doped endohedral fullerenes using model potentials. We have used Brenner potential, Lennard-Jones potential and Gupta potential to describe the C-C (Si, Ge), C-metal and metal-metal interaction, respectively. We have done total energy calculations to find out the minimum energy structures. In the case of Sin@C60 complex, a maximum of nine atoms can be doped inside the fullerene cage. The addition of a tenth Si atom leads to the breaking of the fullerene cage. Similarly for Ge, Au and Tl, a maximum of four, two and two atoms, respectively, can be doped inside the fullerene cage. It has been observed that the stability of fullerene decreases with an increase in the number of dopant atoms. These calculations prove the change of characteristics of fullerenes upon doping.

  4. Biological activities of water-soluble fullerene derivatives

    NASA Astrophysics Data System (ADS)

    Nakamura, S.; Mashino, T.

    2009-04-01

    Three types of water-soluble fullerene derivatives were synthesized and their biological activities were investigated. C60-dimalonic acid, an anionic fullerene derivative, showed antioxidant activity such as quenching of superoxide and relief from growth inhibition of E. coli by paraquat. C60-bis(7V,7V-dimethylpyrrolidinium iodide), a cationic fullerene derivative, has antibacterial activity and antiproliferative effect on cancer cell lines. The mechanism is suggested to be respiratory chain inhibition by reactive oxygen species produced by the cationic fullerene derivative. Proline-type fullerene derivatives showed strong inhibition activities on HIV-reverse transcriptase. The IC50 values were remarkably lower than nevirapine, a clinically used anti-HIV drug. Fullerene derivatives have a big potential for a new type of lead compound to be used as medicine.

  5. Thermal transport in C20 fullerene-chained carbon nanobuds

    NASA Astrophysics Data System (ADS)

    Loh, G. C.; Baillargeat, D.

    2013-03-01

    Carbon nanobuds, which are hybrid fullerene-nanotube structures, have previously shown glimpses of their potential in nanotechnology applications. By performing molecular dynamics simulations, a novel study of thermal conduction in a compact form of carbon nanobuds is presented. We demonstrate that nanobuds conduct thermal energy relatively well, within an order compared to nanotubes. Alike their close relatives—the carbon peapod, this essentially extends the dimensionality of thermal management applications. A rigorous calculation of the vibrational entropy and specific heat at the interfacial locations suggests that both functions are relatively identical in magnitude at fullerene-fullerene and fullerene-nanotube interfaces. Two common nanobud configurations are compared: while both are comparable in mechanical stability, a type 2 carbon nanobud (perfect fullerene, nanotube with vacancies) is less thermally conductive than a type 1 nanobud (perfect fullerene, perfect nanotube) due to more scattering of long-wavelength modes at the defect sites of the nanotube.

  6. Synthesis of Endohedral Fullerene Using ECR Ion Source

    SciTech Connect

    Minezaki, Hidekazu; Uchida, Takashi; Tanaka, Kiyokatsu; Asaji, Toyohisa; Muramatsu, Masayuki; Kitagawa, Atsushi; Kato, Yushi; Racz, Richard; Biri, Sandor; Yoshida, Yoshikazu

    2011-01-07

    We are developing an ECRIS apparatus which is designed for the production of endohedral fullerenes. Our promising approaches to produce the endohedral fullerenes using the ECRIS are the ion-ion collision reaction of fullerenes and the other atom in their mixture plasma and simple ion implantation of atom into fullerene layer. In this study, we tried to synthesize the endohedral nitrogen-fullerenes by ion implantation. N{sup +} beam was irradiated to a fullerene target with a specific energy and dose. As a result, we could observe the peak of N+C{sub 60} from targets after N{sup +} beam irradiation with TOF-SIMS and LDI-TOF-MS.

  7. Memory operation mechanism of fullerene-containing polymer memory

    SciTech Connect

    Nakajima, Anri Fujii, Daiki

    2015-03-09

    The memory operation mechanism in fullerene-containing nanocomposite gate insulators was investigated while varying the kind of fullerene in a polymer gate insulator. It was cleared what kind of traps and which positions in the nanocomposite the injected electrons or holes are stored in. The reason for the difference in the easiness of programming was clarified taking the role of the charging energy of an injected electron into account. The dependence of the carrier dynamics on the kind of fullerene molecule was investigated. A nonuniform distribution of injected carriers occurred after application of a large magnitude programming voltage due to the width distribution of the polystyrene barrier between adjacent fullerene molecules. Through the investigations, we demonstrated a nanocomposite gate with fullerene molecules having excellent retention characteristics and a programming capability. This will lead to the realization of practical organic memories with fullerene-containing polymer nanocomposites.

  8. Higher fullerenes: Compositional analysis by EDXD and molecular dynamics

    SciTech Connect

    Carbone, Marilena; Gontrani, Lorenzo

    2014-06-19

    A carbon soot of higher fullerenes was studied by Energy Dispersive X-ray Diffraction (EDXD) aiming at defining the overall structure as accurately as possible to define the overall structure, without lengthy separation and purification procedures. EDXD pattern was compared with model curves obtained for single homogeneous fullerenes already crystallized and for the hypothesized C180. All fullerenes contribute to the overall experimental curve to different extents, with C96 giving the best agreement. The presence of even higher fullerenes is very likely, since the hypothesized C180 gives a very good match as well.

  9. 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.

  10. Generation of singlet oxygen in fullerene-containing media: 2. Fullerene-containing solutions

    SciTech Connect

    Bagrov, I V; Belousova, I M; Grenishin, A S; Danilov, O B; Ermakov, A V; Kiselev, V M; Kislyakov, I M; Murav'eva, T D; Sosnov, E N

    2008-03-31

    The generation of singlet oxygen in fullerene solutions is studied by luminescence methods upon excitation by pulsed, repetitively pulsed, and continuous radiation sources. The concentration of singlet oxygen in solutions is measured in stationary and pulsed irradiation regimes. The rate constants of quenching of O{sub 2}({sup 1}{delta}{sub g}) by fullerenes C{sub 70} and C{sub 60} in the CCl{sub 4} solution are measured to be (7.2{+-}0.1)x10{sup 7} L mol{sup -1} s{sup -1} and less than 6x10{sup 4} L mol{sup -1} s{sup -1}, respectively. The temperature and photolytic variations in the generation properties of the fullerene solution exposed to intense continuous radiation are studied by the methods of optical and EPR spectroscopy. Pulsed irradiation resulted in the production of singlet oxygen in suspensions of fullerene-like structures, in particular, astralenes. A liquid pulsed singlet-oxygen generator based on the fullerene solution in CCl{sub 4} is developed and studied, in which the yield of O{sub 2} ({sup 1}{delta}{sub g}) to the gas phase at concentrations up to 5x10{sup 16} cm{sup -3} is obtained. (laser applications and other topics in quantum electronics)

  11. Investigating oxygen flooding at oblique 2 and 1 keV oxygen sputtering for microelectronics support applications

    NASA Astrophysics Data System (ADS)

    Jahnel, F.; von Criegern, R.

    2003-01-01

    Low energy (2.1 and 1 keV) oxygen bombardment at oblique incidence in combination with oxygen flooding was applied to two kinds of epitaxially grown, boron-doped samples. The angles of incidence ranged between 54° and 44°, realized in a Cameca 6f. At surface saturation conditions, no indication of ripples formation was found up to at least 700 nm depth. In comparison to measurements at perpendicular oxygen beam incidence (no flooding), the boron decay lengths were about equal, whereas the apparent profile shift was clearly lower (roughly half) in the flooding case. Thus, no disadvantage is found for these oxygen flooding conditions as compared to perpendicular oxygen bombardment conditions.

  12. [Factors influence on transformation by particle bombardment in Indica rice].

    PubMed

    Tao, L Z; Xu, Q S; Liang, C Y; Ling, D H

    2000-03-01

    Four factors influence on transformation of indica rice, which were high osmotic treatment; different explant as the target tissue; pressure of rupture disk and quantity of plasmid DNA, were investigated in this experiment. High osmotic treatment of target tissue prior to and after bombardment increased 3.2-fold for Gus transient expression than control. The best treatment of high osmotic was that the target tissues were kept in the target-bed medium which contained 0.4-0.6 mol/L sorbitol and manitol each for 4 h prior to bombardment and for 16 h after bombardment. Four explants: scutellum from mature seed, young panicle, embryogenic callus and suspension cells of indica rice were tested as target explant by particle bombardment. The results of Gus transient showed that the highest expression was scutellum and for other three explants, the order from high to low was young panicle, embryogenic callus and suspension cell. Transgenic plants were obtained from all of the explants except young panicle. For the pressure of rupture disk on transformation, 1100 psi or 1300 psi of the pressure of rupture disk were best one for the transformation and higher than 1300 psi could damage the target tissue which become black and died in the following culture duration. For the quantity of plasmid DNA, the results showed that 0.83 microgram of plasmid DNA per bombardment was preferred for the transformation of indica rice. PMID:12548856

  13. Carbon and fullerene nanomaterials in plant system

    PubMed Central

    2014-01-01

    Both the functionalized and non functionalized carbon nanomaterials influence fruit and crop production in edible plants and vegetables. The fullerene, C60 and carbon nanotubes have been shown to increase the water retaining capacity, biomass and fruit yield in plants up to ~118% which is a remarkable achievement of nanotechnology in recent years. The fullerene treated bitter melon seeds also increase the phytomedicine contents such as cucurbitacin-B (74%), lycopene (82%), charantin (20%) and insulin (91%). Since as little as 50 ?g mL?1 of carbon nanotubes increase the tomato production by about 200%, they may be exploited to enhance the agriculture production in future. It has been observed that, in certain cases, non functionalized multi-wall carbon nanotubes are toxic to both plants and animals but the toxicity can be drastically reduced if they are functionalized. PMID:24766786

  14. Uraninite and fullerene in atmospheric particulates.

    PubMed

    Utsunomiya, Satoshi; Jensen, Keld A; Keeler, Gerald J; Ewing, Rodney C

    2002-12-01

    Particulates emitted from coal-burning power plants typically contain very small amounts of uranium (<10 ppm). Because of the extremely low concentrations, the form of the uranium has been unknown. Using a variety of advanced electron microscopy techniques, we have identified for the first time nanocrystals of uraninite, UO2+x, encapsulated in carbonaceous matter (< or = 50 nm) similar to fullerene. We have also identified, for the first time, closely associated fullerenes, C60. The "carbon-caged" nanocrystals of uraninite are protected from the immediate oxidation that would lead to increased mobility of uranium in the environment. Still, the presence of uranium in the very fine fraction of atmospheric particulates provides another pathway for radiation exposure. PMID:12523404

  15. A dendritic fullerene-porphyrin dyad.

    PubMed

    Campidelli, Stéphane; Deschenaux, Robert; Swartz, Angela; Rahman, G M Aminur; Guldi, Dirk M; Milic, Dragana; Vázquez, Ester; Prato, Maurizio

    2006-12-01

    We describe the synthesis, characterization and photophysical properties of a fullerene derivative whose structure includes a Zn-porphyrin and a second generation liquid-crystalline (LC) dendrimer. The size of the fullerene and porphyrin units with respect to the size of the LC dendrimer prevents the formation of liquid-crystalline phases. However, this system gives interesting photoinduced electron transfer phenomena. Compound has been investigated by steady state and time resolved fluorescence as well as transient absorption spectroscopy in polar and apolar solvents. We demonstrate that the fluorescence of the porphyrin unit in is quenched compared to the Zn-tetraphenylporphyrin used as reference. Femto- and picosecond transient absorption permit to identify the formation of a radical ion pair while nanosecond experiments allowed the determination of the charge recombination lifetimes. PMID:17136279

  16. Polymer-fullerene composite solar cells.

    PubMed

    Thompson, Barry C; Fréchet, Jean M J

    2008-01-01

    Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Polymer-based organic photovoltaic systems hold the promise for a cost-effective, lightweight solar energy conversion platform, which could benefit from simple solution processing of the active layer. The function of such excitonic solar cells is based on photoinduced electron transfer from a donor to an acceptor. Fullerenes have become the ubiquitous acceptors because of their high electron affinity and ability to transport charge effectively. The most effective solar cells have been made from bicontinuous polymer-fullerene composites, or so-called bulk heterojunctions. The best solar cells currently achieve an efficiency of about 5%, thus significant advances in the fundamental understanding of the complex interplay between the active layer morphology and electronic properties are required if this technology is to find viable application. PMID:18041798

  17. Preparation of fullerene/glass composites

    DOEpatents

    Mattes, B.R.; McBranch, D.W.; Robinson, J.M.; Koskelo, A.C.; Love, S.P.

    1995-05-30

    Synthesis of fullerene/glass composites is described. A direct method for preparing solid solutions of C{sub 60} in silicon dioxide (SiO{sub 2}) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these ``guests`` in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C{sub 60}. Depending upon the preparative procedure, C{sub 60} dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C{sub 60} in a solid glass matrix, is generated by the present method.

  18. Preparation of fullerene/glass composites

    DOEpatents

    Mattes, Benjamin R. (Santa Fe, NM); McBranch, Duncan W. (Santa Fe, NM); Robinson, Jeanne M. (Los Alamos, NM); Koskelo, Aaron C. (Los Alamos, NM); Love, Steven P. (Los Alamos, NM)

    1995-01-01

    Synthesis of fullerene/glass composites. A direct method for preparing solid solutions of C.sub.60 in silicon dioxide (SiO.sub.2) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these "guests" in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C.sub.60. Depending upon the preparative procedure, C.sub.60 dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C.sub.60 in a solid glass matrix, is generated by the present method.

  19. Phase transition, formation and fragmentation of fullerenes

    NASA Astrophysics Data System (ADS)

    Hussien, A.; Yakubovich, A. V.; Solov'yov, A. V.; Greiner, W.

    2010-04-01

    We present a statistical mechanics model treating the formation and the fragmentation of fullerenes as a phase transition. Based on this model, we investigate the formation and fragmentation of C60 and C240 fullerenes from and to a gas of carbon dimers by means of molecular dynamics (MD) simulations. These simulations were conducted for 500 ns using a topologically-constrained forcefield. At the phase transition temperature, both the cage and gaseous phases were found to coexist and the system continuously oscillates between the two phases. Combining the results of the MD simulations and the statistical mechanics approach, we obtain the dependence of the phase transition temperature on pressure and compare the results of our model with arc-discharge experiments.

  20. Delayed Ionization of Fullerenes and Fullerene Derivatives upon Laser Desorption and Surface Collision

    NASA Astrophysics Data System (ADS)

    Beck, R. D.; Weis, P.; Rockenberger, J.; Kappes, M. M.

    Delayed electron emission has been observed upon laser desorption for several fullerenes, endohedral metallofullerenes, and large carbon clusters formed by coalescence reactions. Odd-numbered carbon clusters and fullerene derivatives with exohedral functional groups do not show delayed ionization under similar conditions, presumably due to lower dissociation energies. Thus, delayed electron emission is suggested to be a characteristic indicator for strongly bound fullerene structures. Measurements of the rate of delayed electron emission are used together with structural information from other sources to calculate ionization potentials for these species. Selective observation of delayed electron emission from scattered {C}60* after surface impact and neutralization of {C}+{60 on graphite confirms an earlier report of this process by Whetten et al.6

  1. Thermoelectricity in fullerene-metal heterojunctions.

    PubMed

    Yee, Shannon K; Malen, Jonathan A; Majumdar, Arun; Segalman, Rachel A

    2011-10-12

    Thermoelectricty in heterojunctions, where a single-molecule is trapped between metal electrodes, has been used to understand transport properties at organic-inorganic interfaces. (1) The transport in these systems is highly dependent on the energy level alignment between the molecular orbitals and the Fermi level (or work function) of the metal contacts. To date, the majority of single-molecule measurements have focused on simple small molecules where transport is dominated through the highest occupied molecular orbital. (2, 3) In these systems, energy level alignment is limited by the absence of electrode materials with low Fermi levels (i.e., large work functions). Alternatively, more controllable alignment between molecular orbitals and the Fermi level can be achieved with molecules whose transport is dominated by the lowest unoccupied molecular orbital (LUMO) because of readily available metals with lower work functions. Herein, we report molecular junction thermoelectric measurements of fullerene molecules (i.e., C(60), PCBM, and C(70)) trapped between metallic electrodes (i.e., Pt, Au, Ag). Fullerene junctions demonstrate the first strongly n-type molecular thermopower corresponding to transport through the LUMO, and the highest measured magnitude of molecular thermopower to date. While the electronic conductance of fullerenes is highly variable, due to fullerene's variable bonding geometries with the electrodes, the thermopower shows predictable trends based on the alignment of the LUMO with the work function of the electrodes. Both the magnitude and trend of the thermopower suggest that heterostructuring organic and inorganic materials at the nanoscale can further enhance thermoelectric performance, therein providing a new pathway for designing thermoelectric materials. PMID:21882860

  2. Optical limiting materials based on fullerene derivatives

    SciTech Connect

    Prato, Maurizio; Maggini, Michele; Scorrano, Gianfranco; Brusatin, Giovanna; Guglielmi, Massimo; Meneghetti, Moreno; Signorini, Raffaella; Bozio, Renato; Guldi, Dirk M.

    1999-09-30

    A functionalized fulleropyrrolidine has been synthesized and investigated for optical limiting applications. Solid materials have been prepared for optical limiting devices by incorporation in sol-gel glasses. Their nonlinear transmission properties have been measured and found comparable with those of solution samples. We show that clustering of the fullerene spheres, which might affect the optical limiting properties, is not relevant. Multilayer structures following a bottleneck design are prepared and their NL transmission properties are characterized. (c) 1999 American Institute of Physics.

  3. Magnetospheric ion bombardment profiles of satellites - Europa and Dione

    SciTech Connect

    Pospieszalska, M.K.; Johnson, R.E.

    1989-03-01

    Bombardment profiles generated by tracking ions in magnetospheric plasmas onto the surface of a satellite with a suitable description of the ion motion are used to calculate the spatial dependence across a satellite surface of the ion bombardment/implantation rate for satellites embedded in planetary magnetospheric plasmas. Attention is given to the results of a parameter study; a general dependency on ion gyroradius and pitch angle is noted, together with a strong dependence of access to the leading hemisphere on pitch-angle distribution. Gyromotion is found to cause differences in the bombardment of the inner and outer hemisphere. Reasonable speed and pitch-angle distributions are used to calculate profiles for sulfur ions incident on Europa and oxygen ones incident on Dione. 28 references.

  4. Simulation of Carbon Nanotube Welding through Ar bombardment

    E-print Network

    Kucukkal, Mustafa U

    2014-01-01

    Single-walled carbon nanotubes show promise as nanoscale transistors, for nanocomputing applications. This use will require appropriate methods for creating electrical connections between distinct nanotubes, analogous to welding of metallic wires at larger length scales, but methods for performing nanoscale chemical welding are not yet sufficiently understood. This study examined the effect of Ar bombardment on the junction of two crossed single-walled carbon nanotubes, to understand the value and limitations of this method for generating connections between nanotubes. A geometric criterion was used to assess the quality of the junctions formed, with the goal of identifying the most productive conditions for experimental ion bombardment. In particular, the effects of nanotube chirality, Ar impact kinetic energy, impact particle flux and fluence, and annealing temperature were considered. The most productive bombardment conditions, leading to the most crosslinking of the tubes with the smallest loss of graphit...

  5. Electron bombardment propulsion system characteristics for large space systems

    NASA Technical Reports Server (NTRS)

    Byers, D. C.; Rawlin, V. K.

    1976-01-01

    The results of an anlaysis of electron bombardment ion propulsion systems for use in the transportation and on-orbit operations of large space systems are presented. Using baseline technology from the ongoing primary propulsion program and other sources, preliminary estimates of the expected characteristics of key system elements such as thrusters and propellant storage systems were performed. Projections of expected thruster performance on argon are presented based on identified constraints which limit the achievable thrust and/or power density of bombardment thrusters. System characteristics are then evaluated as a function of thruster diameter and specific impulse.

  6. Formation of paramagnetic defects in oxide glasses during the bombardment of their surface with charged particles

    SciTech Connect

    Bogomolova, L.D.; Stefanovsky, S.V.; Teplyakov, Y.G.; Dmitriev, S.A.

    1997-12-31

    In the present work some results of EPR study of point defects formed in silicate, borate, borosilicate, phosphate and other oxide glasses irradiated with different charge particles (C, N, O, Ar, Mn, Cu, Pb) at energy E = 150 keV and large total fluence of ions (up to 10{sup 17} cm{sup {minus}2}) are reported. Electron paramagnetic resonance (EPR) is a very sensitive technique which gives information on the structure of point defects and their content. It is shown that in some cases (for example, in borate glasses) the oxygen hole centers similar to ones observed in {gamma}-irradiated glasses are formed after ion bombardment. However, in the majority of cases new defects which are not typical of {gamma}-irradiated oxide glasses were found. They were large molecular oxygen ions (O{sub 2}{sup {minus}}, O{sub 3}{sup {minus}}, O{sub 4}{sup {minus}}) located in the cavities formed under ion bombardment in the near surface layer of glass. It should be noted that the relative content of these defects is of the order of several tens per 1,000 incident ions. This content decreases with increasing fluence and atomic mass of incident ions. It indicates indirectly that point defects are clustered when the damage of the near surface layer becomes strong. The formation of gaseous oxygen is possible in cavities of the damage surface layer. It was found that some elements (for example C, N and transition metals) form chemical compounds with oxygen. The migration of alkali ions promotes the formation of such compounds since the chemical compounds were detected by means EPR in glasses rich in alkali oxides.

  7. 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...

  8. Accurate Calculation, Prediction, and Assignment of 3 Chemical Shifts of Helium-3-Encapsulated Fullerenes and

    E-print Network

    Wang, Guan-Wu

    -Encapsulated Fullerenes and Fullerene Derivatives Guan-Wu Wang,*, Xin-Hao Zhang, Huan Zhan, Qing-Xiang Guo-3 NMR chemical shifts of various 3 He-encapsulated fullerenes (3 He@Cn) and their derivatives have of the experimental and calculated 3 He NMR chemical shifts over a wide range of 3 He-encapsulated fullerene compounds

  9. Self-Assembled Fullerene-Derivative Monolayers on a Gold Substrate Using Phenanthroline-Au Interactions

    E-print Network

    Tao, Nongjian

    Self-Assembled Fullerene-Derivative Monolayers on a Gold Substrate Using Phenanthroline of the final product, phenanthrolyl[60]fullerene, compound 1, in a 43% isolated yield. Spontaneous self in the formation of a secondary layer of fullerene moieties. Since the fullerene diameter is approximately 1.0 nm

  10. Theory of scanning tunneling spectroscopy of fullerene peapods C. L. Kane,1,3

    E-print Network

    Kane, Charles

    Theory of scanning tunneling spectroscopy of fullerene peapods C. L. Kane,1,3 E. J. Mele,1,3 A. T for fullerene peapods: carbon nanotubes encapsulating molecular C60 . The interaction between tube encapsulated fullerene, with an encapsulated dimer, and with a periodic fullerene peapod lattice

  11. Fullerene-like models for microporous carbon Peter J. F. Harris

    E-print Network

    Harris, Peter J F

    REVIEW Fullerene-like models for microporous carbon Peter J. F. Harris Received: 8 June 2012. The discovery of fullerenes and fullerene-related structures such as carbon nanotubes gave us a new perspective to that of the fullerenes. Recently, evidence in support of such a structure has been obtained using aberration

  12. Energetics and packing of fullerenes in nanotube peapods Mina Yoon,* Savas Berber,

    E-print Network

    Tománek, David

    Energetics and packing of fullerenes in nanotube peapods Mina Yoon,* Savas Berber, and David to study the equilibrium packing of fullerenes in carbon nanotube peapods. Our results for nanotubes containing Cn fullerenes with 60 n 84 atoms indicate that the fullerenes are more densely packed

  13. Topographic and crystallographic characterization of a grazing-ion-bombarded GaAs(110) surface by time-of-flight ion-scattering spectrometry

    SciTech Connect

    Gayone, J.E.; Pregliasco, R.G.; Gomez, G.R.; Sanchez, E.A.; Grizzi, O.

    1997-08-01

    We studied the topography and the atomic structure of a clean GaAs(110) surface by time-of-flight ion-scattering spectrometry (TOF-ISS). In a first series of measurements the surface was cleaned by standard cycles of ion bombardment and annealing (500 eV Ar{sup +}, 500{degree}C). This method was very efficient to remove surface contaminants but not to smooth out the damage produced in TOF-ISS experiments. A cleaning method consisting of grazing bombardment with 20 keV Ar{sup +} combined with annealing at 500{degree}C resulted in a clear improvement of the surface flatness. This was confirmed by measurements of electron energy distributions recorded under grazing proton bombardment and by a topographical analysis with an atomic force microscope. The crystallographic structure of the grazing ion bombarded surface was then studied by TOF-ISS. The quasisingle backscattered intensity measured for 5 keV Ne{sup +} presented strong variations with the incident and azimuthal angles which are consistent with the generally accepted relaxed GaAs(110) surface. From the comparison of critical angles measured and focusing regions calculated with a code recently developed we have obtained an As-Ga first interlayer spacing {Delta}Z=(0.66{plus_minus}0.08){Angstrom}, and the spacings between the first and second As layers {Delta}Z{sub 1,2}{sup As}=(2.25{plus_minus}0.08) {Angstrom} and between the first and second Ga layers {Delta}Z{sub 1,2}{sup Ga}=(1.57{plus_minus}0.1) {Angstrom}. {copyright} {ital 1997} {ital The American Physical Society}

  14. Incomplete Exciton Harvesting from Fullerenes in Bulk Heterojunction Solar

    E-print Network

    McGehee, Michael

    with active layers using a bulk heterojunction structure obtained by blending a polymer donor with a fullerene to phase segregation of the polymer and fullerene. The morphology of the nanostructure is somewhat tunable (P3HT:PCBM), the PCBM emission is extremely weak and its emission spectrum overlaps

  15. Fullerene stability: One rule for the electron-rich...

    NASA Astrophysics Data System (ADS)

    Fowler, Patrick

    2015-11-01

    A vast number of possible isomers exist for each fullerene, yet few are observed experimentally. Neutral fullerenes typically minimize adjacent pentagons, but charged ones often tolerate them. Now, a simple model taking into account structural strain and ? electronic aspects predicts the asymmetric relative stabilities of charged isomers.

  16. Transport of Fullerene Nanoparticles in Saturated Porous Media

    EPA Science Inventory

    The high strength, electrical conductivity, and electron affinity of fullerenes has lead to their utilization in fuel cells and drug-delivery devices, as well as in cosmetics and other applications. Though C60 fullerene is very insoluble in water, studies have shown that C60 ful...

  17. Fullerenes and Noble Gases in the Murchison and Allende Meteorites

    NASA Technical Reports Server (NTRS)

    Becker, Luann; Poreda, Robert J.; Bunch, Ted E.

    2000-01-01

    In this work we report the detection of fullerenes (C60 to C250) in the Murchison and Allende meteorites. By exploiting the unique ability of these molecules to trap noble gases, we have determined that fullerene is indeed a new carrier phase for noble gases in meteorites.

  18. Fullerene derivatives as electron donor for organic photovoltaic cells

    SciTech Connect

    Zhuang, Taojun; Wang, Xiao-Feng E-mail: ziruo@yz.yamagata-u.ac.jp; Sano, Takeshi; Kido, Junji; Hong, Ziruo E-mail: ziruo@yz.yamagata-u.ac.jp; Department of Materials Science and Engineering, University of California, Los Angeles, California 90095 ; Yang, Yang

    2013-11-11

    We demonstrated the performance of unconventional, all-fullerene-based, planar heterojunction (PHJ) organic photovoltaic (OPV) cells using fullerene derivatives indene-C{sub 60} bisadduct (ICBA) and phenyl C{sub 61}-butyric acid methyl ester as the electron donors with fullerene C{sub 70} as the electron acceptor. Two different charge generation processes, including charge generation in the fullerene bulk and exciton dissociation at the donor-acceptor interface, have been found to exist in such all-fullerene-based PHJ cells and the contribution to the total photocurrent from each process is strongly dependent on the thickness of fullerene donor. The optimized 5?nm ICBA/40?nm C{sub 70} PHJ cell gives clear external quantum efficiency responses for the long-wavelength photons corresponding to the dissociation of strongly bound Frenkel excitons, which is hardly observed in fullerene-based single layer reference devices. This approach using fullerene as a donor material provides further possibilities for developing high performance OPV cells.

  19. 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.

  20. Storage of nuclear materials by encapsulation in fullerenes

    DOEpatents

    Coppa, Nicholas V. (Los Alamos, NM)

    1994-01-01

    A method of encapsulating radioactive materials inside fullerenes for stable long-term storage. Fullerenes provide a safe and efficient means of disposing of nuclear waste which is extremely stable with respect to the environment. After encapsulation, a radioactive ion is essentially chemically isolated from its external environment.

  1. Fullerenes Can Induce Toxic Physical Changes of DNA

    NASA Astrophysics Data System (ADS)

    Czerwinski, Fabian; Oddershede, Lene B.

    2008-03-01

    Fullerenes are fascinating symmetric carbon nanostructures. Nowadays, they are widely used because of their characteristic physical and chemical properties. Until now research has mainly been focused on commercial applications of fullerenes. Only a few investigations have addressed the potential biological hazards, one of which is that fullerenes are believed to alter the elastic properties of DNA upon binding. In our experiments we use optical tweezers with sub-piconewton and nanometer resolution to probe the structural changes and the potential damages which fullerenes might induce on single DNA molecules. Therefore, force-extension relations can be obtained under physiological conditions while varying the concentration of different types of fullerenes. It has theoretically been predicted [1], that certain fullerenes can function as a minor-groove binder to double-stranded DNA, thus altering its elastic properties significantly. Fullerenes are capable of causing severe damage inside living organisms by forming DNA regions which are not accessible for proper enzymatic functions. A further goal of the study is to establish fullerenes as a tool for a more detailed investigation of DNA-protein interactions, such as the trafficing of polymerases or the packing by procaryotic proteins. [1] Zhao X, Striolo A, and Cummings PT: C60 Binds to and Deforms Nucleotides. BiophysJ (89):3856-62, 2005.

  2. M Sub-Shell Cross Sections For 75-300 keV Proton Impact On W, Pt And Pb

    SciTech Connect

    Cipolla, Sam J.

    2011-06-01

    M sub-shell x-ray production cross sections from 75-300 keV proton bombardment of thick elemental targets of W, Pt, and Pb were measured and compared with ECPSSR and relativistic RPWBA-BC cross sections using different data bases of fluorescence yields, Coster-Kronig factors, and x-ray transition rates. With a few exceptions, the differences between the various data base comparisons were not significant. For different sub-shells, either ECPSSR or RPWBA-BC compared better with the measurements. In all cases, agreement with theory improved as the collision energy increased.

  3. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. 334.950 Section 334...REGULATIONS § 334.950 Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. (a) The danger...

  4. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. 334.950 Section 334...REGULATIONS § 334.950 Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. (a) The danger...

  5. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. 334.950 Section 334...REGULATIONS § 334.950 Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. (a) The danger...

  6. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. 334.950 Section 334...REGULATIONS § 334.950 Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. (a) The danger...

  7. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. 334.950 Section 334...REGULATIONS § 334.950 Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. (a) The danger...

  8. Functional transient genetic transformation of Arabidopsis leaves by biolistic bombardment

    E-print Network

    Citovsky, Vitaly

    with genetically modified Arabidopsis plants. Floral dip, however, is designed for the production of transgenicFunctional transient genetic transformation of Arabidopsis leaves by biolistic bombardment Shoko. Arabidopsis thaliana is the most widely used model organism for plant biology research due to the availability

  9. Advances in fast-atom-bombardment mass spectroscopy

    SciTech Connect

    Hemling, M.E.

    1986-01-01

    A comparison of fast atom bombardment and field desorption mass spectrometry was made to determine relative sensitivity and applicability. A series of glycosphingolipids and a series of protected oligonucleotides of known structure were analyzed to ascertain the potential utility of fast atom bombardment mass spectrometry in the structural elucidation of novel compounds in these classes. Negative ion mass markers were also developed. Fast atom bombardment was found to be one-to-two orders of magnitude more sensitive than field desorption based on the analysis of a limited number of compounds from several classes. Superior sensitivity was not universal and field desorption was clearly better in certain cases. In the negative ion mode in particular, fast atom bombardment was found to be a useful tool for the determination of the primary structure of glycosphingolipids and oligonucleotides. Carbohydrate sequence and branching information, and a fatty acid and lipid base composition were readily obtained from the mass spectra of glycosphingolipids while bidirectional nucleotide sequence, nucleotide base, and protecting group assignments were obtained for oligonucleotides. Based on this knowledge, a tentative structure of a human peripheral nervous system glycosphingolipid implicated in certain cases of disorders such as amyotrophic lateral sclerosis, Lou Gehrig's Disease, was proposed. Suitable negative ion mass markers were found in dispersions of poly(ethylene) and poly(propylene)glycols in a triethylenetetramine matrix, a matrix which also proved useful in the analysis of glycosphingolipids. These polyglycol dispersions provided ions for calibration to 2300 daltons.

  10. JOVIAN EARLY BOMBARDMENT: PLANETESIMAL EROSION IN THE INNER ASTEROID BELT

    SciTech Connect

    Turrini, D.; Coradini, A.; Magni, G.

    2012-05-01

    The asteroid belt is an open window on the history of the solar system, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions (SFDs). In this work, we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of the primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depends on the SFD of the primordial planetesimals. If the asteroid belt was dominated by planetesimals less than 100 km in diameter, the primordial bombardment would have caused the erosion of bodies smaller than 200 km in diameter. If the asteroid belt was instead dominated by larger planetesimals, the bombardment would have resulted in the destruction of bodies as big as 500 km.

  11. 42nd Bombardment Squadron (Heavy). Monthly Squadron Histories and Documents, 18 July 1942- 7 February 1943 

    E-print Network

    United States Army Air Corps

    1946-01-01

    =ISO-8859-1 42nd Bombardment Squadron (H) Missions: 18 July 1942 ? 7 February 1943. 42nd Bombardment Squadron (H), 11th Bombardment Group (H), 7th Air Force (1941-January 1943); 13th Air Force (January 1943 - ) Air Force...

  12. Stability of carbonaceous dust analogues and glycine under UV irradiation and electron bombardment.

    PubMed

    Maté, Belén; Tanarro, Isabel; Moreno, Miguel A; Jiménez-Redondo, Miguel; Escribano, Rafael; Herrero, Víctor J

    2014-01-01

    The effect of UV photon (120-200 nm) and electron (2 keV) irradiation of analogues of interstellar carbonaceous dust and of glycine were investigated by means of IR spectroscopy. Films of hydrogenated amorphous carbon (HAC), taken as dust analogues, were found to be stable under UV photon and electron bombardment. High fluences of photons and electrons, of the order of 10(19) cm(-2), were needed for a film depletion of a few percent. UV photons were energetically more effective than electrons for depletion and led to a certain dehydrogenation of the HAC samples, whereas electrons led seemingly to a gradual erosion with no appreciable changes in the hydrocarbon structure. The rates of change observed may be relevant over the lifetime of a diffuse cloud, but cannot account for the rapid changes in hydrocarbon IR bands during the evolution of some proto-planetary nebulae. Glycine samples under the same photon and electron fluxes decay at a much faster rate, but tend usually to an equilibrium value different from zero, especially at low temperatures. Reversible reactions re-forming glycine, or the build-up of less transparent products, could explain this behavior. CO2 and methylamine were identified as UV photoproducts. Electron irradiation led to a gradual disappearance of the glycine layers, also with formation of CO2. No other reaction products were clearly identified. The thicker glycine layers (a few hundred nm) were not wholly depleted, but a film of the order of the electron penetration depth (80 nm), was totally destroyed with an electron fluence of -1 x 10(18) cm(-2). A 60 nm ice layer on top of glycine provided only partial shielding from the 2 keV electrons. From an energetic point of view, 2 keV electrons are less efficient than UV photons and, according to literature data, much less efficient than MeV protons for the destruction of glycine. The use of keV electrons to simulate effects of cosmic rays on analogues of interstellar grains should be taken with care, due to the low penetration depths of electrons in many samples of interest. PMID:25302385

  13. Stoichiometric changes of Si, CoSi 2 and TiSi 2 during low energy oxygen bombardment in combination with oxygen bleed-in

    NASA Astrophysics Data System (ADS)

    Brijs, B.; Deleu, J.; Storm, W.; De Coster, W.; Vandervorst, W.

