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Sample records for c60 molecule adsorbed

  1. Controlled contact to a C-60 molecule

    DEFF Research Database (Denmark)

    Neel, N.; Kröger, J.; Limot, L.

    2007-01-01

    The tip of a low-temperature scanning tunneling microscope is approached towards a C-60 molecule adsorbed at a pentagon-hexagon bond on Cu(100) to form a tip-molecule contact. The conductance rapidly increases to approximate to 0.25 conductance quanta in the transition region from tunneling...... the tip-molecule distance....

  2. An ab initio study of the field-induced position change of a C-60 molecule adsorbed on a gold tip

    DEFF Research Database (Denmark)

    Stadler, Robert; Kubatkin, Sergey; Bjørnholm, Thomas

    2007-01-01

    be based on such junctions if the mechanism of the process is understood. We present density functional theory based plane wave calculations, where we studied the energetics of the molecule's adsorption under the influence of an external field. Particular emphasis was placed on investigating a possible...... lightning rod effect which might explain the switching between configurations found in experiments. We also analyse our results for the adsorption energetics in terms of an electrostatic expression for the total energy, where the dependence of the polarizability of the junction on the position of the C60...

  3. Hindered rotation of a copper phthalocyanine molecule on C60 : Experiments and molecular mechanics calculations

    NARCIS (Netherlands)

    Fendrich, M.; Wagner, Th.; Stöhr, M.; Möller, R.

    2006-01-01

    If copper phthalocyanine (CuPc) molecules are deposited on a Au(111) surface covered with a monolayer of C60, the molecules are found to adsorb individually onto the close-packed layer of C60. As the adsorption site of the CuPc is not symmetric with respect to the underlying C60 layer, the CuPc

  4. An ab initio study of the field-induced position change of a C60 molecule adsorbed on a gold tip

    DEFF Research Database (Denmark)

    Stadler, Robert; Kubatkin, S.; Bjørnholm, Thomas

    2007-01-01

    lightning rod effect which might explain the switching between configurations found in experiments. We also analyse our results for the adsorption energetics in terms of an electrostatic expression for the total energy, where the dependence of the polarizability of the junction on the position of the C60...

  5. Modeling the interaction of nanoparticles with mineral surfaces: adsorbed C60 on pyrophyllite.

    Science.gov (United States)

    Zhu, Runliang; Molinari, Marco; Shapley, Thomas V; Parker, Stephen C

    2013-08-01

    We have applied DFT and molecular modeling to investigate the interaction between carbon-based nanoparticles (CNPs) and geosorbents using the adsorption of buckminsterfullerene (C60) on pyrophyllite and comparing it to the aggregation of C60 molecules. The approach is transferable and can be readily applied to more complex CNP-clay systems. We predict that C60 molecules adsorb preferably on the mineral surface and that the most stable adsorption site is the ditrigonal cavity of the surface. The free energy of adsorption on pyrophyllite was calculated to be more favorable than aggregation both in a vacuum (-0.47 vs -0.41 eV) and in water (-0.25 vs -0.19 eV). In aqueous environments, there are energy barriers as the C60 molecule approaches either a surface or another C60 molecule, and these occur upon disruption of the hydration layers that surround each component. There are also free energy minima that correspond to outer-sphere and more favorable inner-sphere complexes. We expect this adsorptive behavior to be a general feature of CNP-clay systems, and as clays are ubiquitous in the environment, it will offer an inexpensive remediative method to prevent the widespread impact of molecular C60 and CNPs.

  6. Research on Electrostatic Propulsion Using C60 Molecules

    National Research Council Canada - National Science Library

    Goodwin, David

    1997-01-01

    ... and station keeping missions. However, the viability of this concept depends on properties of the C60 molecule such as the ionization cross section, thermal stability, and resistance to fragmentation in a plasma environment...

  7. Formation and reinforcement of clusters composed of C60 molecules

    Directory of Open Access Journals (Sweden)

    Kurosu Shunji

    2011-01-01

    Full Text Available Abstract We carry out two experiments: (1 the formation of clusters composed of C60 molecules via self-assembly and (2 the reinforcement of the clusters. Firstly, clusters such as fibres and helices composed of C60 molecules are produced via self-assembly in supercritical carbon dioxide. However, C60 molecules are so weakly bonded to each other in the clusters that the clusters are broken by the irradiation of electron beams during scanning electron microscope observation. Secondly, UV photons are irradiated inside a chamber in which air is filled at 1 atm and the above clusters are placed, and it was found that the clusters are reinforced; that is, they are not broken by electron beams any more. C60 molecules located at the surface of the clusters are oxidised, i.e. C60On molecules, where n = 1, 2, 3 and 4, are produced according to time-of-flight mass spectroscopy. It is supposed that oxidised C60 molecules at the surface of the clusters may have an important role for the reinforcement, but the actual mechanism of the reinforcement of the clusters has not yet been clearly understood and therefore is an open question.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Heekeun [Penn State University; Schwarze, A [Penn State University; Diehl, R D [Penn State University; Pussi, K [Lappeenranta University of Technology; Colombier, A [Universite de Lorraine; Gaudry, E. [Universite de Lorraine; Ledieu, J [Universite de Lorraine; McGuirk, G M [Universite de Lorraine; Serkovic Loli, L N [Universite de Lorraine; Fournee, V [Universite de Lorraine; Wang, Lin-Lin [Ames Laboratory; Schull, G [Universite de Strasbourg; Berndt, R [Christian-Albrechts-Universitt zu Kiel

    2014-06-01

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

  9. The nano-science of C60 molecule

    International Nuclear Information System (INIS)

    Rafii-Tabar, H.

    2002-01-01

    Over the past few years, nano-science and its associated nano-technology have emerged into prominence in research institutions across the world. They have brought about new scientific and engineering paradigms, allowing for the manipulation of single atoms and molecules, designing and fabricating new materials, atom-by-atom, and devices that operate on significantly reduced time and length scales. One important area of research in nano-science and nano technology is carbon-based physics in the form of fullerene physics. The C 6 0 molecule, and other cage-like fullerenes, together with carbon nano tubes provide objects that can be combined to generate three-dimensional functional structures for use in the anticipated nano-technology of future. The unique properties of C 6 0 can also be exploited in designing nano-phase thin films with applications in nano-scope device technology and processes such as nano-lithography. This requires a deep understanding of the highly complex process of adsorption of this molecule on a variety of substrates. We review the field of nano-scale nucleation and growth of C 6 0 molecules on some of the technologically important substrates. In addition to experimental results, the results of a set of highly accurate computational simulations are also reported

  10. Direct observation of hindered eccentric rotation of an individual molecule : Cu-phthalocyanine on C60

    NARCIS (Netherlands)

    Stöhr, Meike; Wagner, T; Gabriel, M; Weyers, B; Moller, R

    2002-01-01

    Individual Cu-phthalocyanine molecules have been investigated by scanning tunnel microscopy on a closed packed film of C-60 at various temperatures. The molecules are found to bind asymmetrically to one C-60. While they remain in one position at low temperature, they can hop between six equivalent

  11. Alignment of paired molecules of C60 within a hexagonal platform networked through hydrogen-bonds.

    Science.gov (United States)

    Hisaki, Ichiro; Nakagawa, Shoichi; Sato, Hiroyasu; Tohnai, Norimitsu

    2016-07-28

    We demonstrate, for the first time, that a hydrogen-bonded low-density organic framework can be applied as a platform to achieve periodic alignment of paired molecules of C60, which is the smallest example of a finite-numbered cluster of C60. The framework is a layered assembly of a hydrogen-bonded 2D hexagonal network (LA-H-HexNet) composed of dodecadehydrotribenzo[18]annulene derivatives.

  12. Nanoelectromechanical switch operating by tunneling of an entire C-60 molecule

    DEFF Research Database (Denmark)

    Danilov, Andrey V.; Hedegård, Per; Golubev, Dimitrii S.

    2008-01-01

    We present a solid state single molecule electronic device where switching between two states with different conductance happens predominantly by tunneling of an entire C-60 molecule. This conclusion is based on a novel statistical analysis of similar to 10(5) switching events. The analysis yields...

  13. Self-interaction corrections applied to Mg-porphyrin, C60, and pentacene molecules

    International Nuclear Information System (INIS)

    Pederson, Mark R.; Baruah, Tunna; Basurto, Luis; Kao, Der-you

    2016-01-01

    We have applied a recently developed method to incorporate the self-interaction correction through Fermi orbitals to Mg-porphyrin, C 60 , and pentacene molecules. The Fermi-Löwdin orbitals are localized and unitarily invariant to the Kohn-Sham orbitals from which they are constructed. The self-interaction-corrected energy is obtained variationally leading to an optimum set of Fermi-Löwdin orbitals (orthonormalized Fermi orbitals) that gives the minimum energy. A Fermi orbital, by definition, is dependent on a certain point which is referred to as the descriptor position. The degree to which the initial choice of descriptor positions influences the variational approach to the minimum and the complexity of the energy landscape as a function of Fermi-orbital descriptors is examined in detail for Mg-porphyrin. The applications presented here also demonstrate that the method can be applied to larger molecular systems containing a few hundred electrons. The atomization energy of the C 60 molecule within the Fermi-Löwdin-orbital self-interaction-correction approach is significantly improved compared to local density approximation in the Perdew-Wang 92 functional and generalized gradient approximation of Perdew-Burke-Ernzerhof functionals. The eigenvalues of the highest occupied molecular orbitals show qualitative improvement.

  14. Coupling of Surface and Volume Dipole Oscillations in C60 Molecules

    Science.gov (United States)

    Brack, M.; Winkler, P.; Murthy, M. V. N.

    We first give a short review of the "local-current approximation" (LCA), derived from a general variation principle, which serves as a semiclassical description of strongly collective excitations in finite fermion systems starting from their quantum-mechanical mean-field ground state. We illustrate it for the example of coupled translational and compressional dipole excitations in metal clusters. We then discuss collective electronic dipole excitations in C60 molecules (Buckminster fullerenes). We show that the coupling of the pure translational mode ("surface plasmon") with compressional volume modes in the semiclasscial LCA yields semi-quantitative agreement with microscopic time-dependent density functional (TDLDA) calculations, while both theories yield qualitative agreement with the recent experimental observation of a "volume plasmon".

  15. Coupling of surface and volume dipole oscillations in C60 molecules

    International Nuclear Information System (INIS)

    Brack, M.; Winkler, P.; Murthy, M.V.N.

    2008-01-01

    We first give a short review of the "local-current approximation" (LCA), derived from a general variation principle, which serves as a semiclassical description of strongly collective excitations in finite fermion systems starting from their quantum-mechanical mean-field ground state. We illustrate it for the example of coupled translational and compressional dipole excitations in metal clusters. We then discuss collective electronic dipole excitations in C 60 molecules (Buckminster fullerenes). We show that the coupling of the pure translational mode ("surface plasmon") with compressional volume modes in the semiclasscial LCA yields semi-quantitative agreement with microscopic time-dependent density functional (TDLDA) calculations, while both theories yield qualitative agreement with the recent experimental observation of a "volume plasmon". (author)

  16. Electrical bistabilities and memory stabilities of nonvolatile bistable devices fabricated utilizing C60 molecules embedded in a polymethyl methacrylate layer

    International Nuclear Information System (INIS)

    Cho, Sung Hwan; Lee, Dong Ik; Jung, Jae Hun; Kim, Tae Whan

    2009-01-01

    Current-voltage (I-V) measurements on Al/fullerene (C 60 ) molecules embedded in polymethyl methacrylate/Al devices at 300 K showed a current bistability due to the existence of the C 60 molecules. The on/off ratio of the current bistability for the memory devices was as large as 10 3 . The retention time of the devices was above 2.5 x 10 4 s at room temperature, and cycling endurance tests on these devices indicated that the ON and OFF currents showed no degradation until 50 000 cycles. Carrier transport mechanisms for the nonvolatile bistable devices are described on the basis of the I-V experimental and fitting results.

  17. Evaluation of the Electronic Structure of Single-Molecule Junctions Based on Current-Voltage and Thermopower Measurements: Application to C60 Single-Molecule Junction.

    Science.gov (United States)

    Komoto, Yuki; Isshiki, Yuji; Fujii, Shintaro; Nishino, Tomoaki; Kiguchi, Manabu

    2017-02-16

    The electronic structure of molecular junctions has a significant impact on their transport properties. Despite the decisive role of the electronic structure, a complete characterization of the electronic structure remains a challenge. This is because there is no straightforward way of measuring electron spectroscopy for an individual molecule trapped in a nanoscale gap between two metal electrodes. Herein, a comprehensive approach to obtain a detailed description of the electronic structure in single-molecule junctions based on the analysis of current-voltage (I-V) and thermoelectric characteristics is described. It is shown that the electronic structure of the prototypical C 60 single-molecule junction can be resolved by analyzing complementary results of the I-V and thermoelectric measurement. This combined approach confirmed that the C 60 single-molecule junction was highly conductive with molecular electronic conductances of 0.033 and 0.003 G 0 and a molecular Seebeck coefficient of -12 μV K -1 . In addition, we revealed that charge transport was mediated by a LUMO whose energy level was located 0.5≈0.6 eV above the Fermi level of the Au electrode. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Simulations of the Static Friction Due to Adsorbed Molecules

    OpenAIRE

    He, Gang; Robbins, Mark O.

    2001-01-01

    The static friction between crystalline surfaces separated by a molecularly thin layer of adsorbed molecules is calculated using molecular dynamics simulations. These molecules naturally lead to a finite static friction that is consistent with macroscopic friction laws. Crystalline alignment, sliding direction, and the number of adsorbed molecules are not controlled in most experiments and are shown to have little effect on the friction. Temperature, molecular geometry and interaction potenti...

  19. The T1u x 8 hg Jahn-Teller system - an improved model for the C60-molecule

    International Nuclear Information System (INIS)

    Rough, S.M.; Dunn, J.L.; Bates, C.A.

    1997-01-01

    The ground state of C 60 - gives rise to a T 1u x 8 h g Jahn-Teller (JT) system. A proof is presented showing that the presence of eight active h g modes rather than one makes little difference to the mathematical complexity of this problem compared to the simpler single-mode variant. After showing that the T 1u x 8 h g Jahn-Teller system has the same electronic eigenstates as the T 1u x h g Jahn-Teller system, the inversion splitting and first-order reduction factors are derived. (orig.)

  20. Hydrogen molecule on lithium adsorbed graphene: A DFT study

    International Nuclear Information System (INIS)

    Kaur, Gagandeep; Gupta, Shuchi; Gaganpreet; Dharamvir, Keya

    2016-01-01

    Electronic structure calculations for the adsorption of molecular hydrogen on lithium (Li) decorated and pristine graphene have been studied systematically using SIESTA code [1] within the framework of the first-principle DFT under the Perdew-Burke-Ernzerhof (PBE) form of the generalized gradient approximation (GGA)[2], including spin polarization. The energy of adsorption of hydrogen molecule on graphene is always enhanced by the presence of co-adsorbed lithium. The most efficient adsorption configuration is when H 2 is lying parallel to lithium adsorbed graphene which is in contrast to its adsorption on pristine graphene (PG) where it prefers perpendicular orientation.

  1. Self-Assembly of Individually Addressable Complexes of C-60 and Phthalocyanines on a Metal Surface : Structural and Electronic Investigations

    NARCIS (Netherlands)

    Samuely, Tomas; Liu, Shi-Xia; Haas, Marco; Decurtins, Silvio; Jung, Thomas A.; Stoehr, Meike

    2009-01-01

    The hosting properties of a close-packed layer of phenoxy-substituted phthalocyanine derivatives adsorbed on Ag(III) were investigated for the adsorption of C-60 molecules. The C-60 molecules bind to two clearly distinguishable sites, namely, to the underlying metal substrate in between two adjacent

  2. Controlling the magnetism of adsorbed metal-organic molecules.

    Science.gov (United States)

    Kuch, Wolfgang; Bernien, Matthias

    2017-01-18

    Gaining control on the size or the direction of the magnetic moment of adsorbed metal-organic molecules constitutes an important step towards the realization of a surface-mounted molecular spin electronics. Such control can be gained by taking advantage of interactions of the molecule's magnetic moment with the environment. The paramagnetic moments of adsorbed metal-organic molecules, for example, can be controlled by the interaction with magnetically ordered substrates. Metalloporphyrins and -phthalocyanines display a quasi-planar geometry, allowing the central metal ion to interact with substrate electronic states. This can lead to magnetic coupling with a ferromagnetic or even antiferromagnetic substrate. The molecule-substrate coupling can be mediated and controlled by insertion layers such as oxygen atoms, graphene, or nonmagnetic metal layers. Control on the magnetic properties of adsorbed metalloporphyrins or -phthalocyanines can also be gained by on-surface chemical modification of the molecules. The magnetic moment or the magnetic coupling to ferromagnetic substrates can be changed by adsorption and thermal desorption of small molecules that interact with the fourfold-coordinated metal center via the remaining axial coordination site. Spin-crossover molecules, which possess a metastable spin state that can be switched by external stimuli such as temperature or light, are another promising class of candidates for control of magnetic properties. However, the immobilization of such molecules on a solid surface often results in a quench of the spin transition due to the interaction with the substrate. We present examples of Fe(II) spin-crossover complexes in direct contact with a solid surface that undergo a reversible spin-crossover transition as a function of temperature, by illumination with visible light, or can be switched by the tip of a scanning tunneling microscope.

  3. DFT calculations of the charged states of N@C60 and Fe4 single molecule magnets investigated in tunneling spectroscopy

    Science.gov (United States)

    Nossa, Javier; Islam, Fhokrul; Canali, Carlo; Pederson, Mark

    2012-02-01

    For device applications of single molecule magnets (SMMs) in high-density information storage and quantum-state control it is essential that the magnetic properties of the molecules remain stable under the influence of metallic contacts or surface environment. Recent tunneling experiments [1, 2] on N@C60 and Fe4 SMM have shown that these molecules preserve their magnetic characteristics when they are used as the central island of single-electron transistors. Although quantum spin models have been used extensively to study theoretically tunneling spectroscopy of SMMs, it has been shown recently that the orbital degrees of freedom, which is absent in spin models, can significantly affect the tunneling conductance [3]. In this work we present first-principles calculations of the neutral and charged states of N@C60 and Fe4 SMMs, and discuss a strategy to include their properties into a theory of quantum transport. We also present results of the magnetic anisotropy for the different charge states of Fe4 and discuss their relevance for experiments [2] in the sequential tunneling and cotunnelling regimes. [4pt] [1]. N. Roch et al., Phys. Rev. B 83, 081407 (2011). [0pt] [2]. A.S. Zyazin et al., Nano Lett. 10, 3307 (2010). [0pt] [3]. L. Michalak et al., Phys. Rev. Lett. 104, 017202 (2010).

  4. Detection of individual gas molecules adsorbed on graphene.

    Science.gov (United States)

    Schedin, F; Geim, A K; Morozov, S V; Hill, E W; Blake, P; Katsnelson, M I; Novoselov, K S

    2007-09-01

    The ultimate aim of any detection method is to achieve such a level of sensitivity that individual quanta of a measured entity can be resolved. In the case of chemical sensors, the quantum is one atom or molecule. Such resolution has so far been beyond the reach of any detection technique, including solid-state gas sensors hailed for their exceptional sensitivity. The fundamental reason limiting the resolution of such sensors is fluctuations due to thermal motion of charges and defects, which lead to intrinsic noise exceeding the sought-after signal from individual molecules, usually by many orders of magnitude. Here, we show that micrometre-size sensors made from graphene are capable of detecting individual events when a gas molecule attaches to or detaches from graphene's surface. The adsorbed molecules change the local carrier concentration in graphene one by one electron, which leads to step-like changes in resistance. The achieved sensitivity is due to the fact that graphene is an exceptionally low-noise material electronically, which makes it a promising candidate not only for chemical detectors but also for other applications where local probes sensitive to external charge, magnetic field or mechanical strain are required.

  5. Porous polymer monoliths functionalized through copolymerization of a C60 fullerene-containing methacrylate monomer for highly efficient separations of small molecules

    KAUST Repository

    Chambers, Stuart D.

    2011-12-15

    Monolithic poly(glycidyl methacrylate-co-ethylene dimethacrylate) and poly(butyl methacrylate-co-ethylene dimethacrylate) capillary columns, which incorporate the new monomer [6,6]-phenyl-C 61-butyric acid 2-hydroxyethyl methacrylate ester, have been prepared and their chromatographic performance have been tested for the separation of small molecules in the reversed phase. While addition of the C60-fullerene monomer to the glycidyl methacrylate-based monolith enhanced column efficiency 18-fold, to 85 000 plates/m at a linear velocity of 0.46 mm/s and a retention factor of 2.6, when compared to the parent monolith, the use of butyl methacrylate together with the carbon nanostructured monomer afforded monolithic columns with an efficiency for benzene exceeding 110 000 plates/m at a linear velocity of 0.32 mm/s and a retention factor of 4.2. This high efficiency is unprecedented for separations using porous polymer monoliths operating in an isocratic mode. Optimization of the chromatographic parameters affords near baseline separation of 6 alkylbenzenes in 3 min with an efficiency of 64 000 plates/m. The presence of 1 wt % or more of water in the polymerization mixture has a large effect on both the formation and reproducibility of the monoliths. Other factors such as nitrogen exposure, polymerization conditions, capillary filling method, and sonication parameters were all found to be important in producing highly efficient and reproducible monoliths. © 2011 American Chemical Society.

  6. Fragmentation of the C60 molecule in collision with light ions studied by a multi-correlation technique. Cross-sections, electron spectroscopy

    International Nuclear Information System (INIS)

    Rentenier, A.

    2004-04-01

    A quantitative study of the C60 fullerenes fragmentation in collision with light ions (H n + with n=1,2,3, He q+ with q=1,2) in the velocity range 0,1 - 2,3 u.a.) is presented. The multi-correlation technique, developed between fragment ions and electrons with well defined energy, has enlightened some of the dependences and properties of fragmentation mechanisms (cross sections, electron spectroscopy, size distributions, kinetic energy of fragment ions, Campi's scatter plot, activation energies). The deposited energy hence appeared as an important parameter. Cross sections have been measured, for the first time, for all the collisional processes. Ionisation and capture only depends on the collision velocity. On the other hand, scaling laws with the deposited energy have been observed for the cross sections of multifragmentation, which depends on the collision energy and the nature of the projectile. The deposited energy has also been found as an essential parameter to understand the evolution of the charged fragment size distributions. The electron spectroscopy, achieved at an emission angle of 35 degrees, showed spectra peaked at important energies (from 5 to 20 eV). The spectra shape depends on the collision velocity. A first theoretical analysis points out the link between the observed energy distribution and the presence of a centrifugal potential barrier. Finally, correlation experiments between produced ions and electron energy reveal that electron energy increases with internal energy. (author)

  7. Growth of C60 thin films on Al2O3/NiAl(100) at early stages

    Science.gov (United States)

    Hsu, S.-C.; Liao, C.-H.; Hung, T.-C.; Wu, Y.-C.; Lai, Y.-L.; Hsu, Y.-J.; Luo, M.-F.

    2018-03-01

    The growth of thin films of C60 on Al2O3/NiAl(100) at the earliest stage was studied with scanning tunneling microscopy and synchrotron-based photoelectron spectroscopy under ultrahigh-vacuum conditions. C60 molecules, deposited from the vapor onto an ordered thin film of Al2O3/NiAl(100) at 300 K, nucleated into nanoscale rectangular islands, with their longer sides parallel to direction either [010] or [001] of NiAl. The particular island shape resulted because C60 diffused rapidly, and adsorbed and nucleated preferentially on the protrusion stripes of the crystalline Al2O3 surface. The monolayer C60 film exhibited linear protrusions of height 1-3 Å, due to either the structure of the underlying Al2O3 or the lattice mismatch at the boundaries of the coalescing C60 islands; such protrusions governed also the growth of the second layer. The second layer of the C60 film grew only for a C60 coverage >0.60 ML, implying a layer-by-layer growth mode, and also ripened in rectangular shapes. The thin film of C60 was thermally stable up to 400 K; above 500 K, the C60 islands dissociated and most C60 desorbed.

  8. Thermal conductivity of pressure polymerized C60

    International Nuclear Information System (INIS)

    Soldatov, A.; Andersson, O.

    1997-01-01

    We have studied the kinetics of C 60 polymerization in the temperature interval 450-500 K at pressures below 1 GPa by measurements of the time dependence of the thermal conductivity. It has been found at 450 K that the polymerization process at 0.8 GPa is slower than the reverse transformation from ''polymeric'' to ''monomeric'' phase at 0.08 GPa. The thermal conductivity λ of polymerized C 60 was measured in the temperature range 100-430 K and found to increase with increasing temperature, which reflects strong phonon scattering. Both the presence of non-bonded C 60 molecules and a high degree of structural disorder in the crystalline lattice of the polymeric phase might be responsible for the behaviour of λ(T). The results for λ(T) are qualitatively similar to those reported previously for C 60 polymerized at higher p, T but an order of magnitude smaller. (orig.)

  9. Core Level Spectra of Organic Molecules Adsorbed on Graphene

    Directory of Open Access Journals (Sweden)

    Abhilash Ravikumar

    2018-03-01

    Full Text Available We perform first principle calculations based on density functional theory to investigate the effect of the adsorption of core-excited organic molecules on graphene. We simulate Near Edge X-ray absorption Fine Structure (NEXAFS and X-ray Photoemission Spectroscopy (XPS at the N and C edges for two moieties: pyridine and the pyridine radical on graphene, which exemplify two different adsorption characters. The modifications of molecular and graphene energy levels due to their interplay with the core-level excitation are discussed. We find that upon physisorption of pyridine, the binding energies of graphene close to the adsorption site reduce mildly, and the NEXAFS spectra of the molecule and graphene resemble those of gas phase pyridine and pristine graphene, respectively. However, the chemisorption of the pyridine radical is found to significantly alter these core excited spectra. The C 1s binding energy of the C atom of graphene participating in chemisorption increases by ∼1 eV, and the C atoms of graphene alternate to the adsorption site show a reduction in the binding energy. Analogously, these C atoms also show strong modifications in the NEXAFS spectra. The NEXAFS spectrum of the chemisorbed molecule is also modified as a result of hybridization with and screening by graphene. We eventually explore the electronic properties and magnetism of the system as a core-level excitation is adiabatically switched on.

  10. Vibrational properties of water molecules adsorbed in different zeolitic frameworks

    International Nuclear Information System (INIS)

    Crupi, V; Longo, F; Majolino, D; Venuti, V

    2006-01-01

    The perturbation of water 'sorbed' in samples of zeolites of different structural type, genesis, and cation composition (K-, Na-, Mg- and Ca-rich zeolites), namely the CHA framework of a synthetic K-chabazite, the LTA framework of synthetic Na-A and Mg50-A zeolites, and the NAT framework of a natural scolecite, has been studied by FTIR-ATR spectroscopy, in the -10 to +80 o C temperature range. The aim was to show how differences in the chemical composition and/or in the topology of the zeolite framework and, in particular, the possibility for the guest water molecules to develop guest-guest and/or host-guest interactions, lead to substantial differences in their vibrational dynamical properties. The spectra, collected in the O-H stretching and H 2 O bending mode regions, are complex, with multiple bands being observed. As far as water in the CHA and LTA frameworks is concerned, whose behaviour is governed by the balance of water-water, water-framework and water-extra-framework cations interactions, the assignment of the resolved components of the O-H stretching band has been discussed by fitting the band shapes into individual components attributed to H 2 O molecules engaged in different degrees of hydrogen bonding. A detailed quantitative picture of the connectivity pattern of water, as a function of temperature and according to the chemical and topological properties of the environment, is furnished. The H 2 O bending vibrational bands give additional information that perfectly agrees with the results obtained from the analysis of the O-H stretching spectral region. In the case of scolecite, a small-pored zeolite where water-water interactions are eliminated, the increased complexity observed in the infrared spectra in the O-H stretching and H 2 O bending regions was explained as due to the hydrogen bonding between the water molecules and the network, and also with the extra-framework cation. Furthermore, these observations have been correlated with the different

  11. Nanospectroscopy of thiacyanine dye molecules adsorbed on silver nanoparticle clusters

    Science.gov (United States)

    Ralević, Uroš; Isić, Goran; Anicijević, Dragana Vasić; Laban, Bojana; Bogdanović, Una; Lazović, Vladimir M.; Vodnik, Vesna; Gajić, Radoš

    2018-03-01

    The adsorption of thiacyanine dye molecules on citrate-stabilized silver nanoparticle clusters drop-cast onto freshly cleaved mica or highly oriented pyrolytic graphite surfaces is examined using colocalized surface-enhanced Raman spectroscopy and atomic force microscopy. The incidence of dye Raman signatures in photoluminescence hotspots identified around nanoparticle clusters is considered for both citrate- and borate-capped silver nanoparticles and found to be substantially lower in the former case, suggesting that the citrate anions impede the efficient dye adsorption. Rigorous numerical simulations of light scattering on random nanoparticle clusters are used for estimating the electromagnetic enhancement and elucidating the hotspot formation mechanism. The majority of the enhanced Raman signal, estimated to be more than 90%, is found to originate from the nanogaps between adjacent nanoparticles in the cluster, regardless of the cluster size and geometry.

  12. Radioiodination of C60 derivative

    International Nuclear Information System (INIS)

    Li Yuguo; Zhang Xiaodong; Li Qingnuan; Li Wenxin

    2001-01-01

    The water-soluble C 60 derivative was iodo-labelled radioactively with Iodogen method. The labelled yield was measured by Silica GF254 TLC. The effects of pH value, time, temperature and the amount of Iodogen on the labelled yield were studied. 125 I-C 60 (OH) x O y was purified by Sephadex G-25 column chromatography and then the stability of 125 I-C 60 (OH) x O y was examined. The results showed that the radiochemical purity of 125 I-C 60 (OH) x O y solution with 2% benzylalcohol remained 82.7% after 43h

  13. Dynamics of Molecules Adsorbed in Zeolitic Systems: Neutron Scattering and MD Simulation Studies

    Science.gov (United States)

    Mitra, S.; Sharma, V. K.; Mukhopadhyay, R.

    2011-07-01

    Zeolites represent a class of technologically important materials because of their characteristic properties of molecular sieving and catalysis, which makes them indispensable in the petroleum industries. While the catalytic properties depend upon many factors, a major role is played by the dynamics of hydrocarbon gases. In order to be able to tailor make these materials for use in industry for catalytic and sieving purposes, it is important to understand the dynamical properties of the guest molecules adsorbed in the zeolitic materials. It is of interest to study the effects of size and shape of guest molecules and also the host zeolitic structure, governing the diffusion mechanism of the adsorbed species. Here we report the results of Quasielastic Neutron Scattering (QENS) and classical molecular dynamics (MD) simulation studies of two hydrocarbons namely acetylene and propylene adsorbed in two structurally different zeolites Na-Y and ZSM-5.