    1996-09-01

    Rutherford backscattering spectrometry was used to investigate the near surface compositional changes and the internal layer variations of Si, CoSi 2 and TiSi 2 during 12 keV O 2+ bombardment with and without oxygen bleed-in. Experiments have been carried out with the angle of incidence between the sputter beam and the normal at 26 and 40°. The results show the incorporation of oxygen, leading to oxide formation, preferential sputtering of Si in the silicides and the formation of a surface oxide during oxygen flooding.

  14. Solitonic fullerene structures in light atomic nuclei

    E-print Network

    R. A. Battye; P. M. Sutcliffe

    2001-02-16

    The Skyrme model is a classical field theory which has topological soliton solutions. These solitons are candidates for describing nuclei, with an identification between the numbers of solitons and nucleons. We have computed numerically, using two different minimization algorithms, minimum energy configurations for up to 22 solitons. We find, remarkably, that the solutions for seven or more solitons have nucleon density isosurfaces in the form of polyhedra made of hexagons and pentagons. Precisely these structures arise, though at the much larger molecular scale, in the chemistry of carbon shells, where they are known as fullerenes.

  15. Current through fullerenes with calcium atom encapsulated

    NASA Astrophysics Data System (ADS)

    Vanaie, Hamidreza; Yaghobi, Mojtaba; Asvar, Adel; Heidari, Ebrahim; Sedaghat, Zahra

    2015-09-01

    A theoretical study of quantum transport through Ca@C60 or Ca2+@C60 molecules is considered by using the non-equilibrium Green’s function (NEGF) formalism. The effects of gate and bias voltages, encapsulation, position and displacement of ion into the cage are important factors in endohedral molecular junction that are considered in the calculations of our study. The current value against the bias voltage, independent of the contacts strength, decreases when the calcium atom lies far from the cage center. Also, negative differential resistance (NDR) behavior is observed when it is in center of fullerene.

  16. Organic hard masks utilizing fullerene derivatives

    NASA Astrophysics Data System (ADS)

    Frommhold, Andreas; Brown, Alan G.; Palmer, Richard E.; Lada, Tom; Robinson, Alex P.

    2015-03-01

    We have developed a series of fullerene containing materials for use as organic hard masks. Films with a thickness of up to 250 nm were deposited via spin coating. After a crosslinking bake the films exhibit good thermal stability - in the best case a mass loss of less than 3% at 400 °C is seen. Etch resistance of the different formulations are presented and hig-hresolution patterning is demonstrated. During the transfer into silicon no adverse "wiggling" is observed at high resolution. We attribute this to the low levels of aliphatic hydrogen present in the materials.

  17. Effects of 70-keV electrons on two polyarylene ether ketones

    NASA Technical Reports Server (NTRS)

    Kingsbury, Kevin B.; Hawkins, Douglas S.; Orwoll, Robert A.; Kiefer, Richard L.; Long, Sheila A. T.

    1989-01-01

    Films prepared from two polyarylene ether ketones with the repeat units -PhC(O)PhC(O)-PhOPhXPhO- where X = C(CH3)2 or CH2 and Ph = C6H4, were bombarded with 70-keV electrons. The effects of irradiation were determined from the fraction of gel formed; the intrinsic viscosities, gel permeation chromatography, and NMR spectroscopy of the soluble portion of the irradiated films; and the changes in the IR spectra of the materials. In a Charlesby-Pinner analysis of the gel fractions of the polyarylene ether ketone with the isopropylidene group, the numbers of scission and cross-linking events per 100 eV (9649 kJ/mol) absorbed were found to be small with G(S) = 0.002 and G(X) = 0.009, respectively.

  18. 200 keV Xe+ ions irradiation effects on Zr-Ti binary films

    NASA Astrophysics Data System (ADS)

    Wang, Weipeng; Chai, Maosheng; Feng, Wei; Li, Zhengcao; Zhang, Zhengjun

    2015-05-01

    200 keV Xenon irradiation experiments were performed on magnetron sputtered Zr-Ti films under different doses up to 9 * 1015 ions/cm2. XRD, FE-SEM, AFM, HRTEM, nano-indentation and white light interferometer characterizations were applied to study the structural and mechanical properties modification introduced by the bombardment. Upon Xenon irradiation, structure of film matrix kept stable while the crystallinity of the top surface degraded significantly. Meanwhile, properties of irradiated films such as hardness, modulus and sheet resistance evolved with the same tendency, i.e. increased firstly and decrease with further increasing the irradiation dose. By selective area irradiation, competition between the surface sputtering and swelling was revealed, by which surface defects evolution was highlighted. The micro-defects evolution during Xenon irradiation was believed to be responsible for the macro-properties' modification.

  19. Process for the removal of impurities from combustion fullerenes

    SciTech Connect

    Alford, J. Michael; Bolskar, Robert

    2005-08-02

    The invention generally relates to purification of carbon nanomaterials, particularly fullerenes, by removal of PAHs and other hydrocarbon impurities. The inventive process involves extracting a sample containing carbon nanomaterials with a solvent in which the PAHs are substantially soluble but in which the carbon nanomaterials are not substantially soluble. The sample can be repeatedly or continuously extracted with one or more solvents to remove a greater amount of impurities. Preferred solvents include ethanol, diethyl ether, and acetone. The invention also provides a process for efficiently separating solvent extractable fullerenes from samples containing fullerenes and PAHs wherein the sample is extracted with a solvent in which both fullerenes and PAHs are substantially soluble and the sample extract then undergoes selective extraction to remove PAHs. Suitable solvents in which both fullerenes and PAHs are soluble include o-xylene, toluene, and o-dichlorobenzene. The purification process is capable of treating quantities of combustion soot in excess of one kilogram and can produce fullerenes or fullerenic soot of suitable purity for many applications.

  20. Fe embedded in ice: The impacts of sublimation and energetic particle bombardment

    NASA Astrophysics Data System (ADS)

    Frankland, Victoria L.; Plane, John M. C.

    2015-05-01

    Icy particles containing a variety of Fe compounds are present in the upper atmospheres of planets such as the Earth and Saturn. In order to explore the role of ice sublimation and energetic ion bombardment in releasing Fe species into the gas phase, Fe-dosed ice films were prepared under UHV conditions in the laboratory. Temperature-programmed desorption studies of Fe/H2O films revealed that no Fe atoms or Fe-containing species co-desorbed along with the H2O molecules. This implies that when noctilucent ice cloud particles sublimate in the terrestrial mesosphere, the metallic species embedded in them will coalesce to form residual particles. Sputtering of the Fe-ice films by energetic Ar+ ions was shown to be an efficient mechanism for releasing Fe into the gas phase, with a yield of 0.08 (Ar+ energy=600 eV). Extrapolating with a semi-empirical sputtering model to the conditions of a proton aurora indicates that sputtering by energetic protons (>100 keV) should also be efficient. However, the proton flux in even an intense aurora will be too low for the resulting injection of Fe species into the gas phase to compete with that from meteoric ablation. In contrast, sputtering of the icy particles in the main rings of Saturn by energetic O+ ions may be the source of recently observed Fe+ in the Saturnian magnetosphere. Electron sputtering (9.5 keV) produced no detectable Fe atoms or Fe-containing species. Finally, it was observed that Fe(OH)2 was produced when Fe was dosed onto an ice film at 140 K (but not at 95 K). Electronic structure theory shows that the reaction which forms this hydroxide from adsorbed Fe has a large barrier of about 0.7 eV, from which we conclude that the reaction requires both translationally hot Fe atoms and mobile H2O molecules on the ice surface.

  1. Continuum simulations of water flow past fullerene molecules

    NASA Astrophysics Data System (ADS)

    Popadi?, A.; Praprotnik, M.; Koumoutsakos, P.; Walther, J. H.

    2015-09-01

    We present continuum simulations of water flow past fullerene molecules. The governing Navier-Stokes equations are complemented with the Navier slip boundary condition with a slip length that is extracted from related molecular dynamics simulations. We find that several quantities of interest as computed by the present model are in good agreement with results from atomistic and atomistic-continuum simulations at a fraction of the cost. We simulate the flow past a single fullerene and an array of fullerenes and demonstrate that such nanoscale flows can be computed efficiently by continuum flow solvers, allowing for investigations into spatiotemporal scales inaccessible to atomistic simulations.

  2. Parameterization of the fullerene coarse-grained model We parameterized a coarse-grained fullerene consistent with the MARTINI coarse-grained force field

    E-print Network

    Wong-Ekkabut, Jirasak

    1 Parameterization of the fullerene coarse-grained model We parameterized a coarse-grained fullerene consistent with the MARTINI coarse-grained force field for lipids1 and proteins2 . In the MARTINI. For fullerene, this means mapping approximately 4 carbons to 1 coarse-grained particle. An initial approximation

  3. Silver(i)-mediated three-component annulation reaction of [60]fullerene, sulfonylhydrazones, and nitriles: leading to diverse disubstituted [60]fullerene-fused dihydropyrroles.

    PubMed

    Chao, Di; Liu, Tong-Xin; Ma, Nana; Zhang, Pengling; Fu, Zheng; Ma, Jinliang; Liu, Qingfeng; Zhang, Fengjin; Zhang, Zhiguo; Zhang, Guisheng

    2016-01-01

    A novel Ag(i)-induced three-component annulation reaction of [60]fullerene with sulfonylhydrazones and nitriles has been developed for the efficient synthesis of diverse disubstituted [60]fullerene-fused dihydropyrroles. The reaction exhibits a broad substrate scope and excellent functional-group tolerance, and also allows for the synthesis of fullerene-bound macromolecules. PMID:26594033

  4. On the 17-keV neutrino

    SciTech Connect

    Hime, A.

    1993-04-01

    A brief review on the status of the 17-keV neutrino is presented. Several different experiments found spectral distortions which were consistently interpreted as evidence for a heavy neutrino admixture in {beta} decay. Recent experiments, however, rule out the existence of a 17-keV neutrino as well as escaping criticisms of earlier null results. Moreover, the majority of positive results have been reinterpreted in terms of instrumental effects, despite the need for a different explanation in each case. Anomalies persist in the low energy region of the tritium spectrum which deserve further investigation.

  5. Feasibility of fullerene waste as carbonaceous adsorbent

    SciTech Connect

    Cleveland, T.G.; Garg, S.; Rixey, W.G.

    1996-03-01

    This note investigates using the waste soot generated in fullerene manufacture as an adsorbent. Both oven-dried and air-activated samples of waste soot are compared with three commercially available powdered activated carbons (PACs): Nuchar-SA, HDH, and Calgon-RC. Three model compounds were chosen for adsorption tests--TCE, Benzene, and Phenol--representing a small branched molecule, a small nonpolar ring molecule, and relatively polar ring molecule. Additionally, the effectiveness of total organic carbon (TOC) removal from wastewater was evaluated. Oven-dried soot performed poorly as compared to the commercial carbons, but activation of the waste soot for 60 min at 450 C in air resulted in an activated carbon (aFWS) with properties similar to those of commercially available PACs. The aFWS performed better than one would predict from the typical characterization measures of iodine number, molasses number, and methylene blue number. The data for phenol suggest some functional groups are created during the activation of the waste soot. These results show that large-scale fullerene manufacturing can be a zero-waste industry, because its primary waste product can be converted into a useful material.

  6. Interaction of C(60) fullerene with lipids.

    PubMed

    Cataldo, Franco

    2010-06-01

    Unsaturated lipids when exposed to air at room temperature undergo a slow autoxidation. When fullerene C(60) was dissolved in selected lipids (ethyl oleate, ethyl linoleate, linseed oil and castor oil) the spectrophotometric analysis shows that the oxidation is concentrated to C(60) which is converted to an epoxide C(60)O. Thus, fullerene C(60) displays antioxidant activity not only when dissolved in unsaturated lipids but also, more generally, when dissolved in unsaturated solvents subjected to autoxidation like, for example, in cyclohexene. The behaviour of C(60) in ethyl oleate has been compared with that of the known antioxidant TMPPD (N,N',N,N,'-tetramethyl-p-phenylenediamine) in ethyl oleate. The mechanism of the antioxidant action of C(60) in lipids has been proposed. The kinetics of C(60) oxidation in lipids was determined spectrophotometrically both at room temperature in the dark and under UV irradiation. The oxidized products derived from C(60) photo-oxidation in lipids have been identified. PMID:20338159

  7. Stress relaxation in unirradiated and in helium ion bombarded glass plates: Dimensional stability

    NASA Astrophysics Data System (ADS)

    Primak, William

    1984-02-01

    The deformation of thin glass plates during bombardment with 140-keV He+ ions was measured with an external capacitor. The contour of the plates was determined interferometrically before irradiation, after irradiation, and after aging for several years. These results showed that the calibration of the capacitor equipment by dead-weight loading a silica plate was faulty. The deflection of a vitreous silica free cantilever on dead-weight loading was measured interferometrically, and the results showed that deformation occurred within the clamp. It was confirmed that placing a ground shield about the electrode of the capacitor increases the calculated deflections. Data for the permanent deformation of a stressed plate of vitreous silica are analyzed, and it is concluded that stress relaxation by a bulk viscoelastic deformation cannot be detected by a change in plate contour because the maximum precision for such a determination could not detect apparent viscosities greater than ˜1029 P. The stress relaxation of the irradiated vitreous silica plates was about 10% in three years corresponding to an apparent post-irradiation viscosity of ˜1020 P. The stress relaxations observed for the other glasses, Pyrex, BK7, and LF2 were much greater, and it is uncertain to what extent they were a viscoelastic effect or an annealing effect. The behavior of a sample of a facsimile radioactive waste storage glass, 76-68 indicated it was not a uniform product; the contour became irregular; hence, these techniques were not appropriate for it.

  8. The effect of electron bombardment on optical properties of n-type silicon

    NASA Astrophysics Data System (ADS)

    Sari, Amir H.; Osman, F.; Ghoranneviss, M.; Hora, H.; Höpfl, R.; Hantehzadeh, M. R.

    2004-10-01

    The production of p-n junctions and polar transistors in silicon to small scale lengths may be possible by plasma and electron beam techniques using the sub-threshold change of n-silicon into p-silicon by electron beam and its reversion at higher electron beam intensities. As a first step, in this study, experimental observation of the effect of electron beam on optical properties of n-type silicon samples is described. Electron bombardment with the energy of 20 keV and different doses in the range of 10 16 to 10 19 electron/cm 2 has been carried out. Use was made of a new design of an electron beam gun as described in details, using a helium obstructed discharge of a concave cold cathode. Optical properties of irradiated samples were determined by a UV-vis-NIR spectrophotometer. The results show an increase in the longer wave length than the fundamental band gap absorption with increasing electron dose.

  9. Intravenous coronary angiography utilizing K-emission and bremsstrahlung X-rays produced by electron bombardment

    SciTech Connect

    1992-12-31

    The screening of the general population for coronary artery disease would be practical if a method existed for visualizing the extent of occlusion after an intravenous injection of contrast agent. Measurements performed with synchrotron radiation at SSRL and NSLS have shown that such an intravenous angiography procedure would be possible with an intense source of monochromatic X-rays. Because of the high cost of an electron synchrotron, theoretical analysis and experiments using inanimate phantoms has been undertaken to demonstrate the feasibility of using the spectrum produced by two appropriately chosen anode materials when bombarded with electrons in the 100--500 keV energy range for angiography. By using the X-rays emitted at 120{degree} to the incident electron direction, about 20--30% of the X-ray intensity would be due to K-emission lines. Calculations using the TIGERP Monte Carlo Code, have shown that high quality angiograms of human coronary arteries should be possible with a contrast agent containing ytterbium, if an electron beam pulses of 16 kJ were used for each anode target. The experimental program supported in part by the DOE has consisted of these theoretical calculations and experiments at the Dynamitron Electron Accelerator Facility at BNL.

  10. Study on the keV neutron capture reaction in 56Fe and 57Fe

    NASA Astrophysics Data System (ADS)

    Wang, Taofeng; Lee, Manwoo; Kim, Guinyun; Ro, Tae-Ik; Kang, Yeong-Rok; Igashira, Masayuki; Katabuchi, Tatsuya

    2014-03-01

    The neutron capture cross-sections and the radiative capture gamma-ray spectra from the broad resonances of 56Fe and 57Fe in the neutron energy range from 10 to 90keV and 550keV have been measured with an anti-Compton NaI(Tl) detector. Pulsed keV neutrons were produced from the 7Li 7Be reaction by bombarding the lithium target with the 1.5ns bunched proton beam from the 3MV Pelletron accelerator. The incident neutron spectrum on a capture sample was measured by means of a time-of-flight (TOF) method with a 6Li -glass detector. The number of weighted capture counts of the iron or gold sample was obtained by applying a pulse height weighting technique to the corresponding capture gamma-ray pulse height spectrum. The neutron capture gamma-ray spectra were obtained by unfolding the observed capture gamma-ray pulse height spectra. To achieve further understanding on the mechanism of neutron radiative capture reaction and study on physics models, theoretical calculations of the -ray spectra for 56Fe and 57Fe with the POD program have been performed by applying the Hauser-Feshbach statistical model. The dominant ingredients to perform the statistical calculation were the Optical Model Potential (OMP), the level densities described by the Mengoni-Nakajima approach, and the -ray transmission coefficients described by -ray strength functions. The comparison of the theoretical calculations, performed only for the 550keV point, show a good agreement with the present experimental results.

  11. Synthesis of [60]fullerene acetals and ketals: reaction of [60]fullerene with aldehydes/ketones and alkoxides.

    PubMed

    Wang, Guan-Wu; Li, Fa-Bao; Chen, Zhong-Xiu; Wu, Ping; Cheng, Bin; Xu, Yu

    2007-06-22

    The reaction of C(60) with propionaldehyde (butyraldehyde or phenylacetaldehyde) and MeONa-MeOH or EtONa-EtOH in anhydrous chlorobenzene in the presence of air at room temperature unexpectedly gave rare fullerene acetals 2aa-cb, while the reaction of C(60) with acetone (acetophenone, cyclohexanone, or cyclopentanone) and MeONa-MeOH or EtONa-EtOH under the same conditions afforded the uncommon fullerene ketals 4aa-db. A possible reaction mechanism for the formation of the fullerene acetals and ketals is proposed based on further experimental results. PMID:17523665

  12. Thermo-mechanical design aspects of mercury bombardment ion thrusters.

    NASA Technical Reports Server (NTRS)

    Schnelker, D. E.; Kami, S.

    1972-01-01

    The mechanical design criteria are presented as background considerations for solving problems associated with the thermomechanical design of mercury ion bombardment thrusters. Various analytical procedures are used to aid in the development of thruster subassemblies and components in the fields of heat transfer, vibration, and stress analysis. Examples of these techniques which provide computer solutions to predict and control stress levels encountered during launch and operation of thruster systems are discussed. Computer models of specific examples are presented.

  13. Enhancing Fullerene-Based Solar Cell Lifetimes by Addition of a Fullerene Dumbbell**

    PubMed Central

    Schroeder, Bob C; Li, Zhe; Brady, Michael A; Faria, Gregório Couto; Ashraf, Raja Shahid; Takacs, Christopher J; Cowart, John S; Duong, Duc T; Chiu, Kar Ho; Tan, Ching-Hong; Cabral, João T; Salleo, Alberto; Chabinyc, Michael L; Durrant, James R; McCulloch, Iain

    2014-01-01

    Cost-effective, solution-processable organic photovoltaics (OPV) present an interesting alternative to inorganic silicon-based solar cells. However, one of the major remaining challenges of OPV devices is their lack of long-term operational stability, especially at elevated temperatures. The synthesis of a fullerene dumbbell and its use as an additive in the active layer of a PCDTBT:PCBM-based OPV device is reported. The addition of only 20?% of this novel fullerene not only leads to improved device efficiencies, but more importantly also to a dramatic increase in morphological stability under simulated operating conditions. Dynamic secondary ion mass spectrometry (DSIMS) and TEM are used, amongst other techniques, to elucidate the origins of the improved morphological stability. PMID:25264304

  14. Simple and Onion-type Fullerenes shells as resonators and amplifiers

    E-print Network

    Amusia, M Ya

    2009-01-01

    We discuss the influence of a single or double fullerenes shell upon photoionization and vacancy decay of an atom, stuffed inside the fullerenes construction. The main manifestations of this influence are additional structures in the photoionization cross-section and variation of the vacancy decay probability. The main mechanisms, with which fullerenes shells affect the processes in caged atoms is the scattering of the outgoing electrons by the fullerenes shell and modification of the photon beam due to fullerenes shell polarization. General consideration will be illustrated by numeric calculations where C60 and C240 will be chosen as fullerenes and Ar and Xe as caged atoms.

  15. Evolution of SiC Nanocluster from Carbon Fullerene: A Density Functional Theoretic Study

    SciTech Connect

    Huda, M. N.; Ray, A. K.

    2008-01-01

    Stability of SiC fullerene type structures is still an unsolved issue as no experimental confirmation has been reported so far regarding its existence. However, theoretical reports are available in the literature where carbon fullerenes were taken as base models for SiC fullerene structures. In this present Letter we show by a systematic study on the C{sub 20} fullerene that this approach may not always produce the ground state structure in fullerene form. Instead, the energetically favorable structure could be highly distorted and open structure. However, we observed a very systematic linear trend in the evolution of binding energies of SiC clusters from the carbon fullerene.

  16. Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers.

    PubMed

    Doshi, Mona; Gesquiere, Andre J

    2015-01-01

    In this article a method for the fabrication and reproducible in-vitro evaluation of conducting polymer nanoparticles blended with fullerene as the next generation photosensitizers for Photodynamic Therapy (PDT) is reported. The nanoparticles are formed by hydrophobic interaction of the semiconducting polymer MEH-PPV (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) with the fullerene PCBM (phenyl-C61-butyric acid methyl ester) in the presence of a non-compatible solvent. MEH-PPV has a high extinction coefficient that leads to high rates of triplet formation, and efficient charge and energy transfer to the fullerene PCBM. The latter processes enhance the efficiency of the PDT system through fullerene assisted triplet and radical formation, and ultrafast deactivation of MEH-PPV excited stated. The results reported here show that this nanoparticle PDT sensitizing system is highly effective and shows unexpected specificity to cancer cell lines. PMID:26556528

  17. Effect of a Fullerene Water Suspension on Bacterial

    E-print Network

    Alvarez, Pedro J.

    Effect of a Fullerene Water Suspension on Bacterial Phospholipids and Membrane Phase Behavior J I, Texas 77005, Department of Civil and Environmental Engineering, Duke University, Durham, North Carolina 27708, and Characterization Facility, Institute of Technology, University of Minnesota, Minneapolis

  18. Synthesis of highly quenching fullerene derivatives for biosensor applications

    E-print Network

    Pérez, Vanessa Virginia, 1981-

    2004-01-01

    This dissertation examines the synthesis of fullerene-based fluorescence quenchers for numerous biosensor applications. The Introduction describes the need for biosensors in our society, what they are and various biosensing ...

  19. Fullerene-Encapsulated Atoms in the Light of Synchrotron Radiation

    SciTech Connect

    Mueller, A.; Schippers, S.; Esteves, D.; Habibi, M.; Phaneuf, R. A.; Kilcoyne, A. L. D.; Aguilar, A.; Dunsch, L.

    2009-12-03

    Mass-selected beams of endohedral fullerene Ce-C{sub 82}{sup +} ions, of atomic Ce{sup q+} ions (q = 2, 3, 4), and of empty fullerene-cage C{sub 82}{sup +} ions were employed to study photoionization of fullerene-encapsulated and free cerium atoms. The Ce 4d inner-shell contributions to single and double ionization of the endohedral Ce-C{sub 82}{sup +} fullerene have been extracted from the data and compared with expectations based on theory and the experiments with atomic Ce ions. Dramatic reduction and redistribution of the ionization contributions to Ce 4d photoabsorption is observed. More than half of the Ce 4d oscillator strength is apparently diverted to additional decay channels of the Ce-C{sub 82}{sup +} complex.

  20. Stabilized-jellium description of neutral and multiply charged fullerenes

    E-print Network

    Yannouleas, Constantine; 10.1016/0009-2614(93)E1404-5

    2010-01-01

    A description of neutral and multiply charged fullerenes is proposed based on a stabilized jellium (structureless pseudopotential) approximation for the ionic background and the local density approximation for the sigma and pi valence electrons. A recently developed shell-correction method is used to calculate total energies and properties of both the neutral and multiply charged anionic and cationic fullerenes. The effect of the icosahedral symmetry is included perturbatively. The calculated single-particle energy level spectrum of C_60 is in good correspondence with experimentally measured ones and previous self-consistent local-density-approximation calculations. For the multiply charged fullerenes, we calculate microscopically the charging energies for up to 12 excess charges. A semiclassical interpretation of these results is developed, which views the fullerenes as Coulomb islands possessing a classical capacitance. The calculated values for the first ionization potential and the first electron affinity...

  1. Production and Consumption of Reactive Oxygen Species by Fullerenes

    EPA Science Inventory

    Reactive oxygen species (ROS) are one of the most important intermediates in chemical, photochemical, and biological processes. To understand the environmental exposure and toxicity of fullerenes better, the production and consumption of ROS (singlet oxygen, superoxide, hydrogen ...

  2. Substantial reduction of Stone-Wales activation barrier in fullerene

    E-print Network

    Kabir, Mohammad Mukul

    Stone-Wales (SW) transformation is a key mechanism responsible for the growth, transformation, and fusion in fullerenes, carbon nanotubes, and other carbon nanostructures. These topological defects also substantially alter ...

  3. The role of fullerene shell upon stuffed atom polarization potential

    E-print Network

    Amusia, M Ya

    2015-01-01

    We have demonstrated that the polarization of the fullerene shell considerably alters the polarization potential of an atom, stuffed inside a fullerene. This essentially affects the electron elastic scattering phases as well as corresponding cross-sections. We illustrate the general trend by concrete examples of electron scattering by endohedrals of Neon and Argon. To obtain the presented results, we have suggested a simplified approach that permits to incorporate the effect of fullerenes polarizability into the Neon and Argon endohedrals polarization potential. As a result, we obtained numeric results that show strong variations in shape and magnitudes of scattering phases and cross-sections due to effect of fullerene polarization upon the endohedral polarization potential.

  4. Role of Conformation in - Interactions and Polymer/Fullerene Miscibility

    SciTech Connect

    Sumpter, Bobby G; Bucknall, David G.; Thio, Yonathan S; Gurun, Bilge; Campbell, Katie

    2011-01-01

    The origin of the miscibility between C60 fullerene and a series of phenylic vinyl polymers has been investigate using a combination of wide-angle x-ray (WAXS) and neutron (WANS) scattering and density functional theory (DFT) computational modeling. The solubility limit of the C60 in the polymers was found to increase non-linearly with increasing phenylic groups in the side-chain from 1 wt% in polystyrene (PS) to 12 wt% in poly(9-vinyl phenanthrene) (P9VPh). The DFT calculations showed that the polymer interacts with the fullerene preferentially with the phenylic groups in these vinyl polymers. However, due to the backbone these phenyl groups are unable to form the energetically favorable T-junction or planar - stacks with the fullerene, and are randomly oriented to the cage. The non-linear increase in solubility is believed to be associated with shape conformity of the three ring phenanthrene to the curvature of the fullerene.

  5. Ground state of antiferromagnetic ordering in fullerene $C_{60}$ molecule

    E-print Network

    C. V. Usenko; V. C. Usenko

    2001-01-15

    Theoretical study of mutual orientation of fullerene $C_{60}$ molecule atom spins is presented in this work. Spin-spin interaction was described by Habbard's model. Existence of antiferromagnetic sturcture of spin sub-system in ground state is found.

  6. Polynuclear aromatic hydrocarbons for fullerene synthesis in flames

    DOEpatents

    Alford, J. Michael; Diener, Michael D.

    2006-12-19

    This invention provides improved methods for combustion synthesis of carbon nanomaterials, including fullerenes, employing multiple-ring aromatic hydrocarbon fuels selected for high carbon conversion to extractable fullerenes. The multiple-ring aromatic hydrocarbon fuels include those that contain polynuclear aromatic hydrocarbons. More specifically, multiple-ring aromatic hydrocarbon fuels contain a substantial amount of indene, methylnapthalenes or mixtures thereof. Coal tar and petroleum distillate fractions provide low cost hydrocarbon fuels containing polynuclear aromatic hydrocarbons, including without limitation, indene, methylnapthalenes or mixtures thereof.

  7. Nanoscale surface structuring during ion bombardment of elemental semiconductors

    NASA Astrophysics Data System (ADS)

    Anzenberg, Eitan

    2013-01-01

    Nano-patterning of surfaces with uniform ion bombardment yields a rich phase-space of topographic patterns. Particle irradiation can cause surface ultra-smoothing or self-organized nanoscale pattern formation in surface topography. Topographic pattern formation has previously been attributed to the effects of the removal of target atoms by sputter erosion. In this thesis, the surface morphology evolution of Si(100) and Ge(100) during low energy ion bombardment of Ar+ and Kr+ ions, respectively, is studied. Our facilities for studies of surface processes at the National Synchrotron Light Source (NSLS) allow in-situ characterization of surface morphology evolution during ion bombardment using grazing incidence small angle x-ray scattering (GISAXS). This technique is used to measure in reciprocal space the kinetics of formation or decay of correlated nanostructures on the surface, effectively measuring the height-height correlations. A linear model is used to characterize the early time kinetic behavior during ion bombardment as a function of ion beam incidence angle. The curvature coefficients predicted by the widely used erosive model of Bradley and Harper are quantitatively negligible and of the wrong sign when compared to the observed effect in both Si and Ge. A mass-redistribution model explains the observed ultra-smoothing at low angles, exhibits an instability at higher angles, and predicts the observed 45° critical angle separating these two regimes in Si. The Ge surface evolution during Kr+ irradiation is qualitatively similar to that observed for Ar+ irradiation of Si at the same ion energy. However, the critical angle for Ge cannot be quantitatively reproduced by the simple mass redistribution model. Crater function theory, as developed by Norris et al., incorporates both mass redistributive and erosive effects, and predicts constraining relationships between curvature coefficients. These constraints are compared to experimental data of both Si and Ge. There is good agreement at low incidence angles; however, at higher angles the data disagrees with the predictions of the crater function formalism. This calls into question the ability of crater function theory to model the surface morphology evolution during ion bombardment.

  8. Time-resolved fluorescence studies of fullerene derivatives.

    PubMed

    Andreoni, Alessandra; Nardo, Luca; Bondani, Maria; Zhao, Baozhong; Roberts, Joan E

    2013-06-20

    Fullerene (nano-C60) and its water-soluble derivatives have several clinical applications including use as a drug carrier to bypass the blood-ocular and blood-brain barriers. However, in vitro and in vivo detection of these nanomaterials is limited by their very low fluorescence quantum yield. The accumulation of fullerene and its derivatives in cells is particularly difficult to measure using standard fluorescence microscopy because their fluorescence is barely detectable in aqueous media. We have developed a time-correlated single-photon counting apparatus with which we were not only able to detect the fluorescence of fullerene and its derivatives in water but could also measure fluorescence temporal decays and determine lifetimes in the range of tens of picoseconds. The compounds studied in this report are C60 (fullerene), the partially hydrogenated hydride C60H36, a monomeric cyclodextrin complexed fullerene [(?-CyD)2/C60], and C60(OH)24 (fullerol). In addition, we examined the effect of aggregation on photophysical properties and identified a very short lifetime component belonging to the fluorescence decay of monomeric fullerene, which is lost with increasing aggregation. These data will help to design nanoparticles that have the appropriate structural and photophysical properties to ultimately be of use in a clinical setting. PMID:23646878

  9. Histopathology of fathead minnow (Pimephales promelas) exposed to hydroxylated fullerenes

    PubMed Central

    Whitley, Elizabeth M.; Pali?, Dušan

    2014-01-01

    Hydroxylated fullerenes are reported to be very strong antioxidants, acting to quench reactive oxygen species, thus having strong potential for important and widespread applications in innovative therapies for a variety of disease processes. However, their potential for toxicological side effects is still largely controversial and unknown. Effects of hydroxylated fullerenes C60(OH)24 on the fathead minnow (Pimephales promelas) were investigated microscopically after a 72-hour (acute) exposure by intraperitoneal injection of 20 ppm of hydroxylated fullerenes per gram of body mass. Cumulative, semi-quantitative histopathologic evaluation of brain, liver, anterior kidney, posterior kidney, skin, coelom, gills and the vestibuloauditory system revealed significant differences between control and hydroxylated fullerene-treated fish. Fullerene-treated fish had much higher cumulative histopathology scores. Histopathologic changes included loss of cellularity in the interstitium of the kidney, a primary site of haematopoiesis in fish, and loss of intracytoplasmic glycogen in liver. In the coelom, variable numbers of leukocytes, including many macrophages and fewer heterophils and rodlet cells, were admixed with the nanomaterial. These findings raise concern about in vivo administration of hydroxylated fullerenes in experimental drugs and procedures in human medicine, and should be investigated in more detail. PMID:23883179

  10. Fullerene derivatives protect endothelial cells against NO-induced damage.

    PubMed

    Lao, Fang; Li, Wei; Han, Dong; Qu, Ying; Liu, Ying; Zhao, Yuliang; Chen, Chunying

    2009-06-01

    Functional fullerene derivatives have been demonstrated with potent antioxidation properties. Nitric oxide (NO) is a free radical that plays a part in leading to brain damage when it is accumulated to a high concentration. The possible scavenging activity of NO by the hydroxylated fullerene derivative C60(OH)22 and malonic acid derivative C60(C(COOH)2)2 was investigated using primary rat brain cerebral microvessel endothelial cells (CMECs). Results demonstrate that sodium nitroprusside (SNP), used as an NO donor, caused a marked decrease in cell viability and an increase in apoptosis. However, fullerene derivatives can remarkably protect against the apoptosis induced by NO assault. In addition, fullerene derivatives can also prevent NO-induced depolymerization of cytoskeleton and damage of the nucleus and accelerate endothelial cell repair. Further investigation shows that the sudden increase of the intercellular reactive oxygen species (ROS) induced by NO was significantly attenuated by post-treatment with fullerene derivatives. Our results suggest that functional fullerene derivatives are potential applications for NO-related disorders. PMID:19433873

  11. Effects of Two Fullerene Derivatives on Monocytes and Macrophages

    PubMed Central

    Pacor, Sabrina; Grillo, Alberto; ?or?evi?, Luka; Zorzet, Sonia; Da Ros, Tatiana; Prato, Maurizio

    2015-01-01

    Two fullerene derivatives (fullerenes 1 and 2), bearing a hydrophilic chain on the pyrrolidinic nitrogen, were developed with the aim to deliver anticancer agents to solid tumors. These two compounds showed a significantly different behaviour on human neoplastic cell lines in vitro in respect to healthy leukocytes. In particular, the pyrrolidinium ring on the fullerene carbon cage brings to a more active compound. In the present work, we describe the effects of these fullerenes on primary cultures of human monocytes and macrophages, two kinds of immune cells representing the first line of defence in the immune response to foreign materials. These compounds are not recognized by circulating monocytes while they get into macrophages. The evaluation of the pronecrotic or proapoptotic effects, analysed by means of analysis of the purinergic receptor P2X7 activation and of ROS scavenging activity, has allowed us to show that fullerene 2, but not its analogue fullerene 1, displays toxicity, even though at concentrations higher than those shown to be active on neoplastic cells. PMID:26090460

  12. Binding of fullerenes to amyloid beta fibrils: size matters.

    PubMed

    Huy, Pham Dinh Quoc; Li, Mai Suan

    2014-10-01

    Binding affinity of fullerenes C20, C36, C60, C70 and C84 for amyloid beta fibrils is studied by docking and all-atom molecular dynamics simulations with the Amber force field and water model TIP3P. Using the molecular mechanic-Poisson Boltzmann surface area method one can demonstrate that the binding free energy linearly decreases with the number of carbon atoms of fullerene, i.e. the larger is the fullerene size, the higher is the binding affinity. Overall, fullerenes bind to A?9-40 fibrils stronger than to A?17-42. The number of water molecules trapped in the interior of 12A?9-40 fibrils was found to be lower than inside pentamer 5A?17-42. C60 destroys A?17-42 fibril structure to a greater extent compared to other fullerenes. Our study revealed that the van der Waals interaction dominates over the electrostatic interaction and non-polar residues of amyloid beta peptides play the significant role in interaction with fullerenes providing novel insight into the development of drug candidates against Alzheimer's disease. PMID:25123396

  13. Fullerene Embedded Shape Memory Nanolens Array

    PubMed Central

    Jeon, Sohee; Jang, Jun Young; Youn, Jae Ryoun; Jeong, Jun-ho; Brenner, Howard; Song, Young Seok

    2013-01-01

    Securing fragile nanostructures against external impact is indispensable for offering sufficiently long lifetime in service to nanoengineering products, especially when coming in contact with other substances. Indeed, this problem still remains a challenging task, which may be resolved with the help of smart materials such as shape memory and self-healing materials. Here, we demonstrate a shape memory nanostructure that can recover its shape by absorbing electromagnetic energy. Fullerenes were embedded into the fabricated nanolens array. Beside the energy absorption, such addition enables a remarkable enhancement in mechanical properties of shape memory polymer. The shape memory nanolens was numerically modeled to impart more in-depth understanding on the physics regarding shape recovery behavior of the fabricated nanolens. We anticipate that our strategy of combining the shape memory property with the microwave irradiation feature can provide a new pathway for nanostructured systems able to ensure a long-term durability. PMID:24253423

  14. Towards a fullerene-based quantum computer

    E-print Network

    Simon C Benjamin; Arzhang Ardavan; G Andrew D Briggs; David A Britz; Daniel Gunlycke; John Jefferson; Mark A G Jones; David F Leigh; Brendon W Lovett; Andrei N Khlobystov; S A Lyon; John J L Morton; Kyriakos Porfyrakis; Mark R Sambrook; Alexei M Tyryshkin

    2005-11-21

    Molecular structures appear to be natural candidates for a quantum technology: individual atoms can support quantum superpositions for long periods, and such atoms can in principle be embedded in a permanent molecular scaffolding to form an array. This would be true nanotechnology, with dimensions of order of a nanometre. However, the challenges of realising such a vision are immense. One must identify a suitable elementary unit and demonstrate its merits for qubit storage and manipulation, including input / output. These units must then be formed into large arrays corresponding to an functional quantum architecture, including a mechanism for gate operations. Here we report our efforts, both experimental and theoretical, to create such a technology based on endohedral fullerenes or 'buckyballs'. We describe our successes with respect to these criteria, along with the obstacles we are currently facing and the questions that remain to be addressed.