  14. Removal of sulfur-containing organic molecules adsorbed on inorganic supports by Rhodococcus Rhodochrous spp.

    Science.gov (United States)

    Carvajal, P; Dinamarca, M Alejandro; Baeza, P; Camú, E; Ojeda, J

    2017-02-01

    To remove dibenzothiophene (DBT) and 4,6-dimethyl-dibenzothiophene (4,6-DMDBT) adsorbed on alumina, silica and sepiolite through biodesulfurization (BDS) using Rhodococcus Rhodochrous spp., that selectively reduce sulfur molecules without generating of gaseous pollutants. The adsorption of DBT and 4,6-DMDBT was affected by the properties of the supports, including particle size and the presence of surface acidic groups. The highest adsorption of both sulfur-containing organic molecules used particle sizes of 0.43-0.063 mm. The highest percentage removal was with sepiolite (80 % for DBT and 56 % for 4,6-DMDBT) and silica (71 % for DBT and 37 % for 4,6-DMDBT). This is attributed to the close interaction between these supports and the bacteria. Biodesulfurization is effective for removing the sulfur-containing organic molecules adsorbed on inorganic materials and avoids the generation of gaseous pollutants.

  15. Electronic excited states of Si(100) and organic molecules adsorbed on Si(100).

    Science.gov (United States)

    Besley, Nicholas A; Blundy, Adam J

    2006-02-02

    The electronically excited states of the Si(100) surface and acetylene, benzene, and 9,10-phenanthrenequinone adsorbed on Si(100) are studied with time-dependent density functional theory. The computational cost of these calculations can be reduced through truncation of the single excitation space. This allows larger cluster models of the surface in conjunction with large adsorbates to be studied. On clean Si(100), the low-lying excitations correspond to transitions between the pi orbitals of the silicon-silicon dimers. These excitations are predicted to occur in the range 0.4-2 eV. When organic molecules are adsorbed on the surface, surface --> molecule, molecule --> surface, and electronic excitations localized within the adsorbate are also observed at higher energies. For acetylene and benzene, the remaining pipi* excitations are found to lie at lower energies than in the corresponding gas-phase species. Even though the aromaticity of 9,10-phenanthrenequinone is retained, significant shifts in the pipi* excitations of the aromatic rings are predicted. This is in part due to structural changes that occur upon adsorption.

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

    Directory of Open Access Journals (Sweden)

    Marine E Bozdaganyan

    Full Text Available 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.

  17. STM imagery and density functional calculations of C60 fullerene adsorption on the 6H-SiC(0001)-3×3 surface

    Science.gov (United States)

    Ovramenko, T.; Spillebout, F.; Bocquet, F. C.; Mayne, A. J.; Dujardin, G.; Sonnet, Ph.; Stauffer, L.; Ksari, Y.; Themlin, J.-M.

    2013-04-01

    Scanning tunneling microscopy (STM) studies of the fullerene C60 molecule adsorbed on the silicon carbide SiC(0001)-3×3 surface, combined with density functional theory (DFT) calculations, show that chemisorption of individual C60 molecules occurs through the formation of one bond to one silicon adatom only in contrast to multiple bond formation on other semiconducting surfaces. We observe three stable adsorption sites with respect to the Si adatoms of the surface unit cell. Comprehensive DFT calculations give different adsorption energies for the three most abundant sites showing that van der Waals forces between the C60 molecule and the neighboring surface atoms need to be considered. The C60 molecules are observed to form small clusters even at low coverage indicating the presence of a mobile molecular precursor state and nonnegligible intermolecular interactions.

  18. Modeling the binding of fulvic acid by goethite: the speciation of adsorbed FA molecules

    Science.gov (United States)

    Filius, Jeroen D.; Meeussen, Johannes C. L.; Lumsdon, David G.; Hiemstra, Tjisse; van Riemsdijk, Willem H.

    2003-04-01

    Under natural conditions, the adsorption of ions at the solid-water interface may be strongly influenced by the adsorption of organic matter. In this paper, we describe the adsorption of fulvic acid (FA) by metal(hydr)oxide surfaces with a heterogeneous surface complexation model, the ligand and charge distribution (LCD) model. The model is a self-consistent combination of the nonideal competitive adsorption (NICA) equation and the CD-MUSIC model. The LCD model can describe simultaneously the concentration, pH, and salt dependency of the adsorption with a minimum of only three adjustable parameters. Furthermore, the model predicts the coadsorption of protons accurately for an extended range of conditions. Surface speciation calculations show that almost all hydroxyl groups of the adsorbed FA molecules are involved in outer sphere complexation reactions. The carboxylic groups of the adsorbed FA molecule form inner and outer sphere complexes. Furthermore, part of the carboxylate groups remain noncoordinated and deprotonated.

  19. Fragmentation of the C60 molecule in collision with light ions studied by a multi-correlation technique. Cross-sections, electron spectroscopy; Fragmentation de la molecule C60 par impact d'ions legers etudiee en multicorrelation. Sections efficaces, spectroscopie d'electrons

    Energy Technology Data Exchange (ETDEWEB)

    Rentenier, A

    2004-04-01

    A quantitative study of the C60 fullerenes fragmentation in collision with light ions (H{sub n}{sup +} with n=1,2,3, He{sup q+} with q=1,2) in the velocity range 0,1 - 2,3 u.a.) is presented. The multi-correlation technique, developed between fragment ions and electrons with well defined energy, has enlightened some of the dependences and properties of fragmentation mechanisms (cross sections, electron spectroscopy, size distributions, kinetic energy of fragment ions, Campi's scatter plot, activation energies). The deposited energy hence appeared as an important parameter. Cross sections have been measured, for the first time, for all the collisional processes. Ionisation and capture only depends on the collision velocity. On the other hand, scaling laws with the deposited energy have been observed for the cross sections of multifragmentation, which depends on the collision energy and the nature of the projectile. The deposited energy has also been found as an essential parameter to understand the evolution of the charged fragment size distributions. The electron spectroscopy, achieved at an emission angle of 35 degrees, showed spectra peaked at important energies (from 5 to 20 eV). The spectra shape depends on the collision velocity. A first theoretical analysis points out the link between the observed energy distribution and the presence of a centrifugal potential barrier. Finally, correlation experiments between produced ions and electron energy reveal that electron energy increases with internal energy. (author)

  20. Stability, structural and electronic properties of benzene molecule adsorbed on free standing Au layer

    Energy Technology Data Exchange (ETDEWEB)

    Katoch, Neha, E-mail: nehakatoch2@gmail.com; Kapoor, Pooja; Sharma, Munish; Ahluwalia, P. K. [Physics Department, Himachal Pradesh University, Shimla, Himachal Pradesh, India 171005 (India); Kumar, Ashok [Center for Physical Sciences, School of Basic and Applied Sciences, Central University of Punjab, Bathinda, India, 151001 (India)

    2016-05-23

    We report stability and electronic properties of benzene molecule adsorbed on the Au atomic layer within the framework of density function theory (DFT). Horizontal configuration of benzene on the top site of Au monolayer prefers energetically over other studied configurations. On the adsorption of benzene, the ballistic conductance of Au monolayer is found to decrease from 4G{sub 0} to 2G{sub 0} suggesting its applications for the fabrications of organic sensor devices based on the Au atomic layers.

  1. Nanocomposite Materials of Alternately Stacked C60 Monolayer and Graphene

    International Nuclear Information System (INIS)

    Ishikawa, M.; Miura, K.; Kamiya, S.; Yoshimoto, S.; Suzuki, M.; Kuwahara, D.; Sasaki, N.

    2010-01-01

    We synthesized the novel nanocomposite consisting alternately of a stacked single graphene sheet and a C 60 monolayer by using the graphite intercalation technique in which alkylamine molecules help intercalate large C 60 molecules into the graphite. Moreover, it is found that the intercalated C 60 molecules can rotate in between single graphene sheets by using C 13 NMR measurements. This preparation method provides a general way for intercalating huge fullerene molecules into graphite, which will lead to promising materials with novel mechanical, physical, and electrical properties.

  2. Nanocomposite Materials of Alternately Stacked C60 Monolayer and Graphene

    Directory of Open Access Journals (Sweden)

    Makoto Ishikawa

    2010-01-01

    Full Text Available We synthesized the novel nanocomposite consisting alternately of a stacked single graphene sheet and a C60 monolayer by using the graphite intercalation technique in which alkylamine molecules help intercalate large C60 molecules into the graphite. Moreover, it is found that the intercalated C60 molecules can rotate in between single graphene sheets by using C13 NMR measurements. This preparation method provides a general way for intercalating huge fullerene molecules into graphite, which will lead to promising materials with novel mechanical, physical, and electrical properties.

  3. Attenuated total reflectance spectroscopy of coumarin organosilane molecules adsorbed on a fused silica surface

    International Nuclear Information System (INIS)

    Bratescu, Maria Antoaneta; Saito, Nagahiro; Takai, Osamu

    2010-01-01

    Attenuated total reflectance (ATR) spectroscopy was used to investigate the adsorption of coumarin organosilane molecules onto a fused silica surface. The difference between the absorption spectra of the molecules on the surface and in solution was explained by the interaction of the adsorbed coumarin organosilane molecules with the hydroxyl groups on the fused silica surface. This interaction produces a perturbation of the π electron distribution and the electronic transitions of the coumarin chromophore of the organosilane molecules adsorbed on the surface. From the kinetics adsorption curves, the calculated enthalpy values of 74.8 ± 5.2 kJ mol -1 and free energy of -38.22 ± 0.70 kJ mol -1 at 23 deg. C indicates a chemisorption process. The high sensitivity of ATR spectroscopy allows the detection of a monolayer formed by a 10 nM concentration of coumarin organosilane molecules, which covers more than half of the maximum surface coverage at 60 deg. C.

  4. TCNE-modified graphene as an adsorbent for N2O molecule: a DFT study.

    Science.gov (United States)

    Rastegar, Somayeh F; Osouleddini, Noushin

    2017-11-22

    Adsorption behavior of nitrous oxide (N 2 O) on pristine graphene (PG) and tetracyanoethylene (TCNE) modified PG surfaces is investigated using density functional theory. A number of initial adsorbate geometries are considered on both surfaces and the most stable ones are chosen upon calculation of the adsorption energies (E ads ). N 2 O is found to adsorb in a weakly exoergic process (E ads  ∼ -3.18 kJ mol -1 ) at the equilibrium distance of 3.52 Å on the PG surface. N 2 O adsorption can be greatly enhanced with the presence of a TCNE molecule (E ads  = -87.00 kJ mol -1 ). Mulliken charge analysis confirms that adsorption of N 2 O is not accompanied by distinct charge transfer from the surfaces to the molecule (˂ 0.001 │e│ for each case). Moreover, on the basis of calculated changes in the HOMO/LUMO energy gap, it is found that electronic properties of PG and TCNE modified PG are not sensitive toward adsorption of N 2 O, indicating that both surfaces are not good enough to introduce as an N 2 O detector. However, the considerable amount of E ads in TCNE modified PG can be a guide to the design of graphene-based adsorbents for N 2 O capture.

  5. Mechanochemistry at Solid Surfaces: Polymerization of Adsorbed Molecules by Mechanical Shear at Tribological Interfaces.

    Science.gov (United States)

    Yeon, Jejoon; He, Xin; Martini, Ashlie; Kim, Seong H

    2017-01-25

    Polymerization of allyl alcohol adsorbed and sheared at a silicon oxide interface is studied using tribo-tests in vapor phase lubrication conditions and reactive molecular dynamics simulations. The load dependences of product formation obtained from experiments and simulations were consistent, indicating that the atomic-scale processes observable in the simulations were relevant to the experiments. Analysis of the experimental results in the context of mechanically assisted thermal reaction theory, combined with the atomistic details available from the simulations, suggested that the association reaction pathway of allyl alcohol molecules induced by mechanical shear is quite different from chemically induced polymerization reactions. Findings suggested that some degree of distortion of the molecule from its equilibrium state is necessary for mechanically induced chemical reactions to occur and such a distortion occurs during mechanical shear when molecules are covalently anchored to one of the sliding surfaces.

  6. C-60(+) Secondary Ion Microscopy Using a Delay Line Detector

    NARCIS (Netherlands)

    Klerk, Leendert A.; Lockyer, Nicholas P.; Kharchenko, Andriy; MacAleese, Luke; Dankers, Patricia Y. W.; Vickerman, John C.; Heeren, Ron M. A.

    2010-01-01

    Buckminsterfullerene (C-60) as a primary ion for secondary ion mass spectrometry (SIMS) has shown many benefits over classical SIMS sources in the analysis of large organic molecules including many of biological significance. One constraint has been the limited focusing capabilities of the C-60(+)

  7. Explaining the symmetry breaking observed in the endofullerenes H2@C60, HF@C60, and H2O@C60.

    Science.gov (United States)

    Felker, Peter M; Vlček, Vojtěch; Hietanen, Isaac; FitzGerald, Stephen; Neuhauser, Daniel; Bačić, Zlatko

    2017-11-29

    Symmetry breaking has been recently observed in the endofullerenes M@C 60 (M = H 2 , HF, H 2 O), manifesting in the splittings of the three-fold degenerate ground states of the endohedral ortho-H 2 , ortho-H 2 O and the j = 1 level of HF. The nature of the interaction causing the symmetry breaking is established in this study. A fragment of the solid C 60 is considered, comprised of the central C 60 molecule surrounded by twelve nearest-neighbor (NN) C 60 molecules. The fullerenes have either P (major) or H (minor) orientational orderings, and are assumed to be rigid with I h symmetry. Only the central C 60 is occupied by the guest molecule M, while the NN fullerenes are all empty. The key proposition of the study is that the electrostatic interactions between the charge densities on the NN C 60 molecules and that on M inside the central C 60 give rise to the symmetry breaking responsible for the measured level splittings. Using this model, the M@C 60 level splittings of interest are calculated variationally and using perturbation theory, for both the P and H orientations. Those obtained for the dominant P orientation are in excellent agreement with the experimental results, with respect to the splitting magnitudes and patterns, for all three M@C 60 systems considered, pointing strongly to the quadrupolar M-NN interactions as the main cause of the symmetry breaking. The level splittings calculated for the H orientation are about 30 times smaller than the ones in the P orientation.

  8. Mechanism of melting in submonolayer films of nitrogen molecules adsorbed on the basal planes of graphite

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Bruch, Ludwig Walter; Taub, H.

    1995-01-01

    The melting mechanism in submonolayer films of N-2 molecules adsorbed on the basal planes of graphite is studied using molecular-dynamics simulations. The melting is strongly correlated with the formation of vacancies in the films. As the temperature increases, the edges of the submonolayer patch...... become atomically rough and vacancies are first created there. Then there is an onset temperature at which the vacancies penetrate into the patch. At an intermediate region of coverages similar to 0.3-0.8 commensurate layers, there is sufficient free volume for the film to melt at that temperature...

  9. Studies of C60 in fossil of dinosaur egg shell

    International Nuclear Information System (INIS)

    Wang Zhenxia; Li Xuepeng; Wang Wenmin; Xu Xunjiang; Tang Zichao; Huang Rongbin; Zheng Lansun

    1998-01-01

    The occurrence of C 60 in unearthed fossil of dinosaur egg shell about 70 million years ago was reported. The results are discussed considering possible effects of the conceivable atmosphere pollution on the growth of fullerene molecules

  10. Bioapplication and activity of fullerenol C60(OH)24

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-29

    Kratschmer et al., 1990). Fullerenes are hydrophobic molecules best dissolved in .... cellular localization of these derivatives, is structural analogy between the C60 cage and that of the clathrin- coated vesicles. These last structures are ...

  11. Magnetization switching in ferromagnets by adsorbed chiral molecules without current or external magnetic field

    Science.gov (United States)

    Ben Dor, Oren; Yochelis, Shira; Radko, Anna; Vankayala, Kiran; Capua, Eyal; Capua, Amir; Yang, See-Hun; Baczewski, Lech Tomasz; Parkin, Stuart Stephen Papworth; Naaman, Ron; Paltiel, Yossi

    2017-02-01

    Ferromagnets are commonly magnetized by either external magnetic fields or spin polarized currents. The manipulation of magnetization by spin-current occurs through the spin-transfer-torque effect, which is applied, for example, in modern magnetoresistive random access memory. However, the current density required for the spin-transfer torque is of the order of 1 × 106 A.cm-2, or about 1 × 1025 electrons s-1 cm-2. This relatively high current density significantly affects the devices' structure and performance. Here we demonstrate magnetization switching of ferromagnetic thin layers that is induced solely by adsorption of chiral molecules. In this case, about 1013 electrons per cm2 are sufficient to induce magnetization reversal. The direction of the magnetization depends on the handedness of the adsorbed chiral molecules. Local magnetization switching is achieved by adsorbing a chiral self-assembled molecular monolayer on a gold-coated ferromagnetic layer with perpendicular magnetic anisotropy. These results present a simple low-power magnetization mechanism when operating at ambient conditions.

  12. Spins of adsorbed molecules investigated by the detection of Kondo resonance

    Science.gov (United States)

    Komeda, Tadahiro

    2014-12-01

    Surface magnetism has been one of the platforms to explore the magnetism in low dimensions. It is also a key component for the development of quantum information processes, which utilizes the spin degree of freedom. The Kondo resonance is a phenomenon that is caused by an interaction between an isolated spin and conduction electrons. First observed in the 1930s as an anomalous increase in the low-temperature resistance of metals embedded with magnetic atoms, the Kondo physics mainly studied the effects of bulk magnetic impurities in the resistivity. In the last 15 years it has undergone a revival by a scanning tunneling microscope (STM) which enables the measurement of the Kondo resonance at surfaces using an atomic scale point contact. The detection of the Kondo resonance can be a powerful tool to explore surface magnetism. In this article, I review recent studies of the surface spin of adsorbed molecules by the detection of the Kondo resonance. Researches on metal phthalocyanine (MPc) and porphyrin molecules will be examined. In addition, the Kondo resonance for double-decker lanthanoide Pc molecules will be discussed. Some of the double-decker Pc molecules show single-molecule magnet (SMM) behavior, which attracts attention as a material for electronic devices. For both classes, the ligand plays a crucial role in determining the parameters of the Kondo resonance, such as the Kondo temperature and the change of the shape from peak to Fano-dip. In addition, the spin in delocalized molecular orbital forms the Kondo resonance, which shows significant differences from the Kondo resonance formed by the metal spins. Since molecular orbital can be tuned in a flexible manner by the design of the molecule, the Kondo resonance formed by delocalized molecular orbital might expand the knowledge of this field.

  13. Adsorption of meso-tetraphenylporphines on thin films of C60 fullerene

    International Nuclear Information System (INIS)

    Bassiouk, Maria; Álvarez-Zauco, Edgar; Basiuk, Vladimir A.

    2013-01-01

    Noncovalent porphyrin–fullerene hybrids represent promising materials for organic photovoltaic applications and the construction of novel platforms for the immobilization of diverse molecules. In such hybrids, a structural aspect of particular interest is self-assembled monolayers (SAMs) of porphyrins on fullerene films supported on solid substrates. In the present work, we performed combined theoretical-experimental analysis of the behavior of meso-tetraphenylporphine (or 5,10,15,20-tetraphenyl-21H,23H-porphine, H 2 TPP) and its complexes with Ni(II) and Co(II) (NiTPP and CoTPP, respectively) when adsorbed from gas phase in vacuum (by means of physical vapor deposition, PVD) onto HOPG-supported fullerene C 60 films. The general film morphology was characterized by atomic force microscopy, whereas more detailed molecular structure as well as the adsorption of porphyrins was studied by scanning tunneling microscopy (STM). The results of STM imaging were compared with theoretical models, consisting of graphene sheets covered with a dense monolayer of fullerene cages and accommodating H 2 TPP molecules in different ways; their geometry was optimized by using MM+ force field. The results showed that NiTPP and CoTPP molecules are able to form ordered surface structures on the C 60 thin films. The geometries observed included such basic structural elements as equilateral triangles or parallel rows formed by porphyrin molecules. Nevertheless, the areas of the assemblies on C 60 turned out to be very limited, owing to the fact that the C 60 thin films are composed of overlapping 20–70 nm-sized clusters, whereas each individual cluster exhibits additional imperfections; altogether resulting in a highly irregular surface, inconvenient for the formation of extended porphyrin arrays

  14. C60 as an Atom Trap to Capture Co Adatoms

    DEFF Research Database (Denmark)

    Yang, Peng; Li, Dongzhe; Repain, Vincent

    2015-01-01

    C60 molecules were used to trap Co adatoms and clusters on a Au(111) surface using atomic/molecular manipulation with a scanning tunneling microscope. Two manipulation pathways (successive integration of single Co atoms in one molecule or direct integration of a Co cluster) were found...... to efficiently allow the formation of complexes mixing a C60 molecule with Co atoms. Scanning tunneling spectroscopy reveals the robustness of the pi states of C60 that are preserved after Co trapping. Scanning tunneling microscopy images and density functional theory calculations reveal that dissociated Co...... clusters of up to nine atoms can be formed at the molecule-substrate interface. These results open new perspectives in the interactions between metal adatoms and molecules, for applications in metal-organic devices...

  15. Formation of buckminsterfullerene (C60) in interstellar space

    Science.gov (United States)

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

    2012-01-01

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

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

    International Nuclear Information System (INIS)

    Liu Wei; Gao Xiang

    2008-01-01

    The C 60 dianion is used to reduce tetrachloroauric acid (HAuCl 4 ) for the first time; three-dimensional C 60 bound gold (Au-C 60 ) nanoclusters are obtained from C 60 -directed self-assembly of gold nanoparticles due to the strong affinities of Au-C 60 and C 60 -C 60 . The process was monitored in situ by UV-vis-NIR spectroscopy. The resulting Au-C 60 nanoclusters were characterized using transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy-dispersive spectroscopy (EDS), x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and FT-IR and Raman spectroscopies. TEM demonstrates the formation of 3D nanonetwork aggregates, which are composed of discrete gold nanocores covered with a C 60 monolayer. The SAED and XRD patterns indicate that the gold nanocores inside the capped C 60 molecules belong to the face-centred cubic crystal structure, while the C 60 molecules are amorphous. The EDS and XPS measurements validate that the Au-C 60 nanoclusters contain only Au and C elements and Au 3+ is reduced to Au 0 . FT-IR spectroscopy shows the chemiadsorption of C 60 to the gold nanocores, while Raman spectroscopy demonstrates the electron transfer from the gold nanocores to the chemiadsorbed C 60 molecules. Au-C 60 nanoclusters embedded in tetraoctyl-n-ammonium bromide (TOAB) on glassy carbon electrodes (GCEs) have been fabricated and have shown stable and well-defined electrochemical responses in aqueous solution

  17. Detection of adsorbed explosive molecules using thermal response of suspended microfabricated bridges

    DEFF Research Database (Denmark)

    Yi, Dechang; Greve, Anders; Hales, Jan Harry

    2008-01-01

    Here we present a thermophysical technique that is capable of differentiating vapor phase adsorbed explosives from nonexplosives and is additionally capable of differentiating individual species of common explosive vapors. This technique utilizes pairs of suspended microfabricated silicon bridges...... that can be heated in a controlled fashion. The differential thermal response of the bridges with and without adsorbed explosive vapor shows unique and reproducible characteristics depending on the nature of the adsorbed explosives. The tunable heating rate method described here is capable of providing...... unique signals for subnanogram quantities of adsorbed explosives within 50 ms. (C) 2008 American Institute of Physics....

  18. Incorporating C2 into C60 films.

    Science.gov (United States)

    Ulas, Seyithan; Strelnikov, Dmitry; Weis, Patrick; Böttcher, Artur; Kappes, Manfred M

    2012-01-07

    The material formed by depositing C(2)(-) anions onto/into thin C(60) films (on graphite) at room temperature has been studied by means of thermal desorption mass spectroscopy, ultraviolet photoionization spectroscopy, atomic force microscopy (AFM), and surface enhanced Raman spectroscopy. As-prepared, C(2)/C(60) films manifest thermal desorption behaviour which differs significantly from pure C(60) films. Whereas the latter can be fully sublimed, we observe decomposition of C(2)/C(60) films to a high-temperature-stable material while predominantly C(60), C(62), and C(64) are desorbed in parallel. Deposition of C(2)(-) also leads to significantly modified electronic and vibrational properties. Based on DFT model calculations of the Raman spectra, we suggest that as-prepared C(2)/C(60) films contain appreciable amounts of polymeric networks comprising -C(2)-C(60)-C(2)-C(60)- chains. Detection of sublimed C(62) and C(64) upon heating implies that thermal decomposition of C(2)/C(60) films involves addition/uptake of C(2) units into individual fullerene cages. Correspondingly, annealing films up to various intermediate temperatures results in significant modifications to valence-band UP spectra as well as to surface topographies as imaged by AFM. The novel carbonaceous material obtained by heating to T > 950 K has a finite density of states at the Fermi level in contrast to as-prepared C(2)/C(60). It comprises fused fullerene cages.

  19. Effect of Adsorbed Alcohol Layers on the Behavior of Water Molecules Confined in a Graphene Nanoslit: A Molecular Dynamics Study.

    Science.gov (United States)

    Gao, Qingwei; Zhu, Yudan; Ruan, Yang; Zhang, Yumeng; Zhu, Wei; Lu, Xiaohua; Lu, Linghong

    2017-10-24

    With the rapid development of a two-dimensional (2D) nanomaterial, the confined liquid binary mixture has attracted increasing attention, which has significant potential in membrane separation. Alcohol/water is one of the most common systems in liquid-liquid separation. As one of the most focused systems, recent studies have found that ethanol molecules were preferentially adsorbed on the inner surface of the pore wall and formed an adsorbed ethanol layer under 2D nanoconfinement. To evaluate the effect of the alcohol adsorption layer on the mobility of water molecules, molecular simulations were performed to investigate four types of alcohol/water binary mixtures confined under a 20 Å graphene slit. Residence times of the water molecules covering the alcohol layer were in the order of methanol/water molecules and the surrounding water molecules could induce a small degree of damage to the H-bond network of the water molecules covering the alcohol layer, resulting in the long residence time of the water molecules.

  20. Adsorption and photophysics of fullerene C60 at liquid-zeolite particle interfaces: unusually high affinity for hydrophobic, ultrastabilized zeolite Y.

    Science.gov (United States)

    Ellison, Eric H

    2006-06-15

    Adsorption of fullerene C60 from solution to the external surface of zeolite particles has been investigated. The most intriguing result of this study was the nature of C60 adsorption to ultrastablized zeolite Y (or USY). Two commercial samples of USY were tested: CBV780 (Y780) and CBV901 (Y901). Y901 was shown in previous reports to be more hydrophobic than Y780. Higher affinity of C60 for Y901 was found relative to Y780 in a variety of hydrocarbon solvents, including toluene and cyclohexane. In these same solvents, weak or no affinity for Y901 of typical arenes such as naphthalene or pyrene was observed. In toluene, adsorption isotherms for C60 gave dissociation constants (and values of saturation binding) = 0.5 microM (5.8 micromol g(-1)) and 8 microM (1.4 micromol g(-1)) for Y901 and Y780, respectively. C60 was estimated to cover nearly one-half of the estimated external surface area of Y901 particles at saturation. Significant adsorption of C60 to the ionic zeolites NaX, NaY, and KL was observed in cyclohexane but not in toluene, consistent with the pi-cation effect as a driving force for adsorption to these materials. The main driving force for C60 adsorption to Y901 is postulated to involve the interaction of C60 with lone pair electrons of framework oxygen atoms of the 12-ring entry aperture to the supercage. In the 12-ring site, C60 is located in half-supercage bowls on the exterior particle surface. The adsorptive interaction on Y901 relies on the spherical shape of C60 and the hydrophobicity of the zeolite surface. On ionic zeolites, the presence of specific adsorption sites such as exchangeable cations and hydroxyl groups hinder the special positioning necessary for C60 interaction with the 12-ring site. The ground-state and triplet-state absorption spectrum of adsorbed C60 was solution-like on all zeolites. Quenching of the C60 triplet state was examined by using transient absorption spectroscopy. Rate constants for quenching by rubrene, ferrocene, and

  1. Processing of C60 thin films by Matrix-Assisted Pulsed Laser Evaporation (MAPLE)

    DEFF Research Database (Denmark)

    Canulescu, Stela; Schou, Jørgen; Fæster, Søren

    2011-01-01

    has been applied for deposition of fullerenes for the first time and we have studied the growth of thin films of solid C60. The fragmentation of C60 fullerene molecules induced by ns ablation in vacuum of a frozen anisole target with C60 was investigated by matrix-assisted laser desorption...

  2. Superconductivity in alkali-doped C60

    International Nuclear Information System (INIS)

    Ramirez, Arthur P.

    2015-01-01

    Highlight: • Superconductivity in alkali-doped C 60 (A 3 C 60 ) is well described by an s-wave state produced by phonon mediated pairing. • Moderate coupling of electrons to high-frequency shape-changing intra-molecular vibrational modes produces transition temperatures up to 33 K in single-phase material. • The good understanding of pairing in A 3 C 60 offers a paradigm for the development of new superconducting materials. - Abstract: Superconductivity in alkali-doped C 60 (A 3 C 60 , A = an alkali atom) is well described by an s-wave state produced by phonon mediated pairing. Moderate coupling of electrons to high-frequency shape-changing intra-molecular vibrational modes produces transition temperatures (T c ) up to 33 K in single-phase material. The good understanding of pairing in A 3 C 60 offers a paradigm for the development of new superconducting materials

  3. Photodetachment of negative C60- ions

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Baltenkov, A.S.; Krakov, B.G.

    1998-01-01

    A model that describes the electron structure of negative fullerene C 60 - ions is proposed. The model contains only two experimentally observed parameters, namely the fullerene radius and the affinity energy of the electron to neutral C 60 . In the frame of this model, cross sections are calculated of elastic scattering of slow electrons on neutral fullerene, of C 60 - photodetachment near the threshold of this process and of radiative recombination of slow electrons with neutral fullerenes. (orig.)

  4. Identification of adsorbed molecules via STM tip manipulation: CO, H₂O, and O₂ on TiO₂ anatase (101).

    Science.gov (United States)

    Setvin, Martin; Daniel, Benjamin; Aschauer, Ulrich; Hou, Weiyi; Li, Ye-Fei; Schmid, Michael; Selloni, Annabella; Diebold, Ulrike

    2014-10-21

    While Scanning Tunneling Microscopy (STM) has evolved as an ideal tool to study surface chemistry at the atomic scale, the identification of adsorbed species is often not straightforward. This paper describes a way to reliably identify H2O, CO and O2 on the TiO2 anatase (101) surface with STM. These molecules are of a key importance in the surface chemistry of this and many other (photo-) catalytic materials. They exhibit a wide variety of contrasts in STM images, depending on the tip condition. With clean, metallic tips the molecules appear very similar, i.e., as bright, dimer-like features located in the proximity of surface Ti5c atoms. However, each species exhibits a specific response to the electric field applied by the STM tip. It is shown that this tip-adsorbate interaction can be used to reliably ascertain the identity of such species. The tip-adsorbate interactions, together with comparison of experimental and calculated STM images, are used to analyse and revisit the assignments of molecular adsorbed species reported in recent studies.