  15. Lifetime measurement of the 167.1 keV state in {sup 41}Ar

    SciTech Connect

    White, E. R.; Mach, H.; Fraile, L. M.; Koester, U.; Arndt, O.; Blazhev, A.; Braun, N.; Fransen, C.; Jolie, J.; Boelaert, N.; Borge, M. J. G.; Boutami, R.; Reillo, E.-M.; Tengblad, O.; Bradley, H.; Dlouhy, Z.; Ugryumov, V.; Fynbo, H. O. U.; Hinke, Ch.; Kroell, T.

    2007-11-15

    The Advanced-Time-Delayed method was used to measure lifetimes of the states in {sup 41}Ar populated in the {beta} decay of {sup 41}Cl. The nuclei {sup 41}Cl were produced at ISOLDE by 1.4-GeV proton bombardment of a thick UC{sub x} target and mass-separated as molecular ions, XeCl{sup +}. Our measured half-life of the 167.1-keV state, T{sub 1/2}=315(15) ps, is significantly lower than the previously measured value of 410(30) ps. We have also determined T{sub 1/2}=260(80) ps and T{sub 1/2}{<=}46 ps for the 515.9- and 1867.7-keV states, respectively. These are the shortest lifetimes measured so far with the ultrafast timing method using the new LaBr{sub 3}(Ce) crystals for {gamma}-ray detection.

  16. Photophysical Properties and Singlet Oxygen Generation Efficiencies of Water-Soluble Fullerene Nanoparticles

    PubMed Central

    Stasheuski, Alexander S; Galievsky, Victor A; Stupak, Alexander P; Dzhagarov, Boris M; Choi, Mi Jin; Chung, Bong Hyun; Jeong, Jin Young

    2014-01-01

    As various fullerene derivatives have been developed, it is necessary to explore their photophysical properties for potential use in photoelectronics and medicine. Here, we address the photophysical properties of newly synthesized water-soluble fullerene-based nanoparticles and polyhydroxylated fullerene as a representative water-soluble fullerene derivative. They show broad emission band arising from a wide-range of excitation energies. It is attributed to the optical transitions from disorder-induced states, which decay in the nanosecond time range. We determine the kinetic properties of the singlet oxygen (1O2) luminescence generated by the fullerene nanoparticles and polyhydroxylated fullerene to consider the potential as photodynamic agents. Triplet state decay of the nanoparticles was longer than 1O2 lifetime in water. Singlet oxygen quantum yield of a series of the fullerene nanoparticles is comparably higher ranging from 0.15 to 0.2 than that of polyhydroxylated fullerene, which is about 0.06. PMID:24893622

  17. Cage connectivity and frontier ? orbitals govern the relative stability of charged fullerene isomers.

    PubMed

    Wang, Yang; Díaz-Tendero, Sergio; Alcamí, Manuel; Martín, Fernando

    2015-11-01

    Fullerene anions and cations have unique structural, electronic, magnetic and chemical properties that make them substantially different from neutral fullerenes. Although much theoretical effort has been devoted to characterizing and predicting their properties, this has been limited to a fraction of isomeric forms, mostly for fullerene anions, and has practically ignored fullerene cations. Here we show that the concepts of cage connectivity and frontier ? orbitals allow one to understand the relative stability of charged fullerene isomers without performing elaborate quantum chemistry calculations. The latter is not a trivial matter, as the number of possible isomers for a medium-sized fullerene is many more than 100,000. The model correctly predicts the structures observed experimentally and explains why the isolated pentagon rule is often violated for fullerene anions, but the opposite is found for fullerene cations. These predictions are relevant in fields as diverse as astrophysics, electrochemistry and supramolecular chemistry. PMID:26492014

  18. Cage connectivity and frontier ? orbitals govern the relative stability of charged fullerene isomers

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Díaz-Tendero, Sergio; Alcamí, Manuel; Martín, Fernando

    2015-11-01

    Fullerene anions and cations have unique structural, electronic, magnetic and chemical properties that make them substantially different from neutral fullerenes. Although much theoretical effort has been devoted to characterizing and predicting their properties, this has been limited to a fraction of isomeric forms, mostly for fullerene anions, and has practically ignored fullerene cations. Here we show that the concepts of cage connectivity and frontier ? orbitals allow one to understand the relative stability of charged fullerene isomers without performing elaborate quantum chemistry calculations. The latter is not a trivial matter, as the number of possible isomers for a medium-sized fullerene is many more than 100,000. The model correctly predicts the structures observed experimentally and explains why the isolated pentagon rule is often violated for fullerene anions, but the opposite is found for fullerene cations. These predictions are relevant in fields as diverse as astrophysics, electrochemistry and supramolecular chemistry.

  19. Photophysical properties and singlet oxygen generation efficiencies of water-soluble fullerene nanoparticles.

    PubMed

    Stasheuski, Alexander S; Galievsky, Victor A; Stupak, Alexander P; Dzhagarov, Boris M; Choi, Mi Jin; Chung, Bong Hyun; Jeong, Jin Young

    2014-01-01

    As various fullerene derivatives have been developed, it is necessary to explore their photophysical properties for potential use in photoelectronics and medicine. Here, we address the photophysical properties of newly synthesized water-soluble fullerene-based nanoparticles and polyhydroxylated fullerene as a representative water-soluble fullerene derivative. They show broad emission band arising from a wide-range of excitation energies. It is attributed to the optical transitions from disorder-induced states, which decay in the nanosecond time range. We determine the kinetic properties of the singlet oxygen ((1)O2) luminescence generated by the fullerene nanoparticles and polyhydroxylated fullerene to consider the potential as photodynamic agents. Triplet state decay of the nanoparticles was longer than (1)O2 lifetime in water. Singlet oxygen quantum yield of a series of the fullerene nanoparticles is comparably higher ranging from 0.15 to 0.2 than that of polyhydroxylated fullerene, which is about 0.06. PMID:24893622

  20. Exploring the Early Bombardment of the Inner Solar System

    NASA Astrophysics Data System (ADS)

    Bottke, W.

    2014-04-01

    The early bombardment history of the Inner Solar System is recorded in a number of interesting places (e.g., the surprisingly high abundance of highly siderophile abundances found in the Earth, Moon, and Mars, the observed impact basins found on Mercury, the Moon and Mars, various properties of main belt asteroids and meteorites, etc.). To date, two dominant scenarios have been used to explain these constraints: (i) most impacts came from the tail end of a monotonically-decreasing impactor population created by planet formation processes, and (ii) most impacts were produced by a terminal cataclysm that caused a spike in the impactor flux starting ~4 Gy ago. Interestingly, using numerical studies linked to the available constraints, we find that both scenarios are needed to explain observations. For (i), we will show that leftover planetesimals from the terrestrial planet region were long-lived enough to hit various worlds long after the end of core formation. The record left behind can be used in interesting ways to probe the nature of terrestrial planet formation. For (ii), we will explore new applications of the so-called Nice model, which provides a plausible dynamical mechanism capable of creating a spike of comets/asteroid impactors. Our results suggest that many "late heavy bombardment" impactors came from an unexpected source, and that they possibly continued to hit Earth, Venus, and Mars well after basin formation terminated on the Moon. Interestingly, the history of the Hadean Earth (ca. 4.0-4.5 billion years ago) may be closely linked to this bombardment. With few known rocks older than ~3.8 Ga, the main constraints from this era come from ancient submillimeter zircon grains. Using our bombardment model, we will argue that the surface of the Hadean Earth was widely reprocessed by impacts through mixing and heating of its uppermost layers. This model not only may explains the Pb-Pb age distribution of ancient zircons but also the absence of most early terrestrial rocks. We predict life originating in the Hadean would need to be both hardy and mobile enough to survive these extreme conditions.

  1. Electron-bombarded CCD detectors for ultraviolet atmospheric remote sensing

    NASA Technical Reports Server (NTRS)

    Carruthers, G. R.; Opal, C. B.

    1983-01-01

    Electronic image sensors based on charge coupled devices operated in electron-bombarded mode, yielding real-time, remote-readout, photon-limited UV imaging capability are being developed. The sensors also incorporate fast-focal-ratio Schmidt optics and opaque photocathodes, giving nearly the ultimate possible diffuse-source sensitivity. They can be used for direct imagery of atmospheric emission phenomena, and for imaging spectrography with moderate spatial and spectral resolution. The current state of instrument development, laboratory results, planned future developments and proposed applications of the sensors in space flight instrumentation is described.

  2. 40 CFR 721.10270 - [5,6]Fullerene-C84-D2d.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false [5,6]Fullerene-C84-D2d. 721.10270 Section...Substances § 721.10270 [5,6]Fullerene-C84-D2d. (a) Chemical substance...chemical substance identified as [5,6]Fullerene-C84-D2d (PMN...

  3. 40 CFR 721.10270 - [5,6]Fullerene-C84-D2d.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false [5,6]Fullerene-C84-D2d. 721.10270 Section...Substances § 721.10270 [5,6]Fullerene-C84-D2d. (a) Chemical substance...chemical substance identified as [5,6]Fullerene-C84-D2d (PMN...

  4. 2.8 Carbon Nanotubes (Fullerenes) 2.8.1 Background

    E-print Network

    to as "buckyballs". Fullerenes were the seventh allotropic form of carbon to be discovered (together with the two85 2.8 Carbon Nanotubes (Fullerenes) 2.8.1 Background After long being available only in research or apparently under consideration, though the concept has been discussed. Carbon nanotubes and fullerenes

  5. Free Carrier Generation in Fullerene Acceptors and Its Effect on Polymer Photovoltaics

    E-print Network

    McGehee, Michael

    Free Carrier Generation in Fullerene Acceptors and Its Effect on Polymer Photovoltaics George F is this also true for many of the soluble fullerene derivatives commonly used in organic photovoltaics of free carrier generation in fullerenes can have a significant impact on the interpretation of data

  6. Design of a Supercritical Fluid Expansion Source for Gas-Phase Spectroscopy of Fullerenes

    E-print Network

    McCall, Benjamin J.

    Design of a Supercritical Fluid Expansion Source for Gas-Phase Spectroscopy of Fullerenes of Illinois Bradley M. Gibson 20 February 2013 271 RAL 2:00 PM #12;I. Introduction The fullerenes, including C-poor and also presented data showing fullerene and PAH emission features together in other planetary nebulae

  7. FT-ICR studies of metal-carbon binary clusters for formation mechanism of endohedral fullerene

    E-print Network

    Maruyama, Shigeo

    FT-ICR studies of metal-carbon binary clusters for formation mechanism of endohedral fullerene the clustering process of endohedral metallo-fullerene (Figure 1). Cluster beams were generated by laser-vaporizations of various sample materials used for arc-discharge generation of metal- containing fullerene and SWNT (single

  8. Interpolation Method and Topological Indices: The case of Fullerenes C12k+4

    E-print Network

    Klavzar, Sandi

    Interpolation Method and Topological Indices: The case of Fullerenes C12k+4 Yaser Alizadeh are pointed out. This is illustrated on fullerenes C12k+4 and four topological in- dices: the Wiener index topological indices of fullerenes C12k+4. We conclude the paper by giving related formulas for cyclic

  9. Real Time Microscopy, Kinetics, and Mechanism of Giant Fullerene Evaporation J. Y. Huang*

    E-print Network

    Powles, Rebecca

    Real Time Microscopy, Kinetics, and Mechanism of Giant Fullerene Evaporation J. Y. Huang* Center microscopy observing the shrinkage of single- layer giant fullerenes (GF). At temperatures 2000 C, the GF volume reduces by greater than one 100-fold while the fullerene shell remains intact, evolving from

  10. Implications and potential applications of bactericidal fullerene water suspensions: effect of nC60 concentration,

    E-print Network

    Alvarez, Pedro J.

    Implications and potential applications of bactericidal fullerene water suspensions: effect of nC60, Houston, TX 77005, USA E-mail: alvarez@rice.edu Stable fullerene water suspensions (nC60) exhibited potent and microbial control. Key words | bacteria, fullerenes, nanomaterial, nC60 INTRODUCTION With the current

  11. Interpolation Method and Topological Indices: The case of Fullerenes C 12k+4

    E-print Network

    Klavzar, Sandi

    Interpolation Method and Topological Indices: The case of Fullerenes C 12k+4 Yaser Alizadeh are pointed out. This is illustrated on fullerenes C 12k+4 and four topological indices: the Wiener index of fullerenes C 12k+4 . We conclude the paper by giving related formulas for cyclic phenylenes. Let G

  12. Comparison of protons, carbon and fullerene impacts on a carbon cylinder

    E-print Network

    Webb, Roger P.

    Comparison of protons, carbon and fullerene impacts on a carbon cylinder R.P. Webb *, I.H. Wilson between the impacts of protons, carbon atoms and fullerene molecules on an elongated strong of carbon; 887.15.K; 36.40 Keywords: Ion beams; Molecular dynamics simulation; Carbon; DNA; Fullerene 1

  13. FULLERENE, WHICH IS ALSO KNOWN AS A BUCKYBALL, exhibits a hollow sphere

    E-print Network

    Aazhang, Behnaam

    TECH BEAT FULLERENE, WHICH IS ALSO KNOWN AS A BUCKYBALL, exhibits a hollow sphere cage structure of graphite and is remarkably stable. Since fullerene was discovered in 1985, this compound has been evalu- fullerenes. Our initial work showed that hydroxyfullerenes chelate ferric ions (Fe3+ ) to form a water

  14. Bimolecular Crystals of Fullerenes in Conjugated Polymers and the Implications of Molecular Mixing for Solar Cells

    E-print Network

    McGehee, Michael

    Bimolecular Crystals of Fullerenes in Conjugated Polymers and the Implications of Molecular Mixing) (MDMO-PPV)) and an electron accepting fullerene (either phenyl-c61- butyric acid methyl ester (PC[61]BM of polymer:fullerene BHJ solar cells have been explored and it has been found that some systems optimize

  15. Charge Transfer and Chemisorption of Fullerene Molecules on Metal Surfaces: Application to Dynamics of Nanocars

    E-print Network

    Charge Transfer and Chemisorption of Fullerene Molecules on Metal Surfaces: Application to Dynamics Information ABSTRACT: It is widely believed that the dynamics of surface-bound fullerene molecules theoretical approach to describe charge transfer and chemisorption processes for fullerenes on gold surfaces

  16. Ultrafast conductivity in a low-band-gap polyphenylene and fullerene blend studied by terahertz spectroscopy

    E-print Network

    Ku?el, Petr

    Ultrafast conductivity in a low-band-gap polyphenylene and fullerene blend studied by terahertz-band-gap polyphenylene copolymer and fullerene derivative. The optical excitation pulse generates free holes delocalized in these systems. The pri- mary excitation in polymer/fullerene bulk heterojunctions is an exciton on the polymer

  17. Chemical reaction of metal-fullerene in gas phase (2) >Masamichi Konoa

    E-print Network

    Maruyama, Shigeo

    f18-068 Chemical reaction of metal-fullerene in gas phase (2) ·>Masamichi Konoa , Syuhei Inoueb.of Tokyo Since the discovery of macroscopic generation and purification procedure of fullerenes and endohedral fullerenes, the geometric structure and the formation mechanism of them has been one of the most

  18. Ni-dispersed fullerenes: Hydrogen storage and desorption properties Weon Ho Shin and Seong Ho Yang

    E-print Network

    Goddard III, William A.

    Ni-dispersed fullerenes: Hydrogen storage and desorption properties Weon Ho Shin and Seong Ho Yang; published online 31 January 2006 Our study shows that the H2 storage media using Ni-dispersed fullerenes on the fullerene surface can store up to three H2 molecules. Consequently, at high Ni coverage, Ni

  19. Ultrafast nonresonant third-order optical nonlinearity of fullerene-containing polyurethane films at telecommunication wavelengths

    E-print Network

    Sargent, Edward H. "Ted"

    Ultrafast nonresonant third-order optical nonlinearity of fullerene- containing polyurethane films a high load of 60 fullerene (C60) were prepared by reaction of the hydroxy-containing C60 fullerene films with the capacity to realize a high number density of C60 moieties. These resulted in more

  20. ON THE NUMERICAL SIMULATION OF FULLERENE NANOTUBES: C 100:000:000 AND BEYOND !

    E-print Network

    Burstedde, Carsten

    ON THE NUMERICAL SIMULATION OF FULLERENE NANOTUBES: C 100:000:000 AND BEYOND ! ATTILA CAGLAR properties of fullerenes and especially nanotubes in experiments is very difficult. Here, computer of our numerical experiments. We considered the reactive collision of C 60 fullerenes with benzyne and

  1. Creation of a gradient polymer-fullerene interface in photovoltaic devices by thermally controlled interdiffusion

    E-print Network

    Heflin, Randy

    Creation of a gradient polymer-fullerene interface in photovoltaic devices by thermally controlled 24062-1704 Received 29 July 2002; accepted 27 September 2002 Efficient polymer-fullerene photovoltaic the semiconducting polymer to the fullerene acceptor. We describe studies in which a bilayer system consisting

  2. Substituent and solvent e ects on photoexcited states of functionalized fullerene[60

    E-print Network

    Huang, Yanyi

    Substituent and solvent eþ ects on photoexcited states of functionalized fullerene[60] Chuping Luo and photophysical properties of fullerenes, such as and have been widely investigated in recentC 60 C 70 , years.1h6 in material and biological science.7h12 Fullerene chemistry has also been developed by the introduction

  3. Printed on November 11, 1993 Collective electronic excitations in carbon fullerene clusters

    E-print Network

    Tománek, David

    Printed on November 11, 1993 Collective electronic excitations in carbon fullerene clusters David fullerenes in bulk quantities [2] has triggered an enormous interest in the scientific community in these systems. All fullerenes have a hollow graphitic shell structure composed of three-fold coordinated carbon

  4. Parametrization and Application of a Coarse Grained Force Field for Benzene/Fullerene Interactions with Lipids

    E-print Network

    Nielsen, Steven O.

    Parametrization and Application of a Coarse Grained Force Field for Benzene/Fullerene Interactions Recently, we reported new coarse grain (CG) force fields for lipids and phenyl/fullerene based molecules. In the C60 lipid systems, the fullerenes were shown to aggregate even at the lowest concentrations

  5. Impact of Local Curvature and Structural Defects on Graphene-C60 Fullerene Fusion Reaction Barriers

    E-print Network

    Deymier, Pierre

    Impact of Local Curvature and Structural Defects on Graphene-C60 Fullerene Fusion Reaction Barriers the energetics of the graphene-C60 fullerene fusion. We show that there is an optimal value of the bond systems. Specifically, chemical attachment of a C60 fullerene to a single-layer graphene sheet

  6. A semi-empirical molecular orbital study of freestanding and fullerene-encapsulated Mo nanoclusters

    E-print Network

    Elliott, James

    A semi-empirical molecular orbital study of freestanding and fullerene-encapsulated Mo nanoclusters as implemented in the VAMP module of Materials Studiow , of both freestanding and fullerene by opening of hexagon­hexagon (6­6) carbon bonds that lead eventually to a splitting open of the fullerene

  7. Fullerene doped glasses Fucheng Lin, Sen Mao, Zhicong Meng, and Heping Zeng

    E-print Network

    Guo, Ting

    Fullerene doped glasses Fucheng Lin, Sen Mao, Zhicong Meng, and Heping Zeng Shanghai Institute 1994; accepted for publication 15 September 1994 Optical glasses doped with a fullerene mixture of C60/C70 were made in our lab. Three peaks, corresponding to C60, C70, and a modified fullerene possibly

  8. Relative stabilities of fullerene, cumulene, and polyacetylene structures for C,:n=18-60

    E-print Network

    Simons, Jack

    Relative stabilities of fullerene, cumulene, and polyacetylene structures for C,:n=18-60 Martin) primitive orbital basis set, contracted to [ 3~2~1. For n>32, the fullerenes are predicted to be the most of the fullerene structures are expected to be lowered even further as larger basis sets are employed. Hence

  9. Electron and Hole Contributions to the Terahertz Photoconductivity of a Conjugated Polymer:Fullerene Blend Identified

    E-print Network

    Ku?el, Petr

    Electron and Hole Contributions to the Terahertz Photoconductivity of a Conjugated Polymer:Fullerene, negative charges are transferred to fullerenes, while positive polarons remain on polymers/monomers. Vastly/ fullerene bulk heterojunction systems,2 comprehensive study focusing on the charge transport on the earliest

  10. 40 CFR 721.10267 - [5,6]Fullerene-C60-Ih.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fullerene-C60-Ih. 721.10267 Section... Substances § 721.10267 Fullerene-C60-Ih. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Fullerene-C60-Ih (PMN P-09-54; CAS No. 99685-96-8)...

  11. Remarks on the Relations Between the Permanental and Characteristic Polynomials of Fullerenes

    E-print Network

    Bai, Fengshan

    Remarks on the Relations Between the Permanental and Characteristic Polynomials of Fullerenes Qiang of characteristic polynomial of fullerene graph are proposed by Balasubramanian [17]. Then some relations between]. In this paper, some more formulas on ak and bk and the relations between them are given for fullerene graph. 2

  12. A Molecular Dynamics Simulation of Metal-Containing Fullerene Formation Yasushi Shibutaa

    E-print Network

    Maruyama, Shigeo

    A Molecular Dynamics Simulation of Metal-Containing Fullerene Formation Yasushi Shibutaa and Shigeo dynamics simulations of the clustering process of carbon atoms to investigate the fullerene formation mechanism [1,2], and a new formation model of empty fullerene including the temperature effect was proposed

  13. A Molecular Dynamics Simulation for the Formation Mechanism of Fullerene Shigeo Maruyama and Yasutaka Yamaguchi

    E-print Network

    Maruyama, Shigeo

    A Molecular Dynamics Simulation for the Formation Mechanism of Fullerene Shigeo Maruyama and Yasutaka Yamaguchi Abstract The formation mechanism of fullerene, the new type of carbon molecule to investigate the formation mechanism of fullerene, the clustering process starting from isolated carbon atoms

  14. Importance of the Donor:Fullerene Intermolecular Arrangement for High-Efficiency Organic Photovoltaics

    E-print Network

    McGehee, Michael

    Importance of the Donor:Fullerene Intermolecular Arrangement for High-Efficiency Organic are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis

  15. Addition Energies of Fullerenes and Carbon Nanotubes as Quantum Dots: The Role of Symmetry

    E-print Network

    Baranger, Harold U.

    Addition Energies of Fullerenes and Carbon Nanotubes as Quantum Dots: The Role of Symmetry San calculations, we investigate the addition energy (AE) of quantum dots formed of fullerenes or closed single. In the highly symmetric fullerenes the oscillation period is large because of the large level degeneracy

  16. MOLECULAR SIMULATIONS OF THE FORMATION PROCESS OF FULLERENE Yasutaka YAMAGUCHI and Shigeo MARUYAMA

    E-print Network

    Maruyama, Shigeo

    MOLECULAR SIMULATIONS OF THE FORMATION PROCESS OF FULLERENE Yasutaka YAMAGUCHI and Shigeo MARUYAMA. The formation mechanism of fullerene, a new type of carbon molecule with hollow caged structure, was studied, yielding the graphitic sheet for Tc fullerene-like caged structure for 2600 K

  17. Express Letter Fullerene-like carbon nanostructures in the Allende meteorite

    E-print Network

    Harris, Peter J F

    Express Letter Fullerene-like carbon nanostructures in the Allende meteorite P.J.F. Harris aY *, R. These closed particles, which are probably fullerene-like in structure, are strong candidates to be carriers of planetary gases. ß 2000 Elsevier Science B.V. All rights reserved. Keywords: fullerenes; molecular structure

  18. Molecular Packing and Solar Cell Performance in Blends of Polymers with a Bisadduct Fullerene

    E-print Network

    McGehee, Michael

    Molecular Packing and Solar Cell Performance in Blends of Polymers with a Bisadduct Fullerene with the conventional electron acceptor phenyl-C61-butyric acid methyl ester (PCBM) to fullerenes with one to three indene adducts. We find that the multiadduct fullerenes with lower electron affinity improve

  19. Leaving the fullerene road: presence and stability of sp chains in sp2

    E-print Network

    Powles, Rebecca

    Leaving the fullerene road: presence and stability of sp chains in sp2 carbon clusters and cluster carbon sp chains are essential ingredients for the formation of carbon fullerenes and nanotubes [6, 7 identified as a fundamental ingredient to transform sp structures into fullerenes and nanotubes

  20. Saturated Ionization of Fullerenes in Intense Laser Fields A. Jaron-Becker,1,2

    E-print Network

    Becker, Andreas

    Saturated Ionization of Fullerenes in Intense Laser Fields A. Jaron´-Becker,1,2 A. Becker,2 and F the ionization of icosahedral fullerenes (C20, C60, C80, and C180) in an intense laser pulse using the S saturation intensities of the Buckminster fullerene and its multiply charged ions. Our analysis strongly

  1. Thermal Contraction of Carbon Fullerenes and Nanotubes Young-Kyun Kwon,* Savas Berber, and David Tomanek

    E-print Network

    Tománek, David

    Thermal Contraction of Carbon Fullerenes and Nanotubes Young-Kyun Kwon,* Savas Berber, and David to study shape changes of carbon fullerenes and nanotubes with increasing temperature. At moderate [8,9] such as NaTi2P3O12 and ZrW2O8. Since carbon fullerenes and nanotubes consist of sp2 bonded

  2. Comparison of bond character in hydrocarbons and fullerenes D. W. Snoke

    E-print Network

    Snoke, David

    Comparison of bond character in hydrocarbons and fullerenes D. W. Snoke Department of Physics a comparison of the bond polarizabilities for carbon-carbon bonds in hydrocarbons and fullerenes, using two different models for the fullerene Raman spectrum and the results of Raman measure- ments on ethane

  3. Study of a hydrogen-bombardment process for molecular cross-linking within thin films

    SciTech Connect

    Liu, Y.; Yang, J.; Yang, D. Q.; Nie, H.-Y.; Lau, W. M.

    2011-02-21

    A low-energy hydrogen bombardment method, without using any chemical additives, has been designed for fine tuning both physical and chemical properties of molecular thin films through selectively cleaving C-H bonds and keeping other bonds intact. In the hydrogen bombardment process, carbon radicals are generated during collisions between C-H bonds and hydrogen molecules carrying {approx}10 eV kinetic energy. These carbon radicals induce cross-linking of neighboring molecular chains. In this work, we focus on the effect of hydrogen bombardment on dotriacontane (C{sub 32}H{sub 66}) thin films as growing on native SiO{sub 2} surfaces. After the hydrogen bombardment, XPS results indirectly explain that cross-linking has occurred among C{sub 32}H{sub 66} molecules, where the major chemical elements have been preserved even though the bombarded thin film is washed by organic solution such as hexane. AFM results show the height of the perpendicular phase in the thin film decreases due to the bombardment. Intriguingly, Young's modulus of the bombarded thin films can be increased up to {approx}6.5 GPa, about five times of elasticity of the virgin films. The surface roughness of the thin films can be kept as smooth as the virgin film surface after thorough bombardment. Therefore, the hydrogen bombardment method shows a great potential in the modification of morphological, mechanical, and tribological properties of organic thin films for a broad range of applications, especially in an aggressive environment.

  4. Dynamical Structures in Phase-Separated Films Deposited under Ion Bombardment

    SciTech Connect

    He, J. H.; Carosella, C. A.; Hubler, G. K.; Knies, D. L.; Qadri, S. B.; Grabowski, K. S.

    2009-03-10

    We report our experimental observation of ion bombardment effect on the film structures generated by co-evaporation of Au and silica. Three states are identified depending on the incident ion energy and beam current. Moderate ion bombardment creates nanoscale compositional modulations along the film growth direction. Strong ion bombardment induces disappearance of the compositional modulations. At still higher energy and flux, energetic ions sputter away all deposited atoms. The observed phenomena reflect synergistic effects of ion bombardment on the film growth in phase separated systems. Our observations suggest that ion beams can be employed to control the film structures in the deposition of phase-separated films.

  5. Molecular dynamics studies of the C(60) fullerene associations in aqueous solutions and a biological membrane

    NASA Astrophysics Data System (ADS)

    Li, Liwei

    The associative behavior of C60 fullerenes in water and a biological membrane was studied using computer molecular dynamics (MD) simulations. Multiple histogram method combined with umbrella sampling technique was used in calculating the fullerene pairwise free energy as a function of separation. It was observed that water wets the fullerene surface due to the high fullerene atomic density and therefore the strong fullerene-water dispersion interaction. Despite the fact of the insolubility of fullerenes, water was found to promote the dispersion of fullerenes in aqueous solution. A decomposition of the solvent-induced potential of mean force between fullerenes into entropy and energy (enthalpy) contributions revealed that the water-induced repulsion between fullerenes is energetic in origin, contrasting strongly to entropy-driven association observed for conventional non-polar solutes. The repulsive interaction was observed to decrease at elevated temperature due to an increasing contribution from a relatively weak entropy-driven association. The surface curvature effect was surveyed by studying nanoparticles of different shapes (fullerene, carbon nanotubes and graphenes) with similar chemical structures. As for a potential application of fullerene in biomedical systems, the poly(ethylene oxide) (PEO) modified fullerene derivative interactions in aqueous solution and the bare fullerene-fullerene interactions inside a dimyristoylphosphatidylcholine (DMPC) lipid bilayer were investigated. It shows that while the attraction between two PEO-modified fullerenes is stronger and longer range than that between two bare C60 fullerenes in aqueous solution, the PEO-modified fullerenes do not phase-separate in water but rather aggregate in chainlike clusters at concentrations where unmodified fullerenes completely phase-separate. The results of pairwise fullerene interactions inside a DMPC lipid shows that fullerenes, constrained in the same lateral plane, was found to be significantly less attractive inside the lipid bilayer than in an alkane melt of the same molecular weight as the surfactant tails. Contrasting to small hydrophobic solutes, fullerene situates off the bilayer center in favor of the stronger dispersion interactions with the denser region of the bilayer.