  5. NMR diffusion and relaxation measurements of organic molecules adsorbed in porous media

    International Nuclear Information System (INIS)

    Gjerdaaker, Lars

    2002-01-01

    a bipolar form of the pulsed field gradient has proved to be an efficient method for both reducing the cross-term between the applied and internal gradient and reducing the eddy current dead time. Without the use of a bipolar sequence, the measured diffusivities are likely to be underestimated. In order to get sufficient attenuation of the signal a stimulated-echo sequence together with magnetic field gradients have been used. It was then possible to increase the z-storage period to compensate for insufficient gradient strength. However, the employed diffusion probe and gradient power supply are able to generate magnetic field gradients that make the z-storage period unnecessary. In this work we also present a spin-echo analogue to the 13-interval PFGSTE sequence presented by Cotts et al., a so-called 11-interval bipolar PFGSE sequence. Conclusions: The molecular dynamics of four organic adsorbates confined in porous materials have been investigated. The confinement gives rise to substantial changes in the phase behaviour and molecular dynamics. From the line shape of the confined substances a narrow-line component superimposed on a broad resonance is observed at temperatures well below the transition point of the bulk material. This narrow-line component is, in the freezing region, attributed to the surface layer and the undercooled liquid in the smaller pores that remains unfrozen. In the low-temperature region, the narrow-line component corresponds to the surface layer, while the broad component originates from the crystalline phase at the centre of the pores. The persistent surface layer does not appear to crystallize at all, and a relatively high diffusion rate of this liquid-like phase is observed over a wide temperature range, even well below the transition point of the bulk material. However, with decreasing temperature T2 of the molecules in the surface layer becomes shorter and the contribution to the NMR signal decreases gradually. For pivalic acid and

  6. Deuterium-hydrogen isotopic exchange in water molecules adsorbed on Teflon under atomic-molecular hydrogen beams

    International Nuclear Information System (INIS)

    Grankin, V.P.; Savinkov, N.A.; Styrov, V.V.; Tyurin, Yu.I.

    1994-01-01

    Processes of deuterium-hydrogen exchange in the course of interaction between hydrogen molecular beam and H+H 2 atomic-molecular beam with adsorbed water molecules from D 2 O, HDO, H 2 O on Teflon have been studied. Desorption of the above molecules into vacuum, as well as their desorption under conditions of molecular and atomic-molecular hydrogen beam effect on Teflon surface have been investigated experimentally. Relative probabilities of hydrogen isotopes desorption from Teflon surface have been defined, relative probabilities and cross sections of diverse reactions of isotopic exchange have been found. 2 refs.; 3 figs

  7. Binary molecular layers of C-60 and copper phthalocyanine on Au(111) : Self-organized nanostructuring

    NARCIS (Netherlands)

    Stöhr, Meike; Wagner, Thorsten; Gabriel, Markus; Weyers, Bastian; Möller, Rolf

    The binary molecular system of C-60 and copper phthalocyanine(CuPc) molecules has been investigated by scanning tunneling microscopy (STM) at room temperature and at 50 K. As substrate Au(111) was chosen. When C-60 and CuPc molecules are sequentially deposited, it is found that well-ordered domains

  8. C60 interactions with surfaces, gaseous species and photons: An overview

    International Nuclear Information System (INIS)

    Gruen, D.M.

    1992-01-01

    The behavior of C 60 in collisions with surfaces, with other gaseous species, and with photons is discussed. The focus is on the processes leading to fragmentation of the molecule, the identification of fragmentation products, and the mechanism of fragmentation. The nature of the fragmentation process of C 60 is of considerable interest in itself and needs to be understood in detail if C 60 cluster ion beams are to be fully exploited technologically. In addition, one may anticipate that an understanding of C 60 fragmentation will contribute mutatis mutandis to an elucidation of the elementary steps leading to the assembly of C 60 from smaller carbon clusters

  9. Thermal expansion of C60 single crystals under pressure

    International Nuclear Information System (INIS)

    Grube, K.D.

    1995-12-01

    The thermal expansion and compressibility of C 60 single crystals have been investigated by a newly developed capacitive dilatometer. The dilatometer was integrated in a high pressure cell and exposed to a hydrostatic pressure of maximal 0.85 GPa with He or Ar as pressure transmitting medium. The relative length change of the C 60 -samples was measured with a resolution of ΔL/L∼10 -9 . The crystals consist of weakly bonded C 60 -molecules which can rotate nearly free at room temperature. The gradual freezing-in of the rotational motions leads to a first order phase transition at 260 K and a glass transition at 90 K. The pressure dependence of these transitions was determined in a temperature range from 50 K to 325 K up to a pressure of 0.85 GPa. The phase transition at 260 K shows a positive pressure dependence of 174 K/GPa. The glass transition temperature first increases with 75 K/GPa under pressure, then it jumps discontinuously by 10 K at 0.15 GPa followed by a further increase with a slope of 54 K/GPa. The jump in the glass transition temperature at 0.15 GPa can be explained with an orientation-dependent interaction between the C 60 -molecules. (orig.) [de

  10. Heat capacity measurements of atoms and molecules adsorbed on evaporated metal films

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, T.W.

    1989-05-01

    Investigations of the properties of absorbed monolayers have received great experimental and theoretical attention recently, both because of the importance of surface processes in practical applications such as catalysis, and the importance of such systems to the understanding of the fundamentals of thermodynamics in two dimensions. We have adapted the composite bolometer technology to the construction of microcalorimeters. For these calorimeters, the adsorption substrate is an evaporated film deposited on one surface of an optically polished sapphire wafer. This approach has allowed us to make the first measurements of the heat capacity of submonolayer films of /sup 4/He adsorbed on metallic films. In contrast to measurements of /sup 4/He adsorbed on all other insulating substrates, we have shown that /sup 4/He on silver films occupies a two-dimensional gas phase over a broad range of coverages and temperatures. Our apparatus has been used to study the heat capacity of Indium flakes. CO multilayers, /sup 4/He adsorbed on sapphire and on Ag films and H/sub 2/ adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs.

  11. Heat capacity measurements of atoms and molecules adsorbed on evaporated metal films

    International Nuclear Information System (INIS)

    Kenny, T.W.

    1989-05-01

    Investigations of the properties of absorbed monolayers have received great experimental and theoretical attention recently, both because of the importance of surface processes in practical applications such as catalysis, and the importance of such systems to the understanding of the fundamentals of thermodynamics in two dimensions. We have adapted the composite bolometer technology to the construction of microcalorimeters. For these calorimeters, the adsorption substrate is an evaporated film deposited on one surface of an optically polished sapphire wafer. This approach has allowed us to make the first measurements of the heat capacity of submonolayer films of 4 He adsorbed on metallic films. In contrast to measurements of 4 He adsorbed on all other insulating substrates, we have shown that 4 He on silver films occupies a two-dimensional gas phase over a broad range of coverages and temperatures. Our apparatus has been used to study the heat capacity of Indium flakes. CO multilayers, 4 He adsorbed on sapphire and on Ag films and H 2 adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs

  12. Sensitivity of photoelectron diffraction to conformational changes of adsorbed molecules: Tetra-tert-butyl-azobenzene/Au(111

    Directory of Open Access Journals (Sweden)

    A. Schuler

    2017-01-01

    Full Text Available Electron diffraction is a standard tool to investigate the atomic structure of surfaces, interfaces, and adsorbate systems. In particular, photoelectron diffraction is a promising candidate for real-time studies of structural dynamics combining the ultimate time resolution of optical pulses and the high scattering cross-sections for electrons. In view of future time-resolved experiments from molecular layers, we studied the sensitivity of photoelectron diffraction to conformational changes of only a small fraction of molecules in a monolayer adsorbed on a metallic substrate. 3,3′,5,5′-tetra-tert-butyl-azobenzene served as test case. This molecule can be switched between two isomers, trans and cis, by absorption of ultraviolet light. X-ray photoelectron diffraction patterns were recorded from tetra-tert-butyl-azobenzene/Au(111 in thermal equilibrium at room temperature and compared to patterns taken in the photostationary state obtained by exposing the surface to radiation from a high-intensity helium discharge lamp. Difference patterns were simulated by means of multiple-scattering calculations, which allowed us to determine the fraction of molecules that underwent isomerization.

  13. Interaction between poly(vinyl pyrrolidone) PVP and fullerene C60 at the interface in PVP-C60 nanofluids–A spectroscopic study

    Science.gov (United States)

    Behera, M.; Ram, S.

    2018-03-01

    Fourier transform infrared and Raman bands shows a discernible enhancement in band intensity of C–H stretching, C=O stretching, C–N stretching, C–H2 bending, and C–H2 in-plane bending in PVP molecules in the presence of C60 molecules. Amplification in intensity is ascribed to microscopic interactions results when a donation of nonbonding electron (n) occurs from a “>N–C=O” entity of PVP into a lowest unoccupied molecular orbital of the C60 molecule in PVP-C60 charge transfer (CT) complex. The C=O stretching band intensity (integrated) Vs C60 content plot exhibits a peak near a critical 13.9 μM C60 value owing to percolation effect. Light emission spectra show that even a small addition of 4.63 μM C60 able to suppress the band intensity by ~23% as a result of an energy loss. The integrated band intensity also decreases through a peak near 13.9 μM when plotted against the C60-content. In correlation to the vibration spectra, the maximum effect observed both in light emission and excitation spectra suggests a percolation effect in the CT complex. Exhibition of percolation threshold in C60-PVP donor-acceptor complex will be helpful in optimizing the photovoltaic properties vital for solar cell applications.

  14. Electron Impact Ionization of C60

    International Nuclear Information System (INIS)

    Duenser, B.; Lezius, M.; Scheier, P.; Deutsch, H.; Maerk, T.D.

    1995-01-01

    Absolute partial and total cross sections for the electron impact ionization of C 60 have been measured using a novel approach for the absolute calibration. The results obtained reveal not only an anomalous large parent ion cross section (as compared to the other ionization channels), but also anomalies for the production of multiply charged parent and fragment ions. This special behavior has its origin in the specific electronic and geometric structure of C 60 . Semiclassical calculations for singly charged ions support the measured data

  15. Laser-assisted deposition of thin C60 films

    DEFF Research Database (Denmark)

    Schou, Jørgen; Canulescu, Stela; Fæster, Søren

    Metal and metal oxide films with controlled thickness from a fraction of a monolayer up more than 1000 nm and known stoichiometry can be produced by pulsed laser deposition (PLD) relatively easily, and (PLD) is now a standard technique in all major research laboratories within materials science...... bound carbon molecule with a well-defined mass (M = 720 amu) and therefore a good, organic test molecule. C60 fullerene thin films of average thickness of more than 100 nm was produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was directed onto a frozen target...

  16. Preparation and characterization of a new hydrophilic C60 derivative (OH)16C60CHCOOH.

    Science.gov (United States)

    Zhu, Engao; Liu, Ruili; Lv, Min; Li, Qingnuan; Li, Wenxin; Zhao, Yun; Huang, Qing

    2010-02-01

    C60 and its derivatives are very important nanomaterials in biological and materials science. Unfortunately, due to the high hydrophobicity of the C60 cage, most of these materials are insoluble in water and their usages are quitely restricted. Here we reported the preparation and characterization of (OH)16C60CHCOOH, a new multihydroxylated methanofullerene carboxylic acid (MMFCA) derivative with high aqueous solubility. The elementary analysis, FT-IR and 1HNMR confirmed the structure of this material. Like other C60 and its derivatives, this new derivative also contains the free radical scavenging ability, measured by electron spin resonance (ESR) test. On the other hand, the MTT assay showed it had low cytotoxicity. Therefore, this new MMFCA derivative might be a potential vehicle for the introduction of hydrophobic C60 derivatives into water or a hydrophilic environment.

  17. Detection of gas molecules on single Mn adatom adsorbed graphyne: a DFT-D study

    Science.gov (United States)

    Lu, Zhansheng; Lv, Peng; Ma, Dongwei; Yang, Xinwei; Li, Shuo; Yang, Zongxian

    2018-02-01

    As one of the prominent applications in intelligent systems, gas sensing technology has attracted great interest in both industry and academia. In the current study, the pristine graphyne (GY) without and with a single Mn atom is investigated to detect the gas molecules (CO, CH4, CO2, NH3, NO and O2). The pristine GY is promising to detect O2 molecules because of its chemical adsorption on GY with large electron transfer. The great stability of the Mn/GY is found, and the Mn atom prefers to anchor at the alkyne ring as a single atom. Upon single Mn atom anchoring, the sensitivity and selectivity of GY based gas sensors is significantly improved for various molecules, except CH4. The recovery time of the Mn/GY after detecting the gas molecules may help to appraise the detection efficiency for the Mn/GY. The current study will help to understand the mechanism of detecting the gas molecules, and extend the potentially fascinating applications of GY-based materials.

  18. Slow Diffusive Motions in a Monolayer of Tetracosane Molecules Adsorbed on Graphite

    DEFF Research Database (Denmark)

    Taub, H.; Hansen, Flemming Yssing; Criswell, L.

    2004-01-01

    Monolayers of intermediate-length alkane molecules such as tetracosane (n-C24H50 or C24) serve as prototypes for studying the interfacial dynamics of more complex polymers, including bilayer lipid membranes. Using high-resolution quasielastic neutron scattering (QNS) and exfoliated graphite...... to a temperature of similar to230 K, we observe the QNS energy width to be dispersionless, consistent with molecular dynamics simulations showing rotational motion of the molecules about their long axis. At 260 K, the QNS energy width begins to increase with wave vector transfer, suggesting onset of nonuniaxial...... rotational motion and bounded translational motion. We continue to observe QNS up to the monolayer melting temperature at similar to340 K where our simulations indicate that the only motion slow enough to be visible within our energy window results from the creation of gauche defects in the molecules....

  19. Dynamics of molecules adsorbed on a die wall during polymer melt extrusion

    NARCIS (Netherlands)

    Tchesnokov, M.A.; Molenaar, J.; Slot, J.J.M.

    2005-01-01

    A new, quantitative model to describe the dynamics of polymer molecules grafted on a solid wall is presented. This model is based on the bond vector probability distribution function (BVPDF) which contains the necessary information about the spatial conformations of the grafted chains. All

  20. Molecular dynamics investigation into the structural features and transport properties of C60 in liquid argon.

    Science.gov (United States)

    Fang, Kuan-Chuan; Weng, Cheng-I

    2007-07-05

    Molecular dynamics (MD) simulations were performed to investigate the structural features and transport properties of C60 in liquid argon. The results reveal that an organized structure shell of liquid argon is formed close to the surface of a C60 fullerene molecule, thereby changing the solid/liquid interfacial structure. Furthermore, the simulation indicates that the C60-liquid argon fluid becomes structurally more stable as the C60 molecule volume fraction and the temperature increase. The viscosity of the fluid increases significantly as the C60 molecule loading is increased, particularly at a lower temperature. The thermal conductivity enhancement of the fluid in the present simulations is anomalously an order of magnitude higher than the theoretical predictions from either the Maxwell or the Lu and Liu models, and is found to vary approximately linearly with the C60 molecule volume fraction. The increased thermal conductivity is attributed to the nature of heat conduction in C60 molecule suspensions and an organized structure at the solid/liquid interface.

  1. Nucleation and growth of C60 overlayers on the Ag/Pt(111) dislocation network surface

    International Nuclear Information System (INIS)

    Ait-Mansour, K; Ruffieux, P; Xiao, W; Fasel, R; Groening, P; Groening, O

    2007-01-01

    We have investigated the room temperature growth of C 60 overlayers on the strainrelief dislocation network formed by two monolayers of Ag on Pt(111) by means of scanning tunneling microscopy. Extended domains of highly ordered dislocation networks with a typical superlattice parameter of 6.8 nm have been prepared, serving as templates for subsequent C 60 depositions. For low C 60 coverages, the molecules decorate the step-edges, where also the first islands nucleate. This indicates that at room temperature the C 60 molecules are sufficiently mobile to cross the dislocation lines and to diffuse to the step-edges. For C 60 coverages of 0.4 monolayer, besides the islands nucleated at the step-edges, C 60 islands also grow in the middle of terraces. The C 60 islands typically extend over several unit cells of the dislocation network and show an unusual orientation of the hexagonally close-packed C 60 lattice as compared to that found on the bare Ag(111) surface. Whereas C 60 grows preferentially in a (2 √3 x 2 √3) R30 0 structure on Ag(111), on the Ag/Pt(111) dislocation network the C 60 lattice adopts an orientation rotated by 30 0 , with the close-packed C 60 rows aligned along the dislocations which themselves are aligned along the Ag(1-10) directions. For higher coverages in the range of 1-2 monolayers, the growth of C 60 continues in a layer-by-layer fashion

  2. C(60)-exTTF-C(60) Dumbbells: cooperative effects stemming from two C(60)s on the radical ion pair stabilization.

    Science.gov (United States)

    Sánchez, Luis; Sierra, María; Martín, Nazario; Guldi, Dirk M; Wienk, Martijn W; Janssen, René A J

    2005-04-28

    [structure: see text] The presence of a second C(60) cage in C(60)-exTTF-C(60) triads [exTTF = 9,10-bis(1,3-dithiol-2-ylidene)-9,10-anthraquinone] has beneficial effects on the stabilization of the radical ion pair formed upon irradiation in comparison with the related C(60)-exTTF dyad. Although C(60)-exTTF-C(60) ensembles show no electronic interaction between the electroactive units in the ground state, their irradiation leads to C(60)(*)(-)-exTTF(*)(+)-C(60) species with lifetimes on the order of 600 ns in benzonitrile; these lifetimes are twice those determined for the analogous C(60)-exTTF dyad.

  3. Phase properties of elastic waves in systems constituted of adsorbed diatomic molecules on the (001) surface of a simple cubic crystal

    Science.gov (United States)

    Deymier, P. A.; Runge, K.

    2018-03-01

    A Green's function-based numerical method is developed to calculate the phase of scattered elastic waves in a harmonic model of diatomic molecules adsorbed on the (001) surface of a simple cubic crystal. The phase properties of scattered waves depend on the configuration of the molecules. The configurations of adsorbed molecules on the crystal surface such as parallel chain-like arrays coupled via kinks are used to demonstrate not only linear but also non-linear dependency of the phase on the number of kinks along the chains. Non-linear behavior arises for scattered waves with frequencies in the vicinity of a diatomic molecule resonance. In the non-linear regime, the variation in phase with the number of kinks is formulated mathematically as unitary matrix operations leading to an analogy between phase-based elastic unitary operations and quantum gates. The advantage of elastic based unitary operations is that they are easily realizable physically and measurable.

  4. Transfer of chirality from adsorbed chiral molecules to the substrates highlighted by circular dichroism in angle-resolved valence photoelectron spectroscopy

    DEFF Research Database (Denmark)

    Contini, G.; Turchini, S.; Sanna, Simone

    2012-01-01

    Studies of self-assembled chiral molecules on achiral metallic surfaces have mostly focused on the determination of the geometry of adsorbates and their electronic structure. The aim of this paper is to provide direct information on the chirality character of the system and on the chirality trans...

  5. Surface Chemistry Dependence of Mechanochemical Reaction of Adsorbed Molecules-An Experimental Study on Tribopolymerization of α-Pinene on Metal, Metal Oxide, and Carbon Surfaces.

    Science.gov (United States)

    He, Xin; Kim, Seong H

    2018-02-20

    Mechanochemical reactions between adsorbate molecules sheared at tribological interfaces can induce association of adsorbed molecules, forming oligomeric and polymeric products often called tribopolymers). This study revealed the role or effect of surface chemistry of the solid substrate in mechanochemical polymerization reactions. As a model reactant, α-pinene was chosen because it was known to readily form tribopolymers at the sliding interface of stainless steel under vapor-phase lubrication conditions. Eight different substrate materials were tested-palladium, nickel, copper, stainless steel, gold, silicon oxide, aluminum oxide, and diamond-like carbon (DLC). All metal substrates and DLC were initially covered with surface oxide species formed naturally in air or during the oxidative sample cleaning. It was found that the tribopolymerization yield of α-pinene is much higher on the substrates that can chemisorb α-pinene, compared to the ones on which only physisorption occurs. From the load dependence of the tribopolymerization yield, it was found that the surfaces capable of chemisorption give a smaller critical activation volume for the mechanochemical reaction, compared to the ones capable of physisorption only. On the basis of these observations and infrared spectroscopy analyses of the adsorbed molecules and the produced polymers, it was concluded that the mechanochemical reaction mechanisms might be different between chemically reactive and inert surfaces and that the chemical reactivity of the substrate surface greatly influences the tribochemical polymerization reactions of adsorbed molecules.

  6. Optical High Harmonic Generation in C60

    Science.gov (United States)

    Zhang, Guoping

    2005-03-01

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

  7. Preparation and biodistribution of radiolabeled fullerene C60 nanocrystals

    International Nuclear Information System (INIS)

    Nikolic, Nadezda; Vranjes-Duric, Sanja; Jankovic, Drina; Dokic, Divna; Mirkovic, Marija; Bibic, Natasa; Trajkovic, Vladimir

    2009-01-01

    The present study describes for the first time a procedure for the radiolabeling of fullerene (C 60 ) nanocrystals (nanoC 60 ) with Na 125 I, as well as the biodistribution of radiolabeled nanoC 60 ( 125 I-nanoC 60 ). The solvent exchange method with tetrahydrofuran was used to make colloidal water suspensions of radiolabeled nanoC 60 particles. The radiolabeling procedure with the addition of Na 125 I to tetrahydrofuran during dissolution of C 60 gave a higher radiochemical yield of radiolabeled nanoC 60 particles in comparison to the second option, in which Na 125 I was added after C 60 was dissolved. Using photon correlation spectroscopy and transmission electron microscopy, 125 I-nanoC 60 particles were found to have a crystalline structure and a mean diameter of 200-250 nm. The 125 I-nanoC 60 had a particularly high affinity for human serum albumin, displaying 95% binding efficiency after 1 h. Biodistribution studies of 125 I-nanoC 60 in rats indicated significant differences in tissue accumulation of 125 I-nanoC 60 and the radioactive tracer Na 125 I. The higher accumulation of radiolabeled nanoC 60 was observed in liver and spleen, while accumulation in thyroid, stomach, lungs and intestines was significantly lower in comparison to Na 125 I. In addition to being useful for testing the biological distribution of nanoC 60 , the described radiolabeling procedure might have possible applications in cancer radiotherapy.

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

    Science.gov (United States)

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

    2017-09-15

    Recent studies of single-molecule thermoelectricity have identified families of high-performance molecules. However, in order to translate this discovery into practical thin-film energy-harvesting devices, there is a need for an understanding of the fundamental issues arising when such junctions are placed in parallel. This is relevant because controlled scalability might be used to boost electrical and thermoelectric performance over the current single-junction paradigm. As a first step in this direction, we investigate here the properties of two C 60 molecules placed in parallel and sandwiched between top and bottom graphene electrodes. In contrast with classical conductors, we find that increasing the number of parallel junctions from one to two can cause the electrical conductance to increase by more than a factor of 2. Furthermore, we show that the Seebeck coefficient is sensitive to the number of parallel molecules sandwiched between the electrodes, whereas classically it should be unchanged. This non-classical behaviour of the electrical conductance and Seebeck coefficient are due to inter-junction quantum interference, mediated by the electrodes, which leads to an enhanced response in these vertical molecular devices.

  9. The non-exponential relaxation of the C60 crystal around glass transition temperature

    International Nuclear Information System (INIS)

    Yan, F; Wang, Y.N.

    1999-01-01

    A model of the energy barrier of a molecule between two orientational states in the C 60 crystal, which depends on the neighboring molecules, is first proposed. Based on this model, the orientational relaxation of C 60 molecules around 90 K was simulated with the Monte Carlo method. The simulation results show that the relaxation is slightly non-exponential and can fit the Kohlrausch-Williams-Watts function with the non-exponential factor β = 0.962 ± 0.002, which is equal to the experimental data that has not been explained before. (orig.)

  10. Atomic collisions involving C60 and collective excitation

    Science.gov (United States)

    Tribedi, L. C.; Kelkar, A. H.

    2011-12-01

    Here we review and discuss some of our recent investigations on collective excitation in a free C60 molecule and its influence on the atomic collisions. In particular, emphasis has been given for collisions with fast highly charged ions. It is demonstrated, from the charge-state-dependence studies of recoil-ion spectra, that the plasmon excitation plays a dominant role in the single and double ionization process. The observed linear charge-state-dependence is in contrast to the expected behavior predicted by ion-atom collisions models. This behavior was observed for different projectiles and at different energies. The time-of-flight recoil-ion mass spectroscopy experiments involve 1-5 MeV/u C, O, F and Si ion beams with different charge states, ranging between 4+ and 14+. In addition, the influence of the collective excitation on the electron capture process was also investigated. The wake-field induced Stark-mixing and splitting of sub-levels of projectile-ions following electron capture from C60 carries signature of the collective plasmon excitation. For the electron capture studies X-ray spectroscopic technique was used for collisions with bare and dressed S and Cl ion beams. The results on the TOF data on fullerene target obtained in last few years will be summarized.

  11. Thermoelectric properties of Bi0.5Sb1.5Te3/C60 nanocomposites

    NARCIS (Netherlands)

    Blank, V.D.; Buga, S.G.; Kulbachinskii, V.A.; Kytin, V.G.; Medvedev, Viacheslav; Popov, Y.M.; Stepanov, P.B.; Skok, V.F.

    2012-01-01

    A thermoelectric nanocomposite of Bi0.5Sb1.5Te3 with the C60 fullerene molecules has been synthesized and studied. The fullerene molecules provide the phonons blocking, reducing the lattice thermal conductivity. The reduction of the electrical conductivity is much less than the heat conductivity

  12. Strain Lattice Imprinting in Graphene by C60 Intercalation at the Graphene/Cu Interface

    NARCIS (Netherlands)

    Monazami, Ehsan; Bignardi, Luca; Rudolf, Petra; Reinke, Petra

    2015-01-01

    Intercalation of C60 molecules at the graphene-substrate interface by annealing leads to amorphous and crystalline intercalated structures. A comparison of topography and electronic structure with wrinkles and moiré patterns confirms intercalation. The intercalated molecules imprint a local

  13. The manipulation of C60 in molecular arrays with an STM tip in regimes below the decomposition threshold

    International Nuclear Information System (INIS)

    Olyanich, Dmitry A; Kotlyar, Vasily G; Utas, Tatiana V; Zotov, Andrey V; Saranin, Alexander A

    2013-01-01

    The ability of scanning tunneling microscopy to manipulate selected C 60 molecules within close packed C 60 arrays on a (Au,In)/Si(111) surface has been examined for mild conditions below the decomposition threshold. It has been found that knockout of the chosen C 60 molecule (i.e., vacancy formation) and shifting of the C 60 molecule to the neighboring vacant site (if available) can be conducted for wide ranges of bias voltages (from −1.5 to +0.5 V), characteristic manipulation currents (from 0.02 to 100 nA) and powers (from 2 × 10 −8 to 0.1 μW). This result implies that the manipulation is not associated with the electrical effects but rather has a purely mechanical origin. The main requirement for successful C 60 knockout has been found to be to ensure a proper ‘impact parameter’ (deviation from central impact on the C 60 sphere by the tip apex), which should be less than ∼1.5 Å. A certain difference has been detected for the manipulation of C 60 in extended molecular arrays and molecular islands of a limited size. While it is possible to manipulate a single C 60 molecule in an array, in the case of a C 60 island it appears difficult to manipulate a given fullerene without affecting the other ones constituting the island. (paper)

  14. Degradability of aged aquatic suspensions of C60 nanoparticles

    DEFF Research Database (Denmark)

    Hartmann, B.; Buendia, Inmaculada M.; Baun, Anders

    2011-01-01

    While studies of the potential human and environmental effects of C60 and its derivatives are emerging in the scientific literature, the environmental fate of C60 is still largely unknown. In this study, aged aqueous suspensions of C60 (nC60) were investigated in the respirometric OECD test...... for ready biodegradability. Two suspensions of nC60 were prepared by stirring and aged under indirect exposure to sunlight for 36 months, which resulted in relatively stable suspensions with a dark-brown colour. The suspended nC60 could not be extracted into toluene and indicating that the particles were...... no longer present as underivatised nC60 but had undergone a transformation. TEM images and particle tracking analysis showed that the suspension consisted of particle aggregates with a size of 156 nm (SD=54nm) and 139nm (Sd=49), respectively, but also contained smaller aggregates. Samples of the nC60...

  15. Electron attachment to C60 and C70 in the gas phase

    International Nuclear Information System (INIS)

    Smith, David; Spanel, Patrik

    1996-01-01

    The fullerene molecule C 60 is known to attach several electrons in the solid phase, but only recently has it been recognized that it can also attach electrons in the gas phase. The first electron-molecular beam results showed that C 60 and C 70 molecules non-dissociatively attached a single electron over the unusually wide electron energy range from near thermal to about 10 eV, but these studies were not able to provide either the magnitude of the cross sections or describe the low-energy attachment behaviour. But using our flowing afterglow-Langmuir probe (FALP) apparatus we have been able to determine the absolute attachment rate coefficients for both C 60 and C 70 over the electron temperature range 300-4500 K. These FALP experiments have shown that attachment to C 60 at low electron energies ( 70 except that for this fullerene molecule there is evidence that at very low electron energies ( 60 and C 70 , and when the mean thermal cross sections derived from these FALP data are used to normalize the crossed electron-molecular beam data at the common low energies accessible in both experiments, it is clear that electron attachment to these fullerene molecules is very efficient over a wide electron energy range from about 0.3-10 eV above which electron thermionic emission occurs from the hot C 60 - and C 70 - nascent negative ions. (author)

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

    Science.gov (United States)

    Li, Aigen

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

  17. Degradability of aged aquatic suspensions of C60 nanoparticles

    DEFF Research Database (Denmark)

    Hartmann, Nanna Isabella Bloch; Buendia, Inmaculada M.; Bak, Jimmy

    2011-01-01

    In this study, aged aqueous suspensions of C(60) (nC(60)) were investigated in the respirometric OECD test for ready biodegradability. Two suspensions of nC(60) were prepared by stirring and aged under indirect exposure to sunlight for 36 months. ATR-FTIR analyses confirmed the presence of C(60......)-structures in the suspensions. Samples of the nC(60) suspensions (20mg/l) were inoculated with activated sludge (30mgTSS/L) and incubated in a mineral medium under aerobic conditions. Since no mineralisation of nC(60) was observed after 28 days of incubation, 5mg/l sodium acetate was added to the media...

  18. Photoelectron diffraction of C6H8/Si(001) : A model case for photoemission study of organic molecules adsorbed on silicon surfaces

    Science.gov (United States)

    Gunnella, R.; Shimomura, M.; D'Amico, F.; Abukawa, T.; Kono, S.

    2006-06-01

    The core-level photoemission of 1,4-cyclohexadiene molecules on the quasi-single-domain 2×1-Si(001) surface below the saturation condition was studied. Taking advantage of core-level-shift photoelectron diffraction of the C 1s core level, the details of the surface structure were found. The model was essentially constituted by an unbuckled (planar) molecule chemisorbed on the surface, inclined at an angle of about 18° with respect to the surface normal, keeping one double bond unsaturated. An accurate analysis of the line shape parameters of the strongly asymmetric C 1s core level was mandatory for the structural study. Conversely, the success of the structural determination represented a confirmation of the correct deconvolution procedure. Such a feedback loop was decisive in reducing the indeterminacy affecting the analysis of core-level photoemission in the case of complex molecules adsorbed on surfaces.

  19. C60-DOM interactions and effects on C60 apparent solubility: a molecular mechanics and density functional theory study.

    Science.gov (United States)

    Wang, Zhuang; Chen, Jingwen; Sun, Qian; Peijnenburg, Willie J G M

    2011-08-01

    Dissolved organic matter (DOM) plays a critical role in the transport of carbon nano-particles (e.g. C(60)) in the aquatic environment. However, the mechanism for C(60)-DOM interactions and its environmental implications needs further investigations. In this study, the interaction of C(60) with relevant reference compounds of DOM (DOM(R)) is computationally simulated by molecular mechanics and density functional theory (DFT). All the C(60)-DOM(R) complexes are firstly optimized by classical annealing, and then DFT using the Dmol(3) code. The adsorption energies of C(60) on DOM(R) were computed. The computed electrostatic potential indicates that DOM(R) are electron acceptors in the C(60)-DOM(R) complexes, and the thermodynamic calculations indicate that electrostatic interaction is the dominant driving force for the C(60)-gallic acid complexation process in water. The presence of DOM(R) increases the apparent water solubility of C(60). It is also observed that the C(60) apparent water solubility decrease with the increase of the energy gaps of frontier molecular orbitals (E(LUMO)-E(HOMO)) for each C(60)-DOM(R) complex. These findings indicate that computational simulation is an important tool for predicting the behavior and fate of carbon nano-particles in the aquatic environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Electronic Structure Investigation of Doping C60 with Metal Oxide

    Science.gov (United States)

    Wang, Chenggong; Gao, Yongli

    2014-03-01

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

  1. Auger electron spectroscopy of the surface of a pipe-like solid C60+18n

    International Nuclear Information System (INIS)

    Khvostov, V.V.; Chernozatonskij, L.A.; Kosakovskaya, Z.Ya.; Babaev, V.V.; Guseva, M.B.

    1992-01-01

    Auger and electron energy loss spectra obtained when probing the surface of nanofiber carbon material by an electron beam point out to C 60 football-type of covers with the outlet to the surface of nanopipe carbon molecules

  2. Electronic structure and properties of highly ordered C60 nano arrays on Au (111): STM & DFT study

    Science.gov (United States)

    Win, Zaw-Myo; HUANG, Chao; ZHANG, Rui-Qin

    2017-06-01

    Template assisted assembly of molecular nano arrays is one of the key steps towards molecular electronics and fullerene is one of the potential structural building blocks in fabrication of identical molecular nano arrays for miniature devices such as photovoltaic devices and single-molecule transistors. In this report, the reconstructed Au (111) with defect areas (steps) has been used as a template to assemble the highly ordered C60 nano array at low coverage studied with scanning tunnelling microscopy (STM) in conjunction with density functional theory (DFT). The interaction between the substrate and C60 nano arrays is strong enough to change the geometrical shape of C60. As a result of strong interaction, the C60 molecule appears to be deformed into ellipsoidal shape which causes the reduction of C60 nano arrays on step sites of Au (111).

  3. Electronic structure and properties of highly ordered C60 nano arrays on Au (111): STM and DFT study

    International Nuclear Information System (INIS)

    Win, Zaw-Myo; HUANG, Chao; ZHANG, Rui-Qin

    2017-01-01

    Template assisted assembly of molecular nano arrays is one of the key steps towards molecular electronics and fullerene is one of the potential structural building blocks in fabrication of identical molecular nano arrays for miniature devices such as photovoltaic devices and single-molecule transistors. In this report, the reconstructed Au (111) with defect areas (steps) has been used as a template to assemble the highly ordered C 60 nano array at low coverage studied with scanning tunnelling microscopy (STM) in conjunction with density functional theory (DFT). The interaction between the substrate and C 60 nano arrays is strong enough to change the geometrical shape of C 60 . As a result of strong interaction, the C 60 molecule appears to be deformed into ellipsoidal shape which causes the reduction of C 60 nano arrays on step sites of Au (111). (paper)

  4. Element-specific and site-specific ion desorption from adsorbed molecules by deep core-level photoexcitation at the K-edges

    CERN Document Server

    Baba, Y H

    2003-01-01

    This article reviews our recent works on the ion desorption from adsorbed and condensed molecules at low temperature following the core-level photoexcitations using synchrotron soft x-rays. The systems investigated here are adsorbed molecules with relatively heavy molecular weight containing third-row elements such as Si, P, S, and Cl. Compared with molecules composed of second-row elements, the highly element-specific and site-specific fragment-ion desorption were observed when we tune the photon energy at the dipole-allowed 1s -> sigma sup * (3p sup *) resonance. On the basis of the resonance Auger decay spectra around the 1s ionization thresholds, the observed highly specific ion desorption is interpreted by the localization of the excited electrons (here we call as 'spectator electrons') in the antibonding sigma sup * orbital. In order to separate the direct photo-induced process from the indirect processes triggered by the secondary electrons, the photon-stimulated ion desorption was also investigated in...

  5. Laboratory confirmation of C60(+) as the carrier of two diffuse interstellar bands.

    Science.gov (United States)

    Campbell, E K; Holz, M; Gerlich, D; Maier, J P

    2015-07-16

    The diffuse interstellar bands are absorption lines seen towards reddened stars. None of the molecules responsible for these bands have been conclusively identified. Two bands at 9,632 ångströms and 9,577 ångströms were reported in 1994, and were suggested to arise from C60(+) molecules (ref. 3), on the basis of the proximity of these wavelengths to the absorption bands of C60(+) measured in a neon matrix. Confirmation of this assignment requires the gas-phase spectrum of C60(+). Here we report laboratory spectroscopy of C60(+) in the gas phase, cooled to 5.8 kelvin. The absorption spectrum has maxima at 9,632.7 ± 0.1 ångströms and 9,577.5 ± 0.1 ångströms, and the full widths at half-maximum of these bands are 2.2 ± 0.2 ångströms and 2.5 ± 0.2 ångströms, respectively. We conclude that we have positively identified the diffuse interstellar bands at 9,632 ångströms and 9,577 ångströms as arising from C60(+) in the interstellar medium.

  6. Tunable electronic and optical properties of gas molecules adsorbed monolayer graphitic ZnO: Implications for gas sensor and environment monitoring

    Science.gov (United States)

    Zhang, Wei; Du, Qikui; Zhang, Lifa

    2017-12-01

    Due to the large surface area and the peculiar electronic characters, great attention has been paid to 2D materials for the gas sensing applications. Here, using the hybrid density functional calculations, we systematically study the adsorptions of gas molecules on the monolayer graphitic ZnO (g-ZnO), including CO, H2, H2O, H2S, NH3, NO, NO2, O2, and SO2. For most of the molecules, g-ZnO shows superior sensing performance to the well-known MoS2, black phosphorus, blue phosphorus, antimonene, and germanene. H2S, NO, NO2, and SO2 act as charge acceptors, and CO, H2, H2O, and NH3 serve as charge donors. These molecules also induce distinct modifications to the electronic structures, work functions, and optical adsorptions. NO, NO2, and O2 form flat bands in the bandgaps of the spin-up or spin-down states, whereas other molecules mainly tune the bandgaps and the orbital couplings. In particular, g-ZnO is most likely to adsorb the atmospheric pollutant SO2, which has the strongest interaction through hybridizing its widely broadened 2p orbitals with the 3d orbitals of g-ZnO. Moreover, the improved visible light absorption is demonstrated in the NO2 adsorbed g-ZnO. Our results not only confirm that the electronic and optical properties of g-ZnO can be effectively tuned by the selective adsorption of gas molecules but also provide insightful guidance for the potential application of g-ZnO in the field of gas sensors.

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

    NARCIS (Netherlands)

    Wang, Kai; Sanderink, Johannes G.M.; Bolhuis, Thijs; van der Wiel, Wilfred Gerard; de Jong, Machiel Pieter

    2014-01-01

    C 60 fullerenes are interesting molecular semiconductors for spintronics since they exhibit weak spin-orbit and hyperfine interactions, which is a prerequisite for long spin lifetimes. We report spin-polarized transport in spin-valve-like structures containing ultrathin (<10 nm) C 60 layers,

  8. Modulation of the work function of fullerenes C60 and C70 by alkali-metal adsorption: A theoretical study

    International Nuclear Information System (INIS)

    Liang, Hong; Xu, Shunfu; Liu, Weihui; Sun, Yueqiang; Liu, Xiangfa; Zheng, Xinqing; Li, Sen; Zhang, Qiang; Zhu, Ziliang; Zhang, Xiaochun; Dong, Chengguo; Li, Chun; Yuan, Guang; Mimura, Hitenori

    2013-01-01

    The impact of alkali-metal (Li/Na/Cs) adsorption on work function of fullerenes C 60 and C 70 was investigated by first-principles calculations. After adsorption, the work functions of fullerenes C 60 and C 70 decrease distinctly and vary linearly with the electronegativity of the alkali metal elements, and the positions where the alkali atoms are adsorbed considerably influence the work functions. On the contrary, a vacancy defect elevates the work functions of the fullerenes C 60 and C 70 . The variation in the work functions rests with variation in Fermi level (which are attributed to charge transfer) and variation in vacuum levels (which are attributed to the induced dipole moments). Moreover, alkali-metal adsorption can also improve the electric conductivity of a fullerene mixture of C 60 and C 70 .

  9. Growth and Potential Damage of Human Bone-Derived Cells Cultured on Fresh and Aged C60/Ti Films

    Science.gov (United States)

    Kopova, Ivana; Lavrentiev, Vasily; Vacik, Jiri; Bacakova, Lucie

    2015-01-01

    Thin films of binary C60/Ti composites, with various concentrations of Ti ranging from ~ 25% to ~ 70%, were deposited on microscopic glass coverslips and were tested for their potential use in bone tissue engineering as substrates for the adhesion and growth of bone cells. The novelty of this approach lies in the combination of Ti atoms (i.e., widely used biocompatible material for the construction of stomatological and orthopedic implants) with atoms of fullerene C60, which can act as very efficient radical scavengers. However, fullerenes and their derivatives are able to generate harmful reactive oxygen species and to have cytotoxic effects. In order to stabilize C60 molecules and to prevent their possible cytotoxic effects, deposition in the compact form of Ti/C60 composites (with various Ti concentrations) was chosen. The reactivity of C60/Ti composites may change in time due to the physicochemical changes of molecules in an air atmosphere. In this study, we therefore tested the dependence between the age of C60/Ti films (from one week to one year) and the adhesion, morphology, proliferation, viability, metabolic activity and potential DNA damage to human osteosarcoma cells (lines MG-63 and U-2 OS). After 7 days of cultivation, we did not observe any negative influence of fresh or aged C60/Ti layers on cell behavior, including the DNA damage response. The presence of Ti atoms resulted in improved properties of the C60 layers, which became more suitable for cell cultivation. PMID:25875338

  10. New approach for sensitive photothermal detection of C60 and C70 fullerenes on micro-thin-layer chromatographic plates.

    Science.gov (United States)

    Suszyński, Zbigniew; Zarzycki, Paweł K

    2015-03-10

    In this paper the pulse thermovision (photothermal) detection and quantification methods of C60 and C70 fullerenes are presented. Quantification results are compared with optical and fluorescence measurements. Target components were separated under isothermal conditions (30 °C) on micro-TLC plates (RP18WF254S) using n-hexane as the mobile phase. The principle of described analytical protocol is based on sensitive measurement of the temperature contrast generated within TLC stationary phase and fullerenes spots after white light pulse excitation. It has been demonstrated that observed temperature contrast is mainly driven by the optical properties of fullerenes (UV-vis absorption spectra). Contrary to the commonly applied optical reflection or transmission techniques the proposed thermovision method involves dissipated light. The results of presented experimental work have revealed that both types of quantitative measurements provide similar outcome despite the key differences in the signal origin. However, it has been found that thermovision method was characterized by smaller value of LOD, particularly for C60 molecule. We demonstrated that application of correlation technique to post-acquisition analysis of the sequence of temperature contrast images significantly increase detection limits of fullerenes, even in comparison to fluorescence quenching detection mode. Moreover, the thermal contrast images and particularly, computed correlation image, allow detection of stationary phase layer nonuniformities, including changes in the adsorbent thickness and thermal conductivity. Therefore, invented pulsed thermovision methodology can be additionally used for fast quality screening of home made and commercially available TLC plates. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Enantioanalysis of S-deprenyl using enantioselective, potentiometric membrane electrodes based on C60 derivatives

    International Nuclear Information System (INIS)

    Stefan-van Staden, Raluca-Ioana

    2010-01-01

    Enantioselective, potentiometric membrane electrodes based on (1,2-methanofullerene C 60 )-61-carboxylic acid, diethyl (1,2-methanofullerene C 60 )-61-61-dicarboxylate and tert-butyl (1,2-methanofullerene C 60 )-61-carboxylic acid were proposed for the enantioanalysis of S-deprenyl in pharmaceutical compounds. Molecular modeling calculations were performed to prove the reliability of the proposed electrodes. The different characteristics involved in this analysis were explained, namely (i) the stability of each molecule using total energy, hardness and dipole moment, and (ii) the explanation of the mechanism of interaction using intermolecular forces (moderate hydrogen bond interactions), atomic charges and electrostatic potential. Electronic structures as well as molecular interaction have been investigated using Hartree-Fock theory, 3-21G(*) basis set. Stability and feasibility of all the generated structures were supported by their respective energy minima and fundamental frequencies.

  12. Carbon fullerenes (C60s) can induce inflammatory responses in the lung of mice

    International Nuclear Information System (INIS)

    Park, Eun-Jung; Kim, Hero; Kim, Younghun; Yi, Jongheop; Choi, Kyunghee; Park, Kwangsik

    2010-01-01

    Fullerenes (C60s) occur in the environment due to natural and anthropogenic sources such as volcanic eruptions, forest fires, and the combustion of carbon-based materials. Recently, production and application of engineered C60s have also rapidly increased in diverse industrial fields and biomedicine due to C60' unique physico-chemical properties, so toxicity assessment on environmental and human health is being evaluated as a valuable work. However, data related to the toxicity of C60s have not been abundant up to now. In this study, we studied the immunotoxic mechanism and change of gene expression caused by the instillation of C60s. As a result, C60s induced an increase in sub G1 and G1 arrest in BAL cells, an increase in pro-inflammatory cytokines such as IL-1, TNF-α, and IL-6, and an increase of Th1 cytokines such as IL-12 and IFN-r in BAL fluid. In addition, IgE reached the maximum at 1 day after treatment in both BAL fluid and the blood, and decreased in a time-dependent manner. Gene expression of the MHC class II (H2-Eb1) molecule was stronger than that of the MHC class I (H2-T23), and an increase in T cell distribution was also observed during the experiment period. Furthermore, cell infiltration and expression of tissue damage related genes in lung tissue were constantly observed during the experiment period. Based on this, C60s may induce inflammatory responses in the lung of mice.

  13. Electron stimulated desorption of cations from C sub 6 H sub 6 and C sub 6 H sub 1 sub 2 molecules adsorbed on Pt(1 1 1) and Ar spacer layer

    CERN Document Server

    Kawanowa, H; Hanatani, K; Gotoh, Y; Souda, R

    2003-01-01

    Mechanisms of electron stimulated cation desorption have been investigated for adsorbed C sub 6 H sub 6 and C sub 6 H sub 1 sub 2 molecules on the Pt(1 1 1) surface and the Ar spacer layer formed on it. The ion yields from the molecules adsorbed on the Ar spacer layer are highly enhanced at the smallest coverage and decay steeply with increasing coverage. No such enhancement was observed when they are adsorbed directly on the Pt(1 1 1) substrate. This behavior is explained in terms of the Coulombic repulsion of cations confined in nanoclusters, together with the delocalization of valence holes on the Pt(1 1 1) substrate as well as in the multilayer hydrocarbons. The holes in the C sub 6 H sub 6 molecule are more delocalized than those in the C sub 6 H sub 1 sub 2 molecule due to the overlap of pi orbitals.

  14. Surface-Enhanced Raman Spectroscopy of Dye and Thiol Molecules Adsorbed on Triangular Silver Nano structures: A Study of Near-Field Enhancement, Localization of Hot-Spots, and Passivation of Adsorbed Carbonaceous Species

    International Nuclear Information System (INIS)

    Goncalves, M.R.; Marti, O.; Fabian Enderle, F.

    2012-01-01

    Surface-enhanced Raman spectroscopy (SERS) of thiols and dye molecules adsorbed on triangular silver nanostructures was investigated. The SERS hot-spots are localized at the edges and corners of the silver triangular particles. AFM and SEM measurements permit to observe many small clusters formed at the edges of triangular particles fabricated by nanosphere lithography. Finite-element calculations show that near-field enhancements can reach values of more than 200 at visible wavelengths, in the gaps between small spherical particles and large triangular particles, although for the later no plasmon resonance was found at the wavelengths investigated. The regions near the particles showing strong near-field enhancement are well correlated with spatial localization of SERS hot-spots done by confocal microscopy. Silver nanostructures fabricated by thermal evaporation present strong and fast fluctuating SERS activity, due to amorphous carbon contamination. Thiols and dye molecules seem to be able to passivate the undesired SERS activity on fresh evaporated silver. excitation: by far-field illumination of metal nanostructures or rough metal Raman scattering cross-section of gold-palladium target Temporal Fluctuation in SERS Temporal and spectral fluctuations.

  15. Density functional theory study the effects of oxygen-containing functional groups on oxygen molecules and oxygen atoms adsorbed on carbonaceous materials.

    Science.gov (United States)

    Qi, Xuejun; Song, Wenwu; Shi, Jianwei

    2017-01-01

    Density functional theory was used to study the effects of different types of oxygen-containing functional groups on the adsorption of oxygen molecules and single active oxygen atoms on carbonaceous materials. During gasification or combustion reactions of carbonaceous materials, oxygen-containing functional groups such as hydroxyl(-OH), carbonyl(-CO), quinone(-O), and carboxyl(-COOH) are often present on the edge of graphite and can affect graphite's chemical properties. When oxygen-containing functional groups appear on a graphite surface, the oxygen molecules are strongly adsorbed onto the surface to form a four-member ring structure. At the same time, the O-O bond is greatly weakened and easily broken. The adsorption energy value indicates that the adsorption of oxygen molecules changes from physisorption to chemisorption for oxygen-containing functional groups on the edge of a graphite surface. In addition, our results indicate that the adsorption energy depends on the type of oxygen-containing functional group. When a single active oxygen atom is adsorbed on the bridge site of graphite, it gives rise to a stable epoxy structure. Epoxy can cause deformation of the graphite lattice due to the transition of graphite from sp2 to sp3 after the addition of an oxygen atom. For quinone group on the edge of graphite, oxygen atoms react with carbon atoms to form the precursor of CO2. Similarly, the single active oxygen atoms of carbonyl groups can interact with edge carbon atoms to form the precursor of CO2. The results show that oxygen-containing functional groups on graphite surfaces enhance the activity of graphite, which promotes adsorption on the graphite surface.

  16. Crystallinity and properties of C60 nanotubes improved by annealing and alcohol-soaking

    Science.gov (United States)

    Naito, K.; Matsuishi, K.

    2009-04-01

    Well-uniformed C60 nanotubes were grown at -20 °C with irradiation of red light using C60-saturated pyridine solution and isopropyl alcohol by a liquid-liquid interfacial precipitation method without ultrasonic pulverization. We attempted to improve their crystallinity by two post-treatments; thermal annealing and alcohol-soaking. The crystallinity of as-grown and dried C60 nanotubes, which was poor due to the evaporation of solvent molecules from crystals in the drying process, was improved by annealing around 220 °C for 5 hours in vacuum. Dramatic improvement of crystallinity of as-grown samples was achieved by soaking into methanol and then drying in air. Raman, infrared and X-ray diffraction results suggest that the methanol-soaked samples exhibit a solvated tetragonal structure. The crystallinity improved by methanol-soaking did not degrade after removal of methanol molecules from samples by thermal annealing. Photo-polymerization of the structurally-improved C60 nanotubes was examined to investigate an effect of crystallinity on the polymerization kinetics.

  17. Crystallinity and properties of C60 nanotubes improved by annealing and alcohol-soaking

    International Nuclear Information System (INIS)

    Naito, K; Matsuishi, K

    2009-01-01

    Well-uniformed C 60 nanotubes were grown at -20 deg. C with irradiation of red light using C 60 -saturated pyridine solution and isopropyl alcohol by a liquid-liquid interfacial precipitation method without ultrasonic pulverization. We attempted to improve their crystallinity by two post-treatments; thermal annealing and alcohol-soaking. The crystallinity of as-grown and dried C 60 nanotubes, which was poor due to the evaporation of solvent molecules from crystals in the drying process, was improved by annealing around 220 deg. C for 5 hours in vacuum. Dramatic improvement of crystallinity of as-grown samples was achieved by soaking into methanol and then drying in air. Raman, infrared and X-ray diffraction results suggest that the methanol-soaked samples exhibit a solvated tetragonal structure. The crystallinity improved by methanol-soaking did not degrade after removal of methanol molecules from samples by thermal annealing. Photo-polymerization of the structurally-improved C 60 nanotubes was examined to investigate an effect of crystallinity on the polymerization kinetics.

  18. Estimation of the parameters of cytotoxicity of fullerene C60 and C60-containing composites in vitro

    International Nuclear Information System (INIS)

    Priluts'ka, S.V.; Grinyuk, Yi.Yi.; Golub, O.A.; Matishevs'ka, O.P.

    2006-01-01

    The influence of fullerene C 60 and C 60 -containing composites (on the basis of aminopropylaerosyl (ApA)) on the stability of erythrocytes to acid haemolysis and the viability of thymocytes, ascite forms of Erlich and leucosis L1210 cells is studied. The obtained results indicate the possibility to use ApA as a matrix for conjugation with other elements and for the further biological studies of composites photosensitizing the effect

  19. Growth of α-sexithiophene nanostructures on C60 thin film layers

    DEFF Research Database (Denmark)

    Radziwon, Michal Jędrzej; Madsen, Morten; Balzer, Frank

    2014-01-01

    Organic molecular beam grown -sexithiophene (-6T) forms nanostructured thin films on buckminsterfullerene (C60) thin film layers. At substrate temperatures of 300K during growth a rough continuous film is observed, which develop to larger elongated islands and dendritic- as well as needle like ...... fluorescence polarimetry measurements the in-plane orientation of the crystalline sites within the needle like structures is determined. The polarimetry investigations strongly indicate that the needle like structures consist of lying molecules....

  20. DC Characterisation of C60 Whiskers and Nanowhiskers

    DEFF Research Database (Denmark)

    Larsson, Michael; Kjelstrup-Hansen, Jakob; Lucyszyn, Stepan

    2007-01-01

    C60 whiskers exhibit increasing conductivity with decreasing diameter. At diameters of 1 mm and below, a single-crystal structure predominates, and enhanced electrical characteristics are expected; however, no supporting data exists in the literature. Here, results of four-point probe measurements......, indicating strong potential for use in organic electronic applications of the future. Repeated current cycling in air is observed to promote sample degradation, possibly due to progressive oxidation of the carbon structure. A micromachined four-point probe is also used to try to establish non...... on C60 whiskers and nanowhiskers with diameters in the range 650 nm to 1.3 mm are reported for the first time. Samples are attached to pre-patterned planar and raised electrodes using FIB-deposited tungsten. A low resistivity of 3 Wcm is measured in air, on a C60 whisker having a diameter of 650 nm...

  1. Extensive first-principles molecular dynamics study on Li encapsulation into C60 and its experimental confirmation.

    Science.gov (United States)

    Ohno, K; Manjanath, A; Kawazoe, Y; Hatakeyama, R; Misaizu, F; Kwon, E; Fukumura, H; Ogasawara, H; Yamada, Y; Zhang, C; Sumi, N; Kamigaki, T; Kawachi, K; Yokoo, K; Ono, S; Kasama, Y

    2018-01-25

    The aim of increasing the production ratio of endohedral C 60 by impinging foreign atoms against C 60 is a crucial matter of the science and technology employed towards industrialization of these functional building block materials. Among these endohedral fullerenes, Li + @C 60 exhibits a wide variety of physical and chemical phenomena and has the potential to be applicable in areas spanning the medical field to photovoltaics. However, currently, Li + @C 60 can be experimentally produced with only ∼1% ratio using the plasma shower method with a 30 eV kinetic energy provided to the impinging Li + ion. From extensive first-principles molecular dynamics simulations, it is found that the maximum production ratio of Li + @C 60 per hit is increased to about 5.1% (5.3%) when a Li + ion impinges vertically on a six-membered ring of C 60 with 30 eV (40 eV) kinetic energy, although many C 60 molecules are damaged during this collision. On the contrary, when it impinges vertically on a six-membered ring with 10 eV kinetic energy, the production ratio remains at 1.3%, but the C 60 molecules are not damaged at all. On the other hand, when the C 60 is randomly oriented, the production ratio reduces to about 3.7 ± 0.5%, 3.3 ± 0.5%, and 0.2 ± 0.03% for 30 eV, 40 eV, and 10 eV kinetic energy, respectively. Based on these observations we demonstrate the possibility of increasing the production ratio by fixing six-membered rings atop C 60 using the Cu(111) substrate or UV light irradiation. In order to assess the ideal experimental production ratio, the 7 Li solid NMR spectroscopy measurement is also performed for the multilayer randomly oriented C 60 sample irradiated by Li + using the plasma shower method combined with inductively coupled plasma atomic emission spectroscopy (ICP-AES). Time-of-flight mass spectroscopy measurements are also performed to cross check whether Li + @C 60 molecules are produced in the sample. The resulting experimental estimate, 4% for 30 eV incident

  2. Synthesis and properties of endohedral C60 encapsulating molecular hydrogen.

    Science.gov (United States)

    Murata, Michihisa; Murata, Yasujiro; Komatsu, Koichi

    2006-06-21

    We report the details of our study to synthesize a new endohedral fullerene, H2@C60, in more than 100 mg quantities by closure of the 13-membered ring orifice of an open-cage fullerene using four-step organic reactions. The 13-membered ring orifice in a previously synthesized open-cage fullerene incorporating hydrogen in 100% yield was reduced to a 12-membered ring by extrusion of a sulfur atom at the rim of the orifice, and the ring was further reduced into an eight-membered ring by reductive coupling of two carbonyl groups also at the orifice. Final closure of the orifice was completed by a thermal reaction. Purification of H2@C60 was accomplished by recycle HPLC. A gradual downfield shift of the NMR signal for the encapsulated hydrogen observed upon reduction of the orifice size was interpreted based on the gauge-independent atomic orbital (GIAO) and the nucleus-independent chemical shift (NICS) calculations. The spectral as well as electrochemical examination of the properties of H2@C60 has shown that the electronic interaction between the encapsulated hydrogen and outer C60 pi-system is quite small but becomes appreciable when the outer pi-system acquires more than three extra electrons. Four kinds of exohedral derivatives of H2@C60 were synthesized. The tendency in the shift of the NMR signal of the inner hydrogen was found to be quite similar to that observed for the 3He NMR signal of the corresponding derivatives of 3He@C60.

  3. Charging C60 islands with the AFM tip

    Science.gov (United States)

    Hoff, Brice; Henry, Claude R.; Barth, Clemens

    2015-12-01

    We show that electrons can be transferred on demand from an AFM tip into single bulk-like C60 islands, which are supported on the insulating NaCl(001) surface. We exemplify this by controlled charge-manipulation experiments conducted in ultrahigh vacuum by noncontact AFM (nc-AFM), electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM). KPFM shows a homogeneous contrast at the islands, which is a signature for an equal distribution of the electrons in the T1u band. The charge dissipates during half a day due to an interaction of the charged C60 islands with defects in the near surface region of NaCl. Our results open the perspective in photo-voltaics to study charge attachment, stability and charge exchange with the environment of any C60 bulk-like system.We show that electrons can be transferred on demand from an AFM tip into single bulk-like C60 islands, which are supported on the insulating NaCl(001) surface. We exemplify this by controlled charge-manipulation experiments conducted in ultrahigh vacuum by noncontact AFM (nc-AFM), electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM). KPFM shows a homogeneous contrast at the islands, which is a signature for an equal distribution of the electrons in the T1u band. The charge dissipates during half a day due to an interaction of the charged C60 islands with defects in the near surface region of NaCl. Our results open the perspective in photo-voltaics to study charge attachment, stability and charge exchange with the environment of any C60 bulk-like system. Electronic supplementary information (ESI) available. See DOI: 10.1039/C5NR04541J

  4. Relaxation process of self-trapping exciton in C60

    International Nuclear Information System (INIS)

    Sun, X.; Zhang, G.P.; Ma, Y.S.; Fu, R.L.

    1995-09-01

    When C 60 is photoexcited, a self-trapping exciton (STE) is formed. The bond structure is distorted while the states A 1u and A 2u are pulled into the energy gap from HOMO and LUMO respectively. A dynamical scheme is employed to simulate the relaxation of STE. The evolutions of both bond structure and electronic states show that the relaxation time for STE is about 100 fs. It is noticed that this relaxation time is much shorter than that of the charge transfer in C 60 , and the origin for this big difference is discussed. (author). 13 refs, 4 figs

  5. Detection of C60 and C70 in a young planetary nebula.

    Science.gov (United States)

    Cami, Jan; Bernard-Salas, Jeronimo; Peeters, Els; Malek, Sarah Elizabeth

    2010-09-03

    In recent decades, a number of molecules and diverse dust features have been identified by astronomical observations in various environments. Most of the dust that determines the physical and chemical characteristics of the interstellar medium is formed in the outflows of asymptotic giant branch stars and is further processed when these objects become planetary nebulae. We studied the environment of Tc 1, a peculiar planetary nebula whose infrared spectrum shows emission from cold and neutral C60 and C70. The two molecules amount to a few percent of the available cosmic carbon in this region. This finding indicates that if the conditions are right, fullerenes can and do form efficiently in space.