  6. Thermal Science & Engineering Vol.3 No.3 (1995) A Molecular Dynamics Simulation for the Formation Mechanism of Fullerene*

    E-print Network

    Maruyama, Shigeo

    1995-01-01

    Mechanism of Fullerene* Shigeo MARUYAMA and Yasutaka YAMAGUCHI Abstract The formation mechanism of fullerene vaporization fullerene generation, we have calculated the clustering process starting from randomly located yielded the hollow caged carbon network which could be regarded as an imperfect fullerene. Intermediate

  7. New concepts and applications in the macromolecular chemistry of fullerenes.

    PubMed

    Giacalone, Francesco; Martín, Nazario

    2010-10-01

    A new classification on the different types of fullerene-containing polymers is presented according to their different properties and applications they exhibit in a variety of fields. Because of their interest and novelty, water-soluble and biodegradable C(60)-polymers are discussed first, followed by polyfullerene-based membranes where unprecedented supramolecular structures are presented. Next are compounds that involve hybrid materials formed from fullerenes and other components such as silica, DNA, and carbon nanotubes (CNTs) where the most recent advances have been achieved. A most relevant topic is still that of C(60)-based donor-acceptor (D-A) polymers. Since their application in photovoltaics D-A polymers are among the most realistic applications of fullerenes in the so-called molecular electronics. The most relevant aspects in these covalently connected fullerene/polymer hybrids as well as new concepts to improve energy conversion efficiencies are presented.The last topics disccused relate to supramolecular aspects that are in involved in C(60)-polymer systems and in the self-assembly of C(60)-macromolecular structures, which open a new scenario for organizing, by means of non-covalent interactions, new supramolecular structures at the nano- and micrometric scale, in which the combination of the hydrofobicity of fullerenes with the versatility of the noncovalent chemistry afford new and spectacular superstructures. PMID:20799291

  8. Rotor-stator molecular crystals of fullerenes with cubane

    NASA Astrophysics Data System (ADS)

    Pekker, Sándor; Kováts, Éva; Oszlányi, Gábor; Bényei, Gyula; Klupp, Gyöngyi; Bortel, Gábor; Jalsovszky, István; Jakab, Emma; Borondics, Ferenc; Kamarás, Katalin; Bokor, Mónika; Kriza, György; Tompa, Kálmán; Faigel, Gyula

    2005-10-01

    Cubane(C8H8) and fullerene(C60) are famous cage molecules with shapes of platonic or archimedean solids. Their remarkable chemical and solid-state properties have induced great scientific interest. Both materials form polymorphic crystals of molecules with variable orientational ordering. The idea of intercalating fullerene with cubane was raised several years ago but no attempts at preparation have been reported. Here we show that C60 and similarly C70 form high-symmetry molecular crystals with cubane owing to topological molecular recognition between the convex surface of fullerenes and the concave cubane. Static cubane occupies the octahedral voids of the face-centred-cubic structures and acts as a bearing between the rotating fullerene molecules. The smooth contact of the rotor and stator molecules decreases significantly the temperature of orientational ordering. These materials have great topochemical importance: at elevated temperatures they transform to high-stability covalent derivatives although preserving their crystalline appearance. The size-dependent molecular recognition promises selective formation of related structures with higher fullerenes and/or substituted cubanes.

  9. Rotor-stator molecular crystals of fullerenes with cubane.

    PubMed

    Pekker, Sándor; Kováts, Eva; Oszlányi, Gábor; Bényei, Gyula; Klupp, Gyöngyi; Bortel, Gábor; Jalsovszky, István; Jakab, Emma; Borondics, Ferenc; Kamarás, Katalin; Bokor, Mónika; Kriza, György; Tompa, Kálmán; Faigel, Gyula

    2005-10-01

    Cubane (C8H8) and fullerene (C60) are famous cage molecules with shapes of platonic or archimedean solids. Their remarkable chemical and solid-state properties have induced great scientific interest. Both materials form polymorphic crystals of molecules with variable orientational ordering. The idea of intercalating fullerene with cubane was raised several years ago but no attempts at preparation have been reported. Here we show that C60 and similarly C70 form high-symmetry molecular crystals with cubane owing to topological molecular recognition between the convex surface of fullerenes and the concave cubane. Static cubane occupies the octahedral voids of the face-centred-cubic structures and acts as a bearing between the rotating fullerene molecules. The smooth contact of the rotor and stator molecules decreases significantly the temperature of orientational ordering. These materials have great topochemical importance: at elevated temperatures they transform to high-stability covalent derivatives although preserving their crystalline appearance. The size-dependent molecular recognition promises selective formation of related structures with higher fullerenes and/or substituted cubanes. PMID:16142242

  10. Using surface plasmonics to turn on fullerene's dark excitons

    NASA Astrophysics Data System (ADS)

    Despoja, V.; Mowbray, D. J.

    2014-05-01

    Using our recently proposed Bethe-Salpeter G0W0 formulation, we explore the optical absorption spectra of fullerene (C60) near coinage metal surfaces (Cu, Ag, and Au). We pay special attention to how the surface plasmon ?S influences the optical activity of fullerene. We find that the lower-energy fullerene excitons at 3.77 and 4.8 eV only weakly interact with the surface plasmon. However, we find that the surface plasmon strongly interacts with the most intense fullerene ? exciton, i.e., the dipolar mode at ?? +?6.5 eV, and the quadrupolar mode at ?? -?6.8 eV. When fullerene is close to a copper surface (z0?5.3 Å), the dipolar mode ?+ and "localized" surface plasmons in the molecule/surface interface hybridize to form two coupled modes which both absorb light. As a result, the molecule gains an additional optically active mode. Moreover, in resonance, when ?S??±, the strong interaction with the surface plasmon destroys the ?- quadrupolar character and it becomes an optically active mode. In this case, the molecule gains two additional very intense optically active modes. Further, we find that this resonance condition, ?S??±, is satisfied by silver and gold metal surfaces.

  11. The first stable lower fullerene: C{sub 36}

    SciTech Connect

    Piskoti, C.; Zettl, A.

    1998-08-01

    A new pure carbon material, presumably composed of thirty six carbon atom molecules, has been synthesized and isolated in milligram quantities. It appears as though these molecules have a closed cage structure making them the smallest member of a new class of molecules known as fullerenes, most notably of which is the soccer ball shaped C{sub 60}. However, unlike other known fullerenes, any closed, fullerene-like C{sub 36} cage will necessarily contain fused pentagon rings. Therefore, this molecule apparently violates the isolated pentagon rule, a criterion which requires isolated pentagons for stability in fullerene molecules. Striking parallels between this problem and the synthesis of other fused five member fused ring systems will be discussed. Also, it will be shown that certain biological structures known as clathrin behave in a manner which gives excellent predictions about fullerenes and nanotubes. These predictions help to explain the presence of abundant quantities of C{sub 36} in arced graphite soot. {copyright} {ital 1998 American Institute of Physics.}

  12. ON THE EXCITATION AND FORMATION OF CIRCUMSTELLAR FULLERENES

    SciTech Connect

    Bernard-Salas, J.; Jones, A. P.; Groenewegen, M. A. T.

    2012-09-20

    We compare and analyze the Spitzer mid-infrared spectrum of three fullerene-rich planetary nebulae in the Milky Way and the Magellanic Clouds: Tc1, SMP SMC 16, and SMP LMC 56. The three planetary nebulae share many spectroscopic similarities. The strongest circumstellar emission bands correspond to the infrared active vibrational modes of the fullerene species C{sub 60} and little or no emission is present from polycyclic aromatic hydrocarbons. The strengths of the fullerene bands in the three planetary nebulae are very similar, while the ratios of the [Ne III]15.5 {mu}m/[Ne II]12.8 {mu}m fine structure lines, an indicator of the strength of the radiation field, are markedly different. This raises questions about their excitation mechanism and we compare the fullerene emission to fluorescent and thermal models. In addition, the spectra show other interesting and common features, most notably in the 6-9 {mu}m region, where a broad plateau with substructure dominates the emission. These features have previously been associated with mixtures of aromatic/aliphatic hydrocarbon solids. We hypothesize on the origin of this band, which is likely related to the fullerene formation mechanism, and compare it with modeled hydrogenated amorphous carbon that present emission in this region.

  13. Ion-bombardment of nickel (110) at elevated temperature

    NASA Astrophysics Data System (ADS)

    Peddinti, Vijay Kumar

    The goal of this thesis is to study the behavior of ion-induced defects at the Y point on the Ni (110) surface at elevated temperatures. The electronic structure of the surface is examined using inverse photoemission spectroscopy (IPES), and the geometric structure is observed using low energy electron diffraction (LEED). These measurements lead to a better understanding of the surface properties. The clean Ni (110) surface exhibits a peak ˜ 2.6 eV above the Fermi level, indicating an unoccupied surface state near the Y point of the surface Brillouin zone (SBZ). Defects are induced by low energy ion bombardment at various temperatures, which result in a decrease of the peak intensity. The surface state eventually disappears when bombarded for longer times. We also observed that the surface heals faster when the crystal is being simultaneously sputtered and annealed at higher versus lower temperature. Finally the data for annealing while sputtering versus annealing after sputtering does not seem to exhibit much difference.

  14. Model to estimate fractal dimension for ion-bombarded materials

    NASA Astrophysics Data System (ADS)

    Hu, A.; Hassanein, A.

    2014-03-01

    Comprehensive fractal Monte Carlo model ITMC-F (Hu and Hassanein, 2012 [1]) is developed based on the Monte Carlo ion bombardment simulation code, i.e., Ion Transport in Materials and Compounds (ITMC) code (Hassanein, 1985 [2]). The ITMC-F studies the impact of surface roughness on the angular dependence of sputtering yield. Instead of assuming material surfaces to be flat or composed of exact self-similar fractals in simulation, we developed a new method to describe the surface shapes. Random fractal surfaces which are generated by midpoint displacement algorithm and support vector machine algorithm are combined with ITMC. With this new fractal version of ITMC-F, we successfully simulated the angular dependence of sputtering yield for various ion-target combinations, with the input surface roughness exponent directly depicted from experimental data (Hu and Hassanein, 2012 [1]). The ITMC-F code showed good agreement with the experimental data. In advanced, we compare other experimental sputtering yield with the results from ITMC-F to estimate the surface roughness exponent for ion-bombarded material in this research.

  15. Comparative process analysis of fullerene production by the arc and the radio-frequency discharge methods.

    PubMed

    Markovi?, Z; Todorovi?-Markovi?, B; Mohai, I; Farkas, Z; Kovats, E; Szepvolgyi, J; Otasevi?, D; Scheier, P; Feil, S; Romcevi?, N

    2007-01-01

    In this work, comparative analysis of processes in carbon arc and radio frequency (RF) plasma during fullerene synthesis has been presented. The kinetic model of fullerene formation developed earlier has been verified in both types of plasma reactors. The fullerene yield depended on carbon concentration, velocity of plasma flame and rotational temperature of C2 radicals predominantly. When mean rotational temperature of C2 radicals was 3000 K, the fullerene yield was the highest regardless of the type of used reactor. The zone of fullerene formation is larger significantly in RF plasma reactor compared to arc reactor. PMID:17450899

  16. Liposome formulation of fullerene-based molecular diagnostic and therapeutic agents.

    PubMed

    Zhou, Zhiguo

    2013-01-01

    Fullerene medicine is a new but rapidly growing research subject. Fullerene has a number of desired structural, physical and chemical properties to be adapted for biological use including antioxidants, anti-aging, anti-inflammation, photodynamic therapy, drug delivery, and magnetic resonance imaging contrast agents. Chemical functionalization of fullerenes has led to several interesting compounds with very promising preclinical efficacy, pharmacokinetic and safety data. However, there is no clinical evaluation or human use except in fullerene-based cosmetic products for human skincare. This article summarizes recent advances in liposome formulation of fullerenes for the use in therapeutics and molecular imaging. PMID:24300561

  17. Liposome Formulation of Fullerene-Based Molecular Diagnostic and Therapeutic Agents

    PubMed Central

    Zhou, Zhiguo

    2013-01-01

    Fullerene medicine is a new but rapidly growing research subject. Fullerene has a number of desired structural, physical and chemical properties to be adapted for biological use including antioxidants, anti-aging, anti-inflammation, photodynamic therapy, drug delivery, and magnetic resonance imaging contrast agents. Chemical functionalization of fullerenes has led to several interesting compounds with very promising preclinical efficacy, pharmacokinetic and safety data. However, there is no clinical evaluation or human use except in fullerene-based cosmetic products for human skincare. This article summarizes recent advances in liposome formulation of fullerenes for the use in therapeutics and molecular imaging. PMID:24300561

  18. Quantitative UV Spectrophotometric Analysis of Mixtures of Substituted C60 Fullerenes

    NASA Astrophysics Data System (ADS)

    Kuznetsov, S. I.; Yunusova, D. S.; Yumagulova, R. Kh.; Miftakhov, M. S.; Kolesov, S. V.; Spivak, S. I.; Kantor, O. G.

    2015-09-01

    We propose a method for quantitative processing of experimental UV spectrometry data for mixtures of substituted fullerenes, taking into account measurement uncertainties. The experimental data can be represented as a system of Bouguer-Lambert linear equations, including the extinction coefficients for individual substituted fullerenes and the optical densities at wavelengths of the selected absorption maxima for each substituted fullerene. In order to take into account experimental uncertainties, we propose reducing this system of linear algebraic equations to a linear programming problem. Our algorithm allows us to quantitatively determine the fullerene content and the content of substituted fullerene derivatives in the total mixture with uncertainty ?20%.

  19. Tuning the properties of polymer bulk heterojunction solar cells by adjusting fullerene size to control intercalation

    SciTech Connect

    Cates, N.C.

    2010-02-24

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells.

  20. Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source

    E-print Network

    Asaji, T; Uchida, T; Minezaki, H; Ishihara, S; Racz, R; Muramatsu, M; Biri, S; Kitagawa, A; Kato, Y; Yoshida, Y

    2015-01-01

    A synthesis technology of endohedral fullerenes such as Fe@C60 has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C60 was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction.

  1. Fullerene-rare gas mixed plasmas in an electron cyclotron resonance ion source

    SciTech Connect

    Asaji, T. Ohba, T.; Uchida, T.; Yoshida, Y.; Minezaki, H.; Ishihara, S.; Racz, R.; Biri, S.; Kato, Y.

    2014-02-15

    A synthesis technology of endohedral fullerenes such as Fe@C{sub 60} has developed with an electron cyclotron resonance (ECR) ion source. The production of N@C{sub 60} was reported. However, the yield was quite low, since most fullerene molecules were broken in the ECR plasma. We have adopted gas-mixing techniques in order to cool the plasma and then reduce fullerene dissociation. Mass spectra of ion beams extracted from fullerene-He, Ar or Xe mixed plasmas were observed with a Faraday cup. From the results, the He gas mixing technique is effective against fullerene destruction.

  2. Casimir-Polder interaction of fullerene molecules with surfaces

    NASA Astrophysics Data System (ADS)

    Buhmann, Stefan Yoshi; Scheel, Stefan; Ellingsen, Simen Å.; Hornberger, Klaus; Jacob, Andreas

    2012-04-01

    We calculate the thermal Casimir-Polder potential of C60 and C70 fullerene molecules near gold and silicon nitride surfaces, motivated by their relevance for molecular matter-wave interference experiments. We obtain the coefficients governing the asymptotic power laws of the interaction in the thermal, retarded, and nonretarded distance regimes and evaluate the full potential numerically. The interaction is found to be dominated by electronic transitions and hence independent of the internal temperature of the molecules. The contributions from phonon transitions, which are affected by the molecular temperature, give rise to only a small correction. Moreover, we find that the sizable molecular line widths of thermal fullerenes may modify the nonretarded interaction, depending on the model used. Detailed measurements of the nonretarded potential of fullerene thus allow one to distinguish between different theories of incorporating damping.

  3. Formation of Langmuir-Blodgett films of a fullerene

    SciTech Connect

    Nakamura, Takayoshi; Tachibana, Hiroaki; Yumura, Motoo; Matsumoto, Mutsuyoshi; Azumi, Reiko; Tanaka, Motoo; Kawabata, Yasujiro )

    1992-01-01

    The Langmuir-Blodgett (LB) films of the fullerene (C[sub 60]) were formed with and without matrix molecules. The pure C[sub 60] formed a collapsed film at the air-water interface. The surface of the transferred film was inhomogeneous, as observed by atomic force microscopy (AFM). The monolayers of a 1:1 mixture with icosanoic acid were transferred onto substrates with good quality. The LB films had a smooth surface composed of a mixture of C[sub 60] and icosanoic acid dispersed with flat microcrystals of C[sub 60] observed by AFM. The 1:1 mixture with dioctadecyldimethylammonium perchlorate was deposited as Z-type film onto the substrates. The absorption spectra of both of the mixed films were in good agreement with those of evaporated films. These films will be precursors of the molecular systems utilizing the peculiar properties of fullerenes and fullerene anions. 13 refs., 4 figs.

  4. Optical vortex driven charge current loop and optomagnetism in fullerenes

    E-print Network

    Wätzel, Jonas; Schäffer, Alexander; Berakdar, Jamal

    2016-01-01

    Endohedral molecular magnets, e.g. as realized in fullerenes containing $\\rm DySc_{2}N$, are promising candidates for molecular electronics and quantum information processing. For their functionalization an ultrafast local magnetization control is essential. Using full ab-initio quantum chemistry calculations we predict the emergence of charge current loops in fullerenes with an associated orbital magnetic moment upon irradiation with weak light vortex pulses that transfer orbital angular momentum. The generated current is controllable by the frequency, the vortex topological charge, and the intensity of the light. Numerical and analytical results show that an ultraviolet vortex femtosecond pulse with an intensity $\\sim10^{13}$ W/cm$^2$ generates non-invasively nA unidirectional surface current with an associated magnetic field of hundreds $\\mu$T at the center of the fullerene.

  5. Optical vortex driven charge current loop and optomagnetism in fullerenes

    E-print Network

    Jonas Wätzel; Yaroslav Pavlyukh; Alexander Schäffer; Jamal Berakdar

    2016-01-04

    Endohedral molecular magnets, e.g. as realized in fullerenes containing $\\rm DySc_{2}N$, are promising candidates for molecular electronics and quantum information processing. For their functionalization an ultrafast local magnetization control is essential. Using full ab-initio quantum chemistry calculations we predict the emergence of charge current loops in fullerenes with an associated orbital magnetic moment upon irradiation with weak light vortex pulses that transfer orbital angular momentum. The generated current is controllable by the frequency, the vortex topological charge, and the intensity of the light. Numerical and analytical results show that an ultraviolet vortex femtosecond pulse with an intensity $\\sim10^{13}$ W/cm$^2$ generates non-invasively nA unidirectional surface current with an associated magnetic field of hundreds $\\mu$T at the center of the fullerene.

  6. Direct optical excitation of a fullerene-incarcerated metal ion

    E-print Network

    Mark A G Jones; Kyriakos Porfyrakis; G Andrew D Briggs; Robert A Taylor; Arzhang Ardavan

    2006-04-20

    The endohedral fullerene Er3N@C80 shows characteristic 1.5 micron photoluminescence at cryogenic temperatures associated with radiative relaxation from the crystal-field split Er3+ 4I13/2 manifold to the 4I15/2 manifold. Previous observations of this luminescence were carried out by photoexcitation of the fullerene cage states leading to relaxation via the ionic states. We present direct non-cage-mediated optical interaction with the erbium ion. We have used this interaction to complete a photoluminescence-excitation map of the Er3+ 4I13/2 manifold. This ability to interact directly with the states of an incarcerated ion suggests the possibility of coherently manipulating fullerene qubit states with light.

  7. Casimir-Polder interaction of fullerene molecules with surfaces

    E-print Network

    Stefan Yoshi Buhmann; Stefan Scheel; Simen Å. Ellingsen; Klaus Hornberger; Andreas Jacob

    2012-02-09

    We calculate the thermal Casimir--Polder potential of C60 and C70 fullerene molecules near gold and silicon nitride surfaces, motivated by their relevance for molecular matter wave interference experiments. We obtain the coefficients governing the asymptotic power laws of the interaction in the thermal, retarded and nonretarded distance regimes and evaluate the full potential numerically. The interaction is found to be dominated by electronic transitions, and hence independent of the internal temperature of the molecules. The contributions from phonon transitions, which are affected by the molecular temperature, give rise to only a small correction. Moreover, we find that the sizeable molecular line widths of thermal fullerenes may modify the nonretarded interaction, depending on the model used. Detailed measurements of the nonretarded potential of fullerene thus allow one to distinguish between different theories of incorporating damping.

  8. THE FORMATION OF COSMIC FULLERENES FROM AROPHATIC CLUSTERS

    SciTech Connect

    Micelotta, Elisabetta R.; Cami, Jan; Peeters, Els; Fanchini, Giovanni; Jones, Anthony P.; Bernard-Salas, Jeronimo

    2012-12-10

    Fullerenes have recently been identified in space and they may play a significant role in the gas and dust budget of various astrophysical objects including planetary nebulae (PNe), reflection nebulae, and H II regions. The tenuous nature of the gas in these environments precludes the formation of fullerene materials following known vaporization or combustion synthesis routes even on astronomical timescales. We have studied the processing of hydrogenated amorphous carbon (a-C:H or HAC) nanoparticles and their specific derivative structures, which we name ''arophatics'', in the circumstellar environments of young, carbon-rich PNe. We find that UV-irradiation of such particles can result in the formation of fullerenes, consistent with the known physical conditions in PNe and with available timescales.

  9. Toxicity of polyhydroxylated fullerene to mitochondria.

    PubMed

    Yang, Li-Yun; Gao, Jia-Ling; Gao, Tian; Dong, Ping; Ma, Long; Jiang, Feng-Lei; Liu, Yi

    2016-01-15

    Mitochondrial dysfunction is considered as a crucial mechanism of nanomaterial toxicity. Herein, we investigated the effects of polyhydroxylated fullerene (C60(OH)44, fullerenol), a model carbon-based nanomaterial with high water solubility, on isolated mitochondria. Our study demonstrated that fullerenol enhanced the permeabilization of mitochondrial inner membrane to H(+) and K(+) and induced mitochondrial permeability transition (MPT). The fullerenol-induced swelling was dose-dependent and could be effectively inhibited by MPT inhibitors such as cyclosporin A (CsA), adenosine diphosphate (ADP), ruthenium red (RR) and ethylenediaminetetraacetic acid (EDTA). After treating the mitochondria with fullerenol, the mitochondrial membrane potential (MMP) was found collapsed in a concentration-independent manner. The fluorescence anisotropy of hematoporphyrin (HP) changed significantly with the addition of fullerenol, while that of 1,6-diphenyl-hexatriene (DPH) changed slightly. Moreover, a decrease of respiration state 3 and increase of respiration state 4 were observed when mitochondria were energized with complex II substrate succinate. The results of transmission electron microscopy (TEM) provided direct evidence that fullerenol damaged the mitochondrial ultrastructure. The investigations can provide comprehensive information to elucidate the possible toxic mechanism of fullerenols at subcellular level. PMID:26348144

  10. A search for diffuse bands in fullerene planetary nebulae: evidence of diffuse circumstellar bands

    NASA Astrophysics Data System (ADS)

    Díaz-Luis, J. J.; García-Hernández, D. A.; Kameswara Rao, N.; Manchado, A.; Cataldo, F.

    2015-01-01

    Large fullerenes and fullerene-based molecules have been proposed as carriers of diffuse interstellar bands (DIBs). The recent detection of the most common fullerenes (C60 and C70) around some planetary nebulae (PNe) now enable us to study the DIBs towards fullerene-rich space environments. We search DIBs in the optical spectra towards three fullerene-containing PNe (Tc 1, M 1-20, and IC 418). Special attention is given to DIBs which are found to be unusually intense towards these fullerene sources. In particular, an unusually strong 4428 Å absorption feature is a common charateristic of fullerene PNe. Similar to Tc 1, the strongest optical bands of neutral C60 are not detected towards IC 418. Our high-quality (S/N > 300) spectra for PN Tc 1, together with its large radial velocity, permit us to search for the presence of diffuse bands of circumstellar origin, which we refer to as diffuse circumstellar bands (DCBs). We report the first tentative detection of two DCBs at 4428 and 5780 Å in the fullerene-rich circumstellar environment around the PN Tc 1. Laboratory and theoretical studies of fullerenes in their multifarious manifestations (carbon onions, fullerene clusters, or even complex species formed by fullerenes and other molecules like PAHs or metals) may help solve the mystery of some of the diffuse band carriers. Appendix A is available in electronic form at http://www.aanda.org

  11. Mapping fullerene crystallization in a photovoltaic blend: an electron tomography study

    NASA Astrophysics Data System (ADS)

    Bäcke, Olof; Lindqvist, Camilla; Diaz de Zerio Mendaza, Amaia; Gustafsson, Stefan; Wang, Ergang; Andersson, Mats R.; Müller, Christian; Olsson, Eva

    2015-04-01

    The formation of fullerene crystals represents a major degradation pathway of polymer/fullerene bulk-heterojunction thin films that inexorably deteriorates their photovoltaic performance. Currently no tools exist that reveal the origin of fullerene crystal formation vertically through the film. Here, we show that electron tomography can be used to study nucleation and growth of fullerene crystals. A model bulk-heterojunction blend based on a thiophene-quinoxaline copolymer and a fullerene derivative is examined after controlled annealing above the glass transition temperature. We image a number of fullerene nanocrystals, ranging in size from 70 to 400 nanometers, and observe that their center is located close to the free-surface of spin-coated films. The results show that the nucleation of fullerene crystals predominately occurs in the upper part of the films. Moreover, electron tomography reveals that the nucleation is preceded by more pronounced phase separation of the blend components.

  12. Evidence Supporting an Early as Well as Late Heavy Bombardment on the Moon

    NASA Technical Reports Server (NTRS)

    Frey, Herbert

    2015-01-01

    Evidence supporting an intense early bombardment on the Moon in addition to the traditional Late Heavy Bombardment at approx. 4 BY ago include the distribution of N(50) Crater Retention Ages (CRAs) for candidate basins, a variety of absolute age scenarios for both a "young" and an "old" Nectaris age, and the decreasing contrasts in both topographic relief and Bouguer gravity with increasing CRA.

  13. Comparison of silicon potentials for cluster bombardment simulations J. Samela a,*, K. Nordlund a

    E-print Network

    Nordlund, Kai

    Comparison of silicon potentials for cluster bombardment simulations J. Samela a,*, K. Nordlund Available online 10 January 2007 Abstract We have compared three common silicon potentials for molecular dynamics simulations of cluster bombardment of silicon structures. The potentials tested are Stillinger

  14. Theory of the Miscibility of Fullerenes in Random Copolymer Melts

    SciTech Connect

    Dadmun, Mark D; Sumpter, Bobby G; Schweizer, Kenneth; Banerjee, Debapriya

    2013-01-01

    We combine polymer integral equation theory and computational chemistry methods to study the interfacial structure, effective interactions, miscibility and spatial dispersion mechanism of fullerenes dissolved in specific random AB copolymer melts characterized by strong non-covalent electron donor-acceptor interactions with the nanofiller. A statistical mechanical basis is developed for designing random copolymers to optimize fullerene dispersion at intermediate copolymer compositions. Pair correlation calculations reveal a strong sensitivity of interfacial packing near the fullerene to copolymer composition and adsorption energy mismatch. The potential of mean force between fullerenes displays rich trends, often non-monotonic with copolymer composition, reflecting a non-additive competition between direct filler attractions and polymer-mediated bridging and steric stabilization. The spinodal phase diagrams are in qualitative agreement with recent solubility limit experimental observations on three systems, and testable predictions are made for other random copolymers. The distinctive non-monotonic variation of miscibility with copolymer composition is found to be primarily a consequence of composition-dependent, spatially short-range attractions between the A and B monomers with the fullerene. A remarkably rich, polymer-specific temperature dependence of the spinodal diagram is predicted which reflects the thermal sensitivity of spatial correlations which can result in fullerene miscibility either increasing or decreasing with cooling. The calculations are contrasted with a simpler effective homopolymer model and the random structure Flory-Huggins model. The former appears to be qualitatively reasonable but can incur large quantitative errors since it misses preferential packing of monomers near nanoparticles, while the latter appears to fail qualitatively due to its neglect of all spatial correlations.

  15. Fullerenes: A New Carrier Phase for Noble Gases in Meteorites

    NASA Technical Reports Server (NTRS)

    Becker, Luann

    2004-01-01

    The major focus of our research effort has been to measure the noble gases encapsulated within fullerenes, a new carbon carrier phase and compare it to the myriad of components found in the bulk meteorite acid residues. We have concentrated on the carbonaceous chondrites (Allende, Murchison and Tagish Lake) since they have abundant noble gases, typically with a planetary signature that dominates the stepped-release of the meteorite bulk acid residue. They also contain an extractable fullerene component that can be isolated and purified from the same bulk material.

  16. ‘Horror vacui’ or topological in-out isomerism in perhydrogenated fullerenes: C60H60 and monoalkylated perhydrogenated fullerenes

    NASA Astrophysics Data System (ADS)

    Dodziuk, Helena; Nowinski, Krzysztof

    1996-02-01

    In endohedral chemistry, one of the exciting prospects offered by the cage-like structure of fullerenes, several aspects of the calculations on in-out isomerism of perhydrogenated fullerene and their consequences went unnoticed, e.g. the topological character of the isomerism, the instability of C 60F 60, which was thought to revolutionize industry as an ideal lubricant, as well as the possibility of in-out isomerism in alkylated fulleranes. Molecular mechanics calculations indicate that for smaller alkyl groups the 'in' isomer is significantly more stable extending the possibility of endohedral fullerene chemistry. C 60H 60 and its derivatives can be considered as examples of a manifestation of the ancient 'horror vacui' concept.

  17. A Unique Photon Bombardment System for Space Applications

    NASA Technical Reports Server (NTRS)

    Klein, E. J.

    1993-01-01

    The innovative Electromagnetic Radiation Collection and Concentration System (EMRCCS) described is the foundation for the development of a multiplicity of space and terrestrial system formats. The system capability allows its use in the visual, infrared, and ultraviolet ranges of the spectrum for EM collection, concentration, source/receptor tracking, and targeting. The nonimaging modular optical system uses a physically static position aperture for EM radiation collection. Folded optics provide the concentration of the radiation and source autotracking. The collected and concentrated electromagnetic radiation is utilized in many applications, e.g., solar spectrum in thermal and associative photon bombardment applications for hazardous waste management, water purification, metal hardening, hydrogen generation, photovoltaics, etc., in both space and terrestrial segment utilization. Additionally, at the high end of the concentration capability range, i.e., 60,000+, a solar-pulsed laser system is possible.

  18. Uses of ion bombardment in thin-film deposition

    SciTech Connect

    Erck, R.A.; Fenske, G.R.; Erdemir, A.

    1990-10-01

    Use of plasma- and ion-beam-modified surfaces and surface coatings in continually expanding in engineering disciplines. The purpose of these modifications and treatments is to impart favorable properties, such as wear resistance and lubricity, to the surfaces, while at the same time retaining the strength or toughness of the bulk materials. Energetic-ion bombardment can be used to modify the structural and chemical properties of surfaces or applied coatings. Ion-implantation has been used for many years, and recently, other surface-modification techniques, among them ion-beam mixing and ion-beam-assisted deposition, have attracted attention because they permit application of highly adherent lubricious and wear-resistant films. In this paper, ion-beam techniques are described from the viewpoint of ion-surface interactions, and some avenues for the engineering of tribological surfaces are presented. 100 refs., 4 figs.

  19. Bombarding Cancer: Biolistic Delivery of therapeutics using Porous Si Carriers

    NASA Astrophysics Data System (ADS)

    Zilony, Neta; Tzur-Balter, Adi; Segal, Ester; Shefi, Orit

    2013-08-01

    A new paradigm for an effective delivery of therapeutics into cancer cells is presented. Degradable porous silicon carriers, which are tailored to carry and release a model anti-cancer drug, are biolistically bombarded into in-vitro cancerous targets. We demonstrate the ability to launch these highly porous microparticles by a pneumatic capillary gene gun, which is conventionally used to deliver cargos by heavy metal carriers. By optimizing the gun parameters e.g., the accelerating gas pressure, we have successfully delivered the porous carriers, to reach deep targets and to cross a skin barrier in a highly spatial resolution. Our study reveals significant cytotoxicity towards the target human breast carcinoma cells following the delivery of drug-loaded carriers, while administrating empty particles results in no effect on cell viability. The unique combination of biolistics with the temporal control of payload release from porous carriers presents a powerful and non-conventional platform for designing new therapeutic strategies.

  20. Cationization of organometallo carbonyl compounds by fast ion bombardment

    NASA Astrophysics Data System (ADS)

    Siuzdak, Gary; Wendeborn, Sebastian V.; Nicolaou, K. C.

    1992-01-01

    Organodicobalt, organochromium, and organomolybdenum carbonyl complexes have been studied using fast ion bombardment mass spectrometry. It has been found that the addition of cesium iodide to the liquid matrix, m-NBA, can significantly enhance the ability to observed the precursor ions of these organometallics through charge localization. In most cases the [M + Cs]+ ions were more abundant than the radical cations M-, the protonated molecules [M + H]+, or the sodium cationized molecules [M + Na]+ which were either unobservable or less intense than those treated with the cesium iodide salt solution. The decomposition of the compounds took place primarily through the successive loss of carbonyls from the radical cation with some carbonyl loss observed through the protonated and cationized species. The FAB matrix ions produced when cesium iodide was added to m-NBA also allowed for internal calibration.

  1. Changes of Dust Grain Properties Under Particle Bombardment

    SciTech Connect

    Pavlu, J.; Richterova, I.; Safrankova, J.; Nemecek, Z.; Fujita, D.

    2008-09-07

    The dust in space environments is exposed to particle bombardment. Under an impact of ions, electrons, and photons, the charge of a particular grain changes and, in some cases, the grain structure can be modified. The present study deals with spherical melamine formaldehyde resin grains that are frequently used in many dusty plasmas and microgravity experiments and it concentrates on the influence of the electron beam impact on a grain size. We have performed series of experiments based on the SEM technique. Our investigation has shown that the electron impact can cause a significant increase of the grain size. We discuss changes of material properties and consequences for its applications in laboratory and space experiments.

  2. ATS-6 - Cesium bombardment engine north-south stationkeeping experiment

    NASA Technical Reports Server (NTRS)

    Worlock, R. M.; James, E. L.; Hunter, R. E.; Bartlett, R. O.

    1975-01-01

    Two 0.004 N thrust cesium bombardment ion thrustors have been developed and used for north-south stationkeeping in the geostationary Applications Technology Satellite-6 (ATS-6). The thrustor subsystems are mounted on the north and south faces of the earth viewing module such that 0.0026 N of thrust is applied normal to the orbit plane and 0.0036 N is applied radially upward. The change in the orbit inclination of the satellite is maintained at zero by operating the two thrustors alternately so that their thrust components, normal to the orbital plane, are symmetrically applied about the nodal crossings. Initial operation of the thrustors was successful. There was no interference with the satellite communications systems and the predicted spacecraft operating potential was verified. Subsequent trials failed due to a defect in the operation of the propellant reservoirs in zero g. A feed line valve is under development to correct this difficulty.

  3. Plasma properties in electron-bombardment ion thrusters

    SciTech Connect

    Matossian, J.N.; Beattie, J.R.

    1987-05-01

    The paper describes a technique for computing volume-averaged plasma properties within electron-bombardment ion thrusters, using spatially varying Langmuir-probe measurements. Average values of the electron densities are defined by integrating the spatially varying Maxwellian and primary electron densities over the ionization volume, and then dividing by the volume. Plasma properties obtained in the 30-cm-diameter J-series and ring-cusp thrusters are analyzed by the volume-averaging technique. The superior performance exhibited by the ring-cusp thruster is correlated with a higher average Maxwellian electron temperature. The ring-cusp thruster maintains the same fraction of primary electrons as does the J-series thruster, but at a much lower ion production cost. The volume-averaged predictions for both thrusters are compared with those of a detailed thruster performance model. 20 references.

  4. Plasma properties in electron-bombardment ion thrusters

    NASA Technical Reports Server (NTRS)

    Matossian, J. N.; Beattie, J. R.

    1987-01-01

    The paper describes a technique for computing volume-averaged plasma properties within electron-bombardment ion thrusters, using spatially varying Langmuir-probe measurements. Average values of the electron densities are defined by integrating the spatially varying Maxwellian and primary electron densities over the ionization volume, and then dividing by the volume. Plasma properties obtained in the 30-cm-diameter J-series and ring-cusp thrusters are analyzed by the volume-averaging technique. The superior performance exhibited by the ring-cusp thruster is correlated with a higher average Maxwellian electron temperature. The ring-cusp thruster maintains the same fraction of primary electrons as does the J-series thruster, but at a much lower ion production cost. The volume-averaged predictions for both thrusters are compared with those of a detailed thruster performance model.