  6. Stretching the limits of static SIMS with C60+

    International Nuclear Information System (INIS)

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

    2006-01-01

    Pristine and Au-covered molecular films have been analyzed by ToF-SIMS (TRIFT TM ), using 15 keV Ga + (FEI) and 15 keV C 60 + (Ionoptika) primary ion sources. The use of C 60 + leads to an enormous yield enhancement for gold clusters, especially when the amount of gold is low (2 nmol/cm 2 ), i.e. a situation of relatively small nanoparticles well separated in space. It also allows us to extend significantly the traditional mass range of static SIMS. Under 15 keV C 60 + ion bombardment, a series of clusters up to a mass of about 20,000 Da (Au 100 - : 19,700 Da) is detected. This large yield increase is attributed to the hydrocarbon matrix (low-atomic mass), because the yield increase observed for thick metallic films (Ag, Au) is much lower. The additional yield enhancement factors provided by the Au metallization procedure for organic ions (MetA-SIMS) have been measured under C 60 + bombardment. They reach a factor of 2 for the molecular ion and almost an order of magnitude for Irganox fragments such as C 4 H 9 + , C 15 H 23 O + and C 16 H 23 O -

  7. Electric current induced light emission from C-60

    NARCIS (Netherlands)

    Palstra, TTM; Haddon, RC; Lyons, KB; Kafafi, ZH

    1997-01-01

    We report the luminescence of C-60 crystals and films due to the passage of an electrical current. The current-voltage behaviour is highly non-linear with light-emission beyond a threshold voltage. The emission spectrum is featureless and resembles black body radiation with an effective temperature

  8. Electric Current Induced Light Emission from C60

    NARCIS (Netherlands)

    Palstra, T.T.M.; Haddon, R.C.; Lyons, K.B.

    1997-01-01

    We report the luminescence of C60 crystals and films due to the passage of an electrical current. The current-voltage behavior is highly non-linear with light-emission beyond a threshold voltage. The emission spectrum is featureless and resembles black-body radiation with an effective temperature on

  9. Trapping and proliferation of target cells on C60fullerene nano fibres.

    Science.gov (United States)

    Iwai, Seiki; Kurosu, Shunji; Sasaki, Hideki; Kato, Kazunori; Maekawa, Toru

    2017-08-01

    The ratio of the surface area to the volume of materials increases in inverse proportion to their size and therefore the surface area of nanostructures and nanomaterials is extremely large compared to that of macroscopic materials of the same volume, thanks to which it is supposed that chemical and biochemical reactions may be greatly enhanced and target molecules and cells may be efficiently trapped on the surface of nanomaterials. It is well known that C 60 molecules are stable both physically and chemically and the affinity of C 60 molecules with biomolecules is rather high. Here, we synthesise fibres composed of C 60 and sulphur and immobilise the surface of the fibres with the primary antibody; i.e., epithelial cell adhesion molecules (anti-EpCAM), to trap target cells. The primary antibody is evenly immobilised on the fibres confirmed by a fluorescent secondary antibody attached to the primary one and then TE2 esophageal and DLD-1 colon cancer cells are successfully trapped by the primary antibody immobilised on the fibres thanks to its high affinity with TE2 and DLD-1 cells, whereas few IM9 B lymphoblast cells are captured on the fibres since the affinity of the primary antibody with IM9 cells is extremely low. Furthermore, those cells trapped by the primary antibody immobilised on the fibres proliferate faster than native cells thanks to the primary antibody acting as a growth factor. The present result suggests that different types of cells can be trapped and grown on nano fibres by immobilising appropriate antibody molecules on the surface of the fibres. Even an extremely small number of cells in sample fluids may be analysed and characterised for the detection of diseases such as cancer in the early stage by trapping and proliferating target cells on the fibres.

  10. Trapping and proliferation of target cells on C60 fullerene nano fibres

    Directory of Open Access Journals (Sweden)

    Seiki Iwai

    2017-08-01

    Full Text Available The ratio of the surface area to the volume of materials increases in inverse proportion to their size and therefore the surface area of nanostructures and nanomaterials is extremely large compared to that of macroscopic materials of the same volume, thanks to which it is supposed that chemical and biochemical reactions may be greatly enhanced and target molecules and cells may be efficiently trapped on the surface of nanomaterials. It is well known that C60 molecules are stable both physically and chemically and the affinity of C60 molecules with biomolecules is rather high. Here, we synthesise fibres composed of C60 and sulphur and immobilise the surface of the fibres with the primary antibody; i.e., epithelial cell adhesion molecules (anti-EpCAM, to trap target cells. The primary antibody is evenly immobilised on the fibres confirmed by a fluorescent secondary antibody attached to the primary one and then TE2 esophageal and DLD-1 colon cancer cells are successfully trapped by the primary antibody immobilised on the fibres thanks to its high affinity with TE2 and DLD-1 cells, whereas few IM9 B lymphoblast cells are captured on the fibres since the affinity of the primary antibody with IM9 cells is extremely low. Furthermore, those cells trapped by the primary antibody immobilised on the fibres proliferate faster than native cells thanks to the primary antibody acting as a growth factor. The present result suggests that different types of cells can be trapped and grown on nano fibres by immobilising appropriate antibody molecules on the surface of the fibres. Even an extremely small number of cells in sample fluids may be analysed and characterised for the detection of diseases such as cancer in the early stage by trapping and proliferating target cells on the fibres.

  11. Assembly of individual TiO2-C60/porphyrin hybrid nanoparticles for enhancement of photoconversion efficiency

    International Nuclear Information System (INIS)

    Jang, Jae Kwon; Park, Se Ho; Song, Hyunjoon; Park, Joon T; Kim, Chulwoo; Ko, Jaejung; Seo, Won Seok

    2011-01-01

    Rational organization of porphyrin and C 60 on the electrode surface in photovoltaic structures is essential to yield high quantum efficiency. In the present work, individual TiO 2 nanoparticles were modified by introducing C 60 and porphyrin units on the surface, and then electrophoretically deposited on an ITO/SnO 2 electrode. The morphology of the photoactive layer on the electrode was significantly different from that of the layer produced as a result of separate deposition of C 60 and porphyrin. The maximum incident photon to current efficiency of the resulting electrode approached 88% at 410 nm, which is the highest value among molecule-based photovoltaic cells reported to date. This indicates that molecular assembly of the C 60 and porphyrin units on the individual nanoparticles through strong chemical attachment is a key factor in improving effective electron transfer between the photoactive units and the electrodes.

  12. Enhancing the sensitivity of molecular secondary ion mass spectrometry with C60+-O2+ cosputtering.

    Science.gov (United States)

    Liao, Hua-Yang; Lin, Kang-Yi; Kao, Wei-Lun; Chang, Hsun-Yun; Huang, Chih-Chieh; Shyue, Jing-Jong

    2013-04-02

    In the past decade, the C60-based ion gun has been widely utilized in the secondary ion mass spectrometry (SIMS) analysis of organic and biological materials because molecular secondary-ions of high masses could be generated by cluster-ion bombardment. This technique furthers the development of SIMS in bioanalysis by eliminating the need for either heteroatom or isotope labeling. However, the intensity of high-mass parent ions was usually low and limited the sensitivity of the analysis, thus requiring an enhancement in the intensity of these molecular ions to widen the application of SIMS. In this work, the aim was to preserve samples in their original state while using a low kinetic energy O2(+) beam cosputtered with high-energy C60(+) to enhance the ion intensity through the depth-profile. Although O2(+) is generally used to enhance ion intensities in positive SIMS, it is known to alter the chemical structure and primarily provide elemental information; hence, it is not suitable for profiling organic and biological specimens. Nevertheless, owing to its high sputtering yield, cluster C60(+) ion removes and masks the structural damage, hence O2(+) may be used to enhance the ion intensity. The characteristic molecular ions of polyethylene terephthalate (PET), trehalose, and a peptide (papain inhibitor) are enhanced by 35×, 12×, and 3.5× with the use of the auxiliary O2(+) beam, respectively. This significant enhancement in ionization yield is attributed to the oxidation of molecules and formation of a hydroxyl group that serves as a proton donator. In addition to enhancing molecular SIMS signals, C60(+)-O2(+) cosputtering could also alleviate several problems, including sputtering rate decay, carbon deposition, and surface roughening, that are associated with C60(+) bombardment and produced better depth profiles.

  13. Effects of aqueous stable fullerene nanocrystal (nC60) on copper (trace necessary nutrient metal): Enhanced toxicity and accumulation of copper in Daphnia magna.

    Science.gov (United States)

    Tao, Xianji; He, Yiliang; Fortner, John D; Chen, Yongsheng; Hughes, Joseph B

    2013-08-01

    Our focus herein is to evaluate the potential interaction between nC60 and copper, a trace necessary metal, in light of the impact on toxicity. The non-observable effects concentration (NOEC) of nC60 was confirmed as 100μgL(-1) before. When Daphnia magna was exposed to the mixture of copper solution and nC60 suspension (100μgL(-1)), LC50 of 48h was lower than that when they were exposed to copper solution alone. This result clearly showed the decrease in NOEC of copper at the presence of nC60. Cu(2+)-ATPase activity was enhanced at the presence of nC60, indicating that copper transport involved with the uptake, distribution and depuration in body was increased. We further conducted experiments on accumulation of copper in D. magna. The observed equilibrium copper concentration in D. magna in the mixture of 100μgL(-1) nC60 and 1μgL(-1) copper solution reached 131μg (kg wet weight)(-1), which was more than twice that in copper solution only: 60μg (kg wet weight)(-1). This result demonstrated that the accumulation of copper in D. magna was significantly enhanced at the presence of even low nC60 concentration. Experiments also showed that copper was quickly adsorbed onto nC60. The absorption of copper onto D. magna was statistically correlated to the absorption of nC60 onto D. magna; this might be caused by nC60 facilitating the transfer of copper into D. magna. The absorption and desorption of copper to nC60 (pH=5.0) reached equilibrium quickly, which may be involved with the co-bioaccumulation and decrease in NOEC of Cu(2+) and nC60. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Effect of the structure distortion on the high photocatalytic performance of C60/g-C3N4 composite

    Science.gov (United States)

    Ma, Xiaojuan; Li, Xinru; Li, Mengmeng; Ma, Xiangchao; Yu, Lin; Dai, Ying

    2017-08-01

    C60/g-C3N4 composite was reported experimentally to be of high photocatalytic activity in degrading organics. To investigate the underlying mechanism of high photocatalytic performance, the structural and electronic properties of g-C3N4 monolayers with adsorbing and removing fullerene C60 are studied by means of density functional theory calculations. After 25 possible configurations examination, it is found that C60 prefers to stay upon the ;junction nitrogen; with the carbon atom of fullerene being nearest to monolayers. Correspondingly, a type-I band alignment appears. Our results further demonstrate that the adsorption of C60 can lead to an irreversible structure distortion for g-C3N4 from flat to wrinkle, which plays a crucial role in improving photocatalytic performance other than the separation of carriers at interface due to the formation of type-II heterojunctions as previous report. Compared to flat one, the light absorption of wrinkled structure shows augmented, the valence band maximum shifts towards lower position along with a stronger photo-oxidation capability. Interestingly, the results indicate that the energy, light absorption and band edge all have a particular relationship with wrinkle degree. The work presented here can be helpful to understand the mechanism behind the better photocatalytic performance for C60 modified g-C3N4.

  15. Strong spin-filtering and spin-valve effects in a molecular V–C60–V contact

    Directory of Open Access Journals (Sweden)

    Mohammad Koleini

    2012-08-01

    Full Text Available Motivated by the recent achievements in the manipulation of C60 molecules in STM experiments, we study theoretically the structure and electronic properties of a C60 molecule in an STM tunneljunction with a magnetic tip and magnetic adatom on a Cu(111 surface using first-principles calculations. For the case of a vanadium tip/adatom, we demonstrate how spin coupling between the magnetic V atoms, mediated by the C60, can be observed in the electronic transport, which display a strong spin-filtering effect, allowing mainly majority-spin electrons to pass (>95%. Moreover, we find a significant change in the conductance between parallel and anti-parallel spin polarizations in the junction (86% which suggests that STM experiments should be able to characterize the magnetism and spin coupling for these systems.

  16. Strong spin-filtering and spin-valve effects in a molecular V-C-60-V contact

    DEFF Research Database (Denmark)

    Koleini, Mohammad; Brandbyge, Mads

    2012-01-01

    Motivated by the recent achievements in the manipulation of C-60 molecules in STM experiments, we study theoretically the structure and electronic properties of a C-60 molecule in an STM tunneljunction with a magnetic tip and magnetic adatom on a Cu(111) surface using first-principles calculations....... For the case of a vanadium tip/adatom, we demonstrate how spin coupling between the magnetic V atoms, mediated by the C-60, can be observed in the electronic transport, which display a strong spin-filtering effect, allowing mainly majority-spin electrons to pass (>95%). Moreover, we find a significant change...... in the conductance between parallel and anti-parallel spin polarizations in the junction (86%) which suggests that STM experiments should be able to characterize the magnetism and spin coupling for these systems....

  17. Expansion Hamiltonian model for a diatomic molecule adsorbed on a surface: Vibrational states of the CO/Cu(100) system including surface vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qingyong, E-mail: mengqingyong@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, 116023 Dalian (China); Meyer, Hans-Dieter, E-mail: hans-dieter.meyer@pci.uni-heidelberg.de [Theoretische Chemie, Physikalisch-Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)

    2015-10-28

    Molecular-surface studies are often done by assuming a corrugated, static (i.e., rigid) surface. To be able to investigate the effects that vibrations of surface atoms may have on spectra and cross sections, an expansion Hamiltonian model is proposed on the basis of the recently reported [R. Marquardt et al., J. Chem. Phys. 132, 074108 (2010)] SAP potential energy surface (PES), which was built for the CO/Cu(100) system with a rigid surface. In contrast to other molecule-surface coupling models, such as the modified surface oscillator model, the coupling between the adsorbed molecule and the surface atoms is already included in the present expansion SAP-PES model, in which a Taylor expansion around the equilibrium positions of the surface atoms is performed. To test the quality of the Taylor expansion, a direct model, that is avoiding the expansion, is also studied. The latter, however, requests that there is only one movable surface atom included. On the basis of the present expansion and direct models, the effects of a moving top copper atom (the one to which CO is bound) on the energy levels of a bound CO/Cu(100) system are studied. For this purpose, the multiconfiguration time-dependent Hartree calculations are carried out to obtain the vibrational fundamentals and overtones of the CO/Cu(100) system including a movable top copper atom. In order to interpret the results, a simple model consisting of two coupled harmonic oscillators is introduced. From these calculations, the vibrational levels of the CO/Cu(100) system as function of the frequency of the top copper atom are discussed.

  18. First-principles study on electron transport of carbon dumbbells C60-C(n)-C60.

    Science.gov (United States)

    Wang, R N; Zheng, X H; Song, L L; Zeng, Z

    2011-07-28

    Electronic transport properties of carbon dumbbells, a new type of carbon hybrid nanostructures formed by connecting carbon atomic chains to two fullerenes C(60), are investigated by using nonequilibrium Green's functions in combination with the density-functional theory. Specifically, the transport properties as a function of the carbon chain length n are examined. An obvious metal-insulator-like oscillation has been achieved with the increase of the carbon chain length. When n is even, the device behaves as a metal. In contrast, when n is odd, it behaves as an insulator. It is quite different to the carbon chains directly sandwiched between metallic leads where the low conductance states are observed for even n while the high conductance states are observed for odd n. Such a difference arises from the screening effect of C(60)s. © 2011 American Institute of Physics

  19. Electronic Correlations, Jahn-Teller Distortions and Mott Transition to Superconductivity in Alkali-C60 Compounds

    Directory of Open Access Journals (Sweden)

    Alloul H.

    2012-03-01

    Full Text Available The discovery in 1991 of high temperature superconductivity (SC in A3C60 compounds, where A is an alkali ion, has been rapidly ascribed to a BCS mechanism, in which the pairing is mediated by on ball optical phonon modes. While this has lead to consider that electronic correlations were not important in these compounds, further studies of various AnC60 with n=1, 2, 4 allowed to evidence that their electronic properties cannot be explained by a simple progressive band filling of the C60 six-fold degenerate t1u molecular level. This could only be ascribed to the simultaneous influence of electron correlations and Jahn-Teller Distortions (JTD of the C60 ball, which energetically favour evenly charged C60 molecules. This is underlined by the recent discovery of two expanded fulleride Cs3C60 isomeric phases which are Mott insulators at ambient pressure. Both phases undergo a pressure induced first order Mott transition to SC with a (p, T phase diagram displaying a dome shaped SC, a common situation encountered nowadays in correlated electron systems. NMR experiments allowed us to study the magnetic properties of the Mott phases and to evidence clear deviations from BCS expectations near the Mott transition. So, although SC involves an electron-phonon mechanism, the incidence of electron correlations has an importance on the electronic properties, as had been anticipated from DMFT calculations.

  20. Photoionization of bonding and antibonding-type atom-fullerene hybrid states in Cd@C60 vs Zn@C60

    International Nuclear Information System (INIS)

    Javani, Mohammad H; Manson, Steven T; De, Ruma; Chakraborty, Himadri S; Madjet, Mohamed E

    2014-01-01

    Powerful hybridization of the Cd 4d state with the d-angular momentum state of C 60 π symmetry is found in the local density approximation (LDA) structure of Cd@C 60 ground state. The photoionization of the resulting symmetric and antisymmetric levels are computed using the time dependent LDA method to include electron correlations. Cross sections exhibit effects of the C 60 plasmonic motion coherently coupled to the diffraction-type cavity oscillations induced by local emissions from C 60 . The Cd@C 60 results exhibit a substantial difference from our previous results for Zn@C 60 . (paper)

  1. Enhanced binding capacity of boronate affinity adsorbent via surface modification of silica by combination of atom transfer radical polymerization and chain-end functionalization for high-efficiency enrichment of cis-diol molecules

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; He, Maofang; Wang, Chaozhan; Wei, Yinmao, E-mail: ymwei@nwu.edu.cn

    2015-07-30

    Boronate affinity materials have been widely used for specific separation and preconcentration of cis-diol molecules, but most do not have sufficient capacity due to limited binding sites on the material surface. In this work, we prepared a phenylboronic acid-functionalized adsorbent with a high binding capacity via the combination of surface-initiated atom transfer radical polymerization (SI-ATRP) and chain-end functionalization. With this method, the terminal chlorides of the polymer chains were used fully, and the proposed adsorbent contains dense boronic acid polymers chain with boronic acid on the chain end. Consequently, the proposed adsorbent possesses excellent selectivity and a high binding capacity of 513.6 μmol g{sup −1} for catechol and 736.8 μmol g{sup −1} for fructose, which are much higher than those of other reported adsorbents. The dispersed solid-phase extraction (dSPE) based on the prepared adsorbent was used for extraction of three cis-diol drugs (i.e., epinephrine, isoprenaline and caffeic acid isopropyl ester) from plasma; the eluates were analyzed by HPLC-UV. The reduced amount of adsorbent (i.e., 2.0 mg) could still eliminate interferences efficiently and yielded a recovery range of 85.6–101.1% with relative standard deviations ranging from 2.5 to 9.7% (n = 5). The results indicated that the proposed strategy could serve as a promising alternative to increase the density of surface functional groups on the adsorbent; thus, the prepared adsorbent has the potential to effectively enrich cis-diol substances in real samples. - Highlights: • Boronate adsorbent is prepared via ATRP and chain-end functionalization. • The adsorbent has quite high binding capacity for cis-diols. • Binding capacity is easily manipulated by ATRP condition. • Chain-end functionalization can improve binding capacity significantly. • Reduced adsorbent is consumed in dispersed solid-phase extraction of cis-diols.

  2. Insights into the stability and thermal degradation of P3HT:C60 blended films for solar cell applications

    CSIR Research Space (South Africa)

    Motaung, DE

    2011-03-01

    Full Text Available This paper demonstrates the changes in the nanoscale morphology of the blended films induced by a diffusion of C60 molecules and degradation during longer thermal treatment above the glass transition temperature (130 °C). The results showed...

  3. Spin Resonance Clock Transition of the Endohedral Fullerene ^{15}N@C_{60}.

    Science.gov (United States)

    Harding, R T; Zhou, S; Zhou, J; Lindvall, T; Myers, W K; Ardavan, A; Briggs, G A D; Porfyrakis, K; Laird, E A

    2017-10-06

    The endohedral fullerene ^{15}N@C_{60} has narrow electron paramagnetic resonance lines which have been proposed as the basis for a condensed-matter portable atomic clock. We measure the low-frequency spectrum of this molecule, identifying and characterizing a clock transition at which the frequency becomes insensitive to magnetic field. We infer a linewidth at the clock field of 100 kHz. Using experimental data, we are able to place a bound on the clock's projected frequency stability. We discuss ways to improve the frequency stability to be competitive with existing miniature clocks.

  4. The redox behavior of potassium doped C60 peapods

    Science.gov (United States)

    Kalbáč, Martin; Kavan, Ladislav; Kataura, Hiromichi; Zukalová, Markéta; Dunsch, Lothar

    2004-09-01

    The redox behavior of fullerene peapods C60@SWCNT was studied by spectroelectrochemistry at samples chemically n-doped by K vapor. Strong chemical doping was proven by vanishing of the RBM mode and the downshift of TG mode in Raman spectroelectrochemistry. The K-doped peapods were subsequently studied electrochemically and thus n- and p-doped, respectively. The Ag(2) mode of intratubular fullerene in K-doped peapods contacting air was still red-shifted as referred to its position in a pristine peapod. An air-insensitive residual doping was found to be resistant also to cathodic charging. An explanation is given for this behavior.

  5. Charge transient spectroscopy of C 60 single crystals

    Science.gov (United States)

    Baranc̆ok, D.; Halus̆ka, M.; Kuzmany, H.; Nádaz̆dy, V.

    1994-01-01

    Suitability of the charge transient spectroscopy — QTS for the investigation of fullerites is demonstrated. QTS can yield an information on the electrical properties of both the bulk and the interface of fullerites interfaced with metals (insulators, semiconductors) as well as on its bulk phase transition. Our measurements were carried out on C60 single crystals. We observed a single QTS peak which reflects most probably a thermally activated relaxation process (polarization or trap - limited charge emission) in the crystal. The expected phase transition was detected as a step of QTS signal at 255 K. The influence of a thermal treatment in air on the QTS peak was also observed.

  6. The influence of oxygen adsorption on the NEXAFS and core-level XPS spectra of the C60 derivative PCBM

    International Nuclear Information System (INIS)

    Brumboiu, Iulia Emilia; Eriksson, Olle; Brena, Barbara; Ericsson, Leif; Hansson, Rickard; Moons, Ellen

    2015-01-01

    Fullerenes have been a main focus of scientific research since their discovery due to the interesting possible applications in various fields like organic photovoltaics (OPVs). In particular, the derivative [6,6]-phenyl-C 60 -butyric acid methyl ester (PCBM) is currently one of the most popular choices due to its higher solubility in organic solvents compared to unsubstituted C 60 . One of the central issues in the field of OPVs is device stability, since modules undergo deterioration (losses in efficiency, open circuit voltage, and short circuit current) during operation. In the case of fullerenes, several possibilities have been proposed, including dimerization, oxidation, and impurity related deterioration. We have studied by means of density functional theory the possibility of oxygen adsorption on the C 60 molecular moiety of PCBM. The aim is to provide guidelines for near edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) measurements which can probe the presence of atomic or molecular oxygen on the fullerene cage. By analysing several configurations of PCBM with one or more adsorbed oxygen atoms, we show that a joint core level XPS and O1s NEXAFS investigation could be effectively used not only to confirm oxygen adsorption but also to pinpoint the bonding configuration and the nature of the adsorbate

  7. Impact of Ultrathin C60 on Perovskite Photovoltaic Devices.

    Science.gov (United States)

    Liu, Dianyi; Wang, Qiong; Traverse, Christopher J; Yang, Chenchen; Young, Margaret; Kuttipillai, Padmanaban S; Lunt, Sophia Y; Hamann, Thomas W; Lunt, Richard R

    2018-01-23

    Halide perovskite solar cells have seen dramatic progress in performance over the past several years. Certified efficiencies of inverted structure (p-i-n) devices have now exceeded 20%. In these p-i-n devices, fullerene compounds are the most popular electron-transfer materials. However, the full function of fullerenes in perovskite solar cells is still under investigation, and the mechanism of photocurrent hysteresis suppression by fullerene remains unclear. In previous reports, thick fullerene layers (>20 nm) were necessary to fully cover the perovskite film surface to make good contact with perovskite film and avoid large leakage currents. In addition, the solution-processed fullerene layer has been broadly thought to infiltrate into the perovskite film to passivate traps on grain boundary surfaces, causing suppressed photocurrent hysteresis. In this work, we demonstrate an efficient perovskite photovoltaic device with only 1 nm C 60 deposited by vapor deposition as the electron-selective material. Utilizing a combination of fluorescence microscopy and impedance spectroscopy, we show that the ultrathin C 60 predominately acts to extract electrons from the perovskite film while concomitantly suppressing the photocurrent hysteresis by reducing space charge accumulation at the interface. This work ultimately helps to clarify the dominant role of fullerenes in perovskite solar cells while simplifying perovskite solar cell design to reduce manufacturing costs.

  8. Synthesis of mesogenic phthalocyanine-C60 donor–acceptor dyads designed for molecular heterojunction photovoltaic devices

    Directory of Open Access Journals (Sweden)

    Yves Henri Geerts

    2009-10-01

    Full Text Available A series of phthalocyanine-C60 dyads 2a–d was synthesized. Key steps in their synthesis are preparation of the low symmetry phthalocyanine intermediate by the statistical condensation of two phthalonitriles, and the final esterification of the fullerene derivative bearing a free COOH group. Structural characterization of the molecules in solution was performed by NMR spectroscopy, UV–vis spectroscopy and cyclic voltammetry. Preliminary studies suggest formation of liquid crystalline (LC mesophases for some of the prepared dyads. To the best of our knowledge, this is the first example of LC phthalocyanine-C60 dyads.

  9. Fast ion collisions with C 60 in vapour phase and collective excitation: Comparison with other gaseous targets

    Science.gov (United States)

    Tribedi, Lokesh C.; Kelkar, Aditya H.; Kasthurirangan, Siddharth

    2010-10-01

    The single and double ionization of a free C 60 molecule in collisions with fast heavy (F and Si) ions is investigated using a recoil ion time-of-flight mass spectrometer. The projectile charge state ( qp) dependence has also been investigated. A linear qp-dependence has been explained in terms of a plasmon excitation model. In addition, continuum electron spectroscopy has been used to detect the electron emission from fullerenes. The measured electron angular distribution for the fullerene target is compared with that for a gaseous target at a fixed electron energy. The ratio of forward-to-backward cross section for C 60 is quite different from that for Ne.

  10. The preparation and physico-chemical characterization of aluminum hydroxide/TLR7a, a novel vaccine adjuvant comprising a small molecule adsorbed to aluminum hydroxide.

    Science.gov (United States)

    Malyala, Padma; Laera, Donatello; Cianetti, Simona; Bufali, Simone; Aggravi, Marianna; Ianni, Elvira; Judge, Casey; Otten, Gillis; Singh, Manmohan; O' Hagan, Derek T

    2018-02-05

    Adjuvants are necessary to enable vaccine development against a significant number of challenging pathogens for which effective vaccines are not available [1]. We engineered a novel small-molecule immune potentiator (SMIP), a benzonaphthyridine agonist targeting toll-like receptor 7 (TLR7), as a vaccine adjuvant. TLR7 agonist (TLR7a) was engineered to be adsorbed onto aluminum hydroxide (AlOH), and the resulting AlOH/TLR7a was evaluated as a vaccine adjuvant [2-6]. AlOH/TLR7a exploits the flexibility of AlOH formulations, has an application in many vaccine candidates, and induced good efficacy and safety profiles against all tested antigens (bacterial- and viral-derived protein antigens, toxoids, glycoconjugates, etc.) in many animal models, including non-human primates [7]. In this paper, we describe the outcome of the physico-chemical characterization of AlOH/TLR7a. Reverse phase ultra-performance liquid chromatography (RP-UPLC), confocal microscopy, flow cytometry (FC), zeta potential (ZP) and phosphophilicity assays were used as tools to demonstrate the association of TLR7a to AlOH and to characterize this novel formulation. Raman spectroscopy, nuclear magnetic resonance and mass spectroscopy were also used to investigate the interaction between TLR7a and AlOH (data not shown). This pivotal work paved the way for AlOH/TLR7a to progress into the clinic for evaluation as an adjuvant platform for vaccines against challenging preventable diseases. Copyright © 2018. Published by Elsevier Inc.

  11. Measurement of laser activated electron tunneling from semiconductor zinc oxide to adsorbed organic molecules by a matrix assisted laser desorption ionization mass spectrometer

    International Nuclear Information System (INIS)

    Zhong Hongying; Fu Jieying; Wang Xiaoli; Zheng Shi

    2012-01-01

    Highlights: ► Irradiation of photons with energies more than the band gap generates electron–hole pairs. ► Electron tunneling probability is dependent on the electron mobility. ► Tunneling electrons are captured by charge deficient atoms. ► Unpaired electrons induce cleavages of chemical bonds. - Abstract: Measurement of light induced heterogeneous electron transfer is important for understanding of fundamental processes involved in chemistry, physics and biology, which is still challenging by current techniques. Laser activated electron tunneling (LAET) from semiconductor metal oxides was observed and characterized by a MALDI (matrix assisted laser desorption ionization) mass spectrometer in this work. Nanoparticles of ZnO were placed on a MALDI sample plate. Free fatty acids and derivatives were used as models of organic compounds and directly deposited on the surface of ZnO nanoparticles. Irradiation of UV laser (λ = 355 nm) with energy more than the band gap of ZnO produces ions that can be detected in negative mode. When TiO 2 nanoparticles with similar band gap but much lower electron mobility were used, these ions were not observed unless the voltage on the sample plate was increased. The experimental results indicate that laser induced electron tunneling is dependent on the electron mobility and the strength of the electric field. Capture of low energy electrons by charge-deficient atoms of adsorbed organic molecules causes unpaired electron-directed cleavages of chemical bonds in a nonergodic pathway. In positive detection mode, electron tunneling cannot be observed due to the reverse moving direction of electrons. It should be able to expect that laser desorption ionization mass spectrometry is a new technique capable of probing the dynamics of electron tunneling. LAET offers advantages as a new ionization dissociation method for mass spectrometry.

  12. Dynamics of cyanophenyl alkylbenzoate molecules in the bulk and in a surface layer adsorbed onto aerosil. Variation of the lengths of the alkyl chain

    Energy Technology Data Exchange (ETDEWEB)

    Frunza, Stefan [National Institute of Materials Physics, R-077125 Magurele (Romania); Schoenhals, Andreas [BAM Federal Institute of Materials Research and Testing, D-12205 Berlin (Germany); Frunza, Ligia, E-mail: lfrunza@infim.ro [National Institute of Materials Physics, R-077125 Magurele (Romania); Beica, Traian; Zgura, Irina; Ganea, Paul [National Institute of Materials Physics, R-077125 Magurele (Romania); Stoenescu, Daniel [Telecom-Bretagne, Departement d' Optique, Technopole Brest-Iroise 29238 Cedex (France)

    2010-06-16

    Graphical abstract: The temperature dependence of the molecular mobility in composites shows an Arrhenius-type regime at low temperature and a glassy-type one at higher temperature separated by a crossover phenomenon. - Abstract: The molecular mobility of 4-butyl- and 4-pentyl-4'-cyanophenyl benzoate (CP4B, CP5B) and their composites prepared from aerosil A380 was investigated by broadband dielectric spectroscopy in a large temperature range. Thermogravimetric and infrared investigations were additionally performed. High silica density (larger than 7 g aerosil/1 g of liquid crystal) was selected to observe a thin layer adsorbed on the surface of the silica particles. The data were compared with those of the member of the series with six carbon atoms in the alkyl tail. Bulk CP4B and CP5B show the dielectric behaviour expected for liquid crystals. For the composites one relaxation process is observed at frequencies much lower than those for the corresponding bulk, which was assigned to the dynamics of the molecules in a surface layer. The temperature dependence of the relaxation rates (and of the dielectric strength) shows a crossover behaviour with two distinguished regimes. At higher temperatures the data obey the Vogel-Fulcher-Tammann law, whereas an Arrhenius law is observed at lower temperature, in a close similarity to the behaviour of a constrained dynamic glass transition. The estimated Vogel and crossover temperature is independent on the tail length, while the activation energy for the low temperature branch increases weakly with increasing the alkyl tail.

  13. Continuum modeling investigation of gigahertz oscillators based on a C60 fullerene inside cyclic peptide nanotubes

    Science.gov (United States)

    Sadeghi, F.; Ansari, R.; Darvizeh, M.

    2016-02-01

    Research concerning the fabrication of nano-oscillators with operating frequency in the gigahertz (GHz) range has become a focal point in recent years. In this paper, a new type of GHz oscillators is introduced based on a C60 fullerene inside a cyclic peptide nanotube (CPN). To study the dynamic behavior of such nano-oscillators, using the continuum approximation in conjunction with the 6-12 Lennard-Jones (LJ) potential function, analytical expressions are derived to determine the van der Waals (vdW) potential energy and interaction force between the two interacting molecules. Employing Newton's second law, the equation of motion is solved numerically to arrive at the telescopic oscillatory motion of a C60 fullerene inside CPNs. It is shown that the fullerene molecule exhibits different kinds of oscillation inside peptide nanotubes which are sensitive to the system parameters. Furthermore, for the precise evaluation of the oscillation frequency, a novel semi-analytical expression is proposed based on the conservation of the mechanical energy principle. Numerical results are presented to comprehensively study the effects of the number of peptide units and initial conditions (initial separation distance and velocity) on the oscillatory behavior of C60 -CPN oscillators. It is found out that for peptide nanotubes comprised of one unit, the maximum achievable frequency is obtained when the inner core oscillates with respect to its preferred positions located outside the tube, while for other numbers of peptide units, such frequency is obtained when the inner core oscillates with respect to the preferred positions situated in the space between the two first or the two last units. It is further found out that four peptide units are sufficient to obtain the optimal frequency.

  14. Perspective: C60+ and laboratory spectroscopy related to diffuse interstellar bands.

    Science.gov (United States)

    Campbell, E K; Maier, J P

    2017-04-28

    In the last 30 years, our research has focused on laboratory measurements of the electronic spectra of organic radicals and ions. Many of the species investigated were selected based on their potential astrophysical relevance, particularly in connection with the identification of appealing candidate molecules for the diffuse interstellar absorptions. Notably, carbon chains and derivatives containing hydrogen and nitrogen atoms in their neutral and ionic forms were studied. These data could be obtained after developing appropriate techniques to record spectra at low temperatures relevant to the interstellar medium. The measurement of gas phase laboratory spectra has enabled direct comparisons with astronomical data to be made and though many species were found to have electronic transitions in the visible where the majority of diffuse bands are observed, none of the absorptions matched the prominent interstellar features. In 2015, however, the first carrier molecule was identified: C 60 + . This was achieved after the measurement of the electronic spectrum of C 60 + -He at 6K in a radiofrequency ion trap.

  15. Fullerene (C60) nano-colloids in nematic liquid crystal

    Science.gov (United States)

    Visco, Angelo; Sobczak, Kevin; Mahmood, Rizwan

    2015-03-01

    We report high resolution homodyne light scattering studies to probe director fluctuations in bend/splay mode in bulk nematic liquid crystal and as a function of fullerene (C60) nanoparticles concentration. The preliminary analysis shows that the relaxation time of these fluctuations is fairly constant with in the experimental uncertainty despite the constraints imposed on the director fluctuations due to the insertion of nano colloids. The relaxation time extracted from the data found to be in nano seconds range and the diffusion constant (D) found to be, D = 4.29 x 106 cm/sec. The authors acknowledge the financial support from grants office, Dean, college of Health, Environment & Science and the physics department.

  16. A first principle investigation into effect of B and BN doped C60 in ...

    Indian Academy of Sciences (India)

    22

    Abstract. The present paper reports the effect of B and BN doped C60 as catalyst for lowering the dehydrogenation energy in MXH4 clusters (M = Na and Li; X = Al and B) using density functional calculations. MXH4 interacts strongly with B doped C60 and weakly with BN-doped. C60 in comparison to pure C60 with binding ...

  17. C60 as fine fillers to improve poly(phenylene sulfide) electrical conductivity and mechanical property

    OpenAIRE

    Zhang, Maliang; Wang, Xiaotian; Bai, Yali; Li, Zhenhuan; Cheng, Bowen

    2017-01-01

    Electrical conductive poly(phenylene sulfide) (PPS)/fullerene (C60) composites were prepared by 1-chlornaphthalene blending method, and the interface effects of C60 and PPS on PPS/C60 properties were characterized. C60 is an excellent nanofiller for PPS, and 2 wt% PPS/C60 composite displayed the optimal conductivity which achieved 1.67???10?2?S/cm. However, when C60 concentration reached 2?wt%, the breaking strength and tensile modulus of PPS/C60 fiber achieved maximum 290?MPa and 605?MPa, an...

  18. Vibrational spectra of C60.C8H8 and C70.C8H8 in the rotor-stator and polymer phases.

    Science.gov (United States)

    Klupp, G; Borondics, F; Kováts, E; Pekker, A; Bényei, G; Jalsovszky, I; Hackl, R; Pekker, S; Kamarás, K

    2007-11-01

    C(60).C(8)H(8) and C(70).C(8)H(8) are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C(60)C(8)H(8)) and poly(C(70)C(8)H(8)) resulting from a solid-state reaction occurring on heating. On the basis of the spectra, we propose a connection pattern for the fullerene in poly(C(60)C(8)H(8)), where the symmetry of the C(60) molecule is D(2h). On illuminating the C(60).C(8)H(8) cocrystal with green or blue light, a photochemical reaction was observed leading to a product similar to that of the thermal polymerization.

  19. Extending the range of low energy electron diffraction (LEED) surface structure determination: Co-adsorbed molecules, incommensurate overlayers and alloy surface order studied by new video and electron counting LEED techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ogletree, D.F.

    1986-11-01

    LEED multiple scattering theory is briefly summarized, and aspects of electron scattering with particular significance to experimental measurements such as electron beam coherence, instrument response and phonon scattering are analyzed. Diffuse LEED experiments are discussed. New techniques that enhance the power of LEED are described, including a real-time video image digitizer applied to LEED intensity measurements, along with computer programs to generate I-V curves. The first electron counting LEED detector using a ''wedge and strip'' position sensitive anode and digital electronics is described. This instrument uses picoampere incident beam currents, and its sensitivity is limited only by statistics and counting times. Structural results on new classes of surface systems are presented. The structure of the c(4 x 2) phase of carbon monoxide adsorbed on Pt(111) has been determined, showing that carbon monoxide molecules adsorb in both top and bridge sites, 1.85 +- 0.10 A and 1.55 +- 0.10 A above the metal surface, respectively. The structure of an incommensurate graphite overlayer on Pt(111) is analyzed. The graphite layer is 3.70 +- 0.05 A above the metal surface, with intercalated carbon atoms located 1.25 +- 0.10 A above hollow sites supporting it. The (2..sqrt..3 x 4)-rectangular phase of benzene and carbon monoxide coadsorbed on Pt(111) is analyzed. Benzene molecules adsorb in bridge sites parallel to and 2.10 +- 0.10 A above the surface. The carbon ring is expanded, with an average C-C bond length of 1.72 +- 0.15 A. The carbon monoxide molecules also adsorb in bridge sites. The structure of the (..sqrt..3 x ..sqrt..3) reconstruction on the (111) face of the ..cap alpha..-CuAl alloy has been determined.

  20. Experimental observation of C60 LUMO splitting in the C60(2-) dianions due to the Jahn-Teller effect. Comparison with the C60(˙-) radical anions.

    Science.gov (United States)

    Konarev, Dmitri V; Kuzmin, Alexey V; Simonov, Sergey V; Yudanova, Evgeniya I; Khasanov, Salavat S; Saito, Gunzi; Lyubovskaya, Rimma N

    2013-06-21

    New fullerene salts (TMP(+))2·(C60(2-))·(C6H4Cl2)2 (1), {DB-18-crown-6·[Na(+)]·(C6H5CN)2}2·(C60(2-))·C6H5CN·C6H4Cl2 (2), {cryptand[2,2,2]·(Na(+))}2·(C60(2-)) (3) and (PPN(+))2·(C60(2-))·(C6H4Cl2)2 (4) were obtained as single crystals. Their crystal structures were solved and their optical and magnetic properties were analyzed. The spectra of the salts in the IR and UV-visible-NIR ranges indicate the formation of C60(2-) dianions in 1-4. These salts show similar behavior in EPR measurements, explained by the diamagnetic ground state of the C60(2-) dianions and the thermal population of the excited triplet state, which is separated by an energy gap of 487-540 cm(-1). The magnetic susceptibility of 4 also increased above 130 K due to the population of the excited triplet state. The observed splitting of the C60 LUMO is attributed to the Jahn-Teller (JT) effect. We analyzed the splitting by an extended Hückel method using the single-crystal structural data for the compounds containing neutral, mono- and dianions of C60. The splitting of the initially triply degenerated C60 LUMO produces three molecular orbitals. The gap between the lowest and highest orbitals is very small in neutral C60 (128-140 cm(-1)), it increases in C60(˙-) (500-710 cm(-1)) and increases further in C60(2-) (1080-1670 cm(-1)). It was found that the splitting of the C60 LUMO is realized in different ways for the mono- and dianions. The ground and first excited state are separated in C60(˙-) by a small gap of 55-180 cm(-1) only. This gap is noticeably larger in the C60(2-) dianions and falls into the 760-1390 cm(-1) range.

  1. C60-SIMS imaging of nanoparticles within mammalian cells.

    Science.gov (United States)

    Bloom, Anna N; Tian, Hua; Winograd, Nicholas

    2015-07-01

    To achieve successful drug delivery via nanoparticles the interactions between the nanoparticle and the chemistry of the surrounding biological environment is of central importance. A thorough understanding of these interactions is necessary in order to better elucidate information regarding drug pathways and mechanisms of action in treatment protocols. As such, it is important to identify the location of the nanoparticle, the state of its functionalization, as well as any changes in the cellular environment. The use of cluster secondary ion mass spectrometry (SIMS) using C60 (+) primary ions makes simultaneous acquisition of this information possible. Here, SIMS has been successfully used to chemically image gold nanoparticles (AuNPs) within a model, single cell system involving macrophage-like RAW 264.7 cells. The macrophage-like properties of this cell line make it extremely well-suited for cell-uptake studies. Both AuNPs and two pharmaceutical compounds, amiodarone and elacridar, were successfully imaged within a cellular system using cluster SIMS. To verify that SIMS can also be used to detect functionalization and nanoparticles simultaneously, fluorophore-functionalized AuNPs were studied as a model system. The fluorescent characteristics of these functionalized nanoparticles enabled the visual confirmation of the presence and location of the particles within the cell.

  2. Fragment-fragment correlations in near-binary fragmentation of C60

    International Nuclear Information System (INIS)

    Vandenbosch, R.; Henry, B.; Cooper, C.H.; Liang, J.F.; Will, D.I.

    1997-01-01

    The collision dynamics of C 60 with H 2 and He gas has been studied using reverse kinematics. A beam of C 60 - is obtained by electron attachment to neutral molecules exiting an oven and then accelerated to energies between 75 and 150 keV. The collisions take place in a windowless gas cell. We energy analyze the products in a pair of electrostatic analyzers which are oriented so that coincidences between light and heavy fragments can be observed. Our energy, and hence mass, resolution is sufficient to uniquely identify all C n clusters between n=1 and 60. The principal question we are addressing is whether heavy products in the mass range C 34 to C 56 are produced solely by sequential emission of C 2 fragments, or whether longer chains (and possibly rings) compete with C 2 emission. From our coincidence studies we have conclusive evidence that fragments such as C 8 are fragmentation partners to heavy fragments. In general we find that the products of a binary fragmentation are sufficiently excited that sequential decay follows the initial fragmentation. Although only even-n heavy fragments are observed, the coincident light fragments include both odd and even-n fragments due to subsequent fragmentation of the excited lighter partner of the initial binary fragmentation. This scenario has been confirmed by studying coincidences between two light fragments. copyright 1997 American Institute of Physics

  3. Bioapplication and activity of fullerenol C 60 (OH) | Rade | African ...

    African Journals Online (AJOL)

    In addition, several derivatives have shown immunomodulating, neuroprotective and radioprotective effect. Fullerenes are hydrophobic molecules best dissolved in organic solvents, so potential biomedical applications are restricted by their extremely poor solubility in polar solvents. One of the strategies for improving poor ...

  4. C60as fine fillers to improve poly(phenylene sulfide) electrical conductivity and mechanical property.

    Science.gov (United States)

    Zhang, Maliang; Wang, Xiaotian; Bai, Yali; Li, Zhenhuan; Cheng, Bowen

    2017-06-30

    Electrical conductive poly(phenylene sulfide) (PPS)/fullerene (C 60 ) composites were prepared by 1-chlornaphthalene blending method, and the interface effects of C 60 and PPS on PPS/C 60 properties were characterized. C 60 is an excellent nanofiller for PPS, and 2 wt% PPS/C 60 composite displayed the optimal conductivity which achieved 1.67 × 10 -2  S/cm. However, when C 60 concentration reached 2 wt%, the breaking strength and tensile modulus of PPS/C 60 fiber achieved maximum 290 MPa and 605 MPa, and those values were 7.72 and 11.2 times as that of pure PPS. The excellent conductive and mechanical properties of PPS/C 60 were attributed to the heterogeneous nucleation of C 60 during PPS crystallization, formation of a large number of covalent bond by main C 60 -thiol adducts and minor C 60 -ArCl alkylation between C 60 outer surface and PPS matrix. At same time, PPS/C 60 thermal properties were also investigated.

  5. The effect of water on the stability of C60 fullerene nanowhiskers

    International Nuclear Information System (INIS)

    Miyazawa, Kun’ichi; Hotta, Kayoko

    2011-01-01

    The morphology of C 60 precipitates synthesized by using isopropyl alcohol (IPA) added with water was investigated in order to know the effect of water on the growth of C 60 nanowhiskers (C 60 NWs) in C 60 –toluene–IPA solution systems. The stability of C 60 NWs decreased and granular crystals of C 60 were formed in the solutions when IPA added with an excess amount of water was used in the liquid–liquid interfacial precipitation method. The C 60 NWs were found to be destabilized with time in the solutions added with water. The C 60 NWs dried in air showed similar Raman profiles irrespective of the use of IPA with and without water addition. The Raman profiles of granular C 60 single crystals showed the base lines much flatter than those of C 60 NWs, indicating that C 60 NWs possess a disordered crystal structure. By optimizing the growth condition, short C 60 NWs with aspect ratios ranging from 3 to 10 and an average length of about 1.8 μm were successfully fabricated. The short C 60 NWs are expected to be applicable for electrodes of organic thick film solar cells.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    Electronic transitions at interfaces between MoO 3 layers and organic layers of C 60 , SubPc, MgPc, and nano-composite layers of SubPc:C 60 and MgPc:C 60 have been studied by modulated surface photovoltage (SPV) spectroscopy. For all systems, time dependent and modulated SPV signals pointed to dissociation of excitons at the MoO 3 /organic layer interfaces with a separation of holes towards MoO 3 . The highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps (E HL ) of C 60 , SubPc, and MgPc and the effective E HL of SubPc:C 60 and MgPc:C 60 were measured. The offsets between the LUMO (ΔE L ) or HOMO (ΔE H ) bands were obtained with high precision and amounted to 0.33 or 0.73 eV for SubPc:C 60 , respectively, and to −0.33 or 0.67 eV for MgPc:C 60 , respectively. Exponential tails below E HL and most pronounced sub-bandgap transitions were characterized and ascribed to disorder and transitions from HOMO bands to unoccupied defect states

  7. A first-principle investigation into effect of B- and BN-doped C60 in ...

    Indian Academy of Sciences (India)

    2017-11-23

    Nov 23, 2017 ... Abstract. The present paper reports the effect of B- and BN-doped C60 as catalysts for lowering the dehydrogenation energy in MXH4 clusters (M = Na and Li, X = Al and B) using density functional calculations. MXH4 interacts strongly with. B-doped C60 and weakly with BN-doped C60 in comparison with ...

  8. Effect of He pressure on the superconducting transition temperatures of Na2CsC60 and (NH3)4Na2CsC60

    International Nuclear Information System (INIS)

    Schirber, J.E.; Bayless, W.R.; Rosseinsky, M.J.; Zhou, O.; Fleming, R.M.; Murphy, D.; Fischer, J.E.

    1994-01-01

    The Na based mixed alkali doped C 60 superconductors show anomalous behavior with respect to the ''universal'' superconducting transition temperature T c vs lattice constant a 0 relation followed by most of the fcc A 3 C 60 superconductors. We have measured dt c /dP for Na 2 CsC 60 and (NH 3 ) 4 Na 2 CsC 60 using solid He as the pressure medium to ∼ 6 kbar finding dT c /dP equal to -0.8±(0.01) K/kbar and -1.0(±0.1)K/kbar for Na 2 CsC 60 and Na 2 (NH 3 ) 4 C 60 respectively. Our value for Na 2 CsC 60 differs markedly from that obtained by Mizuki et al of about -1.3 K/kbar. However, using N 2 or Ar, we obtain values for dT c /dP in substantial agreement with Mizuki et al who used fluorinert to generate their pressure. This work emphasizes the need for compressibility measurements with the same pressure medium in the appropriate temperature range so that meaningful comparisons can be made between various pressure measurements and models which are based on lattic spacing

  9. Preparation of Composite Films of a Conjugated Polymer and C60NWs and Their Photovoltaic Application

    Directory of Open Access Journals (Sweden)

    Takatsugu Wakahara

    2016-01-01

    Full Text Available Composite films of conjugated polymers, such as poly[2-methoxy-5-(3′,7′-dimethyloctyloxy-1,4-phenylenevinylene] (MDMO-PPV and poly(3-hexylthiophene (P3HT, with C60 nanowhiskers (C60NWs were prepared. The photoluminescence originating from the conjugated MDMO-PPV polymers was effectively quenched in the composite film, indicating a strong interaction between the conjugated polymer and C60NWs. The photovoltaic devices were fabricated using C60NW (conjugated polymer composite films, resulting in a power conversion efficiency of ~0.01% for P3HT with short length thin C60NWs, which is higher than that previously reported for thick C60 nanorods. The present study gives new guidance on the selection of the type of C60NWs and the appropriate polymer for new photovoltaic devices.

  10. Ionization, evaporation and fragmentation of C60 in collisions with highly charged C, O and F ions-effect of projectile charge state

    International Nuclear Information System (INIS)

    Kelkar, A H; Misra, D; Tribedi, L C

    2007-01-01

    We study the various inelastic processes such ionization, fragmentation and evaporation of C 60 molecule in collisions with fast heavy ions. We have used 2.33 MeV/u C, O and F projectile ion beams. Various ionization and fragmentation products were detected using time-of-flight mass spectrometer. The multiply charged C 60 r+ ions were detected for maximum r = 4. The projectile charge state (q p ) dependence of the single and double ionization cross sections is well reproduced by a model based on the giant dipole plasmon resonance (GDPR). The q p -dependence of the fragmentation yields, was found to be linear. Variation of relative yields of the evaporation products of C 60 2+ (i.e. C 58 2+ , C 56 2+ etc) and C 60 3+ (i.e. C 58 3+ , C 56 3+ etc) with q p has also been investigated for various projectiles

  11. Potential energy and dipole moment surfaces for HF@C60: Prediction of spectral and electric response properties

    Science.gov (United States)

    Kalugina, Yulia N.; Roy, Pierre-Nicholas

    2017-12-01

    We present a five-dimensional potential energy surface (PES) for the HF@C60 system computed at the DF-LMP2/cc-pVTZ level of theory. We also calculated a five-dimensional dipole moment surface (DMS) based on DFT(PBE0)/cc-pVTZ calculations. The HF and C60 molecules are considered rigid with bond length rHF = 0.9255 Å (gas phase ground rovibrational state geometry). The C60 geometry is of Ih symmetry. The ab initio points were fitted to obtain a PES in terms of bipolar spherical harmonics. The minimum of the PES corresponds to a geometry where the center of mass of HF is located 0.11 Å away from the center of the cage with an interaction energy of -6.929 kcal/mol. The DMS was also represented in terms of bipolar spherical harmonics. The PES was used to calculate the rotation-translation bound states of HF@C60, and good agreement was found relative to the available experimental data [A. Krachmalnicoff et al., Nat. Chem. 8, 953 (2016)] except for the splitting of the first rotational excitation levels. We propose an empirical adjustment to the PES in order to account for the experimentally observed symmetry breaking. The form of that effective PES is additive. We also propose an effective Hamiltonian with an adjusted rotational constant in order to quantitatively reproduce the experimental results including the splitting of the first rotational state. We use our models to compute the molecular volume polarizability of HF confined by C60 and obtain good agreement with experiment.

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

    Science.gov (United States)

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

    2016-02-01

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

  13. Modeling adsorption of brominated, chlorinated and mixed bromo/chloro-dibenzo-p-dioxins on C60 fullerene using Nano-QSPR

    Directory of Open Access Journals (Sweden)

    Piotr Urbaszek

    2017-03-01

    Full Text Available Many technological implementations in the field of nanotechnology have involved carbon nanomaterials, including fullerenes such as the buckminsterfullerene, C60. The unprecedented properties of such organic nanomaterials (in particular their large surface area gained extensive attention for their potential use as organic pollutant sorbents. Sorption interactions can be very hazardous and useful at the same time. This work investigates the influence of halogenation by bromine and/or chlorine in dibenzo-p-dioxins on their sorption ability on the C60 fullerene surface. Halogenated dibenzo-p-dioxins (PXDDs, where X = Br or Cl are ever-present in the environment and accidently produced in many technological processes in only approximately known quantities. If all combinatorial Br and/or Cl dioxin substitution possibilities are present in the environment, the experimental characterization and investigation of sorbent effectiveness is more than difficult. In this work, we have developed a quantitative structure–property relationship (QSPR model (R2 = 0.998, predicting the adsorption energy [kcal/mol] for 1,701 PXDDs adsorbed on C60 (PXDD@C60. Based on the QSPR model reported herein, we concluded that the lowest energy PXDD@C60 complexes are those that the World Health Organization (WHO considers to be less dangerous with respect to the aryl hydrocarbon receptor (AhR toxicity mechanism. Therefore, the effectiveness of fullerenes as sorbent agents may be underestimated as sorption could be less effective for toxic congeners than previously believed.

  14. Microscopic insights into the sputtering of thin organic films on Ag{111} induced by C60 and Ga bombardment.

    Science.gov (United States)

    Postawa, Zbigniew; Czerwinski, Bartlomiej; Winograd, Nicholas; Garrison, Barbara J

    2005-06-23

    Molecular dynamics computer simulations have been employed to model the bombardment of Ag{111} covered with three layers of C6H6 by 15 keV Ga and C60 projectiles. The study is aimed toward examining the mechanism by which molecules are desorbed from surfaces by energetic cluster ion beams and toward elucidating the differences between cluster bombardment and atom bombardment. The results show that the impact of the cluster on the benzene-covered surface leads to molecular desorption during the formation of a mesoscopic scale impact crater via a catapulting mechanism. Because of the high yield of C6H6 with both Ga and C60, the yield enhancement is observed to be consistent with related experimental observations. Specific energy and angle distributions are shown to be associated with the catapult mechanism.

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

    Science.gov (United States)

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

    2013-12-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    Although considerable progress has been achieved to create advanced polymer nanocomposites using nanocarbons including fullerene (C 60 ) and graphene, it remains a major challenge to effectively disperse them in a polymer matrix and to fully exert their extraordinary properties. Here we report a novel approach to fabricate the C 60 @graphene nanocarbon hybrid (C 60 : ∼47.9 wt%, graphene: ∼35.1%) via three-step reactions. The presence of C 60 on a graphene sheet surface can effectively prevent the aggregation of the latter which in turn helps the dispersion of the former in a polymer matrix during melt-processing. C 60 @graphene is found to be uniformly dispersed in a polypropylene (PP) matrix. Compared with pristine C 60 or graphene, C 60 @graphene further improves the thermal stability and mechanical properties of PP. The incorporation of 2.0 wt% C 60 @graphene (relative to PP) can remarkably increase the initial degradation temperature by around 59 ° C and simultaneously enhance the tensile strength and Young’s modulus by 67% and 76%, respectively, all of which are higher than those of corresponding PP/C 60 (graphene) nanocomposites. These significant performance improvements are mainly due to the free-radical-trapping effect of C 60 , and the thermal barrier and reinforcing effects of graphene nanosheets as well as the effective stress load transfer. This work provides a new methodology to design multifunctional nanohybrids for creating advanced materials. (paper)

  17. Toxicity of Aqueous Fullerene nC60 to Activated Sludge: Nitrification Inhibition and Microtox Test

    Directory of Open Access Journals (Sweden)

    Yongkui Yang

    2012-01-01

    Full Text Available The increasing production and use of fullerene nanomaterials raised their exposure potential to the activated sludge during biological wastewater treatment process. In this study, the toxicity of aqueous nanoscaled C60 (nC60 to activated sludge was investigated using nitrification inhibition and Microtox test. The test solutions of nC60 were prepared using two methods: long stirring (Stir/nC60 and toluene exchange (Tol/nC60. The nC60 aggregation in test medium was also evaluated for toxicity assessment. The results showed that the nC60 aggregation behaved differently in two test mediums during the incubation periods. The nC60 toxicity was greatly influenced by the preparation method. Stir/nC60 presented no significant toxicity to both the nitrification sludge and bioluminescent bacteria at the maximum concentration studied. In contrast, the EC20 of Tol/nC60 was obtained to be 4.89 mg/L (3 h for the nitrification inhibition and 3.44 mg/L (30 min for Microtox test, respectively.

  18. Effect of van der Waals interaction on energetics and transport properties of a single anthracene molecule adsorbed or confined inside a carbon nanotube

    Science.gov (United States)

    Debbichi, L.; Dappe, Y. J.; Alouani, M.

    2012-01-01

    The energetics and transport properties of a single aromatic molecule (C14H10) in interaction with a metallic single-walled carbon nanotube (SWCNT) have been studied using state-of-the-art density functional calculations. In both adsorption and encapsulation configurations, we show that the fundamental importance of the weak van der Waals (vdW) interactions is to stabilize the position of the molecule. These interactions have been treated through the ab initio linear combination of atomic orbitals (LCAO-S2) method including the vdW weak interactions. Moreover, we show that the electric conductance of the SWCNT, calculated within a nonequilibrium Green's-function formalism, is very sensitive to the position of the molecule with respect to the nanotube. The change of the conductance is explained in terms of charge transfer strength between the nanotube and the molecule.

  19. Vibrational Cooling in A Cold Ion Trap: Vibrationally Resolved Photoelectron Spectroscopy of Cold C60- Anions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xue B.; Woo, Hin-koon; Wang, Lai S.

    2005-08-01

    We demonstrate vibrational cooling of anions via collisions with a background gas in an ion trap attached to a cryogenically controlled cold head (10 ? 400 K). Photoelectron spectra of vibrationally cold C60- anions, produced by electrospray ionization and cooled in the cold ion trap, have been obtained. Relative to spectra taken at room temperature, vibrational hot bands are completely eliminated, yielding well resolved vibrational structures and a more accurate electron affinity for neutral C60. The electron affinity of C60 is measured to be 2.683 ? 0.008 eV. The cold spectra reveal complicated vibrational structures for the transition to the C60 ground state due to the Jahn-Teller effect in the ground state of C60-. Vibrational excitations in the two Ag modes and eight Hg modes are observed, providing ideal data to assess the vibronic couplings in C60-.

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Song [Vanderbilt University; Zhao, Xiongce [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health; Mo, Yiming [ORNL; Cummings, Peter T [ORNL; Heller, William T [ORNL

    2013-01-01

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

  1. The development of C60 and gold cluster ion guns for static SIMS analysis

    International Nuclear Information System (INIS)

    Hill, R.; Blenkinsopp, P.W.M.

    2004-01-01

    We have designed and tested two primary ion beam systems for the generation of polyatomic beams for high mass SIMS. These are a gold cluster ion gun and a C 60 ion gun. The two systems offer different performance benefits in terms of spatial resolution, mass range and ion yields. The gold system provides a general purpose tool with beams suitable for high spatial resolution and beams suitable for high mass range SIMS; the C 60 system provides outstanding ion yields, especially at high mass. We present results of sputter yield measurements for C 60 bombardment of silicon. These suggest that C 60 sputters with very high efficiency

  2. Energy transfer in anisotropic systems: A. Excitation migration in substitutionally disordered one-dimensional solids. B. The spectroscopy of molecules adsorbed on metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zwemer, D.A.