  5. Generation of singlet oxygen in fullerene-containing media: 1. Photodesorption of singlet oxygen from fullerene-containing surfaces

    SciTech Connect

    Belousova, I M; Belousov, V P; Danilov, O B; Ermakov, A V; Kiselev, V M; Kislyakov, I M; Sosnov, E N

    2008-03-31

    It is shown that upon irradiation of fullerene-containing surfaces by laser or flashlamp pulses, oxygen adsorbed by these surfaces efficiently escapes to the gas phase. The observation of luminescence pulses in the spectral region of 762 and 1268 nm confirms the presence of oxygen molecules in the excited singlet state in the desorbed oxygen. The conditions for optimisation of the efficiency of singlet-oxygen production are studied. It is shown that singlet oxygen at the concentration sufficient for obtaining operation of a fullerene-oxygen-iodine laser can be produced in this way. (laser applications and other topics in quantum electronics)

  6. Surface wet-ability modification of thin PECVD silicon nitride layers by 40 keV argon ion treatments

    NASA Astrophysics Data System (ADS)

    Caridi, F.; Picciotto, A.; Vanzetti, L.; Iacob, E.; Scolaro, C.

    2015-10-01

    Measurements of wet-ability of liquid drops have been performed on a 30 nm silicon nitride (Si3N4) film deposited by a PECVD reactor on a silicon wafer and implanted by 40 keV argon ions at different doses. Surface treatments by using Ar ion beams have been employed to modify the wet-ability. The chemical composition of the first Si3N4 monolayer was investigated by means of X-ray Photoelectron Spectroscopy (XPS). The surface morphology was tested by Atomic Force Microscopy (AFM). Results put in evidence the best implantation conditions for silicon nitride to increase or to reduce the wet-ability of the biological liquid. This permits to improve the biocompatibility and functionality of Si3N4. In particular experimental results show that argon ion bombardment increases the contact angle, enhances the oxygen content and increases the surface roughness.

  7. Atom penetration from a thin film into the substrate during sputtering by polyenergetic Ar{sup +} ion beam with mean energy of 9.4 keV

    SciTech Connect

    Kalin, B.A.; Gladkov, V.P.; Volkov, N.V.; Sabo, S.E.

    1995-12-31

    Penetration of alien atoms (Be, Ni) into Be, Al, Zr, Si and diamond was investigated under Ar{sup +} ion bombardment of samples having thermally evaporated films of 30--50 nm. Sputtering was carried out using a wide energy spectrum beam of Ar{sup +} ions of 9.4 keV to dose D = 1 {times} 10{sup 16}--10{sup 19} ion/cm{sup 2}. Implanted atom distribution in the targets was measured by Rutherford backscattering spectrometry (RBS) of H{sup +} and He{sup +} ions with energy of 1.6 MeV as well as secondary ion mass-spectrometry (SIMS). During the bombardment, the penetration depth of Ar atoms increases with dose linearly. This depth is more than 3--20 times deeper than the projected range of bombarding ions and recoil atoms. This is a deep action effect. The analysis shows that the experimental data for foreign atoms penetration depth are similar to the data calculated for atom migration through the interstitial site in a field of internal (lateral) compressive stresses created in the near-surface layer of the substrate as a result of implantation. Under these experimental conditions atom ratio r{sub i}/r{sub m} (r{sub i} -- radius of dopant, r{sub m} -- radius target of substrate) can play a principal determining role.

  8. Cobalt-catalyzed hydroalkylation of [60]fullerene with active alkyl bromides: selective synthesis of monoalkylated fullerenes.

    PubMed

    Lu, Shirong; Jin, Tienan; Bao, Ming; Yamamoto, Yoshinori

    2011-08-17

    The Co-catalyzed hydroalkylation of C(60) with reactive alkyl bromides 1 (RBr) in the presence of Mn reductant and H(2)O at ambient temperature gave the monoalkylated C(60) (2) in good to high yields. The use of CoLn/Mn/H(2)O under Ar atmosphere is crucial for the success of the present transformation. The reaction most probably proceeds through the Co(0 or I) complex-promoted generation of a radical (R(•)) followed by addition to C(60). This hydroalkylation method was applied to the synthesis of zinc porphyrin attached C(60) (2l), dendrimer attached C(60) (2m), and fullerene dimer (2n), which were not easily available through the previously known methods. PMID:21744823

  9. Optimization of fullerene-based negative tone chemically amplified fullerene resist for extreme ultraviolet lithography

    NASA Astrophysics Data System (ADS)

    Frommhold, A.; Yang, D. X.; McClelland, A.; Xue, X.; Ekinci, Y.; Palmer, R. E.; Robinson, A. P. G.

    2014-03-01

    While the technological progress of Next Generation Lithography (NGL) steadily continues, further progress is required before successful insertion in high volume manufacturing is possible. A key issue is the development of new resists suitable to achieve higher lithographic resolution with acceptable sensitivity and line edge roughness. Molecular resists have been a primary focus of interest for NGL because they promise high resolution and small line edge roughness (LER), but no suitable resist candidate has emerged yet that fulfills all of the industry's criteria. We have previously shown first extreme ultraviolet lithography (EUVL) exposures for a new fullerene derivative based three-component negative tone chemically amplified resist with suitable properties close to or within the target range of the resist metrics as set out in the International Technology Roadmap for Semiconductors for 2016. Here we present the results of our efforts to optimize the EUVL performance of our resist system especially with regards to LER.

  10. Single Molecular Spectroscopy: Identification of Individual Fullerene Molecules Luiz H. G. Tizei, Zheng Liu, Masanori Koshino, Yoko Iizumi, Toshiya Okazaki, and Kazu Suenaga*

    E-print Network

    Single Molecular Spectroscopy: Identification of Individual Fullerene Molecules Luiz H. G. Tizei of individual fullerenes by means of electron spectroscopy based on scanning transmission electron microscopy to discriminate carbon cage structures with different symmetries. Spectroscopy of isolated fullerenes without any

  11. Nanostructure enhanced ionic transport in fullerene reinforced solid polymer electrolytes.

    PubMed

    Sun, Che-Nan; Zawodzinski, Thomas A; Tenhaeff, Wyatt E; Ren, Fei; Keum, Jong Kahk; Bi, Sheng; Li, Dawen; Ahn, Suk-Kyun; Hong, Kunlun; Rondinone, Adam J; Carrillo, Jan-Michael Y; Do, Changwoo; Sumpter, Bobby G; Chen, Jihua

    2015-03-28

    Solid polymer electrolytes, such as polyethylene oxide (PEO) based systems, have the potential to replace liquid electrolytes in secondary lithium batteries with flexible, safe, and mechanically robust designs. Previously reported PEO nanocomposite electrolytes routinely use metal oxide nanoparticles that are often 5-10 nm in diameter or larger. The mechanism of those oxide particle-based polymer nanocomposite electrolytes is under debate and the ion transport performance of these systems is still to be improved. Herein we report a 6-fold ion conductivity enhancement in PEO/lithium bis(trifluoromethanesulfonyl) imide (LiTFSI)-based solid electrolytes upon the addition of fullerene derivatives. The observed conductivity improvement correlates with nanometer-scale fullerene crystallite formation, reduced crystallinities of both the (PEO)6:LiTFSI phase and pure PEO, as well as a significantly larger PEO free volume. This improved performance is further interpreted by enhanced decoupling between ion transport and polymer segmental motion, as well as optimized permittivity and conductivity in bulk and grain boundaries. This study suggests that nanoparticle induced morphological changes, in a system with fullerene nanoparticles and no Lewis acidic sites, play critical roles in their ion conductivity enhancement. The marriage of fullerene derivatives and solid polymer electrolytes opens up significant opportunities in designing next-generation solid polymer electrolytes with improved performance. PMID:25733054

  12. Bangbang control of fullerene qubits using ultrafast phase gates

    E-print Network

    Loss, Daniel

    of unprecedented speed3,4 on a nuclear spin qubit in a fullerene molecule, and use it to bang­bang decouple there is the idea of dynamical suppression of coupling: making some rapid, low-level manipulation of the system so, the finite probability of flipping will be realized). In a related technique that is part of the bang

  13. Uptake and distribution of fullerenes in human mast cells

    PubMed Central

    Dellinger, Anthony; Zhou, Zhiguo; Norton, Sarah K.; Lenk, Robert; Conrad, Daniel; Kepley, Christopher L.

    2010-01-01

    Fullerenes are carbon cages of variable size that can be derivatized with various side chain moieties resulting in compounds that are being developed into nanomedicines. While fullerene use in several pre-clinical in vitro and in vivo models of disease has demonstrated their potential as diagnostic and therapeutic agents, little is known about how they enter cells, what organelles they target, and the time course for their cellular deposition. Fullerenes (C70) that have previously been shown to be potent inhibitors of mast cell (MC)-mediated allergic inflammation were conjugated with Texas Red (TR) and used in conjunction with confocal microscopy to determine mechanisms of uptake, the organelle localization, and the duration they can be detected in situ. We show C70-TR are non-specifically endocytosed into MC where they are shuttled throughout the cytoplasm, lysosomes, mitochondria, and into endoplasmic reticulum at different times. No nuclear or secretory granule localization was observed. The C70-TR remained detectable within cells at one week. These studies show MC endocytose fullerenes where they are shuttled to organelles involved with calcium and reactive oxygen species (ROS) production which may explain their efficacy as cellular inhibitors. PMID:20138243

  14. Stabilized-jellium description of neutral and multiply charged fullerenes

    E-print Network

    Constantine Yannouleas; Uzi landman

    2009-10-18

    A description of neutral and multiply charged fullerenes is proposed based on a stabilized jellium (structureless pseudopotential) approximation for the ionic background and the local density approximation for the sigma and pi valence electrons. A recently developed shell-correction method is used to calculate total energies and properties of both the neutral and multiply charged anionic and cationic fullerenes. The effect of the icosahedral symmetry is included perturbatively. The calculated single-particle energy level spectrum of C_60 is in good correspondence with experimentally measured ones and previous self-consistent local-density-approximation calculations. For the multiply charged fullerenes, we calculate microscopically the charging energies for up to 12 excess charges. A semiclassical interpretation of these results is developed, which views the fullerenes as Coulomb islands possessing a classical capacitance. The calculated values for the first ionization potential and the first electron affinity agree well with the experimental ones. Our calculations support the results from charge transfer bracketing experiments and from direct ionization experiments through electron impact. The doubly charged negative ion is found to be a very long-lived metastable species, in agreement with observations.

  15. Quenching and Sensitizing Fullerene Photoreactions by Natural Organic Matter

    EPA Science Inventory

    Effects of natural organic matter (NOM) on the photoreaction kinetics of fullerenes (i.e., C60 and fullerenol) were investigated using simulated sunlight and monochromatic radiation (365 nm). NOM from several sources quenched (slowed) the photoreaction of C60 aggregates in water ...

  16. Fullerenes, fulleranes and polycyclic aromatic hydrocarbons in the Allende meteorite

    NASA Technical Reports Server (NTRS)

    Becker, L.; Bunch, T. E.

    1997-01-01

    In this paper, we confirm our earlier observations of fullerenes (C60 and C70) in the Allende meteorite (Becker et al., 1994a, 1995). Fullerene C60 was also detected in two separate C-rich (approximately 0.5-1.0%) dark inclusions (Heymann et al., 1987) that were hand picked from the Allende sample. The amounts of C60 detected were approximately 5 and approximately 10 ppb, respectively, which is considerably less than what was detected in the Allende 15/21 sample (approximately 100 ppb; Becker et al., 1994a, 1995). This suggests that fullerenes are heterogeneously distributed in the meteorite. In addition, we present evidence for fulleranes, (C60Hx), detected in separate samples by laser desorption (reflectron) time-of-flight (TOF) mass spectrometry (LDMS). The LDMS spectra for the Allende extracts were remarkably similar to the spectra generated for the synthetic fullerane mixtures. Several fullerane products were synthesized using a Rh catalyst (Becker et al., 1993a) and separated using high-performance liquid chromatography (HPLC). Polycyclic aromatic hydrocarbons (PAHs) were also observed ppm levels) that included benzofluoranthene and corannulene, a cup-shaped molecule that has been proposed as a precursor molecule to the formation of fullerenes in the gas phase (Pope et al., 1993).

  17. 5s correlation confinement resonances in Xe-endo-fullerenes

    NASA Astrophysics Data System (ADS)

    Dolmatov, V. K.; Keating, D. A.

    2012-11-01

    Spectacular trends in the modification of the Xe 5s photoionization via interchannel coupling with confinement resonances emerging in the Xe 4d giant resonance upon photoionization of the Xe@C60, Xe@C240 and Xe@C60@C240 endo-fullerenes are theoretically unraveled and interpreted.

  18. Effect of nitrogen atomic percentage on N+-bombarded MWCNTs in cytocompatibility and hemocompatibility

    NASA Astrophysics Data System (ADS)

    Zhao, Mengli; Cao, Ye; Liu, Xiaoqi; Deng, Jianhua; Li, Dejun; Gu, Hanqing

    2014-03-01

    N+-bombarded multi-walled carbon nanotubes (N+-bombarded MWCNTs), with different nitrogen atomic percentages, were achieved by different N ion beam currents using ion beam-assisted deposition (IBAD) on MWCNTs synthesized by chemical vapor deposition (CVD). Characterizations of N+-bombarded MWCNTs were evaluated by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, and contact angle. For comparison, the in vitro cytocompatibility of the N+-bombarded MWCNTs with different N atomic percentages was assessed by cellular adhesion investigation using human endothelial cells (EAHY926) and mouse fibroblast cells (L929), respectively. The results showed that the presence of nitrogen in MWCNTs accelerated cell growth and proliferation of cell culture. The higher nitrogen content of N+-bombarded MWCNTs, the better cytocompatibility. In addition, N+-bombarded MWCNTs with higher N atomic percentage displayed lower platelet adhesion rate. No hemolysis can be observed on the surfaces. These results proved that higher N atomic percentage led N+-bombarded MWCNTs to better hemocompatibility.

  19. Erosion of frozen sulfur dioxide by ion bombardment - Applications to Io

    NASA Technical Reports Server (NTRS)

    Melcher, C. L.; Lepoire, D. J.; Cooper, B. H.; Tombrello, T. A.

    1982-01-01

    The erosion of frozen SO2 due to bombardment by both light and heavy ions (He and F) was measured for bombarding energies of 0.08 to 1.3 MeV/amu. The number of SO2 molecules ejected from the target per incident ion (i.e., the sputtering yield) was 50 for 1.5 MeV He ions and 7300 for 6 MeV F ions. Ion bombardment followed by heating produced an oxygen/sulfur residue which was much more stable against subsequent ion bombardment than the initial frozen SO2. The erosion rate of SO2 frost on Jupiter's moon Io depends strongly on the elemental composition and energy spectra of the magnetospheric ion flux which bombards the surface. The combined effects of ion bombardment and heating which produced residues on the target substrates may also occur on Io from magnetospheric ion bombardment and heating by volcanism. The experimental results compare favorably with a new model of the sputtering process which considers the energy loss of the incident ion to electronic excitation in the target.

  20. [60]Fullerene Displacement from (Dihapto-Buckminster-Fullerene) Pentacarbonyl Tungsten(0): An Experiment for the Inorganic Chemistry Laboratory, Part II

    ERIC Educational Resources Information Center

    Cortes-Figueroa, Jose E.; Moore-Russo, Deborah A.

    2006-01-01

    The kinetics experiments on the ligand-C[subscript 60] exchange reactions on (dihapto-[60]fullerene) pentacarbonyl tungsten(0), ([eta][superscript 2]-C[subscript 60])W(CO)[subscript 5], form an educational activity for the inorganic chemistry laboratory that promotes graphical thinking as well as the understanding of kinetics, mechanisms, and the…

  1. Effect of proton bombardment on InAs dots and wetting layer in laser structures

    SciTech Connect

    O'Driscoll, I.; Blood, P.; Smowton, P. M.; Sobiesierski, A.; Gwilliam, R.

    2012-06-25

    The effect of proton bombardment on carrier lifetime and photoluminescence of InAs quantum dots was measured. Optical absorption and transmission electron microscopy show the dots retain their integrity under bombardment. A decrease in ground state photoluminescence with increasing dose is not explained by the decrease in dot carrier lifetime alone, but also by bombardment-induced non-radiative recombination in the wetting layer, which reduces the dot electron population at fixed excitation. To exploit the relative radiation immunity of quantum dots, it is necessary to maximise the dot density and capture probability per dot to minimize the effect of wetting layer recombination.

  2. Changes in a surface of polycrystalline aluminum upon bombardment with argon ions

    NASA Astrophysics Data System (ADS)

    Ashkhotov, O. G.; Ashkhotova, I. B.; Bliev, A. P.; Magkoev, T. T.; Krymshokalova, D. A.

    2014-10-01

    The interaction between argon ions and a natural oxide layer of polycrystalline aluminum is studied via Auger electron (AE) and electron energy loss (EEL) spectroscopy. It is found that bombardment with argon ions whose energy is lower than the Al2O3 sputtering threshold results in the accumulation of bombarding ions in interstitial surface voids, thus forming a supersaturated solid solution of target atoms and bombarding ions of argon and nitrogen entrapped by the ion beam from the residual gas of the working chamber of the spectrometer.

  3. Effect of fullerene tris-adducts on the photovoltaic performance of P3HT:fullerene ternary blends.

    PubMed

    Kang, Hyunbum; Kim, Ki-Hyun; Kang, Tae Eui; Cho, Chul-Hee; Park, Sunhee; Yoon, Sung Cheol; Kim, Bumjoon J

    2013-05-22

    Fullerene tris-adducts have the potential of achieving high open-circuit voltages (V(OC)) in bulk heterojunction (BHJ) polymer solar cells (PSCs), because their lowest unoccupied molecular orbital (LUMO) level is higher than those of fullerene mono- and bis-adducts. However, no successful examples of the use of fullerene tris-adducts as electron acceptors have been reported. Herein, we developed a ternary-blend approach for the use of fullerene tris-adducts to fully exploit the merit of their high LUMO level. The compound o-xylenyl C60 tris-adduct (OXCTA) was used as a ternary acceptor in the model system of poly(3-hexylthiophene) (P3HT) as the electron donor and the two soluble fullerene acceptors of OXCTA and fullerene monoadduct (o-xylenyl C60 monoadduct (OXCMA), phenyl C61-butyric acid methyl ester (PCBM), or indene-C60 monoadduct (ICMA)). To explore the effect of OXCTA in ternary-blend PSC devices, the photovoltaic behavior of the device was investigated in terms of the weight fraction of OXCTA (W(OXCTA)). When W(OXCTA) is small (<0.3), OXCTA can generate a synergistic bridging effect between P3HT and the fullerene monoadduct, leading to simultaneous enhancement in both V(OC) and short-circuit current (J(SC)). For example, the ternary PSC devices of P3HT:(OXCMA:OXCTA) with W(OXCTA) of 0.1 and 0.3 exhibited power-conversion efficiencies (PCEs) of 3.91% and 3.96%, respectively, which were significantly higher than the 3.61% provided by the P3HT:OXCMA device. Interestingly, for W(OXCTA) > 0.7, both V(OC) and PCE of the ternary-blend PSCs exhibited nonlinear compositional dependence on W(OXCTA). We noted that the nonlinear compositional trend of P3HT:(OXCMA:OXCTA) was significantly different from that of P3HT:(OXCMA:o-xylenyl C60 bis-adduct (OXCBA)) ternary-blend PSC devices. The fundamental reasons for the differences between the photovoltaic trends of the two different ternary-blend systems were investigated systemically by comparing their optical, electrical, and morphological properties. PMID:23574307

  4. Relief evolution of HOPG under high-fluence 30 keV argon ion irradiation

    NASA Astrophysics Data System (ADS)

    Andrianova, N. N.; Borisov, A. M.; Mashkova, E. S.; Shemukhin, A. A.; Shulga, V. I.; Virgiliev, Yu. S.

    2015-07-01

    The results of the experimental study of sputtering and erosion of the basal plane of HOPG under irradiation with 30-keV Ar+ in the range from RT to 400 °C are presented. It has been found that developed at elevated (?250 °C) temperatures needle-like microscopic relief results in twofold sputtering yield increase (Y ? 2) in comparison with sputtering of a surface with an etch pits microscopic relief at the temperatures less than the ion-induced texture transition temperature Tt ? 150 °C. The effects of ion-induced graphite relief on high-dose sputtering have been studied using binary-collision computer simulation. The relief was modeled as a sine function surface along two mutually perpendicular surface axes. The simulation has shown that at some parameters of the relief the essential part of the bombarding ions undergoes inclined incidence on the walls of surface hillocks, which increases the density of ion-atom collisions near the surface and, correspondingly, the ejection of atoms. This effect leads to non-monotonic behavior of the sputtering yield on the relief aspect ratio (amplitude/period). The sputtering yield decreases upon reaching the maximum at aspect ratio of 4, and becomes lower than that for a flat surface. The simulation permits to estimate the relation of amplitude to period of relief at T < Tt.

  5. Small-angle X-ray scattering study of the structure of powder fullerene C{sub 60} and fullerene soot

    SciTech Connect

    Ginzburg, B. M. Tuichiev, Sh.; Tabarov, S. Kh.; Shepelevskii, A. A.

    2007-03-15

    Powder samples of fullerene C{sub 60} and fullerene soot have been studied by the small-angle X-ray scattering method. The radii of gyration of scattering elements have been determined by constructing small-angle diffraction patterns in Guinier coordinates. The data obtained agree well with the results of wide-angle X-ray scattering study, the available data on the structure of the powder fullerene C{sub 60} prepared by the Huffman-Kraetschmer technique, and the structure of the C{sub 60} molecules. Conglomerates of two C{sub 60} molecules, along with crystallites {approx}20 nm in size that are distributed in an amorphous matrix, are present in fullerene powders. Fullerene soot contains C{sub 60} crystallites 20-25 nm in size and graphite crystallites {approx}2-3 nm in size that are distributed in an amorphous matrix.

  6. Compositional Evolution of Saturn's Rings Due to Meteoroid Bombardment

    NASA Technical Reports Server (NTRS)

    Cuzzi, J.; Estrada, P.; Young, Richard E. (Technical Monitor)

    1997-01-01

    In this paper we address the question of compositional evolution in planetary ring systems subsequent to meteoroid bombardment. The huge surface area to mass ratio of planetary rings ensures that this is an important process, even with current uncertainties on the meteoroid flux. We develop a new model which includes both direct deposition of extrinsic meteoritic "pollutants", and ballistic transport of the increasingly polluted ring material as impact ejecta. Our study includes detailed radiative transfer modeling of ring particle spectral reflectivities based on refractive indices of realistic constituents. Voyager data have shown that the lower optical depth regions in Saturn's rings (the C ring and Cassini Division) have darker and less red particles than the optically thicken A and B rings. These coupled structural-compositional groupings have never been explained; we present and explore the hypothesis that global scale color and compositional differences in the main rings of Saturn arise naturally from extrinsic meteoroid bombardment of a ring system which was initially composed primarily, but not entirely, of water ice. We find that the regional color and albedo differences can be understood if all ring material was initially identical (primarily water ice, based on other data, but colored by tiny amounts of intrinsic reddish, plausibly organic, absorber) and then evolved entirely by addition and mixing of extrinsic, nearly neutrally colored. plausibly carbonaceous material. We further demonstrate that the detailed radial profile of color across the abrupt B ring - C ring boundary can.constrain key unknown parameters in the model. Using new alternates of parameter values, we estimate the duration of the exposure to extrinsic meteoroid flux of this part of the rings, at least, to be on the order of 10(exp 8) years. This conclusion is easily extended by inference to the Cassini Division and its surroundings as well. This geologically young "age" is compatible with timescales estimated elsewhere based on the evolution of ring structure due to ballistic transport, and also with other "short timescales" estimated on the grounds of gravitational torques. However, uncertainty in the flux of interplanetary debris and in the ejects yield may preclude ruling out a ring age as old as the solar system at this time.

  7. Effect of Boron doping on the electronic properties of the fullerenes of different sizes

    SciTech Connect

    Agnihotri, Deepak; Sharma, Hitesh

    2011-12-12

    We report the results of the effect of Boron doping in C{sub n}; n = 28, 32, 36, 40, 44, 50 and 60 using the first principle calculation based on density functional theory. The HOMO-LUMO gap changes significantly with the decreasing fullerene size below C{sub 60}, with maximum gap observed for C{sub 32}. The HOMO-LUMO gap of Boron doped fullerenes varies significantly w.r.t. pure fullerenes. Also, the gap decreases for C{sub n-m}B{sub m}X, the boron doped fullerenes with exohedral alkali metals for n = 28, 32, 36, 40, 44, 50 and 60; m = 1 to 4; X = Li, Na and K. The Mulliken charge transfer from the exohedral alkali metals towards the various fullerene cages is altered marginally by the boron doping in fullerenes and follows the order K>Na>Li.

  8. Interaction of C60 fullerenes with asymmetric and curved lipid membranes: a molecular dynamics study.

    PubMed

    Cherniavskyi, Yevhen K; Ramseyer, Christophe; Yesylevskyy, Semen O

    2016-01-01

    Interaction of fullerenes with asymmetric and curved DOPC/DOPS bicelles is studied by means of coarse-grained molecular dynamics simulations. The effects caused by asymmetric lipid composition of the membrane leaflets and the curvature of the membrane are analyzed. It is shown that the aggregates of fullerenes prefer to penetrate into the membrane in the regions of the moderately positive mean curvature. Upon penetration into the hydrophobic core of the membrane fullerenes avoid the regions of the extreme positive or the negative curvature. Fullerenes increase the ordering of lipid tails, which are in direct contact with them, but do not influence other lipids significantly. Our data suggest that the effects of the membrane curvature should be taken into account in the studies concerning permeability of the membranes to fullerenes and fullerene-based drug delivery systems. PMID:26608905

  9. One-pot selective synthesis of a fullerene bisadduct for organic solar cell applications.

    PubMed

    Zhang, Bolong; Subbiah, Jegadesan; Lai, Yu-Ying; White, Jonathan M; Jones, David J; Wong, Wallace W H

    2015-06-18

    A single isomer of fullerene bisadduct, PC61PF, was obtained from commercially available fullerene derivative, PC61BM, in one pot over two steps. The tether-directed remote functionalization approach provided a very simple and fast method to produce a single isomer of fullerene bisadduct with good yield and easy purification. Bulk heterojunction organic solar cells containing the bisadduct was fabricated and tested. PMID:25990490

  10. 40 CFR 721.10269 - [5,6]Fullerene-C84-D2.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fullerene-C84-D2. 721.10269 Section... Substances § 721.10269 Fullerene-C84-D2. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Fullerene-C84-D2 (PMN P-09-56; CAS No. 145809-19-4)...

  11. 40 CFR 721.10268 - [5,6]Fullerene-C70-D5h(6).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fullerene-C70-D5h(6). 721.10268... Substances § 721.10268 Fullerene-C70-D5h(6). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Fullerene-C70-D5h(6) (PMN P-09-55; CAS No....

  12. 40 CFR 721.10270 - [5,6]Fullerene-C84-D2d.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fullerene-C84-D2d. 721.10270 Section... Substances § 721.10270 Fullerene-C84-D2d. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Fullerene-C84-D2d (PMN P-09-57; CAS No. 145809-20-7)...

  13. Observation of fullerenes (C60-C70) associated with LDEF crater number 31

    NASA Technical Reports Server (NTRS)

    Radicatidibrozolo, Filippo; Fleming, R. H.; Bunch, T. E.

    1992-01-01

    The presence of fullerenes in and around the LDEF crater number 31 is reported. This crater has a high C level associated with it, and is interpreted as having been produced by the impact of a C-rich micrometeoroid. Fullerenes are large 3-D C structures, among which the species C sub 60 (MW 720) and C sub 70 (MW 840) are preeminent. Fullerenes have several UV absorption bands, hence fullerenes should be detectable using UV laser ionization time-of-flight mass spectrometry. We use a LIMA-2A instrument with pulsed UV laser (266 nm) to search for high mass C species associated with LDEF crater number 31. The mass range was 0 to 1200 amu. Low ablating laser power levels were used (less than or = 5 x 10 exp 7 W/sq. cm); 200 mass spectra were acquired and summed. We observed high mass signals near m/z 720, exhibiting 24 amu separation, which is characteristic of fullerenes. Alkali ion signals were also observed. Little or no C clusters of intermediate mass were observed. We interpret the signals around m/z 720 as fullerenes, mainly C sub 60+ with lower levels of C sub 70+. We propose that the mechanism that produces these signals is resonant multiphoton ionization (REMPI). This selective mechanism explains why low mass C cluster ions are not observed along with the fullerenes, since they have much higher ionization potentials. This finding is unexpected, since up to now the search for fullerenes in extraterrestrial materials has not been successful. We conclude that the fullerenes became associated with crater number 31 in space. Two alternative (and exciting) scenarios are being considered at this time: either the fullerenes were carried by the C-rich projectile that formed crater number 31, or the fullerenes formed upon impact with the LDEF. We show the results of experiments at the ARC Vertical Gun Facility, which may establish some constraints on the origin of the fullerenes.

  14. 40 CFR 721.10269 - [5,6]Fullerene-C84-D2.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fullerene-C84-D2. 721.10269 Section... Substances § 721.10269 Fullerene-C84-D2. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Fullerene-C84-D2 (PMN P-09-56; CAS No. 145809-19-4)...

  15. 40 CFR 721.10268 - [5,6]Fullerene-C70-D5h(6).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fullerene-C70-D5h(6). 721.10268... Substances § 721.10268 Fullerene-C70-D5h(6). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Fullerene-C70-D5h(6) (PMN P-09-55; CAS No....

  16. 40 CFR 721.10267 - [5,6]Fullerene-C60-Ih.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fullerene-C60-Ih. 721.10267 Section... Substances § 721.10267 Fullerene-C60-Ih. (a) Chemical substance and significant new uses subject to reporting.(1) The chemical substance identified as Fullerene-C60-Ih (PMN P-09-54;CAS No. 99685-96-8) is...

  17. 40 CFR 721.10270 - [5,6]Fullerene-C84-D2d.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fullerene-C84-D2d. 721.10270 Section... Substances § 721.10270 Fullerene-C84-D2d. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as Fullerene-C84-D2d (PMN P-09-57; CAS No. 145809-20-7)...

  18. Modeling Charge Transfer in Fullerene Collisions via Real-Time Electron Dynamics

    SciTech Connect

    Jakowski, Jacek; Irle, Stephan; Morokuma, Keiji; Sumpter, Bobby G

    2012-01-01

    An approach for performing real-time dynamics of electron transfer in a prototype redox reaction that occurs in reactive collisions between neutral and ionic fullerenes is discussed. The quantum dynamical simulations show that the electron transfer occurs within 60 fs directly preceding the collision of the fullerenes, followed by structural changes and relaxation of electron charge. The consequences of real-time electron dynamics are fully elucidated for the far from equilibrium processes of collisions between neutral and multiply charged fullerenes.

  19. Compact Electron Gun Based on Secondary Emission Through Ionic Bombardment

    PubMed Central

    Diop, Babacar; Bonnet, Jean; Schmid, Thomas; Mohamed, Ajmal

    2011-01-01

    We present a new compact electron gun based on the secondary emission through ionic bombardment principle. The driving parameters to develop such a gun are to obtain a quite small electron gun for an in-flight instrument performing Electron Beam Fluorescence measurements (EBF) on board of a reentry vehicle in the upper atmosphere. These measurements are useful to characterize the gas flow around the vehicle in terms of gas chemical composition, temperatures and velocity of the flow which usually presents thermo-chemical non-equilibrium. Such an instrument can also be employed to characterize the upper atmosphere if placed on another carrier like a balloon. In ground facilities, it appears as a more practical tool to characterize flows in wind tunnel studies or as an alternative to complex electron guns in industrial processes requiring an electron beam. We describe in this paper the gun which has been developed as well as its different features which have been characterized in the laboratory. PMID:22163896

  20. Actinide production from xenon bombardments of curium-248

    SciTech Connect

    Welch, R.B.

    1985-01-01

    Production cross sections for many actinide nuclides formed in the reaction of /sup 129/Xe and /sup 132/Xe with /sup 248/Cm at bombarding energies slightly above the coulomb barrier were determined using radiochemical techniques to isolate these products. These results are compared with cross sections from a /sup 136/Xe + /sup 248/Cm reaction at a similar energy. When compared to the reaction with /sup 136/Xe, the maxima in the production cross section distributions from the more neutron deficient projectiles are shifted to smaller mass numbers, and the total cross section increases for the production of elements with atomic numbers greater than that of the target, and decreases for lighter elements. These results can be explained by use of a potential energy surface (PES) which illustrates the effect of the available energy on the transfer of nucleons and describes the evolution of the di-nuclear complex, an essential feature of deep-inelastic reactions (DIR), during the interaction. The other principal reaction mechanism is the quasi-elastic transfer (QE). Analysis of data from a similar set of reactions, /sup 129/Xe, /sup 132/Xe, and /sup 136/Xe with /sup 197/Au, aids in explaining the features of the Xe + Cm product distributions, which are additionally affected by the depletion of actinide product yields due to deexcitation by fission. The PES is shown to be a useful tool to predict the general features of product distributions from heavy ion reactions.

  1. Seduction of Finding Universality in Sputtering Yields Due to Cluster Bombardment of Solids

    E-print Network

    Zbigniew, Postawa

    kinetic energy E are expressed in quantities scaled by the number of cluster atoms n, that is, Y/n versus simulations of Arn cluster bombardment of molecular (benzene, octane, and -carotene) and atomic (Ag) solids

  2. Polarity-dependent forming in ion bombarded amorphous silicon memory devices

    SciTech Connect

    Gateru, R.G.; Orwa, J.O.; Shannon, J.M.

    2005-01-15

    Polarity-dependent forming in ion bombarded metal-semiconductor-metal (MSM) memory devices of hydrogenated amorphous silicon is reported. It is shown that prior to ion bombardment, current transport in the MSM devices is asymmetric and is controlled by the Schottky barriers at two MS junctions. Upon bombardment, however, there is a bulk component to the current and the I-V characteristics of the devices become symmetric at low bias voltages. The forming voltage in the bombarded devices shows polarity dependence. For positive bias applied on the top contact, we find that devices form at the same electric field independent of the thickness of the amorphous silicon while for negative voltage on the top contact, the electric field needed for forming increases with the thickness. A model involving the difference in energy deposition and heat sinking for the two polarities is proposed.

  3. Fast-atom bombardment mass spectra of some pentapeptides related to natural enkephalins.

    PubMed

    Casy, A F

    1986-08-01

    The mass spectral features of four diastereoisomeric pairs of peptides related to the enkephalins recorded under fast-atom bombardment conditions are presented and shown to provide evidence of molecular weight and amino acid content and sequence. PMID:2876079

  4. Immobilization of [60]fullerene on silicon surfaces through a calix[8]arene layer

    NASA Astrophysics Data System (ADS)

    Busolo, Filippo; Silvestrini, Simone; Armelao, Lidia; Maggini, Michele

    2013-10-01

    In this work, we report the functionalization of flat Si(100) surfaces with a calix[8]arene derivative through a thermal hydrosilylation process, followed by docking with [60]fullerene. Chemical grafting of calix[8]arene on silicon substrates was evaluated by X-ray photoelectron spectroscopy, whereas host-guest immobilization of fullerene was demonstrated by atomic force microscopy and sessile drop water contact angle measurements. Surface topographical variations, modelled on the basis of calix[8]arene and [60]fullerene geometrical parameters, are consistent with the observed morphological features relative to surface functionalization and to non-covalent immobilization of [60]fullerene.