    1978-11-01

    The energy and dynamics of excited states in a variety of anisotropic environments, including isotopically and chemically mixed crystals and molecular overlayers adsorbed on a nickel (111) surface, are investigated. The relationship between local and long-range structure and spectroscopic properties is explored. A theory for energy transfer in substitutionally disordered solids is presented. Explicit expressions for the ''diffusion'' coefficients and the energy partitioning ratios in binary systems are derived. Energy transfer between localized states is found to be facilitated by concurrent tunnelling and thermal promotion. Experimental results for triplet energy partitioning between mobile and stationary trap states as a function of mobile trap concentration in the ternary d/sub 2/-1,2,4,5-tetrachlorobenzene--h/sub 2/-1,2,4,5-tetrachlorobenzene--pyrazine system are analyzed. It is shown that both tunnelling and thermal detrapping contribute to triplet exciton mobility below 4.2 K. Singlet exciton migration makes an important contribution to trap equilibration before intersystem crossing to the triplet manifold. Spin coherence experiments are used to determine the energy level structure, physical geometry, and exciton dynamics of a series of impurity-induced traps in 1,2,4,5-tetrachlorobenzene. The uv spectra of pyrazine, pyridine, and naphthalene adsorbed on a nickel single crystal (111) surface are measured by spectroscopic ellipsometry at low temperatures. The excited electronic and vibronic energy levels measured are similar to bulk molecular crystal values, but pyrazine and pyridine show small, but significant deviations. The ordering of molecular overlays is observed spectroscopically and information about overlayer crystal structure is deduced. 148 references, 48 figures, 5 tables.

  3. Symmetry-breaking in the H2@C60 endofullerene revealed by inelastic neutron scattering at low temperature.

    Science.gov (United States)

    Mamone, Salvatore; Johnson, Mark R; Ollivier, Jacques; Rols, Stéphane; Levitt, Malcolm H; Horsewill, Anthony J

    2016-01-21

    The fine structure of the rotational ground state of molecular ortho-hydrogen confined inside the fullerene cage C60 is investigated by inelastic neutron scattering (INS). The INS line corresponding to transitions between the three sub-levels comprising the ortho ground state to the non-degenerate para ground state was studied as a function of temperature down to 60 mK in neutron energy gain. The experiments show that at ambient pressure the three ortho sub-levels are split into a low energy non-degenerate level and a high energy doubly degenerate level separated by 0.135 ± 0.010 meV. This observation is consistent with hydrogen molecules being located at sites with axial symmetry superseding the icosahedral symmetry of isolated rigid C60 cages in the solid phase. To gain insight into the role of inter-cage interactions in determining the symmetry breaking potential, the effects of hydrostatic pressure on the fine structure of the line was also investigated. The analysis of the INS spectra shows that the potential and the energy levels of H2 are sensitive to the orientation of neighbouring cages, consistent with the low-temperature crystalline phase of C60.

  4. C60 Fullerene Effects on Diphenyl-N-(trichloroacetyl)-amidophosphate Interaction with DNA In Silico and Its Cytotoxic Activity Against Human Leukemic Cell Line In Vitro

    Science.gov (United States)

    Grebinyk, A.; Prylutska, S.; Grynyuk, I.; Kolp, B.; Hurmach, V.; Sliva, T.; Amirkhanov, V.; Trush, V.; Matyshevska, O.; Slobodyanik, M.; Prylutskyy, Yu.; Frohme, M.; Ritter, U.

    2018-03-01

    New representative of carbacylamidophosphates - diphenyl-N-(trichloroacetyl)-amidophosphate (HL), which contains two phenoxy substituents near the phosphoryl group, was synthesized, identified by elemental analysis and IR and NMR spectroscopy, and tested as a cytotoxic agent itself and in combination with C60 fullerene. According to molecular simulation results, C60 fullerene and HL could interact with DNA and form a rigid complex stabilized by stacking interactions of HL phenyl groups with C60 fullerene and DNA G nucleotide, as well as by interactions of HL CCl3 group by ion-π bonds with C60 molecule and by electrostatic bonds with DNA G nucleotide. With the use of MTT test, the cytotoxic activity of HL against human leukemic CCRF-CM cells with IC50 value detected at 10 μM concentration at 72 h of cells treatment was shown. Under combined action of 16 μM C60 fullerene and HL, the value of IC50 was detected at lower 5 μM HL concentration and at earlier 48 h period of incubation, besides the cytotoxic effect of HL was observed at a low 2.5 μM concentration at which HL by itself had no influence on cell viability. Binding of C60 fullerene and HL with minor DNA groove with formation of a stable complex is assumed to be one of the possible reasons of their synergistic inhibition of CCRF-CEM cells proliferation. Application of C60 fullerene in combination with 2.5 μM HL was shown to have no harmful effect on structural stability of blood erythrocytes membrane. Thus, combined action of C60 fullerene and HL in a low concentration potentiated HL cytotoxic effect against human leukemic cells and was not followed by hemolytic effect.

  5. Axial coordination and electronic structure of diatomic NO, CO, and O2 molecules adsorbed onto Co-tetraphenylporphyrin on Au(111), Ag(111), and Cu(111): a density-functional theory study.

    Science.gov (United States)

    Chang, Yun Hee; Kim, Howon; Kahng, Se-Jong; Kim, Yong-Hyun

    2016-11-14

    Based on density functional theory calculations, we investigated the axial bindings of diatomic molecules (NO, CO, and O 2 ) to metalloporphyrins and their spin switching behaviors. These binding reactions provide the ways to control molecular states and spins in metalloporphyrin systems that can be used in bio-sensing and spintronic applications. To microscopically understand the non-trivial axial binding structures and spin-switching behaviors of diatomic molecules (NO, CO, and O 2 ) adsorbed onto Co-tetraphenylporphyrin (CoTPP), we performed spin-polarized density functional theory (DFT) calculations for various CoTPP systems on Au(111), Ag(111), and Cu(111) substrates. We also systematically evaluated the effects of van der Waals and Hubbard U corrections by directly comparing the electronic structure with the results of scanning tunnelling microscopy. From the calculation results, we have found that a NO molecule, almost 60° tilted away from the axial direction, is coordinated with CoTPP with a binding energy of 1.2-1.7 eV depending on substrates, and the spin state of CoTPP is completely switched off due to the charge transfer from NO to CoTPP. On the other hand, CO and O 2 molecules rather weakly interact with a binding energy of 0.4-0.8 eV, and a spin polarization of ∼1μ B is still present at CoTPP. A CO molecule is expected to be almost straightly coordinated along the axial direction of CoTPP, but O 2 is tilted similarly to the NO case. Regarding the substrate effects, we have found that there is noticeable charge transfer from Ag(111) and Cu(111) to CoTPP, but no significant charge transfer from Au(111) to CoTPP. These findings of the axial coordination and spin states for NO, CO, and O 2 adsorbed CoTPP systems will be useful for understanding bio-sensing mechanisms and designing molecular spintronic systems.

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

    Science.gov (United States)

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

    2017-01-01

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

  7. Electronic structure of CoPc adsorbed on Ag(100): Evidence for molecule-substrate interaction mediated by Co 3d orbitals

    Czech Academy of Sciences Publication Activity Database

    Salomon, E.; Amsalem, P.; Marom, N.; Vondráček, Martin; Kronik, L.; Koch, N.; Angot, T.

    2013-01-01

    Roč. 87, č. 7 (2013), "075407-1"-"075407-9" ISSN 1098-0121 R&D Projects: GA MŠk(CZ) LG12003 Institutional support: RVO:68378271 Keywords : cobalt-phthalocyanine * molecule-substrate interaction * photoemission spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.664, year: 2013

  8. Spectroscopic and theoretical studies on the structural, electronic, and optical properties of zinc octaethylporphyrin/C60 co-deposited films

    Science.gov (United States)

    Onoe, Jun; Watanabe, Shinta; Kato, Shiro; Nakaya, Masato; Bucher, Jean-Pierre

    2017-12-01

    We have examined the structural, electronic, and optical properties of zinc-octaethylporphyrin [Zn(OEP)]/C60 co-deposited films to elucidate the donor (D)-acceptor (A) interactions at the D/A interface of heterojunction organic solar cells (OSCs), using Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence (PL) spectroscopy in combination with first-principles and semi-empirical calculations. The FT-IR and XRD results indicated that Zn(OEP) and C60 were mixed with each other at the molecular level in the co-deposited film. The theoretical calculations suggested that in the interfacial region, it is energetically preferable for the C60 molecule to face the center of the planar structure of Zn(OEP) at a distance of 2.8 Å rather than the edge of the structure at a distance of 5.0 Å. After consideration of the C60 solvent effects, this coordination model for C60-Zn(OEP) adequately explained the line shift of the UV-vis peaks with respect to the proportion of C60 in the co-deposited films. A comparison of the energy level diagrams of Zn(OEP) before and after the interaction with C60 revealed that the LUMO, HOMO, and HOMO-1 were significantly affected by the interaction with C60. In particular, the HOMO-1 wave function became spread over a portion of C60, although the charge transfer between Zn(OEP) and C60 was almost negligible. Since no PL peaks (S1 → S0) from the excited Soret band of Zn(OEP) were observed for the Zn(OEP)/C60 co-deposited films, the D/A mixing layers played a crucial role in completely dissolving the photogenerated excitons to electrons-hole pairs that cause the short-circuit current, which is relevant to improving the energy conversion efficiency of OSCs.

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

    Science.gov (United States)

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

    2015-12-01

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

  10. C60fullerene as promising therapeutic agent for correcting and preventing skeletal muscle fatigue.

    Science.gov (United States)

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

    2017-01-13

    Bioactive soluble carbon nanostructures, such as the C 60 fullerene can bond with up to six electrons, thus serving by a powerful scavenger of reactive oxygen species similarly to many natural antioxidants, widely used to decrease the muscle fatigue effects. The aim of the study is to define action of the pristine C 60 fullerene aqueous colloid solution (C 60 FAS), on the post-fatigue recovering of m. triceps surae in anaesthetized rats. During fatigue development, we observed decrease in the muscle effort level before C 60 FAS administration. After the application of C 60 FAS, a slower effort decrease, followed by the prolonged retention of a certain level, was recorded. An analysis of the metabolic process changes accompanying muscle fatigue showed an increase in the oxidative stress markers H 2 O 2 (hydrogen peroxide) and TBARS (thiobarbituric acid reactive substances) in relation to the intact muscles. After C 60 FAS administration, the TBARS content and H 2 O 2 level were decreased. The endogenous antioxidant system demonstrated a similar effect because the GSH (reduced glutathione) in the muscles and the CAT (catalase) enzyme activity were increased during fatigue. C 60 FAS leads to reduction in the recovery time of the muscle contraction force and to increase in the time of active muscle functioning before appearance of steady fatigue effects. Therefore, it is possible that C 60 FAS affects the prooxidant-antioxidant muscle tissue homeostasis, subsequently increasing muscle endurance.

  11. Comparative photoactivity and antibacterial properties of C60 fullerenes and titanium dioxide nanoparticles.

    Science.gov (United States)

    Brunet, Léna; Lyon, Delina Y; Hotze, Ernest M; Alvarez, Pedro J J; Wiesner, Mark R

    2009-06-15

    The production of reactive oxygen species (ROS) by aqueous suspensions of fullerenes and nano-TiO2 (Degussa P25) was measured both in ultrapure water and in minimal Davis (MD) microbial growth medium. Fullerol (hydroxylated C60) produced singlet oxygen (1O2) in ultrapure water and both 1O2 and superoxide (O2-*) in MD medium, but no hydroxyl radicals (OH*) were detected in either case. PVP/C60 (C60 encapsulated with poly(N-vinylpyrrolidone)) was more efficient than fullerol in generating singlet oxygen and superoxide. However, two other aggregates of C60, namely THF/nC60 (prepared with tetrahydofuran as transitional solvent) and aqu/nC60 (prepared by vigorous stirring of C60 powder in water), were not photoactive. Nano-TiO2 (also present as aggregates) primarily produced hydroxyl radicals in pure water and superoxide in MD medium. Bacterial (Escherichia coli) toxicity tests suggest that, unlike nano-TiO2 which was exclusively phototoxic, the antibacterial activity of fullerene suspensions was linked to ROS production. Nano-TiO2 may be more efficient for water treatment involving UV or solar energy, to enhance contaminant oxidation and perhaps for disinfection. However, fullerol and PVP/ C60 may be useful as water treatment agents targeting specific pollutants or microorganisms that are more sensitive to either superoxide or singlet oxygen.

  12. Contributions of different degrees of freedom to thermal transport in the C60 molecular crystal

    Science.gov (United States)

    Kumar, Sushant; Shao, Cheng; Lu, Simon; McGaughey, Alan J. H.

    2018-03-01

    Three models of the C60 molecular crystal are studied using molecular dynamics simulations to resolve the roles played by intermolecular and intramolecular degrees of freedom (DOF) in its structural, mechanical, and thermal properties at temperatures between 35 and 400 K. In the full DOF model, all DOF are active. In the rigid body model, the intramolecular DOF are frozen, such that only center of mass (COM) translations and molecular rotations/librations are active. In the point mass model, the molecule is replaced by a point mass, such that only COM translations are active. The zero-pressure lattice constants and bulk moduli predicted from the three models fall within ranges of 0.15 and 20%. The thermal conductivity of the point mass model is the largest across the temperature range, showing a crystal-like temperature dependence (i.e., it decreases with increasing temperature) due to the presence of phonon modes associated with the COM translations. The rigid body model thermal conductivity is the smallest and follows two distinct regimes. It is crystal-like at low temperatures and becomes temperature invariant at high temperatures. The latter is typical of the behavior of an amorphous material. By calculating the rotational diffusion coefficient, the transition between the two regimes is found to occur at the temperature where the molecules begin to rotate freely. Above this temperature, phonons related to COM translations are scattered by the rotational DOF. The full DOF model thermal conductivity is larger than that of the rigid body model, indicating that intramolecular DOF contribute to thermal transport.

  13. Exploring Chemical Space with Alchemical Derivatives: BN-Simultaneous Substitution Patterns in C60.

    Science.gov (United States)

    Balawender, Robert; Lesiuk, Michał; De Proft, Frank; Geerlings, Paul

    2018-02-13

    With the idea of using alchemical derivatives to explore in an efficient, computer- and cost-effective way Chemical Space was launched several years ago. In the context of Conceptual DFT response functions, these energies vs nuclear charge derivatives permit the estimatation of the energy of transmutants of a given starting or reference molecule showing different nuclear compositions. After an explorative study on small and planar molecules ( Balawender et al. J. Chem. Theory Comput. 2013 , 9 , 5327 ) by the present authors of this paper, the present study fully exploits the computational advantages of the alchemical derivatives in larger three-dimensional systems. Starting from a single reference calculation on C 60 , the complete BN substitution pattern, from single substituted C 58 BN via the belt (C 20 (BN) 20 and the ball C 12 (BN) 24 structures to the fully substituted (BN) 30 , is explored. Successive and simultaneous substitution strategies are followed and compared, indicating that both techniques yield identical results up to 13 substitutions but that for higher substitutions the simultaneous approach needs to be taken. Due to the cost-efficiency of the algorithm this path can indeed be followed as opposed to earlier work in the literature where for each step a full SCF calculation was at stake leading to prohibitively large computational demands for adopting the simultaneous approach. Previously formulated rules governing the substitution pattern by Kar and co-workers are scrutinized in this context and reformulated giving chemical insight in the gradual substitution process and the relative energies of the isomers. In its present form the method offers an interesting venue to study BN substitution patterns in higher fullerenes and graphene and in general paves the way for more efficient exploration of the Chemical Space.

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

    Science.gov (United States)

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

    2016-09-01

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

  15. Synthesis and microstructure characterization of the Ni/C60 composite materials

    International Nuclear Information System (INIS)

    Vacik, J.; Havranek, V.; Subrt, J.; Bakardjieva, S.; Naramoto, H.; Narumi, K.

    2006-01-01

    Structural variability of the Ni/C 60 thin film composites was observed after ion irradiation and/or thermal annealing. Annealing of the irradiated Ni/C 60 /Ni multilayers led to micrometer-large rod-type particles, annealing of the non-irradiated specimens resulted in truncated rectangular footprints. Micrometer-large spherical or dodecahedral Ni droplets were synthesized by annealing of the non-irradiated Ni+C 60 mixtures. The structural variation of the Ni/C 60 systems points out the complex physiochemical processes incited by elevated temperatures. First insight on the microstructural evolution of the Ni/C 60 composites after ion irradiation and/or thermal annealing is presented in this paper (Authors)

  16. Synthesis and enhanced neuroprotective activity of C60-based ebselen derivatives

    International Nuclear Information System (INIS)

    Liu, X.-F.; Guan, W.-C.; Ke, W.-S.

    2007-01-01

    A C 60 -based ebselen derivative 4 was synthesized through the cycloaddition of C 60 with the azide (3) containing the ebselen component. It was obtained in a four-step synthesis starting from 2-(chloroseleno)benzoyl chloride and 2-(2-aminoethoxy)ethanol in 53% yield (based on consumed C 60 ). Its structure was characterized by 1 H NMR, 13 C NMR, IR, UV, and FAB-MS. To verify that the C 60 -based ebselen derivative 4 had enhanced antioxidative and neuroprotective activity, the C 60 derivative 5 and the ebselen derivative 6 were selected to treat cortical neuronal cells using the same procedures as with the C 60 -based ebselen derivative 4. The cellular viability of different derivative treatment groups was estimated by LDH leakage assay and MTT assay. At the same final concentration (30 μmol/L), the results showed that the antioxidative and protective potencies of the C 60 -based ebselen derivative 4 (MTT (OD) 0.340 ± 0.035, LDH release (UL -1 ) 4.80 ± 0.16) against H 2 O 2 -mediated neuronal injury have an advantage over those of C 60 derivative 5 (MTT (OD) 0.297 ± 0.036, LDH release (UL -1 ) 5.37 ± 0.31) and ebselen derivative 6 (MTT (OD) 0.267 ± 0.027, LDH release (UL -1 ) 5.85 ± 0.26). Correspondingly, the GPX activity of 4 (1.62 U/μmol) was higher than that of 5 (0.77 U/μmol) and 6 (1.24 U/μmol). These findings demonstrate that the incorporation of two components with similar biological activity (C 60 component and ebselen component) may be a desirable way of obtaining a new and more biologically effective C 60 -based compound. (author)

  17. The Dynamics and Structures of Adsorbed Surfaces

    DEFF Research Database (Denmark)

    Nielsen, M; Ellenson, W. D.; McTague, J. P.

    1978-01-01

    Reviews neutron scattering work performed on films of simple gas atoms and molecules adsorbed primarily on graphite surfaces. Exfoliated graphite substrates such as Grafoil were first used in this kind of measurements about five years ago and new results have been reported at an increasing pace....... Elastic neutron diffraction measurements, determining the two-dimensional structural ordering of the adsorbed films, have been performed on layers of N2, Ar, H2, D2, O2, Kr, and He. Measurements on layers of larger molecules such as CD4 and ND3 have also been reported. Inelastic neutron scattering...... of molecules such as NH3 or the internal modes of adsorbed molecules such as C4H10. Neutron scattering measurements where substrates other than graphite products are used as the adsorbents will not be reviewed here. However, the power of the technique will be demonstrated in an example of H2 physisorbed...

  18. Effect of pressure on the structure and lattice dynamics of fullerene crystal C60

    International Nuclear Information System (INIS)

    Prilutski, Yu.I.; Shapovalov, G.G.

    1997-01-01

    The low-temperature orientationally ordered crystalline phase of fullerene C 60 was investigated in dependence on the external pressure. An assumption was made that the energy of the lattice includes two contributions: a Lennard-Jones (12-6) potential and electrostatic interaction. The vibrational spectrum of C 60 crystal was calculated using the atom-atom potential method. The frequencies of intermolecular modes as functions of external pressure were studied. The sound velocities, elastic constants and bulk modulus are calculated. The dependence of sound velocities in fullerene crystal C 60 on the external pressure is investigated. The results obtained are in good agreement with the available experimental data. (orig.)

  19. Exciton-Dissociation and Charge-Recombination Processes in Pentacene/C 60 Solar Cells: Theoretical Insight into the Impact of Interface Geometry

    KAUST Repository

    Yi, Yuanping

    2009-11-04

    The exciton-dissociation and charge-recombination processes in organic solar cells based on pentacene/C60 heterojunctions are investigated by means of quantum-mechanical calculations. The electronic couplings and the rates of exciton dissociation and charge recombination have been evaluated for several geometrical configurations of the pentacene/C60 complex, which are relevant to bilayer and bulk heterojunctions. The results suggest that, irrespective of the actual pentacene-fullerene orientation, both pentacene-based and C60-based excitons are able to dissociate efficiently. Also, in the case of parallel configurations of the molecules at the pentacene/C60 interface, the decay of the lowest charge-transfer state to the ground state is calculated to be very fast; as a result, it can compete with the dissociation process into mobile charge carriers. Since parallel configurations are expected to be found more frequently in bulk heterojunctions than in bilayer heterojunctions, the performance of pentacene/C60 bulk-heterojunction solar cells is likely to be more affected by charge recombination than that of bilayer devices. © 2009 American Chemical Society.

  20. Attosecond time delay in the valence photoionization of C240 versus C60

    International Nuclear Information System (INIS)

    Shi, Kele; Magrakvelidze, Maia; Anstine, Dylan; Chakraborty, Himadri; Madjet, Mohamed

    2015-01-01

    We investigate effects of electron correlations on the attosecond time delay of the photoionization from HOMO and HOMO-1 electrons in C 240 . A comparison with earlier C 60 results assesses the molecular size effect. (paper)

  1. Structure and properties of poly(methyl methacrylate) (PMMA)-fullerene (C60) nanocomposites

    Science.gov (United States)

    Kropka, Jamie; Green, Peter

    2006-03-01

    We examined the rheological and dynamical mechanical (DMA) properties of PMMA-C60 nanocomposite materials with relatively low concentrations of C60, 0.1-5wt%. Decreases of the glass transition temperature (Tg), ˜7 ^oC, were observed in samples with 0.5 and 1 wt% C60. The decreases in Tg are connected to decreases of the longest relaxation time measured for the system. The plateau modulus of the composites was enhanced relative to the homopolymer but did not increase monotonically with C60 concentration. The relative changes of the relaxation time, the plateau modulus and Tg cannot be explained by the Doi-Edwards model and appear to be connected to the distribution of the nanoparticles, as determined by electron microscopy.

  2. Design of Spin-Frustrated Monomer-Type C60•− Mott Insulator

    Directory of Open Access Journals (Sweden)

    Akihiro Otsuka

    2018-02-01

    Full Text Available Spin-frustrated monomer-type Mott insulator C60•− solids are discussed in this review article. For the C60•− solids, the interfullerene center-to-center distance (r is the key parameter that controls the competition between covalent bond-formation, itinerancy, and spin frustration. Eight C60•− salts with various compositions and dimensionalities are reviewed. In all of these C60•− salts except one, neither bond-formation nor long-range magnetic ordering was observed down to low temperatures. A plot of Weiss temperature (|ΘCW| against r shows that |ΘCW| grows rapidly below r = 10.0 Å.

  3. Density Functional Theory Study of the Interaction of Hydrogen with Li6C60.

    Science.gov (United States)

    Wang, Qian; Jena, Puru

    2012-05-03

    Hydrogen storage properties of Li-coated C60 fullerene have been studied using density functional theory within the local density as well as generalized gradient approximation. Hydrogen atoms are found to bind to Li6C60 in two distinct forms, with the first set attaching to C atoms, not linked to Li, in atomic form. Once all such C atoms are saturated with hydrogen, the second set of hydrogen atoms bind quasi-molecularly to the Li atoms, five of which remain in the exohedral and the sixth in the endohedral position. The corresponding hydrogen gravimetric density in Li6C60H40 is 5 wt %. Desorption of hydrogen takes place in succession, the ones bound quasi-molecularly desorbing at a temperature lower than the ones bound atomically. The results are compared with the recent experiment on hydrogen adsorption in Li6C60.

  4. The C60(FeCp22-Based Cell Proliferation Accelerator

    Directory of Open Access Journals (Sweden)

    Andrei Soldatov

    2013-01-01

    Full Text Available We studied structural and magnetic proprieties of the fulleride C60(FeCp22. The influence of fulleride particles on the cell proliferative activity was also investigated. We found that the proliferative activity of the RINmF5 cells increases (53% versus control in presence of the C60(FeCp22 nanosized particles. Moreover, it was registered that the cell culture became multilayered and secreted basophile matrix.

  5. Computational designing ultra-sensitive nano-composite based on boron doped and CuO decorated graphene to adsorb H2S and CO gaseous molecules

    Science.gov (United States)

    Asadi, Hamed; Vaezzadeh, Majid

    2017-07-01

    In this paper, interactions of carbon monoxide (CO) and hydrogen sulfide (H2S) with doped and decorated graphene were investigated by using density functional theory and quantum-espresso packages. First of all, impurity effects and properties like adsorption mechanism, the more probable position, binding energy, bond length, Lowdin charge analyze and density of state (DOS) have been determined and then the properties of CO and H2S adsorption calculated, and a brief comparison with other studies has been done. All of these lead to tuning the electronic structure of graphene sheet with impurities that show higher affinities with H2S and CO molecules in comparison to pristine graphene. The obtained results from DOS and charge transfer show that electrical conductance of the B doped graphene sheet and CuO Nano particle decorated—Boron doped graphene sheets are significantly changed compared to the pristine graphene sheet by an increase in the electronic states of near the Fermi’s energy states.

  6. Exploration and characterization of new synthesis methods for C60 colloidal suspensions in water

    Science.gov (United States)

    Hilburn, Martha E.

    Buckminsterfullerene, C60, has been used in the production of several commercial products from badminton racquets and lubricants for their mechanical properties to cosmetics and even dietary supplements for their "antioxidant" properties. Multi-ton production of C60 began in 2003 encouraging serious consideration of its fate in the environment in the case of an accidental release or improper disposal. Although C60 is practically insoluble in water, it readily forms stable aqueous colloidal suspensions (termed nC60) through solvent exchange methods or long-term vigorous stirring in water. Two new solvent exchange methods for synthesizing nC60 are presented. These methods combine key advantages of multiple existing synthesis methods including high yield, narrow particle size distribution, short synthesis time, and an absence of solvents such as tetrahydrofuran that have historically caused problems in laboratory synthesized aggregates. The resulting samples are attractive candidates for use in controlled environmental impact, biological, and toxicity studies. An improved method for quantifying residual solvents in nC60 samples utilizing solid phase micro extraction gas chromatography mass spectrometry (SPME-GC-MS) is also discussed.

  7. Low-frequency excitations of C60 chains inserted inside single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Cambedouzou, J.; Rols, S.; Almairac, R.; Sauvajol, J.-L.; Kataura, H.; Schober, H.

    2005-01-01

    The low-frequency excitations of C 60 chains inserted inside single-walled carbon nanotubes (SWNTs) have been studied by inelastic neutron scattering on a high-quality sample of peapods. The comparison of the neutron-derived generalized phonon density of states (GDOS) of the peapods sample with that of raw SWNTs allows the vibrational properties of the C 60 chains encapsulated in the hollow core of the SWNTs to be probed. Lattice dynamical models are used to calculate the GDOS of chains of monomers, dimers, and polymers inserted into SWNTs, which are compared to the experimental data. The presence of strong interactions between C 60 cages inside the nanotube is clearly demonstrated by an excess of mode density in the frequency range around 10 meV. However, the presence of a quasielastic signal indicates that some of the C 60 's undergo rotational motion. This suggests that peapods are made from a mixture of C 60 monomers and C 60 n-mer (dimer, trimer, ..., polymer) structures

  8. Transmission properties of C60 ions through micro- and nano-capillaries

    International Nuclear Information System (INIS)

    Tsuchida, Hidetsugu; Majima, Takuya; Tomita, Shigeo; Sasa, Kimikazu; Narumi, Kazumasa; Saitoh, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Hirata, Koichi; Shibata, Hiromi; Itoh, Akio

    2013-01-01

    We apply the capillary beam-focusing method for the C 60 fullerene projectiles in the velocity range between 0.14 and 0.2 a.u. We study the C 60 transmission properties through two different types of capillaries: (1) borosilicate glass microcapillary with an outlet diameter of 5.5 μm, and (2) Al 2 O 3 multi-capillary foil with a pore size of about 70 nm and a high aspect ratio of about 750. We measured the transmitted particle composition by using the electrostatic deflection method combined with the microchannel plate imaging technique. For the experiments with the single microcapillary, the main transmission component is found to be primary C 60 beams that are focused in the area equal to the capillary outlet diameter. Minor components are charge-exchanged C 60 ions and charged or neutral fragments (fullerene-like C 60-2m and small C n particles), and their fractions decrease with decreasing the projectile velocity. It is concluded that the C 60 transmission fraction is considerably high for both types of the capillaries in the present velocity range

  9. Development and Characterization of Biocompatible Fullerene [C60]/Amphiphilic Block Copolymer Nanocomposite

    Directory of Open Access Journals (Sweden)

    Alok Chaurasia

    2015-01-01

    Full Text Available We report a supramolecular process for the synthesis of well-defined fullerene (C60/polymer colloid nanocomposites in an aqueous solution via complex formation. A biocompatible triblock poly(4-vinylpyridine-b-polyethylene-b-poly(4-vinylpyridine, P4VP8-b-PEO105-b-P4VP8, was synthesized by atom transfer radical polymerization. The block copolymer formed complexes with C60 in toluene and resulted in fullerene assembly in cluster form. Nanocomposite dispersion in an aqueous solution could be obtained using an aged solution of the polymer/C60/toluene solution by a solvent evaporation technique. The UV-Vis and FTIR spectroscopy confirmed the complex formation of fullerene with the polymer which plays a significant role in controlling the PDI and size of polymer/C60 micelles in the toluene solution. The particle size and morphology of P4VP8-b-PEO105-b-P4VP8 and P4VP8-b-PEO105-b-P4VP8/C60 mixture were studied by dynamic light scattering (DLS and transmission electron microscopy (TEM. In a cytotoxicity test, both pure polymer and the resulting polymer/C60 composite in water showed more than 90% cell viability at 1 mg/mL concentration.

  10. Numerical investigation on the field emission properties of N-doped graphdiyne-C60 nanostructures

    Directory of Open Access Journals (Sweden)

    Xuanjun Dai

    2018-01-01

    Full Text Available A new N-doped graphdiyne-C60 nanostructure was constructed to explore the electronic structure and field emission characteristics. Using density functional theory (DFT, the geometric configuration is optimized and then the corresponding energy of this nanostructure was calculated by considering N-doping. The field emission mechanism has been analyzed through energy gaps change between the highest occupied molecular orbital (HOMO and the lowest unoccupied molecular orbital (LUMO, local electron density distribution, and mulliken population analysis. Owing to the doping of nitrogen atom, the local electron states is generated, and increased at the Fermi level dramatically. The results show that the N-doped graphdiyne-C60 compound has stable structure and excellent semiconducting properties. The calculated work function (WF and ionization potential (IP of N-doped graphdiyne-C60 nanostructure decrease significantly when compared with pristine graphdiyne-C60 composite. The field emission properties of graphdiyne-C60 can be boosted by the doping nitrogen atom, which provides a potential application for N-doped graphdiyne-C60 nanostructures as a field emission cathode in field emission devices.