  5. Controlling Exciton Diffusion and Fullerene Distribution in Photovoltaic Blends by Side Chain Modification.

    PubMed

    Sajjad, Muhammad T; Ward, Alexander J; Kästner, Christian; Ruseckas, Arvydas; Hoppe, Harald; Samuel, Ifor D W

    2015-08-01

    The influence of crystallinity on exciton diffusion and fullerene distribution was investigated by blending amorphous and semicrystalline copolymers. We measured exciton diffusion and fluorescence quenching in such blends by dispersing fullerene molecules into them. We find that the diffusion length is more than two times higher in the semicrystalline copolymer than in the amorphous copolymer. We also find that fullerene preferentially mixes into disordered regions of the polymer film. This shows that relatively small differences in molecular structure are important for exciton diffusion and fullerene distribution. PMID:26267202

  6. Effect of pulse-modulated microwaves on fullerene ion production with electron cyclotron resonance ion source.

    PubMed

    Asaji, T; Uchida, T; Minezaki, H; Oshima, K; Racz, R; Muramatsu, M; Biri, S; Kitagawa, A; Kato, Y; Yoshida, Y

    2012-02-01

    Fullerene plasmas generated by pulse-modulated microwaves have been investigated under typical conditions at the Bio-Nano electron cyclotron resonance ion source. The effect of the pulse modulation is distinct from that of simply structured gases, and then the density of the fullerene plasmas increased as decreasing the duty ratio. The density for a pulse width of 10 ?s at the period of 100 ?s is 1.34 times higher than that for CW mode. We have studied the responses of fullerene and argon plasmas to pulsed microwaves. After the turnoff of microwave power, fullerene plasmas lasted ?30 times longer than argon plasmas. PMID:22380150

  7. The functionalization of fullerenes and nanocarbon materials for photovoltaics and other applications

    E-print Network

    Han, Ggoch Ddeul (Ggoch Ddeul Grace)

    2015-01-01

    Fullerenes and other nanocarbon materials such as carbon nanotubes possess interesting chemical and physical properties. In this thesis, we explore various functionalization methods for nanocarbon materials and their ...

  8. Immobilization of [60]fullerene on silicon surfaces through a calix[8]arene layer

    SciTech Connect

    Busolo, Filippo; Silvestrini, Simone; Maggini, Michele; Armelao, Lidia

    2013-10-28

    In this work, we report the functionalization of flat Si(100) surfaces with a calix[8]arene derivative through a thermal hydrosilylation process, followed by docking with [60]fullerene. Chemical grafting of calix[8]arene on silicon substrates was evaluated by X-ray photoelectron spectroscopy, whereas host-guest immobilization of fullerene was demonstrated by atomic force microscopy and sessile drop water contact angle measurements. Surface topographical variations, modelled on the basis of calix[8]arene and [60]fullerene geometrical parameters, are consistent with the observed morphological features relative to surface functionalization and to non-covalent immobilization of [60]fullerene.

  9. Ultrafast processes of photoinduced charge and energy transfer in nanostructural fullerene-metal films

    SciTech Connect

    Chekalin, S. V.

    2006-11-15

    The primary stages of photoinduced processes in tin-doped C{sub 60} fullerene films have been studied using a femtosecond pump-probe technique with 150-fs laser excitation pulses ({lambda} = 400 nm) and differential transmission and reflection probing in the 1100-1700 nm range. The relaxation dynamics strongly depends both on the metal-to-fullerene ratio in the film and on the mutual distribution (packing) of components in the nanocomposite material. The observed response signal dynamics is related to features in the charge carrier generation, energy transfer between fullerene molecules, and charge transport between metal and fullerene.

  10. Synthesis of Fullerenes in Low Pressure Benzene/Oxygen Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Hebgen, Peter; Howard, Jack B.

    1999-01-01

    The interest in fullerenes is strongly increasing since their discovery by Kroto et al. in 1985 as products of the evaporation of carbon into inert gas at low pressure. Due to their all carbon closed-shell structure, fullerenes have many exceptional physical and chemical properties and a large potential for applications such as superconductors, sensors, catalysts, optical and electronic devices, polymers, high energy fuels, and biological and medical materials. This list is still growing, because the research on fullerenes is still at an early stage. Fullerenes can be formed not only in a system containing only carbon and an inert gas, but also in premixed hydrocarbon flames under reduced pressure and fuel rich conditions. The highest yields of fullerenes in flames are obtained under conditions of substantial soot formation. There is a need for more information on the yields of fullerenes under different conditions in order to understand the mechanisms of their formation and to enable the design of practical combustion systems for large-scale fullerene production. Little work has been reported on the formation of fullerenes in diffusion flames. In order to explore the yields of fullerenes and the effect of low pressure in diffusion flames, therefore we constructed and used a low pressure diffusion flame burner in this study.

  11. Controlling Exciton Diffusion and Fullerene Distribution in Photovoltaic Blends by Side Chain Modification

    PubMed Central

    2015-01-01

    The influence of crystallinity on exciton diffusion and fullerene distribution was investigated by blending amorphous and semicrystalline copolymers. We measured exciton diffusion and fluorescence quenching in such blends by dispersing fullerene molecules into them. We find that the diffusion length is more than two times higher in the semicrystalline copolymer than in the amorphous copolymer. We also find that fullerene preferentially mixes into disordered regions of the polymer film. This shows that relatively small differences in molecular structure are important for exciton diffusion and fullerene distribution. PMID:26267202

  12. Enhancement of the 6.4 keV line in the inner Galactic ridge: Proton-induced fluorescence?

    E-print Network

    Nobukawa, K K; Uchiyama, H; Tsuru, T G; Torii, K; Tanaka, T; Chernyshov, D O; Fukui, Y; Dogiel, V A; Koyama, K

    2015-01-01

    A common idea for the origin of the Galactic diffuse X-ray emission, particularly that of the iron lines from neutral and highly ionized atoms, is a superposition of many cataclysmic variables and coronally active binaries. In this scenario, the flux should symmetrically distribute between the east and west on the plane with respect to Sagittarius A$^*$ because the stellar mass distribution determined by infrared observations is nearly symmetric. This symmetry is confirmed for the highly ionized iron line as well as the continuum emission. However, a clear excess of the neutral iron line in the near east of the Galactic center compared to the near-west side is found. The flux distribution of the excess emission well correlates with molecular column density. The X-ray spectrum of the excess emission is described by a power-law continuum plus a 6.4 keV line with the large equivalent width of $\\sim1.3$ keV, which is hardly explained by the low-energy electron bombardment scenario. The longitudinal and latitudina...

  13. Time-Of Mass Spectrometry with KEV and Mev Projectiles Using Coincidence Counting.

    NASA Astrophysics Data System (ADS)

    Inman, Mark Estes

    The goal of this study was to explore sample-projectile interactions by examining secondary ion (SI) yields in an event-by-event impact and detection mode. Cluster secondary ion mass spectrometry (SIMS) was evaluated in comparison to plasma desorption mass spectrometry (PDMS) and monoatomic SIMS. A cluster ion source was designed based on the spontaneous desorption (SD) process. The parameters affecting the SD were studied to optimize the cluster source performance. These factors were extraction grid vs. aperture, aperture size, source bias, source distance, and time. Under optimized SD conditions signal-to-noise ratios (S/N) up to approximately 27 were obtained for the production of CsI cluster ions. The ions of interest from the source were I^ - and (CsI)_{rm n} I^- clusters (where n is the cluster order). For our source a 3 mm gridless aperture 8 mm from the source foil produced the highest signal-to -noise ratio at 18 kV on the source. A signal-to-noise maximum was reached after the sample was biased for 12 hours. The SI yields from organic targets were compared for monoatomic keV ions, MeV ions (^{252 }Cf fission fragments), and polyatomic keV ions. The energy range of the clusters used was 18 to 27 keV. This comparison was made by calculating secondary ion yields for the molecular ions from a given sample. The organic samples used were epinephrine, gamma -aminobutyric acid, phenylalanine, and valine. For cluster bombardment secondary ion yields ranged from 0.53% for epinephrine to 3.45% for phenylalanine. These yields are less than the molecular ion yields from PDMS which ranged from 3.09% for epinephrine to 7.00% for phenylalanine. The secondary ion yields for monoatomic bombardment were 0.05% for epinephrine and 0.29% for phenylalanine. The higher yields observed with cluster primary ions are attributed to an enhancement effect related to the number of constituents in a cluster. Multiple ions detected from individual desorption events are said to be in coincidence. Coincidence counting can monitor these secondary ions and from which primary ion impact they occurred. This information is used to calculate percent coincidence between secondary ions. Percent coincidence is defined as the percentage of a peak observed in coincidence with another peak. Given the spatial correlations of ions emitted from the same projectile impact, percent coincidence gives indications about the homogeneity of surfaces. We found a linear relationship between a homogeneity factor based on percent coincidences of the secondary ions and particle size. Two types of samples were used, the first of which was a NaF/poly(vinyl methyl ether) (PVME) sample. With these samples we were able to distinguish between the PVME substrate and NaF crystals with diameters down to 1 mum. The second sample was rhodamine doped polystyrene spheres/PVME. The smallest sphere we were able to distinguish had a diameter of 0.48 mum.

  14. Many-Electron Response of Gas-Phase Fullerene Materials to Ultraviolet and Soft X-ray Photons

    NASA Astrophysics Data System (ADS)

    Chakraborty, Himadri S.; Magrakvelidze, Maia

    2015-06-01

    This article briefly reviews primary theoretical methods employed from the beginning of the century to predict the response of empty fullerenes, fullerenes endohedrally confining varieties of atoms, and few-layer fullerene nanoonions to the external electromagnetic radiations from ultraviolet to soft x-ray frequencies. Comparisons with available measurements are shown wherever possible and the success of the time-dependent local density approximation (TDLDA) method is predominantly emphasized. For the ionization process, various effects of the coherence, such as, the plasmon resonances, atom-fullerene dynamical hybridization, many-body correlations based on the interchannel coupling in the continuum, and Auger-intercoulombic hybrid multicenter decays of innershell holes are discussed. Finally, a broad outlook is presented that includes attosecond physics with fullerene materials, photoresponse of non-spherical fullerenes as well as fullerenes with off-centered confinements, the bare ion-impact ionization of fullerenes, and explorations beyond spherical systems to cylindrical carbon-nanotubes.

  15. Synthesis and Atropisomerism of Cascaded Tetraphenylporphyrin-[60]Fullerene Hybrids.

    PubMed

    Schlundt, Sebastian; Bauer, Walter; Hirsch, Andreas

    2015-08-24

    Flexible, linked dendritic tetraphenylporphyrin (TPP)-fullerene hybrids were synthesized. They were designed to gain insight into and mimic the primary events in the natural photosynthetic reaction center. These multiporphyrin moieties are based on a light-harvesting concept. Moreover, they incorporate multiple redox components aligned along a redox gradient. Newkome-type dendrons were added to these TPP-fullerene hybrids. In principle they can mediate pH-dependent water solubility, which, however, could not be observed in this case. A protecting-group strategy using tert-butyldiphenylsilyl groups allows convergent synthesis of the dendritic compounds. The dendritic multiporphyrins were synthesized separately and can be used as individual building blocks. Atropisomerism was observed in the dendritic compounds, and single atropisomers could be assigned to the corresponding peaks of a characteristic pattern in the NMR spectra. Deprotection of the Newkome-type dendrons was shown to be feasible under mild conditions that leave the redox gradient intact. PMID:26235308

  16. Recombination in polymer-fullerene bulk heterojunction solar cells

    SciTech Connect

    Cowan, Sarah; Roy, Anshuman; Heeger, Alan

    2010-12-16

    Recombination of photogenerated charge carriers in polymer bulk heterojunction (BHJ) solar cells reduces the short circuit current (J{sub sc} ) and the fill factor (FF). Identifying the mechanism of recombination is, therefore, fundamentally important for increasing the power conversion efficiency. Light intensity and temperature-dependent current-voltage measurements on polymer BHJ cells made from a variety of different semiconducting polymers and fullerenes show that the recombination kinetics are voltage dependent and evolve from first-order recombination at short circuit to bimolecular recombination at open circuit as a result of increasing the voltage-dependent charge carrier density in the cell. The “missing 0.3 V” inferred from comparison of the band gaps of the bulk heterojunction materials and the measured open-circuit voltage at room-temperature results from the temperature dependence of the quasi-Fermi levels in the polymer and fullerene domains—a conclusion based on the fundamental statistics of fermions.

  17. Modeling Nanotube Caps: The Relationship Between Fullerenes and Caps.

    PubMed

    Melle-Franco, Manuel; Brinkmann, Gunnar; Zerbetto, Francesco

    2015-12-24

    We present a novel method to calculate energies of nanotube caps with different levels of accuracy and a comprehensive study of its application to the IPR caps of the (10,0) carbon nanotube. The two most stable caps for (10,0) have 42 atoms, an energy of 8.7 eV, and correspond to sections of the third most abundant fullerene, C84. These caps are isoenergetic with a chemically unstable cap with 40 carbon atoms related to a C80 isomer that is also chemically unstable. Energies for the other caps are between 9.3 and 10 eV. A method to calculate cap energetics with fullerenes with an error less than 3% is also presented. PMID:26654289

  18. Thermal Isomerizations of Diethynyl Cyclobutadienes and Implications for Fullerene Formation.

    PubMed

    Esselman, Brian J; Emmert, Frank L; Wiederhold, Andrew J; Thompson, Stephanie J; Slipchenko, Lyudmila V; McMahon, Robert J

    2015-12-01

    The mechanism by which carbon condenses to form PAHs or fullerenes is a problem that has garnered considerable theoretical and experimental attention. The ring-coalescence and annealing model for the formation of C60 involves a [2 + 2] cycloaddition reaction of a cyclopolyyne to form a tetraalkynyl cyclobuta-1,3-diene intermediate, followed by a Bergman cycloaromatization reaction of the enediyne moiety. Intramolecular trapping of the incipient p-benzyne diradical across a diyne moiety of the macrocyclic ring affords an aromatic ring that must undergo further intramolecular reactions via polyradical intermediates to produce a condensed graphitic structure or fullerene. Computational studies of a model system for the intriguing tetraalkynylcyclobuta-1,3-diene intermediate, however, reveal that the corresponding p-benzyne diradical lies in a shallow minimum with a very low barrier to ring opening to cyclooctadienediyne. This pathway has not been previously considered in the mechanism for carbon condensation. PMID:26509879

  19. Influence of Substrate on Crystallization in Polythiophene/fullerene Blends

    SciTech Connect

    C He; D Germack; J Kline; D Delongchamp; D Fischer; C Snyder; M Toney; J Kushmerick; L Richter

    2011-12-31

    The nanoscale morphology of the active layer in organic, bulk heterojunction (BHJ) solar cells is crucial to device performance. Often a combination of casting conditions and post deposition thermal treatment is used to optimize the morphology. In general, the development of microscopic crystals is deleterious, as the exciton diffusion length is {approx}10 nm. We find that the microscopic crystallization behavior in polythiophene/fullerene blends is strongly influenced by the substrate on which the BHJ is cast. With a silicon oxide substrate, the crystal nucleation density is high and significant crystallization occurs at a temperature of 140 C. On more hydrophobic substrates, significantly higher temperatures are required for observable crystallization. This difference is attributed to the interfacial segregation of the PCBM, controlled by the substrate surface energy. The substrate dependence of crystallization has significant implications on the fullerene crystal growth mechanisms and practical implications for device studies.

  20. Interface engineering for efficient fullerene-free organic solar cells

    SciTech Connect

    Shivanna, Ravichandran; Narayan, K. S. E-mail: narayan@jncasr.ac.in; Rajaram, Sridhar E-mail: narayan@jncasr.ac.in

    2015-03-23

    We demonstrate the role of zinc oxide (ZnO) morphology and addition of an acceptor interlayer to achieve high efficiency fullerene-free bulk heterojunction inverted organic solar cells. Nanopatterning of the ZnO buffer layer enhances the effective light absorption in the active layer, and the insertion of a twisted perylene acceptor layer planarizes and decreases the electron extraction barrier. Along with an increase in current homogeneity, the reduced work function difference and selective transport of electrons prevent the accumulation of charges and decrease the electron-hole recombination at the interface. These factors enable an overall increase of efficiency to 4.6%, which is significant for a fullerene-free solution-processed organic solar cell.

  1. Linear attenuation coefficients of tissues from 1 keV to 150 keV

    NASA Astrophysics Data System (ADS)

    Böke, Aysun

    2014-09-01

    The linear attenuation coefficients and three interaction processes have been computed for liver, kidney, muscle, fat and for a range of x-ray energies from 1 keV to 150 keV. Molecular photoelectric absorption cross sections were calculated from atomic cross section data. Total coherent (Rayleigh) and incoherent (Compton) scattering cross sections were obtained by numerical integration over combinations of F2m(x) with the Thomson formula and Sm(x) with the Klein-Nishina formula, respectively. For the coherent (Rayleigh) scattering cross section calculations, molecular form factors were obtained from recent experimental data in the literature for values of x<1 Å-1 and from the relativistic modified atomic form factors for values of x?1 Å-1. With the inclusion of molecular interference effects in the coherent (Rayleigh) scattering, more accurate knowledge of the scatter from these tissues will be provided. The number of elements involved in tissue composition is 5 for liver, 47 for kidney, 44 for muscle and 3 for fat. The results are compared with previously published experimental and theoretical linear attenuation coefficients. In general, good agreement is obtained. The molecular form factors and scattering functions and cross sections are incorporated into a Monte Carlo program. The energy distributions of x-ray photons scattered from tissues have been simulated and the results are presented.

  2. Single or functionalized fullerenes interacting with heme group

    SciTech Connect

    Costa, Wallison Chaves; Diniz, Eduardo Moraes

    2014-09-15

    The heme group is responsible for iron transportation through the bloodstream, where iron participates in redox reactions, electron transfer, gases detection etc. The efficiency of such processes can be reduced if the whole heme molecule or even the iron is somehow altered from its original oxidation state, which can be caused by interactions with nanoparticles as fullerenes. To verify how such particles alter the geometry and electronic structure of heme molecule, here we report first principles calculations based on density functional theory of heme group interacting with single C{sub 60} fullerene or with C{sub 60} functionalized with small functional groups (?CH{sub 3}, ?COOH, ?NH{sub 2}, ?OH). The calculations shown that the system heme + nanoparticle has a different spin state in comparison with heme group if the fullerene is functionalized. Also a functional group can provide a stronger binding between nanoparticle and heme molecule or inhibit the chemical bonding in comparison with single fullerene results. In addition heme molecule loses electrons to the nanoparticles and some systems exhibited a geometry distortion in heme group, depending on the binding energy. Furthermore, one find that such nanoparticles induce a formation of spin up states in heme group. Moreover, there exist modifications in density of states near the Fermi energy. Although of such changes in heme electronic structure and geometry, the iron atom remains in the heme group with the same oxidation state, so that processes that involve the iron might not be affected, only those that depend on the whole heme molecule.

  3. Did Saturn's rings form during the Late Heavy Bombardment ?

    E-print Network

    Sebastien Charnoz; Alessandro Morbidelli; Luke H. Dones; Julien Salmon

    2008-11-02

    The origin of Saturn\\' s massive ring system is still unknown. Two popular scenarios - the tidal splitting of passing comets and the collisional destruction of a satellite - rely on a high cometary flux in the past. In the present paper we attempt to quantify the cometary flux during the Late Heavy Bombardment (LHB) to assess the likelihood of both scenarios. Our analysis relies on the so-called Nice model of the origin of the LHB (Tsiganis et al., 2005; Morbidelli et al., 2005; Gomes et al., 2005) and on the size distribution of the primordial trans-Neptunian planetesimals constrained in Charnoz & Morbidelli (2007). We find that the cometary flux on Saturn during the LHB was so high that both scenarios for the formation of Saturn rings are viable in principle. However, a more detailed study shows that the comet tidal disruption scenario implies that all four giant planets should have comparable ring systems whereas the destroyed satellite scenario would work only for Saturn, and perhaps Jupiter. This is because in Saturn\\'s system, the synchronous orbit is interior to the Roche Limit, which is a necessary condition for maintaining a satellite in the Roche zone up to the time of the LHB. We also discuss the apparent elimination of silicates from the ring parent body implied by the purity of the ice in Saturn \\' s rings. The LHB has also strong implications for the survival of the Saturnian satellites: all satellites smaller than Mimas would have been destroyed during the LHB, whereas Enceladus would have had from 40% to 70% chance of survival depending on the disruption model. In conclusion, these results suggest that the LHB is the sweet moment for the formation of a massive ring system around Saturn.

  4. Evolution of Titan's atmosphere during the Late Heavy Bombardment

    NASA Astrophysics Data System (ADS)

    Marounina, Nadejda; Tobie, Gabriel; Carpy, Sabrina; Monteux, Julien; Charnay, Benjamin; Grasset, Olivier

    2015-09-01

    The mass and composition of Titan's massive atmosphere, which is dominated by N2 and CH4 at present, have probably varied all along its history owing to a combination of exogenous and endogenous processes. In the present study, we investigate its fate during the Late Heavy Bombardment (LHB) by modeling the competitive loss and supply of volatiles by cometary impacts and their consequences on the atmospheric balance. For surface albedos ranging between 0.1 and 0.7, we examine the emergence of an atmosphere during the LHB as well as the evolution of a primitive atmosphere with various masses and compositions prior to this event, accounting for impact-induced crustal NH3-N2 conversion and subsequent outgassing as well as impact-induced atmospheric erosion. By considering an impactor population characteristic of the LHB, we show that the generation of a N2-rich atmosphere with a mass equivalent to the present-day one requires ammonia mass fraction of 2-5%, depending on surface albedos, in an icy layer of at least 50 km below the surface, implying an undifferentiated interior at the time of LHB. Except for high surface albedos (AS ? 0.7) where most of the released N2 remain frozen at the surface, our calculations indicate that the high-velocity impacts led to a strong atmospheric erosion. For a differentiated Titan with a thin ammonia-enriched crust (?5 km) and AS < 0.6 , any atmosphere preexisting before the LHB should be more than 5 times more massive than at present, in order to sustain an atmosphere equivalent to the present-day one. This implies that either a massive atmosphere was formed on Titan during its accretion or that the nitrogen-rich atmosphere was generated after the LHB.

  5. Is the Use of Fullerene in Photodynamic Therapy Effective for Atherosclerosis?

    SciTech Connect

    Nitta, Norihisa Seko, Ayumi; Sonoda, Akinaga; Ohta, Shinichi; Tanaka, Toyohiko; Takahashi, Masashi; Murata, Kiyoshi; Takemura, Shizuki; Sakamoto, Tsutomu; Tabata, Yasuhiko

    2008-03-15

    The purpose of this study was to evaluate Fullerene as a therapeutic photosensitizer in the treatment of atherosclerosis. An atherosclerotic experimental rabbit model was prepared by causing intimal injury to bilateral external iliac arteries using balloon expansion. In four atherosclerotic rabbits and one normal rabbit, polyethylene glycol-modified Fullerene (Fullerene-PEG) was infused into the left external iliac artery and illuminated by light emitting diode (LED), while the right external iliac artery was only illuminated by LED. Two weeks later, the histological findings for each iliac artery were evaluated quantitatively and comparisons were made among atherosclerotic Fullerene+LED artery (n = 4), atherosclerotic light artery (n = 4), normal Fullerene+LED artery (n = 1), and normal light artery (n = 1). An additional two atherosclerotic rabbits were studied by fluorescence microscopy, after Fullerene-PEG-Cy5 complex infusion into the left external iliac artery, for evaluation of Fullerene-PEG incorporated within the atherosclerotic lesions. The degree of atherosclerosis in the atherosclerotic Fullerene+LED artery was significantly (p < 0.05) more severe than that in the atherosclerotic LED artery. No pathological change was observed in normal Fullerene+LED and LED arteries. In addition, strong accumulation of Fullerene-PEG-Cy5 complex within the plaque of the left iliac artery of the two rabbits was demonstrated, in contrast to no accumulation in the right iliac artery. We conclude that infusion of a high concentration of Fullerene-PEG followed by photo-illumination resulted not in a suppression of atherosclerosis but in a progression of atherosclerosis in experimental rabbit models. However, this intervention showed no adverse effects on the normal iliac artery.

  6. Thermal Transport in Fullerene Derivatives Using Molecular Dynamics Simulations

    NASA Astrophysics Data System (ADS)

    Chen, Liang; Wang, Xiaojia; Kumar, Satish

    2015-08-01

    In order to study the effects of alkyl chain on the thermal properties of fullerene derivatives, we perform molecular dynamics (MD) simulations to predict the thermal conductivity of fullerene (C60) and its derivative phenyl-C61-butyric acid methyl ester (PCBM). The results of non-equilibrium MD simulations show a length-dependent thermal conductivity for C60 but not for PCBM. The thermal conductivity of C60, obtained from the linear extrapolation of inverse conductivity vs. inverse length curve, is 0.2??W?m-1?K-1 at room temperature, while the thermal conductivity of PCBM saturates at ~0.075??W?m-1?K-1 around 20?nm. The different length-dependence behavior of thermal conductivity indicates that the long-wavelength and low-frequency phonons have large contribution to the thermal conduction in C60. The decrease in thermal conductivity of fullerene derivatives can be attributed to the reduction in group velocities, the decrease of the frequency range of acoustic phonons, and the strong scattering of low-frequency phonons with the alkyl chains due to the significant mismatch of vibrational density of states in low frequency regime between buckyball and alkyl chains in PCBM.

  7. Nanoscale fullerene compression of an yttrium carbide cluster.

    PubMed

    Zhang, Jianyuan; Fuhrer, Tim; Fu, Wujun; Ge, Jiechao; Bearden, Daniel W; Dallas, Jerry; Duchamp, James; Walker, Kenneth; Champion, Hunter; Azurmendi, Hugo; Harich, Kim; Dorn, Harry C

    2012-05-23

    The nanoscale parameters of metal clusters and lattices have a crucial influence on the macroscopic properties of materials. Herein, we provide a detailed study on the size and shape of isolated yttrium carbide clusters in different fullerene cages. A family of diyttrium endohedral metallofullerenes with the general formula of Y(2)C(2n) (n = 40-59) are reported. The high field (13)C nuclear magnetic resonance (NMR) and density functional theory (DFT) methods are employed to examine this yttrium carbide cluster in certain family members, Y(2)C(2)@D(5)(450)-C(100), Y(2)C(2)@D(3)(85)-C(92), Y(2)C(2)@C(84), Y(2)C(2)@C(3v)(8)-C(82), and Y(2)C(2)@C(s)(6)-C(82). The results of this study suggest that decreasing the size of a fullerene cage with the same (Y(2)C(2))(4+) cluster results in nanoscale fullerene compression (NFC) from a nearly linear stretched geometry to a constrained "butterfly" structure. The (13)C NMR chemical shift and scalar (1)J(YC) coupling parameters provide a very sensitive measure of this NFC effect for the (Y(2)C(2))(4+) cluster. The crystal structural parameters of a previously reported metal carbide, Y(2)C(3) are directly compared to the (Y(2)C(2))(4+) cluster in the current metallofullerene study. PMID:22497289

  8. Inhibition of a thermophilic deoxyribonucleic acid polymerase by fullerene derivatives.

    PubMed

    Meng, Xianmei; Li, Bo; Chen, Zhe; Yao, Lu; Zhao, Dongxu; Yang, Xinlin; He, Min; Yu, Qun

    2007-06-01

    Enzyme inhibition by fullerene derivatives has attracted much attention. In this communication, effects of two water-solube fullerene derivatives, fullerol and trimalonic acid C60 (TMA C60) on polymerase chain reaction (PCR) were investigated by using PCR of beta-actin cDNA derived from HeLa cells as an experimental model. Both fullerol and TMA C60 were found to inhibit PCR in a dose-dependent manner. PCR was ultimately inhibited while the concentrations of each compound were not less than 0.01 mM. In contrast, mannitol exerted no effects on PCR while its concentration increased up to 2 mM. Compensation experiments with Thermus aquaticus (Taq) DNA polymerase revealed that both fullerol and TMA C60 inhibited the enzymatic activity of Taq DNA polymerase, and the inhibitory potency of TMA C60 was slightly greater than that of fullerol. Our data provides some novel aspects on the enzyme inhibiting activities of fullerene derivatives. PMID:17674810

  9. Fullerene derivatives as electron acceptors for organic photovoltaic cells.

    PubMed

    Mi, Dongbo; Kim, Ji-Hoon; Kim, Hee Un; Xu, Fei; Hwang, Do-Hoon

    2014-02-01

    Energy is currently one of the most important problems humankind faces. Depletion of traditional energy sources such as coal and oil results in the need to develop new ways to create, transport, and store electricity. In this regard, the sun, which can be considered as a giant nuclear fusion reactor, represents the most powerful source of energy available in our solar system. For photovoltaic cells to gain widespread acceptance as a source of clean and renewable energy, the cost per watt of solar energy must be decreased. Organic photovoltaic cells, developed in the past two decades, have potential as alternatives to traditional inorganic semiconductor photovoltaic cells, which suffer from high environmental pollution and energy consumption during production. Organic photovoltaic cells are composed of a blended film of a conjugated-polymer donor and a soluble fullerene-derivative acceptor sandwiched between a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-coated indium tin oxide positive electrode and a low-work-function metal negative electrode. Considerable research efforts aim at designing and synthesizing novel fullerene derivatives as electron acceptors with up-raised lowest unoccupied molecular orbital energy, better light-harvesting properties, higher electron mobility, and better miscibility with the polymer donor for improving the power conversion efficiency of the organic photovoltaic cells. In this paper, we systematically review novel fullerene acceptors synthesized through chemical modification for enhancing the photovoltaic performance by increasing open-circuit voltage, short-circuit current, and fill factor, which determine the performance of organic photovoltaic cells. PMID:24749413

  10. Thermal Transport in Fullerene Derivatives Using Molecular Dynamics Simulations.

    PubMed

    Chen, Liang; Wang, Xiaojia; Kumar, Satish

    2015-01-01

    In order to study the effects of alkyl chain on the thermal properties of fullerene derivatives, we perform molecular dynamics (MD) simulations to predict the thermal conductivity of fullerene (C60) and its derivative phenyl-C61-butyric acid methyl ester (PCBM). The results of non-equilibrium MD simulations show a length-dependent thermal conductivity for C60 but not for PCBM. The thermal conductivity of C60, obtained from the linear extrapolation of inverse conductivity vs. inverse length curve, is 0.2 W m(-1) K(-1) at room temperature, while the thermal conductivity of PCBM saturates at ~0.075 W m(-1) K(-1) around 20 nm. The different length-dependence behavior of thermal conductivity indicates that the long-wavelength and low-frequency phonons have large contribution to the thermal conduction in C60. The decrease in thermal conductivity of fullerene derivatives can be attributed to the reduction in group velocities, the decrease of the frequency range of acoustic phonons, and the strong scattering of low-frequency phonons with the alkyl chains due to the significant mismatch of vibrational density of states in low frequency regime between buckyball and alkyl chains in PCBM. PMID:26238607

  11. Charge-transfer doping by fullerenes on oxidized Si surfaces

    SciTech Connect

    Tada, Tetsuya; Uchida, Noriyuki; Kanayama, Toshihiko; Hiura, Hidefumi; Kimoto, Kenji

    2007-10-01

    We have studied the charge transfer between various fullerenes (C{sub 60}, C{sub 78}, C{sub 84}, C{sub 60}F{sub 36}, and C{sub 60}F{sub 48}) and oxidized Si surfaces in order to evaluate their capability of charge-transfer doping to form ultrashallow junctions in Si. Although the lowest unoccupied molecular orbitals of these fullerene molecules in isolated states are higher in energy than the valence band maximum (VBM) of Si, the fullerenes C{sub 60}F{sub 36} and C{sub 60}F{sub 48}, which were deposited on oxidized Si substrates, captured electrons from the Si surfaces; this generated hole inversion layers. C{sub 60}, C{sub 78}, and C{sub 84} did not induce such electron transfer. From the densities of the generated holes, we estimated the acceptor levels of C{sub 60}F{sub 36} and C{sub 60}F{sub 48}, which were condensed on the oxidized Si surface, to be 5.6-5.7 and 5.2 eV below the vacuum level, respectively; these values are lower than the VBM of Si.

  12. 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.

  13. Characterisation and determination of fullerenes: A critical review.

    PubMed

    Astefanei, Alina; Núñez, Oscar; Galceran, Maria Teresa

    2015-07-01

    A prominent sector of nanotechnology is occupied by a class of carbon-based nanoparticles known as fullerenes. Fullerene particle size and shape impact in how easily these particles are transported into and throughout the environment and living tissues. Currently, there is a lack of adequate methodology for their size and shape characterisation, identification and quantitative detection in environmental and biological samples. The most commonly used methods for their size measurements (aggregation, size distribution, shape, etc.), the effect of sampling and sample treatment on these characteristics and the analytical methods proposed for their determination in complex matrices are discussed in this review. For the characterisation and analysis of fullerenes in real samples, different analytical techniques including microscopy, spectroscopy, flow field-flow fractionation, electrophoresis, light scattering, liquid chromatography and mass spectrometry have been reported. The existing limitations and knowledge gaps in the use of these techniques are discussed and the necessity to hyphenate complementary ones for the accurate characterisation, identification and quantitation of these nanoparticles is highlighted. PMID:26043086

  14. Thermal Transport in Fullerene Derivatives Using Molecular Dynamics Simulations

    PubMed Central

    Chen, Liang; Wang, Xiaojia; Kumar, Satish

    2015-01-01

    In order to study the effects of alkyl chain on the thermal properties of fullerene derivatives, we perform molecular dynamics (MD) simulations to predict the thermal conductivity of fullerene (C60) and its derivative phenyl-C61-butyric acid methyl ester (PCBM). The results of non-equilibrium MD simulations show a length-dependent thermal conductivity for C60 but not for PCBM. The thermal conductivity of C60, obtained from the linear extrapolation of inverse conductivity vs. inverse length curve, is 0.2??W?m?1?K?1 at room temperature, while the thermal conductivity of PCBM saturates at ~0.075??W?m?1?K?1 around 20?nm. The different length-dependence behavior of thermal conductivity indicates that the long-wavelength and low-frequency phonons have large contribution to the thermal conduction in C60. The decrease in thermal conductivity of fullerene derivatives can be attributed to the reduction in group velocities, the decrease of the frequency range of acoustic phonons, and the strong scattering of low-frequency phonons with the alkyl chains due to the significant mismatch of vibrational density of states in low frequency regime between buckyball and alkyl chains in PCBM. PMID:26238607

  15. New fullerene-based mixed materials: Synthesis and characterization

    SciTech Connect

    McBranch, D.; Kohlman, R.; Klimov, V.; Grigorova, M.; Shi, X.; Smilowitz, L.; Mattes, B.R.; Wang, H.; Wudl, F.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors present results of broadband femtosecond transient absorption and broadband nanosecond optical limiting studies of C{sub 60} and derivatized C{sub 60}. They have investigated both solutions and solid-state mixed materials (sol-gel glass hosts doped with fullerene guests). They show that derivatized fullerenes provide enhanced solubility and processability, with a ground-state absorption extended into the infrared compared with C{sub 60}. They have extensively studied both the dynamic optical response and the excited-state absorption cross sections of solutions and solids for multiple wavelengths in the visible to near infrared. Wavelength-dependent studies show that the optical limiting response improves monotonically at longer wavelengths, demonstrating broadband limiting in all 6,6 mono-adducts and neat C{sub 60}. The authors report new approaches to processing sol-gel glass/fullerene composites to improve the optical limiting performance of solid-state materials to approach the response of solution limiters.

  16. Study of urological devices coated with fullerene-like nanoparticles

    NASA Astrophysics Data System (ADS)

    Goldbart, Ohad; Elianov, Olga; Shumalinsky, Dmitry; Lobik, Leonid; Cytron, Shmuel; Rosentsveig, Rita; Wagner, H. Daniel; Tenne, Reshef

    2013-08-01

    Insertion of endoscopes and other medical devices into the human body are ubiquitous, especially among aged males. The applied force for the insertion/extraction of the device from the urethra must overcome endoscope-surface-human-tissue interactions. In daily practice a gel is applied on the endoscope surface, in order to facilitate its entry into the urethra, providing also for local anesthesia. In the present work, a new solid-state lubricant has been added to the gel, in order to reduce the metal-urethra interaction and alleviate the potential damage to the epithelial tissue. For that purpose, a urethra model was designed and fabricated, which allowed a quantitative assessment of the applied force for extraction of the endoscope from a soft polymer-based ring. It is shown that the addition of MoS2 nanoparticles with fullerene-like structure (IF-MoS2) and in particular rhenium-doped nanoparticles (Re:IF-MoS2) to Esracain gel applied on the metal-lead reduced the friction substantially. The Re:IF-MoS2 showed better results than the undoped fullerene-like nanoparticles and both performed better than the gel alone. The mechanism of friction reduction is attributed to fullerenes' ability to roll and act as a separator between the active parts of the model.

  17. The interaction of He{sup ?} with fullerenes

    SciTech Connect

    Mauracher, Andreas; Daxner, Matthias; Huber, Stefan E.; Postler, Johannes; Renzler, Michael; Denifl, Stephan; Scheier, Paul E-mail: andrew.ellis@le.ac.uk; Ellis, Andrew M. E-mail: andrew.ellis@le.ac.uk

    2015-03-14

    The effects of interactions between He{sup ?} and clusters of fullerenes in helium nanodroplets are described. Electron transfer from He{sup ?} to (C{sub 60}){sub n} and (C{sub 70}){sub n} clusters results in the formation of the corresponding fullerene cluster dianions. This unusual double electron transfer appears to be concerted and is most likely guided by electron correlation between the two very weakly bound outer electrons in He{sup ?}. We suggest a mechanism which involves long range electron transfer followed by the conversion of He{sup +}into He{sub 2}{sup +}, where formation of the He–He bond in He{sub 2}{sup +} releases sufficient kinetic energy for the cation and the dianion to escape their Coulombic attraction. By analogy with the corresponding dications, the observation of a threshold size of n ? 5 for formation of both (C{sub 60}){sub n}{sup 2?} and (C{sub 70}){sub n}{sup 2?} is attributed to Coulomb explosion rather than an energetic constraint. We also find that smaller dianions can be observed if water is added as a co-dopant. Other aspects of He{sup ?} chemistry that are explored include its role in the formation of multiply charged fullerene cluster cations and the sensitivity of cluster dianion formation on the incident electron energy.

  18. Impact of Sunlight and Humic Acid on the Deposition Kinetics of Aqueous Fullerene Nanoparticles (nC60)

    E-print Network

    Alvarez, Pedro J.

    Impact of Sunlight and Humic Acid on the Deposition Kinetics of Aqueous Fullerene Nanoparticles (n, the impact of UVA irradiation and humic acid (HA) on deposition of aqueous fullerene nanoparticles (nC60 the concentrations of fullerenes at the order of magnitude of nanograms per liter to micrograms per liter in surface

  19. In summary, we reported a catalytic method for pro-duction of giant fullerene cages ranging generally from

    E-print Network

    In summary, we reported a catalytic method for pro- duction of giant fullerene cages ranging anticipate that our study might be a starting point for catalytic synthesis of giant fullerene cages, Dresselhaus G, Eklund PC. Science of fullerenes and carbon nanotubes. London: Academic; 1996. [4] Ugarte D

  20. High-temperature formation of concentric fullerene-like structures within foam-like carbon: Experiment and molecular dynamics simulation

    E-print Network

    Powles, Rebecca

    High-temperature formation of concentric fullerene-like structures within foam-like carbon is required to form well-ordered onions concentric fullerene-like spheres , in agreement with experiment of concentric fullerene-like structures, car- bon onions can be formed in a variety of harsh environments

  1. Characterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions with Pure and Mixed Phases

    E-print Network

    McGehee, Michael

    Characterization of the Polymer Energy Landscape in Polymer:Fullerene Bulk Heterojunctions offsets between the charge transport energy levels in different morphological phases of polymer:fullerene spectroscopy to characterize hole energy levels in the polymer phases of polymer:fullerene bulk heterojunctions

  2. Reaction of [60]fullerene with free radicals generated from active methylene compounds by manganese(III) acetate dihydrate

    E-print Network

    Wang, Guan-Wu

    Reaction of [60]fullerene with free radicals generated from active methylene compounds by manganese 2003 The reaction of [60]fullerene with dimethyl malonate and diethyl malonate in the presence of manganese(III) acetate dihydrate (Mn(OAc)3 2H2O) for 20 min afforded singly bonded [60]fullerene dimers 1a

  3. PAPER www.rsc.org/analyst | The Analyst Fullerene-impregnated ionic liquid stationary phases for gas

    E-print Network

    Reid, Scott A.

    PAPER www.rsc.org/analyst | The Analyst Fullerene-impregnated ionic liquid stationary phases A new method has been developed to facilitate the use of fullerenes as stationary phases (SPs) in gas chromatography (GC). In this method, ionic liquids (ILs) are used as solvents to coat fullerenes (C60, amino-C60

  4. Benzyne Adds Across a Closed 5-6 Ring Fusion in C70: Evidence for Bond Delocalization in Fullerenes

    E-print Network

    Wang, Guan-Wu

    Benzyne Adds Across a Closed 5-6 Ring Fusion in C70: Evidence for Bond Delocalization in Fullerenes addition to a 5-6 ring fusion in a fullerene, and the first example of an adduct to a 5-6 ring fusion where about the reactivity of the fullerenes in the short period since they became available in bulk

  5. La, Sc "t[OE",ZqV~...OE[V" Molecular Simulations of the Formation of La, Sc Containing Fullerene

    E-print Network

    Maruyama, Shigeo

    Fullerene "OEZROEû·N--²·CSÛZR­Î·v Yasutaka YAMAGUCHI and Shigeo MARUYAMA, Dept. of Mech. Eng., The University of Tokyo The growth process of metal-containing fullerenes similar to fullerene cage first appeared. Considering the difference of time and temperature scale between

  6. DOI: 10.1002/asia.201300522 Atomic Force Microscopy Study of the Effects of Water-Soluble Fullerenes

    E-print Network

    Tan, Weihong

    -Soluble Fullerenes on the Elasticity of Living Plant Cells Xuejie Zhang,[a] Qiaoling Liu,[a] Tie Xia,[a] Nan Li of the most-popular carbon nanomaterials, fullerenes have appealing photochemical, electrochemical- materials, including fullerenes, both positive and negative ef- fects have been reported.[7] For example

  7. [60]Fullerene-Containing Polyurethane Films with Large Ultrafast Nonresonant Third-Order Nonlinearity at Telecommunication Wavelengths

    E-print Network

    Sargent, Edward H. "Ted"

    [60]Fullerene-Containing Polyurethane Films with Large Ultrafast Nonresonant Third -electrons of the fullerenes are a known contributor to fast response time and large optical nonlinearity of [60]fullerene (C60).4 Furthermore, when double bonds are broken and an electron donor group

  8. Plasmon-Enhanced Photoemission from a Single Y3N@C80 Fullerene Palash Bharadwaj and Lukas Novotny*

    E-print Network

    Novotny, Lukas

    Plasmon-Enhanced Photoemission from a Single Y3N@C80 Fullerene Palash Bharadwaj and Lukas Novotny a C80 fullerene. These molecules, which do not exist naturally, are stabilized by a transfer of 6 absorption cross-section. Here we demonstrate that photoluminescence from fullerene- incarcerated yttrium

  9. The first observation of four-electron reduction in [60]fullerene-metal cluster self-assembled monolayers (SAMs)

    E-print Network

    Kim, Sehun

    The first observation of four-electron reduction in [60]fullerene-metal cluster self being reducible up to tetra- anionic species in their cyclic voltammograms. Thin films of fullerene modification of fullerenes and the development of methodologies to arrange them on a variety of surfaces

  10. SIMS depth profile study using metal cluster complex ion bombardment

    NASA Astrophysics Data System (ADS)

    Tomita, M.; Kinno, T.; Koike, M.; Tanaka, H.; Takeno, S.; Fujiwara, Y.; Kondou, K.; Teranishi, Y.; Nonaka, H.; Fujimoto, T.; Kurokawa, A.; Ichimura, S.

    2007-05-01

    SIMS depth profiles using a metal cluster complex ion of Ir4 (CO)7+were studied. An unusual increase of the sputtering yield under the condition of small incident angle may be attributed to the suppression of taking oxygen from flooding O2 by the formation of a carbon cover-layer derived from Ir4 (CO)7+ion. Even though the roughness of the sputtered surface is small, the depth resolution was not improved by decreasing the cluster ion energy to less than 5 keV, because the carbon cover-layer prevents the formation of surface oxide that buffers atomic mixing. To overcome this issue, it will be necessary to eliminate carbon from the cluster ion.

  11. Dual growth modes in ion bombarded Si surfaces

    SciTech Connect

    Dhillon, Prabhjeet Kaur; Sarkar, Subhendu

    2012-06-05

    Morphological studies were done on Si (001) surfaces after rastering them with a 1 keV O{sub 2}{sup +} ion beam at an angle. The resulting mounded morphology was studied using atomic force microscopy (AFM) measurements. The roughness at different length scales were further extracted and quantified from AFM measurements using scaling analysis. Results indicate two growth regimes of the evolving surface which were evident from the power spectral density (PSD) and interface width analysis of the eroded surfaces. Initially the growth is unstable followed by a stable regime of the nanostructures evolved after about 35 minutes of erosion. Temporal studies done on these surfaces show the onset of shadowing at higher sputtering times thus indicating the breakdown of the growth model at these times.

  12. Conformationally Constrained Macrocyclic Diporphyrin-Fullerene Artificial Photosynthetic Reaction Center

    SciTech Connect

    Garg, Vikas; Kodis, Gerdenis; Chachisvilis, Mirianas; Hambourger, Michael; Moore, Ana L.; Moore, Thomas A.; Gust, Devens

    2011-02-14

    Photosynthetic reaction centers convert excitation energy from absorbed sunlight into chemical potential energy in the form of a charge-separated state. The rates of the electron transfer reactions necessary to achieve long-lived, high-energy charge-separated states with high quantum yields are determined in part by precise control of the electronic coupling among the chromophores, donors, and acceptors and of the reaction energetics. Successful artificial photosynthetic reaction centers for solar energy conversion have similar requirements. Control of electronic coupling in particular necessitates chemical linkages between active component moieties that both mediate coupling and restrict conformational mobility so that only spatial arrangements that promote favorable coupling are populated. Toward this end, we report the synthesis, structure, and photochemical properties of an artificial reaction center containing two porphyrin electron donor moieties and a fullerene electron acceptor in a macrocyclic arrangement involving a ring of 42 atoms. The two porphyrins are closely spaced, in an arrangement reminiscent of that of the special pair in bacterial reaction centers. The molecule is produced by an unusual cyclization reaction that yields mainly a product with C2 symmetry and trans-2 disubstitution at the fullerene. The macrocycle maintains a rigid, highly constrained structure that was determined by UV-vis spectroscopy, NMR, mass spectrometry, and molecular modeling at the semiempirical PM6 and DFT (B3LYP/6-31G**) levels. Transient absorption results for the macrocycle in 2-methyltetrahydrofuran reveal photoinduced electron transfer from the porphyrin first excited singlet state to the fullerene to form a P•--C60•--P charge separated state with a time constant of 1.1 ps. Photoinduced electron transfer to the fullerene excited singlet state to form the same charge-separated state has a time constant of 15 ps. The charge-separated state is formed with a quantum yield of essentially unity and has a lifetime of 2.7 ns. The ultrafast charge separation coupled with charge recombination that is over 2000 times slower is consistent with a very rigid molecular structure having a small reorganization energy for electron transfer, relative to related porphyrin-fullerene molecules.

  13. Synthesis of condensed phases containing polycyclic aromatic hydrocarbons fullerenes and nanotubes

    DOEpatents

    Reilly, Peter T. A.

    2004-10-19

    The invention relates to methods for producing polycyclic aromatic hydrocarbons, fullerenes, and nanotubes, comprising: a. heating at least one carbon-containing material to form a condensed phase comprising at least one polycyclic aromatic hydrocarbon; b. collecting at least some of the condensed phase; c. reacting the condensed phase to form fullerenes and/or nanotubes.

  14. Fullerene Nanoparticles Exhibit Greater Retention in Freshwater Sediment than in Model Porous Media

    EPA Science Inventory

    Increasing production and use of fullerene-based nanomaterials underscore the need to determine their mobility in environmental transport pathways and potential ecological exposures. This study investigated the transport of two fullerenes (i.e., aqu/C(60) and water-soluble C(60) ...

  15. Carbon Onion Films-Molecular Interactions of Multi-Layer Fullerenes Raed A. Alduhaileb,1

    E-print Network

    Ayres, Virginia

    Carbon Onion Films-Molecular Interactions of Multi-Layer Fullerenes Raed A. Alduhaileb,1 Virginia M-8550, Japan ABSTRACT The evolution of carbon onion structure from spherical to polyhedral is correlated-shell fullerenes, or carbon onions, are under investigation as a nano-property enabled solid lubricant

  16. A search of diffuse bands in fullerene planetary nebulae: evidence for diffuse circumstellar bands

    E-print Network

    Diaz-Luis, J J; Rao, N Kameswara; Manchado, A; Cataldo, F

    2014-01-01

    Large fullerenes and fullerene-based molecules have been proposed as carriers of diffuse interstellar bands (DIBs). The recent detection of the most common fullerenes (C60 and C70) around some Planetary Nebulae (PNe) now enable us to study the DIBs towards fullerene-rich space environments. We search DIBs in the optical spectra towards three fullerene-containing PNe (Tc 1, M 1-20, and IC 418). Special attention is given to DIBs which are found to be unusually intense towards these fullerene sources. In particular, an unusually strong 4428A absorption feature is a common charateristic to fullerene PNe. Similarly to Tc 1, the strongest optical bands of neutral C60 are not detected towards IC 418. Our high-quality (S/N > 300) spectra for PN Tc 1 together with its large radial velocity permits us to search for the presence of diffuse bands of circumstellar origin which we refer to as diffuse circumstellar bands (DCBs). We report the first tentative detection of two DCBs at 4428 and 5780 A in the fullerene-rich ci...

  17. The Origin of Fullerenes in the 65 Myr Old Cretaceous/Tertiary Boundary

    NASA Technical Reports Server (NTRS)

    Becker, L.; Poreda, R. J.; Bunch, T. E.

    2000-01-01

    In this work we have searched for extraterrestrial (ET) helium (He) in fullerenes isolated from several K/T boundary (KTB) sediments. Measurements of He in these KTB fullerene residues revealed He-3/He-4 ratios that can only be explained as ET in origin.

  18. Water-soluble fullerene materials for bioapplications: photoinduced reactive oxygen species generation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The photoinduced reactive oxygen species (ROS) generation from several water-soluble fullerenes was examined. Macromolecular or small molecular water-soluble fullerene complexes/derivatives were prepared and their 1O2 and O2•- generation abilities were evaluated by EPR spin-trapping methods. As a r...

  19. Addressing asymmetry of the charge and strain in a two-dimensional fullerene peapod.

    PubMed

    Valeš, V; Verhagen, T; Vejpravová, J; Frank, O; Kalbá?, M

    2015-12-23

    We prepared a two-dimensional C70 fullerene peapod by the sequential assembly of (12)C graphene, C70 fullerenes and (13)C graphene. The local changes in the strain and doping were correlated with local roughness revealing asymmetry in the strain and doping with respect to the top and bottom graphene layers of the peapod. PMID:26661834

  20. Cathodoluminescence studies of C{sub 60} fullerene-based films and nanostructures

    SciTech Connect

    Nashchekin, A. V. Baryshev, S. V.; Sokolov, R. V.; Usov, O. A.

    2007-08-15

    The objects of investigation in this work are submicron Cm fullerene-based films and fullerene nanostructures fabricated by electron-beam lithography. The set of techniques for studying the fullerenes is extended due to attraction of the spectral cathodoluminescence (CL) to either of the initial fullerene films or submicron net structures with period of about 0.9 {mu}m, wall height 0.6 {mu}m, and width about 0.4 {mu}m.The maxima of the CL spectra of the initial C{sub 60} films are in good agreement with the energy-band structure of the amorphous fullerene film. In turn, the CL spectrum of the fullerene net structures possesses both peculiarities of the fullerene energy-band structure and it clearly exhibits the oscillations of the spectrum with a period as large as 0.08 eV. Such periodical fullerence net structures possess the properties of an optical resonator on the system 'fullerene net (n = 2.3)-air (n = 1).'.

  1. Chemical reaction of metal-fullerene in gas phase ^

    E-print Network

    Maruyama, Shigeo

    Chemical reaction of metal-fullerene in gas phase ·^Masamichi Kohno1 , Shuhei·" `··ZZOE±·S ,Q·D"OEfullerenes-ray diffraction study has proven (1) that some metal-fullerenes such as Sc@C82 and Sc2@C84 that were prepared

  2. Size-exclusive Nanosensor for Quantitative Analysis of Fullerene C60: A Concept Paper

    EPA Science Inventory

    This paper presents the first development of a mass-sensitive nanosensor for the isolation and quantitative analyses of engineered fullerene (C60) nanoparticles, while excluding mixtures of structurally similar fullerenes. Amino-modified beta cyclodextrin (?-CD-NH

  3. Changes in Agglomeration of Fullerenes During Ingestion and Excretion in Thamnocephalus Platuyrus

    EPA Science Inventory

    The crustacean Thamnocephalus platyurus was exposed to aqueous suspensions of fullerenes C60 and C70. Aqueous fullerene suspensions were formed by stirring C60 and C70 as received from a commercial vendor in deionized water (term...

  4. Changes in Agglomeration of Fullerenes During Ingestion and Excretion in Thamnocephalus Platyurus

    EPA Science Inventory

    The crustacean Thamnocephalus platyurus was exposed to aqueous suspensions of fullerenes C60 and C70. Aqueous fullerene suspensions were formed by stirring C60 and C70 as received from a commercial vendor in deionized water (termed aqu/C60 and aqu/C70) for approximately 100 d. Th...

  5. Linear Stability and Instability Patterns in Ion Bombarded Silicon Surfaces

    NASA Astrophysics Data System (ADS)

    Madi, Charbel Said

    2011-12-01

    This thesis is a combined experimental and theoretical study of the fundamental physical mechanisms governing nanoscale surface morphology evolution of Ar + ion bombarded silicon surfaces. I experimentally determined the topographical phase diagram resulting from Ar+ ion irradiation of Si surfaces at room temperature in the linear regime of surface dynamics as we vary the control parameters ion beam energy and incidence angle. At all energies, it is characterized by a diverging wavelength bifurcation from a smooth stable surface to parallel mode ripples (wavevector parallel to the projected ion beam on the surface) as the ion beam incidence angle is varied. At sufficiently high angles theta ? 85°, I observed perpendicular mode ripples (wavevector perpendicular to the ion beam). Through real-time Grazing-Incidence Small Angle X-ray Scattering, I have definitively established that ion-induced erosion, which is the consensus predominant cause of pattern formation, is not only of the wrong sign to explain the measured curvature coefficients responsible in driving the surface dynamics, but also is so small in magnitude as to be essentially negligible for pattern formation except possibly at the most grazing angles of incidence where both erosion and redistribution effects converge to zero. That the contribution of ion impact induced prompt atomic redistribution effects entirely overwhelms that of erosion in both the stabilizing and destabilizing regimes is of profound significance, as it overturns the erosion-based paradigm that has dominated the pattern formation field for over two decades. In situ wafer curvature measurements using the Multi-beam Optical Stress Sensor system were performed during amorphization of silicon by normal incidence 250 eV ion irradiation. An average compressive saturation stress built up in the amorphous layer was found to be as large as 1.5 GPa. By assuming the ion-induced amorphization layer to be modeled as a viscoelastic film that is anisotropically stressed by ion beam irradiation, we measure the deformation imparted per ion due to anisotropic deformation to be equal to A =1.15x10-16 cm2/ion. Although compressive stress is being injected into a thin viscoelastic ion-stimulated surface layer, the surface is unconditionally stable to topographic perturbations, corroborating the measured experimental phase diagram.

  6. Is the isolated pentagon rule always satisfied for metallic carbide endohedral fullerenes?

    PubMed

    Yang, Tao; Zhao, Xiang; Li, Sheng-Tao; Nagase, Shigeru

    2012-11-01

    Quantum-chemical calculations reveal that metallic carbide endohedral fullerene Y(2)C(2)@C(84) possesses a novel fullerene cage, C(1)(51383)-C(84), with one pair of pentagon adjacencies. One of the encapsulated yttrium atoms is located on the adjacent pentagons, while the other stays on a hexagonal ring in the fullerene cage. As one of numerous metallic carbide endohedral fullerenes, Y(2)C(2)@C(1)(51383)-C(84) is the first example that violates the well-known isolated pentagon rule (IPR). More interestingly, compared with the fact that Sc(2)C(2)@C(84) has a conventional IPR-satisfying cage, D(2d)(51591)-C(84), Y(2)C(2)@C(84) utilizes the novel fullerene cage C(1)(51383)-C(84) with one pair of pentagon adjacencies. PMID:23046342

  7. Fullerene mixtures enhance the thermal stability of a non-crystalline polymer solar cell blend

    NASA Astrophysics Data System (ADS)

    Lindqvist, Camilla; Bergqvist, Jonas; Bäcke, Olof; Gustafsson, Stefan; Wang, Ergang; Olsson, Eva; Inganäs, Olle; Andersson, Mats R.; Müller, Christian

    2014-04-01

    Printing of polymer:fullerene solar cells at high speed requires annealing at temperatures up to 140 °C. However, bulk-heterojunction blends that comprise a non-crystalline donor polymer often suffer from insufficient thermal stability and hence rapidly coarsen upon annealing above the glass transition temperature of the blend. In addition, micrometer-sized fullerene crystals grow, which are detrimental for the solar cell performance. In this manuscript, we present a strategy to limit fullerene crystallization, which is based on the use of fullerene mixtures of the two most common derivatives, PC61BM and PC71BM, as the acceptor material. Blends of this fullerene mixture and a non-crystalline thiophene-quinoxaline copolymer display considerably enhanced thermal stability and largely retain their photovoltaic performance upon annealing at elevated temperatures as high as 170 °C.

  8. Synthesis of confined electrically conducting carbon nanowires by heavy ion irradiation of fullerene thin film

    SciTech Connect

    Kumar, Amit; Avasthi, D. K.; Tripathi, A.; Kabiraj, D.; Singh, F.; Pivin, J. C.

    2007-01-01

    Conducting nanowires parallel to each other, embedded in fullerene matrix are synthesized by high energy heavy ion irradiation of thin fullerene film at low fluence (up to 5x10{sup 11} ions/cm{sup 2}). The conductivity of the conducting zone is about seven orders of magnitude higher than that of the fullerene matrix. The conducting nanowires are evidenced by conducting atomic force microscopy. The typical diameter of the conducting tracks is observed to be about 40-100 nm. The creation of conducting wires is explained by transformation of fullerene to conducting form of carbon in the ion track, surrounded by the polymerized zone. The polymerization of fullerene is evidenced by Fourier transform infrared spectroscopy.

  9. Encapsulation of radioactive isotopes into C 60 fullerene cage by recoil implantation technique

    NASA Astrophysics Data System (ADS)

    Saha, S. K.; Chowdhury, D. P.; Das, S. K.; Guin, R.

    2006-02-01

    Radioactive isotopes 24Na, 34 mCl, 65Zn, 69Ge, 71As, 72, 73, 75 Se, 77Br, 79Kr, 81Rb, 83Sr, 86Zr and 168Hf with recoil energy ˜3 MeV were implanted in thin film of C 60 for the formation of radioactive endohedral fullerenes by recoil implantation technique. The isotopes of interest were produced by 93-120 MeV 16O, 14N beams from Variable Energy Cyclotron Centre, Kolkata. Since direct interaction of primary heavy ion beams with the fullerene film was avoided in our experimental condition, the damage or degradation of the fullerene matrix could be reduced to insignificant level. The endohedral fullerenes formed were separated radio-chemically and the probabilities of formation of radioactive endohedral fullerenes from different isotopes were determined by ?-spectrometry.

  10. The interactions of high-energy, highly-charged ions with fullerenes

    SciTech Connect

    Ali, R.; Berry, H.G.; Cheng, S.

    1996-03-01

    In 1985, Robert Curl and Richard Smalley discovered a new form of carbon, the fullerene, C{sub 60}, which consists of 60 carbon atoms in a closed cage resembling a soccer ball. In 1990, Kritschmer et al. were able to make macroscopic quantities of fullerenes. This has generated intense activity to study the properties of fullerenes. One area of research involves collisions between fullerenes and atoms, ions or electrons. In this paper we describe experiments involving interactions between fullerenes and highly charged ions in which the center-of-mass energies exceed those used in other work by several orders of magnitude. The high values of projectile velocity and charge state result in excitation and decay processes differing significantly from those seen in studies 3 at lower energies. Our results are discussed in terms of theoretical models analogous to those used in nuclear physics and this provides an interesting demonstration of the unity of physics.

  11. Revisit of polystyrene-modified fullerene core stars: A computational study.

    PubMed

    Zhou, Jia

    2015-09-01

    Density functional theory (DFT) calculations have been used to clarify the number of poly(styryl) lithium anions that are grafted onto C60 fullerene. The computational results suggest that 6-arm-grafted C60 fullerene is the most thermodynamically favorable, and the grafted C60 fullerene with arms more than 6 is only achievable under certain circumstances. This observation is consistent with the previous experiments [Macromolecules 2013; 46:7451-57.]. Both electronic effect and steric effect have been thoroughly examined and they are found to play different roles in the arm-grafted C60 fullerene. The current study will pave a way for the future architecture of polymers on C60 fullerene and the like. PMID:26188799

  12. Electronic structure evolution of fullerene on CH3NH3PbI3

    NASA Astrophysics Data System (ADS)

    Wang, Chenggong; Wang, Congcong; Liu, Xiaoliang; Kauppi, John; Shao, Yuchuan; Xiao, Zhengguo; Bi, Cheng; Huang, Jinsong; Gao, Yongli

    2015-03-01

    The thickness dependence of fullerene on CH3NH3PbI3 perovskite film surface has been investigated by using ultraviolet photoemission spectroscopy (UPS), X-ray photoemission spectroscopy (XPS), and inverse photoemission spectroscopy (IPES). The lowest unoccupied molecular orbital and highest occupied molecular orbital (HOMO) can be observed directly with IPES and UPS. It is observed that the HOMO level in fullerene shifts to lower binding energy. The XPS results show a strong initial shift of core levels to lower binding energy in the perovskite, which indicates that electrons transfer from the perovskite film to fullerene molecules. Further deposition of fullerene forms C60 solid, accompanied by the reduction of the electron transfer. The strongest electron transfer happened at 1/4 monolayer of fullerene.

  13. Influence of C{sub 60} morphology on high-order harmonic generation enhancement in fullerene-containing plasma

    SciTech Connect

    Ganeev, R. A.; Singhal, H.; Naik, P. A.; Chakera, J. A.; Srivastava, A. K.; Dhami, T. S.; Joshi, M. P.; Gupta, P. D.

    2009-11-15

    The morphologies of the fullerene targets and the ablated fullerenes to determine the optimal conditions of excitation of the C{sub 60}-containing targets have been analyzed. The optimization of fullerene-containing plasma conditions allowed the enhanced harmonic generation in these plasmas using laser radiation of different wavelengths, pulse durations, and phase modulation. A comparison between the harmonic generation in single-atom/ion-containing plasmas (using bulk carbon, silver, and indium targets) and fullerene-rich plasma plumes showed better conversion efficiency for the latter medium. The influence of phase modulation of the fundamental radiation in fullerene plasmas on the spectral properties of harmonics has been studied.

  14. Positronium origin of 476 keV galactic feature.

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1973-01-01

    Leventhal noticed that the gamma-ray spectrum due to the annihilation of positronium, which consists of two 511 keV photons from the singlet state and three photons from the triplet state, produces a spectral feature with an apparent peak at an energy less than 511 keV when viewed with a gamma-ray telescope having a Gaussian energy resolution. He calculated that the observed peak will lie at 490 keV. The author calculates that if the positronium spectrum sits atop a steeply falling continuum due to other sources, then the apparent peak can easily fall near 476 keV where it was observed. It is shown that explosive nucleosynthesis is a plausible source of the positrons.

  15. Importance of the donor:fullerene intermolecular arrangement for high-efficiency organic photovoltaics.

    PubMed

    Graham, Kenneth R; Cabanetos, Clement; Jahnke, Justin P; Idso, Matthew N; El Labban, Abdulrahman; Ngongang Ndjawa, Guy O; Heumueller, Thomas; Vandewal, Koen; Salleo, Alberto; Chmelka, Bradley F; Amassian, Aram; Beaujuge, Pierre M; McGehee, Michael D

    2014-07-01

    The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b']dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) (13)C{(1)H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems. PMID:24932575

  16. Investigating the unknown nuclear reaction in a low-energy (E < 330 keV) p + Ti{sup 2}H{sub x} experiment

    SciTech Connect

    Wang, T.; Wang, Z.; Chen, J.; Jin, G.; Piao, Y.

    2000-03-01

    Charged-particle products with {approximately}3.9-MeV energy were observed in a low-energy experiment (E{sub p}{le} 330 keV) with a proton bombarding a Ti{sup 2}H{sub x} target. The features of the charged-particle products were the same as those of an alpha particle. The threshold of the reaction was {approximately}150 keV. The maximum reaction rate reached more than 10{sup 5} r/s, while the proton energy and current were 324 keV and 1.2 mA, respectively. The excitation curve of this unknown reaction increased exponentially with the growth of proton energy. There is no known nuclear reaction induced by a proton that can be applied to interpret this experimental phenomenon. Some interpretations, e.g., an indirect secondary reaction and a multibody reaction model, are discussed, but the origin of this unknown nuclear reaction is still a mystery and under study.

  17. Investigating the Unknown Nuclear Reaction in a Low-Energy (E < 330 keV) p + Ti{sup 2}H{sub x} Experiment

    SciTech Connect

    Wang Tieshan; Wang Zhiguo; Chen Jingen; Jin Genming; Piao Yubo

    2000-03-15

    Charged-particle products with {approx}3.9-MeV energy were observed in a low-energy experiment (E{sub p} {<=} 330 keV) with a proton bombarding a Ti{sup 2}H{sub x} target. The features of the charged-particle products were the same as those of an alpha particle. The threshold of the reaction was {approx}150 keV. The maximum reaction rate reached more than 10{sup 5} r/s, while the proton energy and current were 324 keV and 1.2 mA, respectively. The excitation curve of this unknown reaction increased exponentially with the growth of proton energy. There is no known nuclear reaction induced by a proton that can be applied to interpret this experimental phenomenon. Some interpretations, e.g., an indirect secondary reaction and a multibody reaction model, are discussed, but the origin of this unknown nuclear reaction is still a mystery and under study.

  18. 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

  19. Preparation, characterization and photocatalytic behavior of WO3-fullerene/TiO2 catalysts under visible light

    PubMed Central

    2011-01-01

    WO3-treated fullerene/TiO2 composites (WO3-fullerene/TiO2) were prepared using a sol-gel method. The composite obtained was characterized by BET surface area measurements, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy, and UV-vis analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. Excellent photocatalytic degradation of a MO solution was observed using the WO3-fullerene, fullerene-TiO2, and WO3-fullerene/TiO2 composites under visible light. An increase in photocatalytic activity was observed, and WO3-fullerene/TiO2 has the best photocatalytic activity; it may attribute to the increase of the photo-absorption effect by the fullerene and the cooperative effect of the WO3. PMID:21774800

  20. Sputter yields in diamond bombarded by ultra low energy ions

    NASA Astrophysics Data System (ADS)

    Guzmán de la Mata, B.; Dowsett, M. G.; Twitchen, D.

    2006-07-01

    Artificial diamond is an ideal material for high power, high voltage electronic devices, and for engineering use in extreme environments. Diamond process development requires parallel development in characterization techniques such as ultra low energy SIMS (uleSIMS), especially in the ability to depth profile for impurities and dopants at high depth resolution. As a contribution to the background knowledge required, we have measured the sputter yields of single crystal high pressure high temperature (HPHT) diamond using O 2+, Cs + and Ar + primary ions in the energy range 300 eV to 2 keV. We compare these with yields for silicon and GaAs. We show that the erosion rates with oxygen are ˜10 times what would be expected from ballistic processes and essentially energy independent in the measured range. This result agrees with the anomalously high sputter yield observed in the ion etching context. Conversely, positive ion yields for elements such as boron are very low in comparison with silicon. This points to a reactive ion etching process liberating CO or CO 2 rather than sputtering as the principal erosion process. This is both problematic and beneficial for SIMS analysis. Oxygen can be used to reach buried structures in diamond efficiently, and the effects of the near-normal incidence beam are planarizing as they are in silicon. Conversely, since positive ion yields are low, alternative probes or strategies must be found for high sensitivity profiling of electropositive elements.

  1. Study of NGC2070 at 3-8 Kev and 8-20 Kev using RXTE Survey

    NASA Astrophysics Data System (ADS)

    Bhattarai, Suresh

    2015-08-01

    In the present work, we studied the variation of relative flux density along the primary and secondary maxima in NGC2070 using 3-8 Kev and 8-20 Kev RXTE Survey. These two X-ray pass-bands are responsible for free-free transition and inner transition of electron because of strong radiation field of NGC2070. A similar knoty structure is found in both 3-8 Kev and 8-20 Kev passbands. However, the maxima is found to be located in the different knots. A similar nature of flux density variation is observed in both passbands, suggesting a strong association between the substructures. We conclude that the nebula NGC2070 exhibit X-ray dominated region which generally reduces the initial mass function of the interstellar cloud. A further study is needed in order to know the shaping mechanism of the structure.

  2. Propagation of Surface Ripples on Pyrochlore Single Crystals Induced by Ion Beam Bombardment

    SciTech Connect

    Wei, Q.M.; Lian, Jie; Boatner, Lynn A; Wang, L. M.; Ewing, Rodney C.

    2009-01-01

    The morphological evolution of ripples formed on the surface of Cd2Nb2O7 pyrochlore single crystals by focused ion beam (FIB) bombardment was investigated using in situ electron microscopy. At high ion fluences and off-normal bombardment angles, faceted surface ripples with a terrace-like structure were observed. The ripple propagation direction was oriented along the projected ion beam direction at incident angles ranging from 35 to 65 following high-dose ion bombardment. One side of the terrace was found to be perpendicular to the incident ion beam direction, while the other side was parallel to the ion beam. The terrace propagation velocity and direction were determined and interpreted on the basis of this asymmetric structure. A model based on the propagation of a shock wave that effectively self-selects a stable slope, was developed in order to explain the observed faceted ripple formation.

  3. Beyond fullerenes: design of nonfullerene acceptors for efficient organic photovoltaics.

    PubMed

    Li, Haiyan; Earmme, Taeshik; Ren, Guoqiang; Saeki, Akinori; Yoshikawa, Saya; Murari, Nishit M; Subramaniyan, Selvam; Crane, Matthew J; Seki, Shu; Jenekhe, Samson A

    2014-10-15

    New electron-acceptor materials are long sought to overcome the small photovoltage, high-cost, poor photochemical stability, and other limitations of fullerene-based organic photovoltaics. However, all known nonfullerene acceptors have so far shown inferior photovoltaic properties compared to fullerene benchmark [6,6]-phenyl-C60-butyric acid methyl ester (PC60BM), and there are as yet no established design principles for realizing improved materials. Herein we report a design strategy that has produced a novel multichromophoric, large size, nonplanar three-dimensional (3D) organic molecule, DBFI-T, whose ?-conjugated framework occupies space comparable to an aggregate of 9 [C60]-fullerene molecules. Comparative studies of DBFI-T with its planar monomeric analogue (BFI-P2) and PC60BM in bulk heterojunction (BHJ) solar cells, by using a common thiazolothiazole-dithienosilole copolymer donor (PSEHTT), showed that DBFI-T has superior charge photogeneration and photovoltaic properties; PSEHTT:DBFI-T solar cells combined a high short-circuit current (10.14 mA/cm(2)) with a high open-circuit voltage (0.86 V) to give a power conversion efficiency of 5.0%. The external quantum efficiency spectrum of PSEHTT:DBFI-T devices had peaks of 60-65% in the 380-620 nm range, demonstrating that both hole transfer from photoexcited DBFI-T to PSEHTT and electron transfer from photoexcited PSEHTT to DBFI-T contribute substantially to charge photogeneration. The superior charge photogeneration and electron-accepting properties of DBFI-T were further confirmed by independent Xenon-flash time-resolved microwave conductivity measurements, which correctly predict the relative magnitudes of the conversion efficiencies of the BHJ solar cells: PSEHTT:DBFI-T > PSEHTT:PC60BM > PSEHTT:BFI-P2. The results demonstrate that the large size, multichromophoric, nonplanar 3D molecular design is a promising approach to more efficient organic photovoltaic materials. PMID:25265412

  4. Top-down formation of fullerenes in the interstellar medium

    PubMed Central

    Berné, O.; Montillaud, J.; Joblin, C.

    2015-01-01

    Fullerenes have been recently detected in various circumstellar and interstellar environments, raising the question of their formation pathway. It has been proposed that they can form at the low densities found in the interstellar medium by the photo-chemical processing of large polycyclic aromatic hydrocarbons (PAHs). Following our previous work on the evolution of PAHs in the NGC 7023 reflection nebula, we evaluate, using photochemical modeling, the possibility that the PAH C66H20 (i.e. circumovalene) can lead to the formation of C60 upon irradiation by ultraviolet photons. The chemical pathway involves full dehydrogenation of C66H20, folding into a floppy closed cage and shrinking of the cage by loss of C2 units until it reaches the symmetric C60 molecule. At 10” from the illuminating star and with realistic molecular parameters, the model predicts that 100% of C66H20 is converted into C60 in ~ 105 years, a timescale comparable to the age of the nebula. Shrinking appears to be the kinetically limiting step of the whole process. Hence, PAHs larger than C66H20 are unlikely to contribute significantly to the formation of C60, while PAHs containing between 60 and 66 C atoms should contribute to the formation of C60 with shorter timescales, and PAHs containing less than 60 C atoms will be destroyed. Assuming a classical size distribution for the PAH precursors, our model predicts absolute abundances of C60 are up to several 10?4 of the elemental carbon, i.e. less than a percent of the typical interstellar PAH abundance, which is consistent with observational studies. According to our model, once formed, C60 can survive much longer (> 107 years for radiation fields below G0 = 104) than other fullerenes because of the remarkable stability of the C60 molecule at high internal energies. Hence, a natural consequence is that C60 is more abundant than other fullerenes in highly irradiated environments. PMID:26722131

  5. Synthesis of endohedral iron-fullerenes by ion implantation

    SciTech Connect

    Minezaki, H.; Ishihara, S.; Uchida, T.; Muramatsu, M.; Kitagawa, A.; Rácz, R.; Biri, S.; Kato, Y.; Yoshida, Y.; Bio-Nano Electronics Research Centre, Toyo University, 2100, Kujirai, Kawagoe, Saitama 350-8585

    2014-02-15

    In this paper, we discuss the results of our study of the synthesis of endohedral iron-fullerenes. A low energy Fe{sup +} ion beam was irradiated to C{sub 60} thin film by using a deceleration system. Fe{sup +}-irradiated C{sub 60} thin film was analyzed by high performance liquid chromatography and laser desorption/ ionization time-of-flight mass spectrometry. We investigated the performance of the deceleration system for using a Fe{sup +} beam with low energy. In addition, we attempted to isolate the synthesized material from a Fe{sup +}-irradiated C{sub 60} thin film by high performance liquid chromatography.

  6. Fluorescence of fullerene C 70 in ionic liquids

    NASA Astrophysics Data System (ADS)

    Martins, Sofia; Fedorov, Aleksander; Afonso, Carlos A. M.; Baleizão, Carlos; Berberan-Santos, Mário N.

    2010-09-01

    It is shown that pristine fullerene C 70 can be solubilised in imidazolium, ammonium and phosphonium based ionic liquids (ILs) bearing long alkyl chains (C 8 or higher). The absorption and fluorescence properties are similar to those displayed in conventional polar solvents except in ILs containing chloride as the counter ion, which completely quench the fluorescence of C 70. Fluorescence decay analysis using a sum of Becquerel functions to account for the complex decay of background emission allows the successful recovery of the solute's lifetime.

  7. Diamond-like phases formed from fullerene-like clusters

    NASA Astrophysics Data System (ADS)

    Belenkov, E. A.; Greshnyakov, V. A.

    2015-11-01

    The geometrically optimized structure and properties of thirteen diamond-like carbon phases formed by linking or combining fullerene-like clusters (C4, C6, C8, C12, C16, C24, or C48) have been investigated. Atoms in the structures of these phases are located in crystallographically equivalent positions. The calculations have been performed using the density functional theory in the generalized gradient approximation. The calculated values of the structural characteristics and properties (sublimation energies, bulk moduli, band gaps, X-ray diffraction patterns) of the studied diamond-like phases differ significantly from the corresponding values for cubic diamond.

  8. Fullerenes in the cretaceous-tertiary boundary layer.

    PubMed

    Heymann, D; Chibante, L P; Brooks, R R; Wolbach, W S; Smalley, R E

    1994-07-29

    High-pressure liquid chromatography with ultraviolet-visible spectral analysis of toluene extracts of samples from two Cretaceous-Tertiary (K-T) boundary sites in New Zealand has revealed the presence of C(60) at concentrations of 0.1 to 0.2 parts per million of the associated soot. This technique verified also that fullerenes are produced in similar amounts in the soots of common flames under ambient atmospheric conditions. Therefore, the C(60) in the K-T boundary layer may have originated in the extensive wildfires that were associated with the cataclysmic impact event that terminated the Mezozoic era about 65 million years ago. PMID:17752762

  9. Synthesis and characterization of novel fullerenes and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Piskoti, Charles Richard

    Since the discovery of Buckminsterfullerene, the soccerball shaped carbon-caged molecule consisting of 60 carbon atoms, there has been much speculation about the stability of other "fullerenes" with less than 60 carbon atoms. Although several fullerenes with greater than 60 carbon atoms have since been isolated in bulk, the only evidence of lower fullerenes has come from minute-quantity gas phase experiments. This thesis presents work on the first ever bulk synthesis, extraction and characterization of a lower fullerene: C36. By exploring the parameter space of the Kratschmer-Huffman graphite arc-discharge method, C36 was produced in milligram quantities. This new material which was extracted with pyridine was found by electron diffraction to form a covalently bonded solid with a d-spacing of 6.68 A. This material is electrically insulating in its pure form but it becomes conducting upon intercalation with alkali metals. The resistance vs temperature behavior of the alkali intercalated samples is consistent with variable range hopping. From microwave-loss measurements and current vs. voltage data, there are preliminary results that may indicate the presence of a very small superconducting fraction in these alkali doped samples. This result would be consistent with predictions by Grossman, Cote, Cohen and Louie that a certain isomer of C 36 with D6h symmetry has an exceptionally strong electron-phonon coupling constant. Other developments described in this thesis include a method of synthesizing multi-walled carbon nanotubes in high yield at an accelerated rate using a low pressure mixture of nitrogen and helium as the buffer gas. Also, a simple technique has been developed for synthesizing magnetic nickel-iron clusters that are coated with both electrical insulators and electrical conductors. These clusters may have a variety of applications in the fields of magnetic recording and biochemistry where magnetic manipulation of cells is important. Finally, a preliminary study of doping effects in multi-walled carbon nanotubes was conducted. This study showed that the transport properties of these nanotubes changed dramatically upon intercalation with both oxygen and potassium.

  10. An experiment to study fullerene formation under reduced gravity

    NASA Technical Reports Server (NTRS)

    Wdowiak, Thomas J.

    1992-01-01

    The activity of the summer focused on the design and construction of key components of a carbon arc/inert gas reactor for fullerene production, that is suitable for reduced gravity experiments onboard the KC-135 aircraft. The apparatus will be configured for both floor-mount and free-floating operation providing access to reduction to 10(exp -2) and 10(exp -3) of normal respectively. It is planned to incorporate 'seat belt' restraints that will allow a safe transition from reduced gravity free-float to full gravity, at the end of the parabolic.

  11. Electrically conducting porphyrin and porphyrin-fullerene electropolymers

    DOEpatents

    Gust, Jr., John Devens; Liddell, Paul Anthony; Gervaldo, Miguel Andres; Bridgewater, James Ward; Brennan, Bradley James; Moore, Thomas Andrew; Moore, Ana Lorenzelli

    2014-03-11

    Compounds with aryl ring(s) at porphyrin meso position(s) bearing an amino group in position 4 relative to the porphyrin macrocycle, and at least one unsubstituted 5 (hydrogen-bearing) meso position with the 10-, 15-, and/or 20-relationship to the aryl ring bearing the amino group, and metal complexes thereof, feature broad spectral absorption throughout the visible region. These compounds are electropolymerized to form electrically conducting porphyrin and porphyrin-fullerene polymers that are useful in photovoltaic applications. The structure of one such electrically conducting porphyrin polymer is shown below. ##STR00001##

  12. Fullerene photoemission time delay explores molecular cavity in attoseconds

    E-print Network

    Magrakvelidze, Maia; Dixit, Gopal; Madjet, Mohamed El-Amine; Chakraborty, Himadri S

    2014-01-01

    Time-resolved photoelectron spectroscopy can probe interference oscillations in C60 valence emissions that produce series of minima whose energy separation depends on the molecular size. We show that the quantum phase associated with these minima exhibits rapid variations due to electron correlations, causing rich structures in the photoemission time delay. These findings provide a way to utilize temporal information to access the fullerene cavity size, that is making the time to "see" the space, and can be generalized to photoemissions from clusters and nanostructures.

  13. Viruses and Fullerenes - Symmetry as a Common Thread?

    E-print Network

    Dechant, Pierre-Philippe; Keef, Tom; Twarock, Reidun

    2014-01-01

    We apply here the principle of affine symmetry to the nested fullerene cages (carbon onions) that arise in the context of carbon chemistry. Previous work on affine extensions of the icosahedral group has revealed a new organisational principle in virus structure and assembly. We adapt this group theoretic framework here to the physical requirements dictated by carbon chemistry, and show that we can derive mathematical models for carbon onions within this affine symmetry approach. This suggests the applicability of affine symmetry in a wider context in Nature, as well as offering a novel perspective on the geometric principles underpinning carbon chemistry.

  14. Disorder effect on carrier mobility in Fullerene organic semiconductor

    NASA Astrophysics Data System (ADS)

    Mendil, N.; Daoudi, M.; Berkai, Z.; Belghachi, A.

    2015-10-01

    The critical factor that limits the efficiencies of organic electronic devices is the low charge carrier mobility which is attributed to disorder in organic films. In this context, we have studied the effects of disorder on carrier mobility in organic Schottky diode of electrons for the fullerene (C60). Our results show that the mobility is sensitive probes of structural phase transitions and order-disorder underlying C60. Where it is one reason behind the low mobility which it take as value 1.4x10-2 cm2/V.s above critical temperature Tc =289K.

  15. Subphthalocyanines hydrogen bonded capsules featuring norbornadiene tethers: Promising fullerene receptors

    NASA Astrophysics Data System (ADS)

    Denis, Pablo A.; Yanney, Michael

    2015-11-01

    We have employed density functional theory to study new subphthalocyanine based receptors which feature the 1,4-dithiino and norbornadiene linkages. The latter linkage significantly improves the host binding capabilities with respect to subphthalocyanine based receptors. Moreover, the interaction energy of the new subphthalocyanine-norbornadiene receptor is larger than that computed for the C60H28 buckycatcher. The dimerization of the new receptor forms a hydrogen-bonded capsule. Through a combination of non-bonded interactions, this capsule can bind C60 with an unprecedented affinity. Due to the exceptional stability of this capsule, it is our hope that it can be used for other guests besides fullerenes.

  16. Design molecular rectifier and photodetector with all-boron fullerene

    NASA Astrophysics Data System (ADS)

    Yang, Zhi; Ji, Yu-Long; Lan, Guoqiang; Xu, Li-Chun; Liu, Xuguang; Xu, Bingshe

    2015-09-01

    All-boron fullerene B40 is a highly stable molecule, which has been successfully synthesized in recent experiment. In this paper, with Au as two electrodes, the single-molecule device Au-B40-Au was investigated by using density functional theory and non-equilibrium Green's function method. The results show that the device can exhibit large rectification ratio and significant negative differential resistance. More importantly, the photocurrent of the device has different responses in the infrared, visible and ultraviolet regions. The excellent optoelectronic properties ensure that the device can be used as photodetector.

  17. Donor–acceptor type co-crystals of arylthio-substituted tetrathiafulvalenes and fullerenes

    PubMed Central

    Lu, Xiaofeng; Sun, Jibin; Zhang, Shangxi; Ma, Longfei; Liu, Lei; Qi, Hui; Shao, Yongliang

    2015-01-01

    Summary A series of donor–acceptor type co-crystals of fullerene (as the acceptor) and arylthio-substituted tetrathiafulvalene derivatives (Ar-S-TTF, as the donor) were prepared and their structural features were thoroughly investigated. The formation of co-crystals relies on the flexibility of Ar-S-TTF and the size matches between Ar-S-TTF and fullerene. Regarding their compositions, the studied co-crystals can be divided into two types, where types I and II have donor:acceptor ratios of 1:1 and 1:2, respectively. Multiple intermolecular interactions are observed between the donor and acceptor, which act to stabilize the structures of the resulting co-crystals. In the type I co-crystals, the fullerene molecule is surrounded by four Ar-S-TTF molecules, that is, two Ar-S-TTF molecules form a sandwich structure with one fullerene molecule and the other two Ar-S-TTF molecules interact with the fullerene molecule along their lateral axes. In the type II co-crystals, one fullerene molecule has the donor–acceptor mode similar to that in type I, whereas the other fullerene molecule is substantially surrounded by the aryl groups on Ar-S-TTF molecules and the solvent molecules. PMID:26199659

  18. Fullerenes, PAH, Carbon Nanostructures, and Soot in Low Pressure Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Grieco, William J.; Lafleur, Arthur L.; Rainey, Lenore C.; Taghizadeh, Koli; VanderSande, John B.; Howard, Jack B.

    1997-01-01

    The formation of fullerenes C60 and C7O is known to occur in premixed laminar benzene/oxygen/argon flames operated at reduced pressures. High resolution transmission electron microscopy (HRTEM) images of material collected from these flames has identified a variety of multishelled nanotubes and fullerene 'onions' as well as some trigonous structures. These fullerenes and nanostructures resemble the material that results from commercial fullerene production systems using graphite vaporization. As a result, combustion is an interesting method for fullerenes synthesis. If commercial scale operation is to be considered, the use of diffusion flames might be safer and less cumbersome than premixed flames. However, it is not known whether diffusion flames produce the types and yields of fullerenes obtained from premixed benzene/oxygen flames. Therefore, the formation of fullerenes and carbon nanostructures, as well as polycyclic aromatic hydrocarbons (PAH) and soot, in acetylene and benzene diffusion flames is being studied using high performance liquid chromatography (HPLC) and high resolution transmission electron microscopy (HRTEM).

  19. Wavelength tunability of ion-bombardment-induced ripples on sapphire Hua Zhou, Yiping Wang, Lan Zhou, and Randall L. Headrick*

    E-print Network

    Headrick, Randall L.

    Wavelength tunability of ion-bombardment-induced ripples on sapphire Hua Zhou, Yiping Wang, Lan; published 17 April 2007 A study of ripple formation on sapphire surfaces by 300­2000 eV Ar+ ion bombardment on sapphire 0001 surfaces. We find that the wavelength can be varied over a remarkably wide range--nearly two

  20. Classical-trajectory Monte Carlo calculations of the electronic stopping cross section for keV protons and antiprotons impinging on hydrogen atoms

    SciTech Connect

    Custidiano, Ernesto R.; Jakas, Mario M.

    2005-08-15

    Using the classical-trajectory Monte Carlo (CTMC) method, the electronic stopping cross sections of hydrogen atoms by protons and antiprotons impact are calculated. The results show that the CTMC method compares fairly well with previous quantum mechanics calculations of the stopping cross sections for the same colliding pairs. It turns out therefore that the CTMC method constitutes a reliable and, computationally speaking, convenient alternative to calculate the stopping of ions in matter. The present results also show that the stopping appears to be particularly sensitive to the angular momentum (L) of the electron orbit. In the case of protons, the highest sensitivity to L becomes evident around the energy of the maximum stopping. While for antiprotons the largest sensitivity of the stopping to L is observed down at low bombarding energies, i.e., below 10 keV.

  1. Nonbonding orbitals in fullerenes: nuts and cores in singular polyhedral graphs.

    PubMed

    Sciriha, Irene; Fowler, Patrick W

    2007-01-01

    A zero eigenvalue in the spectrum of the adjacency matrix of the graph representing an unsaturated carbon framework indicates the presence of a nonbonding pi orbital (NBO). A graph with at least one zero in the spectrum is singular; nonzero entries in the corresponding zero-eigenvalue eigenvector(s) (kernel eigenvectors) identify the core vertices. A nut graph has a single zero in its adjacency spectrum with a corresponding eigenvector for which all vertices lie in the core. Balanced and uniform trivalent (cubic) nut graphs are defined in terms of (-2, +1, +1) patterns of eigenvector entries around all vertices. In balanced nut graphs all vertices have such a pattern up to a scale factor; uniform nut graphs are balanced with scale factor one for every vertex. Nut graphs are rare among small fullerenes (41 of the 10 190 782 fullerene isomers on up to 120 vertices) but common among the small trivalent polyhedra (62 043 of the 398 383 nonbipartite polyhedra on up to 24 vertices). Two constructions are described, one that is conjectured to yield an infinite series of uniform nut fullerenes, and another that is conjectured to yield an infinite series of cubic polyhedral nut graphs. All hypothetical nut fullerenes found so far have some pentagon adjacencies: it is proved that all uniform nut fullerenes must have such adjacencies and that the NBO is totally symmetric in all balanced nut fullerenes. A single electron placed in the NBO of a uniform nut fullerene gives a spin density distribution with the smallest possible (4:1) ratio between most and least populated sites for an NBO. It is observed that, in all nut-fullerene graphs found so far, occupation of the NBO would require the fullerene to carry at least 3 negative charges, whereas in most carbon cages based on small nut cubic polyhedra, the NBO would be the highest occupied molecular orbital (HOMO) for the uncharged system. PMID:17691719

  2. Quantitative Analysis of Fullerene Nanomaterials in Environmental Systems: A Critical Review

    PubMed Central

    Isaacson, Carl W.; Kleber, Markus; Field, Jennifer A.

    2009-01-01

    The increasing production and use of fullerene nanomaterials has led to calls for more information regarding the potential impacts that releases of these materials may have on human and environmental health. Fullerene nanomaterials, which are comprised of both fullerenes and surface-functionalized fullerenes, are used in electronic, optic, medical and cosmetic applications. Measuring fullerene nanomaterial concentrations in natural environments is difficult because they exhibit a duality of physical and chemical characteristics as they transition from hydrophobic to polar forms upon exposure to water. In aqueous environments, this is expressed as their tendency to initially (i) self assemble into aggregates of appreciable size and hydrophobicity, and subsequently (ii) interact with the surrounding water molecules and other chemical constituents in natural environments thereby acquiring negative surface charge. Fullerene nanomaterials may therefore deceive the application of any single analytical method that is applied with the assumption that fullerenes have but one defining characteristic (e.g., hydrophobicity). [1] We find that analytical procedures are needed to account for the potentially transitory nature of fullerenes in natural environments through the use of approaches that provide chemically-explicit information including molecular weight and the number and identity of surface functional groups. [2] We suggest that sensitive and mass-selective detection, such as that offered by mass spectrometry when combined with optimized extraction procedures, offers the greatest potential to achieve this goal. [3] With this review, we show that significant improvements in analytical rigor would result from an increased availability of well characterized authentic standards, reference materials, and isotopically-labeled internal standards. Finally, the benefits of quantitative and validated analytical methods for advancing the knowledge on fullerene occurrence, fate, and behavior are indicated. PMID:19764203

  3. Hybrid materials with an increased resistance to hard X-rays using fullerenes as radical sponges.

    PubMed

    Pinna, Alessandra; Malfatti, Luca; Piccinini, Massimo; Falcaro, Paolo; Innocenzi, Plinio

    2012-07-01

    The protection of organic and hybrid organic-inorganic materials from X-ray damage is a fundamental technological issue for broadening the range of applications of these materials. In the present article it is shown that doping hybrid films with fullerenes C(60) gives a significant reduction of damage upon exposure to hard X-rays generated by a synchrotron source. At low X-ray dose the fullerene molecules act as `radical scavengers', considerably reducing the degradation of organic species triggered by radical formation. At higher doses the gradual hydroxylation of the fullerenes converts C(60) into fullerol and a bleaching of the radical sinking properties is observed. PMID:22713894

  4. Donor-acceptor complexes and radical ionic salts based on fullerenes

    NASA Astrophysics Data System (ADS)

    Konarev, Dmitry V.; Lyubovskaya, Rimma N.

    1999-01-01

    The review generalises for the first time the published data on the synthesis and properties of donor-acceptor type of compounds based on fullerenes, various solvates and clathrates, inclusion compounds, molecular complexes and charge-transfer complexes both with inorganic donors and with organoelement donors of the tetrathiafulvalene, amine, metallocene and metalloporphyrin series. Radical ionic salts of fullerenes with bulky cations and alkali metals obtained by intercalation or by direct synthesis in solution are discussed. Results of studies of fullerene compounds by IR, optical, ESR, X-ray photoelectron and 13C NMR spectroscopy, as well as their conducting (including superconducting), magnetic and optical properties are discussed. The bibliography includes 208 references.

  5. Higher-Order Harmonic Generation from Fullerene by Means of the Plasma Harmonic Method

    SciTech Connect

    Ganeev, R. A.; Bom, L. B. Elouga; Abdul-Hadi, J.; Ozaki, T.; Wong, M. C. H.; Brichta, J. P.; Bhardwaj, V. R.

    2009-01-09

    We demonstrate, for the first time, high-order harmonic generation from C{sub 60} by an intense femtosecond Ti:sapphire laser. Laser-produced plasmas from C{sub 60}-rich epoxy and C{sub 60} films were used as the nonlinear media. Harmonics up to the 19th order were observed. The harmonic yield from fullerene-rich plasma is about 25 times larger compared with those produced from a bulk carbon target. Structural studies of plasma debris confirm the presence and integrity of fullerenes within the plasma plume, indicating fullerenes as the source of high-order harmonics.

  6. Binding of fullerenes and nanotubes to MscL

    PubMed Central

    Hilder, Tamsyn A.; Ridone, Pietro; Nakayama, Yoshitaka; Martinac, Boris; Chung, Shin-Ho

    2014-01-01

    Multi-drug resistance is becoming an increasing problem in the treatment of bacterial infections and diseases. The mechanosensitive channel of large conductance (MscL) is highly conserved among prokaryotes. Evidence suggests that a pharmacological agent that can affect the gating of, or block the current through, MscL has significant potential as a new class of antimicrobial compound capable of targeting a range of pathogenic bacteria with minimal side-effects to infected patients. Using molecular dynamics we examine the binding of fullerenes and nanotubes to MscL and demonstrate that both are stable within the MscL pore. We predict that fullerenes will attenuate the flow of ions through MscL by reducing the pore volume available to water and ions, but nanotubes will prevent pore closure resulting in a permanently open pore. Moreover, we confirm experimentally that it is possible to attenuate the flow of ions through MscL using a C60-? cyclodextrin complex. PMID:25030051

  7. Tuning of electronic properties of fullerene-oligothiophene layers

    NASA Astrophysics Data System (ADS)

    Lewandowska, Kornelia; Pilarczyk, Kacper; Podborska, Agnieszka; Kim, Tae-Dong; Lee, Kwang-Sup; Szaci?owski, Konrad

    2015-01-01

    Electronic properties of fullerene derivatives containing oligothiophene pendant chain (1-3 thiophene moieties) were investigated using the Kelvin probe technique and quantum chemistry methods. For electrochemical examination of these systems, Langmuir-Blodgett (LB) layers were prepared by the deposition on a gold substrate. The analysis of the experimental data shows that the value of the work function depends strongly on the length of oligothiophene chain. Similar dependence was also found for the surface photovoltage measurements conducted for the layers consisting of multiple LB films of the examined compounds deposited on gold surfaces. The assumption has been made that these changes are associated with the influence of oligothiophene chain on the electrostatic potential distribution near the surface of the sample. The hypothesis was confirmed by the results of DFT calculations, which revealed that the value of Fermi level energy shifts in the opposite direction to the determined work function. The key highlights of this study are as follows: electronic structure tuning by oligothiophene side chain; DFT calculation on fullerene-thiophene system; work function measurements of thin molecular layers.

  8. Binding of fullerenes and nanotubes to MscL

    NASA Astrophysics Data System (ADS)

    Hilder, Tamsyn A.; Ridone, Pietro; Nakayama, Yoshitaka; Martinac, Boris; Chung, Shin-Ho

    2014-07-01

    Multi-drug resistance is becoming an increasing problem in the treatment of bacterial infections and diseases. The mechanosensitive channel of large conductance (MscL) is highly conserved among prokaryotes. Evidence suggests that a pharmacological agent that can affect the gating of, or block the current through, MscL has significant potential as a new class of antimicrobial compound capable of targeting a range of pathogenic bacteria with minimal side-effects to infected patients. Using molecular dynamics we examine the binding of fullerenes and nanotubes to MscL and demonstrate that both are stable within the MscL pore. We predict that fullerenes will attenuate the flow of ions through MscL by reducing the pore volume available to water and ions, but nanotubes will prevent pore closure resulting in a permanently open pore. Moreover, we confirm experimentally that it is possible to attenuate the flow of ions through MscL using a C60-? cyclodextrin complex.

  9. Fullerene nanowires as a versatile platform for organic electronics

    PubMed Central

    Maeyoshi, Yuta; Saeki, Akinori; Suwa, Shotaro; Omichi, Masaaki; Marui, Hiromi; Asano, Atsushi; Tsukuda, Satoshi; Sugimoto, Masaki; Kishimura, Akihiro; Kataoka, Kazunori; Seki, Shu

    2012-01-01

    The development of organic semiconducting nanowires that act as charge carrier transport pathways in flexible and lightweight nanoelectronics is a major scientific challenge. We report on the fabrication of fullerene nanowires that is universally applicable to its derivatives (pristine C60, methanofullerenes of C61 and C71, and indene C60 bis-adduct), realized by the single particle nanofabrication technique (SPNT). Nanowires with radii of 8–11?nm were formed via a chain polymerization reaction induced by a high-energy ion beam. Fabrication of a poly(3-hexylthiophene) (P3HT): [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) bulk heterojunction organic photovoltaic cell including PC61BM nanowires with precisely-controlled length and density demonstrates how application of this methodology can improve the power conversion efficiency of these inverted cells. The proposed technique provides a versatile platform for the fabrication of continuous and uniform n-type fullerene nanowires towards a wide range of organic electronics applications. PMID:22934128

  10. Tuning of electronic properties of fullerene-oligothiophene layers

    SciTech Connect

    Lewandowska, Kornelia; Pilarczyk, Kacper E-mail: szacilow@agh.edu.pl; Podborska, Agnieszka; Kim, Tae-Dong; Lee, Kwang-Sup; Szaci?owski, Konrad E-mail: szacilow@agh.edu.pl

    2015-01-26

    Electronic properties of fullerene derivatives containing oligothiophene pendant chain (1–3 thiophene moieties) were investigated using the Kelvin probe technique and quantum chemistry methods. For electrochemical examination of these systems, Langmuir–Blodgett (LB) layers were prepared by the deposition on a gold substrate. The analysis of the experimental data shows that the value of the work function depends strongly on the length of oligothiophene chain. Similar dependence was also found for the surface photovoltage measurements conducted for the layers consisting of multiple LB films of the examined compounds deposited on gold surfaces. The assumption has been made that these changes are associated with the influence of oligothiophene chain on the electrostatic potential distribution near the surface of the sample. The hypothesis was confirmed by the results of DFT calculations, which revealed that the value of Fermi level energy shifts in the opposite direction to the determined work function. The key highlights of this study are as follows: electronic structure tuning by oligothiophene side chain; DFT calculation on fullerene-thiophene system; work function measurements of thin molecular layers.

  11. Materials surface modification by plasma bombardment under simultaneous erosion and redeposition conditions

    SciTech Connect

    Hirooka, Y.; Goebel, D.M.; Conn, R.W.; Campbell, G.A.; Leung, W.K.; Wilson, K.L.; Bauer, W.; Causey, R.A.; Morse, D.H.; Bohdansky, J.

    1986-07-01

    The first in-depth investigation of surface modification of materials by continuous, high-flux argon plasma bombardment under simultaneous erosion and redeposition conditions have been carried out for copper and 304 stainless steel using the PISCES facility. The plasma bombardment conditions are: incident ion flux range from 10/sup 17/ to 10/sup 19/ ions sec/sup -1/cm/sup -2/, total ion fluence is controlled between 10/sup 19/ and 10/sup 22/ ions cm/sup -2/, electron temperature range from 5 to 15 eV, and plasma density range from 10/sup 11/ to 10/sup 13/cm/sup -3/. The incident ion energy is 100 eV. The sample temperature is between 300 and 700K. Under redeposition dominated conditions, the material erosion rate due to the plasma bombardment is significantly smaller (by a factor up to 10) than that can be expected from the classical ion beam sputtering yield data. It is found that surface morphologies of redeposited materials strongly depend on the plasma bombardment condition. The effect of impurities on surface morphology is elucidated in detail. First-order modelings are implemented to interpret the reduced erosion rate and the surface evolution. Also, fusion related surface properties of redeposited materials such as hydrogen reemission and plasma driven permeation have been characterized.

  12. Could the Lunar `Late Heavy Bombardment' Have Been Triggered by the Formation of Uranus and Neptune?

    E-print Network

    Levison, Harold F.

    Could the Lunar `Late Heavy Bombardment' Have Been Triggered by the Formation of Uranus and Neptune) of the Moon was triggered by the formation of Uranus and Neptune. As Uranus and Neptune formed, which we accreted about 6 #2; 10 21 g, if we assume that the Uranus-Neptune region initially contained 5 times

  13. Bombardment of gas molecules on single graphene layer at high temperature

    SciTech Connect

    Murugesan, Ramki; Park, Jae Hyun; Ha, Dong Sung

    2014-12-09

    Graphite is widely used as a material for rocket-nozzle inserts due to its excellent thermo-physical properties as well as low density. During the operation of rockets, the surface of the graphite nozzle is subjected to very high heat fluxes and the undesirable erosion of the surface occurs due to the bombardment of gas molecules with high kinetic energy, which causes a significant reduction of nozzle performance. However, the understanding and quantification of such bombardment is not satisfactory due to its complexity: The bond breaking-forming happens simultaneously for the carbon atoms of graphene, some gas molecules penetrate through the surface, some of them are reflected from the surface, etc. In the present study, we perform extensive molecular dynamics (MD) simulations to examine the bombardment phenomena in high temperature environment (several thousand Kelvin). Advanced from the previous studies that have focused on the bombardment by light molecules (e.g., H{sub 2}), we will concentrate on the impact by realistic molecules (e.g., CO{sub 2} and H{sub 2}O). LAMMPS is employed for the MD simulations with NVE ensemble and AIREBO potential for graphene. The molecular understanding of the interaction between graphene and highly energetic gas molecules will enable us to design an efficient thermo-mechanical protection system.

  14. ICARUS75, 423-436(1988) Analysis of Voyager Images of Europa: Plasma Bombardment

    E-print Network

    Johnson, Robert E.

    1988-01-01

    ICARUS75, 423-436(1988) Analysis of Voyager Images of Europa: Plasma Bombardment R. E. JOHNSONFebruary11, 1988 The photometrically corrected normal albedos of Europa, extracted from Voyager data dependence across the surface of Europa predicted by the grain size variation determined previously from

  15. A review of electron bombardment thruster systems/spacecraft field and particle interfaces

    NASA Technical Reports Server (NTRS)

    Byers, D. C.

    1978-01-01

    Information on the field and particle interfaces of electron bombardment ion thruster systems was summarized. Major areas discussed were the nonpropellant particles, neutral propellant, ion beam, low energy plasma, and fields. Spacecraft functions and subsystems reviewed were solar arrays, thermal control systems, optical sensors, communications, science, structures and materials, and potential control.

  16. Defecting controllability of bombarding graphene with different energetic atoms via reactive force field model

    E-print Network

    Park, Harold S.

    Defecting controllability of bombarding graphene with different energetic atoms via reactive force field model Xiao Yi Liu, Feng Chao Wang, Harold S. Park, and Heng An Wu Citation: J. Appl. Phys. 114 of Contents: http://jap.aip.org/resource/1/JAPIAU/v114/i5 Published by the AIP Publishing LLC. Additional

  17. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Pacific Ocean at San Clemente... REGULATIONS § 334.950 Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. (a) The danger zones. (1) The waters of the Pacific Ocean within an area beginning at China Point...

  18. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. 334.950 Section 334.950 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.950 Pacific Ocean at...

  19. 33 CFR 334.950 - Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Pacific Ocean at San Clemente... REGULATIONS § 334.950 Pacific Ocean at San Clemente Island, California; Navy shore bombardment areas. (a) The danger zones. (1) The waters of the Pacific Ocean within an area beginning at China Point...

  20. Trace Elements Reveal a Possible Link Between Jack Hills Detrital Zircons and the Late Heavy Bombardment

    NASA Astrophysics Data System (ADS)

    Bell, E. A.; Harrison, T. M.

    2012-03-01

    The Jack Hills detrital zircons range in age 4.3-3.0 Ga. At ca. 3.9 Ga the record contains a population that appears to have recrystallized during a major thermal event. This may be circumstantial terrestrial evidence for the Late Heavy Bombardment.