  11. C60-based ebselen derivative: synthesis by bingel cyclopropanation and enhanced antioxidative and neuroprotective activity

    International Nuclear Information System (INIS)

    Xufeng Liu; Wenchao Guan; Wengshan Ke

    2007-01-01

    C 60 -based ebselen derivative 3 was synthesized through Bingel cyclopropanation of C 60 with the ebselen malonate 2. Compound 3 was obtained in 42% yield (based on consumed C 60 ) in a three-step synthesis starting from 2-(chloroseleno)benzoyl chloride and 2-(2aminoethoxy)ethanol. Its structure was confirmed by 1H NMR, 13 C NMR, IR, UV and FAB-MS spectroscopy analyses. In order to verify the enhanced antioxidative and neuroprotective activity of 3, a C 60 derivative (4), an ebselen derivative (2), and their mixture (4 plus 2 in equimolar ratio) were employed to treat cortical neuronal cells, following the same procedure used with 3 and at the same final concentration (30 μmol L -1 ). Cell viabilities of the four treated groups were estimated by LDH (lactic dehydrogenase) leakage and MTT (3-(4, 5-dimethylthiazole-2yl)-2,5-diphenyl-tetrazolium bromide) assays. Results showed that the antioxidative and protective activities of C 60 -based ebselen derivative 3 against H 2 O 2 -mediated neuronal injury (MTT(OD) 0.364 ± 0.028; LDH release (UL -1 ) 4.66 ± 0.28) were significantly higher than those of C 6 )0 derivative 4 (MTT(OD) 0.324 ± 0.025; LDH release (UL -1 ) 5.39 ± 0.17), ebselen derivative 2 (MTT(OD) 0.294 ± 0.021; LDH release (UL -1 ) 5.71 ± 0.27), and the mixture of 4 and 2 (MTT(OD) 0.310 ± 0.018; LDH release (UL -1 ) 5.54 ±0.39). These findings demonstrated that the combination of two molecular units with similar biological activities (C 60 and ebselen) may be a desirable way of obtaining new and more biologically effective C 60 -based compounds. (author)

  12. Orthorhombic fulleride (CH3NH2)K3C60 close to Mott-Hubbard instability: Ab initio study

    Science.gov (United States)

    Potočnik, Anton; Manini, Nicola; Komelj, Matej; Tosatti, Erio; Arčon, Denis

    2012-08-01

    We study the electronic structure and magnetic interactions in methylamine-intercalated orthorhombic alkali-doped fullerene (CH3NH2)K3C60 within the density functional theory. As in the simpler ammonia intercalated compound (NH3)K3C60, the orthorhombic crystal-field anisotropy Δ lifts the t1u triple degeneracy at the Γ point and drives the system deep into the Mott-insulating phase. However, the computed Δ and conduction electron bandwidth W cannot alone account for the abnormally low experimental Néel temperature, TN=11 K, of the methylamine compound, compared to the much higher value TN=40 K of the ammonia one. Significant interactions between CH3NH2 and C603- are responsible for the stabilization of particular fullerene-cage distortions and the ensuing low-spin S=1/2 state. These interactions also seem to affect the magnetic properties, as interfullerene exchange interactions depend on the relative orientation of deformations of neighboring C603- molecules. For the ferro-orientational order of CH3NH2-K+ groups we find an apparent reduced dimensionality in magnetic exchange interactions, which may explain the suppressed Néel temperature. The disorder in exchange interactions caused by orientational disorder of CH3NH2-K+ groups could further contribute to this suppression.

  13. Giant plasmon excitation in single and double ionization of C60 by fast highly charged Si and O ions

    Science.gov (United States)

    Kelkar, A. H.; Kadhane, U.; Misra, D.; Tribedi, L. C.

    2007-09-01

    Se have investigated single and double ionization of C60 molecule in collisions with 2.33 MeV/u Siq+ (q=6-14) and 3.125 MeV/u Oq+ (q=5-8) projectiles. The projectile charge state dependence of the single and double ionization yields of C60 are then compared to those for an ion-atom collision system using Ne gas as a target. A large difference between the gas and the cluster target behaviour was partially explained in terms of a model based on collective excitation namely the giant dipole plasmon resonance (GDPR). The qualitative agreement between the data and GDPR model prediction for single and double ionization signifies the importance of single and double plasmon excitations in the ionization process. A large deviation of the GDPR model for triple and quadruple ionization from the experimental data imply the importance of the other low impact parameter processes such as evaporation, fragmentation and a possible solid-like dynamical screening.

  14. Giant plasmon excitation in single and double ionization of C60 by fast highly charged Si and O ions

    International Nuclear Information System (INIS)

    Kelkar, A H; Kadhane, U; Misra, D; Tribedi, L C

    2007-01-01

    Se have investigated single and double ionization of C 60 molecule in collisions with 2.33 MeV/u Si q+ (q=6-14) and 3.125 MeV/u O q+ (q=5-8) projectiles. The projectile charge state dependence of the single and double ionization yields of C 60 are then compared to those for an ion-atom collision system using Ne gas as a target. A large difference between the gas and the cluster target behaviour was partially explained in terms of a model based on collective excitation namely the giant dipole plasmon resonance (GDPR). The qualitative agreement between the data and GDPR model prediction for single and double ionization signifies the importance of single and double plasmon excitations in the ionization process. A large deviation of the GDPR model for triple and quadruple ionization from the experimental data imply the importance of the other low impact parameter processes such as evaporation, fragmentation and a possible solid-like dynamical screening

  15. Depth profiling using C60+ SIMS-Deposition and topography development during bombardment of silicon

    International Nuclear Information System (INIS)

    Gillen, Greg; Batteas, James; Michaels, Chris A.; Chi, Peter; Small, John; Windsor, Eric; Fahey, Albert; Verkouteren, Jennifer; Kim, K.J.

    2006-01-01

    A C 60 + primary ion source has been coupled to an ion microscope secondary ion mass spectrometry (SIMS) instrument to examine sputtering of silicon with an emphasis on possible application of C 60 + depth profiling for high depth resolution SIMS analysis of silicon semiconductor materials. Unexpectedly, C 60 + SIMS depth profiling of silicon was found to be complicated by the deposition of an amorphous carbon layer which buries the silicon substrate. Sputtering of the silicon was observed only at the highest accessible beam energies (14.5 keV impact) or by using oxygen backfilling. C 60 + SIMS depth profiling of As delta-doped test samples at 14.5 keV demonstrated a substantial (factor of 5) degradation in depth resolution compared to Cs + SIMS depth profiling. This degradation is thought to result from the formation of an unusual platelet-like grain structure on the SIMS crater bottoms. Other unusual topographical features were also observed on silicon substrates after high primary ion dose C 60 + bombardment

  16. Self-Cleaning Photocatalytic Polyurethane Coatings Containing Modified C60 Fullerene Additives

    Directory of Open Access Journals (Sweden)

    Jeffrey G. Lundin

    2014-08-01

    Full Text Available Surfaces are often coated with paint for improved aesthetics and protection; however, additional functionalities that impart continuous self-decontaminating and self-cleaning properties would be extremely advantageous. In this report, photochemical additives based on C60 fullerene were incorporated into polyurethane coatings to investigate their coating compatibility and ability to impart chemical decontaminating capability to the coating surface. C60 exhibits unique photophysical properties, including the capability to generate singlet oxygen upon exposure to visible light; however, C60 fullerene exhibits poor solubility in solvents commonly employed in coating applications. A modified C60 containing a hydrophilic moiety was synthesized to improve polyurethane compatibility and facilitate segregation to the polymer–air interface. Bulk properties of the polyurethane films were analyzed to investigate additive–coating compatibility. Coatings containing photoactive additives were subjected to self-decontamination challenges against representative chemical contaminants and the effects of additive loading concentration, light exposure, and time on chemical decontamination are reported. Covalent attachment of an ethylene glycol tail to C60 improved its solubility and dispersion in a hydrophobic polyurethane matrix. Decomposition products resulting from oxidation were observed in addition to a direct correlation between additive loading concentration and decomposition of surface-residing contaminants. The degradation pathways deduced from contaminant challenge byproduct analyses are detailed.

  17. Effects of carboxylic acids on nC60 aggregate formation

    International Nuclear Information System (INIS)

    Chang Xiaojun; Vikesland, Peter J.

    2009-01-01

    The discovery that negatively charged aggregates of C 60 fullerene (nC 60 ) are stable in water has raised concerns regarding the potential environmental and health effects of these aggregates. In this work, we show that nC 60 aggregates produced by extended mixing in the presence of environmentally relevant carboxylic acids (acetic acid, tartaric acid, citric acid) have surface charge and morphologic properties that differ from those produced by extended mixing in water alone. In general, aggregates formed in the presence of these acids have a more negative surface charge and are more homogeneous than those produced in water alone. Carboxylic acid identity, solution pH, and sodium ion concentration, which are all intricately coupled, play an important role in setting the measured surface charge. Comparisons between particle sizes determined by analysis of TEM images and those obtained by dynamic light scattering (DLS) indicate that DLS results require careful evaluation when used to describe nC 60 aggregates. - The effects of carboxylic acids on the formation of nC 60 aggregates are discussed

  18. First Production of C60 Nanoparticle Plasma Jet for Study of Disruption Mitigation for ITER

    Science.gov (United States)

    Bogatu, I. N.; Thompson, J. R.; Galkin, S. A.; Kim, J. S.; Brockington, S.; Case, A.; Messer, S. J.; Witherspoon, F. D.

    2012-10-01

    Unique fast response and large mass-velocity delivery of nanoparticle plasma jets (NPPJs) provide a novel application for ITER disruption mitigation, runaway electrons diagnostics and deep fueling. NPPJs carry a much larger mass than usual gases. An electromagnetic plasma gun provides a very high injection velocity (many km/s). NPPJ has much higher ram pressure than any standard gas injection method and penetrates the tokamak confining magnetic field. Assimilation is enhanced due to the NP large surface-to-volume ratio. Radially expanding NPPJs help achieving toroidal uniformity of radiation power. FAR-TECH's NPPJ system was successfully tested: a coaxial plasma gun prototype (˜35 cm length, 96 kJ energy) using a solid state TiH2/C60 pulsed power cartridge injector produced a hyper-velocity (>4 km/s), high-density (>10^23 m-3), C60 plasma jet in ˜0.5 ms, with ˜1-2 ms overall response-delivery time. We present the TiH2/C60 cartridge injector output characterization (˜180 mg of sublimated C60 gas) and first production results of a high momentum C60 plasma jet (˜0.6 g.km/s).

  19. The effect of gate voltage on the electrical transport properties in the contacts of C60 to carbon nanotube leads

    Directory of Open Access Journals (Sweden)

    AA Shokri

    2012-06-01

    Full Text Available  In this paper, we examined the effect of gate voltage, bias voltage, contact geometries and the different bond lengths on the electrical transport properties in a nanostructure consisting of C60 molecule attached to two semi-infinite leads made of single wall carbon nanotubes in the coherent regime. Our calculation was based on the Green’s function method within nearest-neighbour tight-binding approximation. After the calculation was of transmission, the electrical current was obtained by the Landauer-Buttiker formula. Next, the effect of the mentioned factors was investigated in the nanostructure. The application of the present results may be useful in designing devices based on molecular electronics in nanoscale.

  20. Graphene oxide-Li(+)@C60 donor-acceptor composites for photoenergy conversion.

    Science.gov (United States)

    Supur, Mustafa; Kawashima, Yuki; Ohkubo, Kei; Sakai, Hayato; Hasobe, Taku; Fukuzumi, Shunichi

    2015-06-28

    An ionic endohedral metallofullerene (Li(+)@C60) with mild hydrophilic nature was combined with graphene oxide (GO) to construct a donor-acceptor composite in neat water. The resulting composite was characterised by UV-Vis and Raman spectroscopy, powder X-ray diffraction, dynamic light scattering measurements and transmission electron microscopy. Theoretical calculations (DFT at the B3LYP/6-31(d) level) were also utilized to gain further insight into the composite formation. As detected by electron paramagnetic resonance spectroscopy, photoexcitation of the GO-Li(+)@C60 composite results in electron transfer from GO to the triplet excited state of Li(+)@C60, leading to photocurrent generation at the OTE/SnO2 electrode.

  1. Substrate effects on the analysis of biomolecular layers using Au+, Au3+ and C60+ bombardments

    International Nuclear Information System (INIS)

    Kordys, Jeanette; Fletcher, John S.; Lockyer, Nicholas P.; Vickerman, John C.

    2008-01-01

    Effects of platinum silicon, graphite and PET substrates on the secondary ion yield of sub-monolayer and multilayer samples of Cyclosporin A following 20 keV Au + , Au 3 + and C 60 + impacts have been investigated. The obtained results of sub-monolayer samples show that platinum enhances the yield of the pseudo-molecular ion following Au + and Au 3 + impacts due to the high density of the substrate that enables the energy of the primary ions to be deposited near the surface. C 60 + impacts on sub-monolayer samples are less effective, but there is an enhancement on PET substrates. Impacts of 20 keV Au + and Au 3 + are not very efficient on multilayer samples. 20 keV C 60 + impacts enhance the yields significantly, especially for the relatively high molecular weight [M+H] + ion.

  2. Reproducibility and stability of C60 based organic field effect transistor

    Science.gov (United States)

    Ahmed, Rizwan; Sams, Michael; Simbrunner, Clemens; Ullah, Mujeeb; Rehman, Kamila; Schwabegger, Günther; Sitter, H.; Ostermann, Timm

    2012-01-01

    A comprehensive study concerning the reproducibility and stability of organic n-type field effect transistors is presented. C60 based OFETs were chosen to investigate the fabrication reproducibility and the long term stability because C60 is a high mobility n-type material. We fabricated 48 transistors and each transistor was measured for 24 h inside the glove box. To test for life time stability – long term measurements up to three months have been undertaken. We report about the fluctuations in the device parameters of all investigated transistors by comparing the transfer characteristics, and on/off ratio for short time and long time measurements. C60 based OFETs showed good reproducibility and stability for short time measurements and a decay for long time measurements. PMID:22368321

  3. Single and multiple addition to C60. A computational chemistry study

    OpenAIRE

    Cases Amat, Montserrat

    2003-01-01

    Des del seu descobriment, a la molècula C60 se li coneixen una varietat de derivats segons el tipus de funcionalització amb propietats fisicoquímiques específiques de gran interès científic. Una sel·lecció de derivats corresponents a addicions simple o múltiple al C60 s'ha considerat en aquest treball d'investigació. L'estudi a nivell de química computacional de diversos tipus d'addició al C60 s'han portat a terme per tal de poder donar resposta a aspectes que experimentalment no s'entenen o ...

  4. Nonequilibrium electron-vibration coupling and conductance fluctuations in a C60 junction

    DEFF Research Database (Denmark)

    Ulstrup, Søren; Frederiksen, Thomas; Brandbyge, Mads

    2012-01-01

    displacement. Combined with a vibrational heating mechanism we construct a model from our results that explain the polarity-dependent two-level conductance fluctuations observed in recent scanning tunneling microscopy (STM) experiments [N. Ne´el et al., Nano Lett. 11, 3593 (2011)]. These findings highlight......We investigate chemical bond formation and conductance in a molecular C60 junction under finite bias voltage using first-principles calculations based on density functional theory and nonequilibrium Green's functions (DFT-NEGF). At the point of contact formation we identify a remarkably strong...... coupling between the C60 motion and the molecular electronic structure. This is only seen for positive sample bias, although the conductance itself is not strongly polarity dependent. The nonequilibrium effect is traced back to a sudden shift in the position of the voltage drop with a small C60...

  5. Water-soluble C60 fullerenes reduce manifestations of acute cholangitis in rats

    Science.gov (United States)

    Kuznietsova, H. M.; Lynchak, O. V.; Dziubenko, N. V.; Osetskyi, V. L.; Ogloblya, O. V.; Prylutskyy, Yu I.; Rybalchenko, V. K.; Ritter, U.; Scharff, P.

    2018-03-01

    Sclerosing cholangitis is the liver disease of uncertain etiology, extremely unfavorable prognosis and lack of effective medication therapy. Therefore, the effect of water-soluble biocompatible C60 fullerenes (C60FAS) on the liver functional state on rat acute-cholangitis model was aimed to be discovered. Acute cholangitis was simulated by single α-naphthyl isothiocyanate (ANIT, 100 mg/kg) per os administration; C60FAS (0.5 mg/kg) was administered either per os or intraperitoneally in 24 and 48 h after ANIT ingestion, and in 72 h the animals were sacrificed. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), the total and direct bilirubin, creatinine and urea in the blood serum were determined, and the liver morphological state was assessed. In animals experienced ANIT-induced acute cholangitis, the total and direct bilirubin, creatinine, ALT, AST, ALP and LDH 1.5-4-fold increase were observed, indicating cytolysis of hepatocytes, cholestasis, and renal dysfunction. The features of periductal fibrosis, biliary epithelium atrophy, and portal-portal linking septa formation were detected, confirming the sclerosing cholangitis development. C60FAS promoted to the normalization of direct and total bilirubin levels, the ALT activity and diminution of fibrotic features. In addition, C60FAS intraperitoneal administration also normalized the ALP activity, indicating the attenuation of disease symptoms. However, the AST activity and creatinine level remained unchanged, and the LDH activity even increased, manifesting the partial persistence of cholestasis and renal dysfunction. Thus, the therapeutic application of C60FAS promotes a partial protection of liver against cholangitis.

  6. A theoretical investigation of the N2O + SO2 reaction on surfaces of P-doped C60 nanocage and Si-doped B30N30 nanocage

    Directory of Open Access Journals (Sweden)

    Meysam Najafi

    Full Text Available The mechanism of N2O reduction via SO2 on surfaces of P-doped C60 and Si-doped B30N30 by density functional theory were investigated. The P and Si adsorption energies on surface of C60 and B30N30 were calculated to be −287.5 and −312.1 kcal/mol, respectively. The decomposition of C60-P-N2O and B30N30-Si-N2O and reduction of C60-P-O∗ and B30N30-Si-O∗ by SO2 molecule were investigated. The B30N30-Si-O∗ has lower activation energy and has more negative ΔGad rather than C60-P-O∗ and therefore the process of B30N30-Si-O∗ + SO2 → B30N30-Si + SO3 was spontaneous more than C60-P-O∗ + SO2 → C60-P + SO3 from thermodynamic view point. Results show that activation energies for B30N30-Si-O∗ + N2O → B30N30-Si-O2 + N2 and C60-P-O∗ + N2O → C60-P-O2 + N2 reactions were 33.23 and 35.82 kcal/mol, respectively. The results show that P-doped C60 and Si-doped B30N30 can be observed as a real catalysts for the reduction of N2O. Keywords: Atom doping, Catalyst, Nanocage, Adsorption, N2O reduction

  7. Energy-level alignment at interfaces between manganese phthalocyanine and C60

    Directory of Open Access Journals (Sweden)

    Daniel Waas

    2017-04-01

    Full Text Available We have used photoelectron spectroscopy to determine the energy-level alignment at organic heterojunctions made of manganese phthalocyanine (MnPc and the fullerene C60. We show that this energy-level alignment depends upon the preparation sequence, which is explained by different molecular orientations. Moreover, our results demonstrate that MnPc/C60 interfaces are hardly suited for application in organic photovoltaic devices, since the energy difference of the two lowest unoccupied molecular orbitals (LUMOs is rather small.

  8. Band gap and density of states of the hydrated C60 fullerene system at finite temperature.

    Science.gov (United States)

    Rivelino, Roberto; de Brito Mota, F

    2007-06-01

    We examine the electronic properties of the hydrated C60 fullerene under ambient conditions using a sequential Monte Carlo/density functional theory scheme. In this procedure, the average electronic properties of the first hydration shell of C60 equilibrate for ca. 40 uncorrelated configurations of the fullerene aqueous solution. We obtain a systematic red-shift of 0.8 eV in the band gap of the hydrated system, which is mainly attributed to the thermal fluctuations of the aqueous environment.

  9. Polymerized phase and amorphous diamond synthesized from C60 fullerene by shock compression

    International Nuclear Information System (INIS)

    Niwase, K.; Homae, T.; Nakamura, K.G.; Kondo, K.

    2006-01-01

    C 60 fullerene films were shock compressed to 23 and 52GPa. Both the recovered samples exhibit fracture into platelets and broad photoluminescence, and intensity of these increases with increasing pressure. At 23GPa, a characteristic single broad band appears at 1560-1570cm -1 , which is similar to the one found for three-dimensional (3D) polymerized C 60 fullerene under high-pressure-high-temperature treatment. At 52GPa, on the other hand, the single broad band has disappeared and a diamond peak sometimes appears, depending on platelets

  10. Characterization of a pure C60 powder using transmission electron microscopy

    International Nuclear Information System (INIS)

    Loiseau, A.; Tendeloo, G. van; Bernier, P.

    1993-01-01

    Complementary to neutron and X ray diffraction, electron microscopy (TEM) is a very powerful technique for characterizing crystalline materials at microscopic and atomic scales. This technique has been rapidly used to study C60 and C70 solids and has allowed in particular to identify various lattice defects present in these materials and to determine different phase transitions through in situ experiments. In this paper, we present a preliminary investigation of pure C60 powder under different imaging conditions. The observed peculiarities are compared with previous studies. (orig.)

  11. Excimer-laser-irradiation-induced effects in C60 films for photovoltaic applications

    International Nuclear Information System (INIS)

    Narayanan, K.L.; Yamaguchi, M.; Azuma, H.

    2002-01-01

    Thin films of fullerene C 60 deposited by the molecular-beam epitaxy method have been subjected to a 248 nm excimer laser for various timings. Reduction in the electrical resistance of the films and the spectral evolution of the D and G bands in the Raman spectra, due to the sharp tendency towards graphitization accompanied by an increasing level of structural disorder, are observed during laser irradiation. Based on the above results, an attempt has been carried out on these irradiated C 60 films to make a device sandwiched with n-type Si, and the photovoltaic parameters are reported as a function of the laser exposure times

  12. Mono- and Bis(pyrrolo)tetrathiafulvalene Derivatives Tethered to C60

    DEFF Research Database (Denmark)

    Solano, Marta Vico; Della Pia, E. A.; Jevric, M.

    2014-01-01

    A series of mono- (MPTTF) and bis(pyrrolo) tetrathiafulvalene (BPTTF) derivatives tethered to one or two C-60 moieties was synthesized and characterized. The synthetic strategy for these dumbbell-shaped compounds was based on a 1,3-dipolar cycloaddition reaction between aldehyde-functionalized MP......A series of mono- (MPTTF) and bis(pyrrolo) tetrathiafulvalene (BPTTF) derivatives tethered to one or two C-60 moieties was synthesized and characterized. The synthetic strategy for these dumbbell-shaped compounds was based on a 1,3-dipolar cycloaddition reaction between aldehyde...

  13. Evidence for Stable High Temperature Ferromagnetism in Fluorine Treated C60

    Science.gov (United States)

    2013-01-01

    dimensional polymeric form of C60 produced by high pressure (6 GPa) and high temperature in the vicinity of 1000 K.2,3,4 It is known that C60 when...heat treatment in the presence of iodine was shown to be ferromagnetic having a Curie temperature of 60 K 8,9 Doping with a mix of iodine and bromine...a chilled slide on the top which enabled collection of the condensed vapor . The Raman spectra of the material condensed on the slide is shown at the

  14. A first-principle investigation into effect of B-and BN-doped C60 in ...

    Indian Academy of Sciences (India)

    The present paper reports the effect of B- and BN-doped C 60 as catalysts for lowering the dehydrogenationenergy inMXH4 clusters (M = Na and Li, X = Al and B) using density functional calculations.MXH4 interacts strongly withB-doped C 60 and weakly with BN-doped C 60 in comparison with pure C 60 with binding ...

  15. The interaction of C60 on Si(111 7x7 studied by Supersonic Molecular Beams: interplay between precursor kinetic energy and substrate temperature in surface activated processes.

    Directory of Open Access Journals (Sweden)

    Lucrezia eAversa

    2015-06-01

    Full Text Available Buckminsterfullerene (C60 is a molecule fully formed of carbon that can be used, owing to its electronic and mechanical properties, as clean precursor for the growth of carbon-based materials, ranging from -conjugated systems (graphenes to synthesized species, e.g. carbides such as silicon carbide (SiC. To this goal, C60 cage rupture is the main physical process that triggers material growth. Cage breaking can be obtained either thermally by heating up the substrate to high temperatures (630°C, after C60 physisorption, or kinetically by using Supersonic Molecular Beam Epitaxy (SuMBE techniques. In this work, aiming at demonstrating the growth of SiC thin films by C60 supersonic beams, we present the experimental investigation of C60 impacts on Si(111 7x7 kept at 500°C for translational kinetic energies ranging from 18 to 30 eV. The attained kinetically activated synthesis of SiC submonolayer films is probed by in-situ surface electron spectroscopies (XPS and UPS. Furthermore, in these experimental conditions the C60-Si(111 7×7 collision has been studied by computer simulations based on a tight-binding approximation to Density Functional Theory, DFT. Our theoretical and experimental findings point towards a kinetically driven growth of SiC on Si, where C60 precursor kinetic energy plays a crucial role, while temperature is relevant only after cage rupture to enhance Si and carbon reactivity. In particular, we observe a counterintuitive effect in which for low kinetic energy (below 22 eV, C60 bounces back without breaking more effectively at high temperature due to energy transfer from excited phonons. At higher kinetic energy (22 < K < 30 eV, for which cage rupture occurs, temperature enhances reactivity without playing a major role in the cage break. These results are in good agreement with ab-initio molecular dynamics simulations. SuMBE is thus a technique able to drive materials growth at low temperature regime.

  16. Effects of carbon nanomaterials fullerene C60 and fullerol C60(OH)18–22 on gills of fish Cyprinus carpio (Cyprinidae) exposed to ultraviolet radiation

    International Nuclear Information System (INIS)

    Socoowski Britto, Roberta; Longaray Garcia, Márcia; Martins da Rocha, Alessandra; Artigas Flores, Juliana; Pinheiro, Maurício V. Brant; Monserrat, José María; Ribas Ferreira, Josencler L.

    2012-01-01

    In consequence of their growing use and demand, the inevitable environmental presence of nanomaterials (NMs) has raised concerns about their potential deleterious effects to aquatic environments. The carbon NM fullerene (C 60 ), which forms colloidal aggregates in water, and its water-soluble derivative fullerol (C 60 (OH) 18–22 ), which possesses antioxidant properties, are known to be photo-excited by ultraviolet (UV) or visible light. To investigate their potential hazards to aquatic organisms upon exposure to UV sunlight, this study analyzed (a) the in vitro behavior of fullerene and fullerol against peroxyl radicals (ROO·) under UV-A radiation and (b) the effects of these photo-excited NMs on oxidative stress parameters in functional gills extracted from the fish Cyprinus carpio (Cyprinidae). The variables measured were the total antioxidant capacity, lipid peroxidation (TBARS), the activities of the antioxidant enzymes glutathione reductase (GR) and glutamate cysteine ligase (GCL), and the levels of the non-enzymatic antioxidant glutathione (GSH). The obtained results revealed the following: (1) both NMs behaved in vitro as antioxidants against ROO· in the dark and as pro-oxidants in presence of UV-A, the latter effect being reversed by the addition of sodium azide, which is a singlet oxygen ( 1 O 2 ) quencher; (2) fullerene induced toxicity with or without UV-A incidence, with a significant (p 1 O 2 generation; and (3) fullerol also decreased GCL activity and GSH formation (p 1 O 2 formation.

  17. Adsorbed Water Illustration

    Science.gov (United States)

    2008-01-01

    The Thermal and Electrical Conductivity Probe on NASA's Phoenix Mars Lander detected small and variable amounts of water in the Martian soil. In this schematic illustration, water molecules are represented in red and white; soil minerals are represented in green and blue. The water, neither liquid, vapor, nor solid, adheres in very thin films of molecules to the surfaces of soil minerals. The left half illustrates an interpretation of less water being adsorbed onto the soil-particle surface during a period when the tilt, or obliquity, of Mars' rotation axis is small, as it is in the present. The right half illustrates a thicker film of water during a time when the obliquity is greater, as it is during cycles on time scales of hundreds of thousands of years. As the humidity of the atmosphere increases, more water accumulates on mineral surfaces. Thicker films behave increasingly like liquid water. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  18. Passing Current through Touching Molecules

    DEFF Research Database (Denmark)

    Schull, G.; Frederiksen, Thomas; Brandbyge, Mads

    2009-01-01

    The charge flow from a single C-60 molecule to another one has been probed. The conformation and electronic states of both molecules on the contacting electrodes have been characterized using a cryogenic scanning tunneling microscope. While the contact conductance of a single molecule between two...

  19. Enantiospecific cis-trans isomerization in chiral fulleropyrrolidines: hydrogen-bonding assistance in the carbanion stabilization in H2O@C60.

    Science.gov (United States)

    Maroto, Enrique E; Mateos, Jaime; Garcia-Borràs, Marc; Osuna, Sílvia; Filippone, Salvatore; Herranz, María Ángeles; Murata, Yasujiro; Solà, Miquel; Martín, Nazario

    2015-01-28

    The stereochemical outcome of cis-trans isomerization of optically pure [60], [70], and endohedral H2O@C60 fulleropyrrolidines reveals that the electronic nature of substituents, fullerene size, and surprisingly the incarcerated water molecule plays a crucial role in this rearrangement process. Theoretical DFT calculations are in very good agreement with the experimental findings. On the basis of the experimental results and computational calculations, a plausible reaction mechanism involving the hydrogen-bonding assistance of the inner water molecule in the carbanion stabilization of endofullerene is proposed.

  20. Adsorbate Diffusion on Transition Metal Nanoparticles

    Science.gov (United States)

    2015-01-01

    systematically studied adsorption and diffusion of atomic and diatomic species (H, C, N, O, CO, and NO) on nanometer-sized Pt and Cu nanoparticles with...species and two diatomic molecules (H, C, N, O, CO, and NO) as adsorbates and study the adsorption and diffusion of these adsorbates across the edges...DOE-BES, Division of Chemical Sciences (grant DE-FG02-05ER15731), and by the Air Force Office of Scientific Research under a Basic Research Initiative

  1. Modified denatured lysozyme effectively solubilizes fullerene c60 nanoparticles in water

    Science.gov (United States)

    Siepi, Marialuisa; Politi, Jane; Dardano, Principia; Amoresano, Angela; De Stefano, Luca; Monti, Daria Maria; Notomista, Eugenio

    2017-08-01

    Fullerenes, allotropic forms of carbon, have very interesting pharmacological effects and engineering applications. However, a very low solubility both in organic solvents and water hinders their use. Fullerene C60, the most studied among fullerenes, can be dissolved in water only in the form of nanoparticles of variable dimensions and limited stability. Here the effect on the production of C60 nanoparticles by a native and denatured hen egg white lysozyme, a highly basic protein, has been systematically studied. In order to obtain a denatured, yet soluble, lysozyme derivative, the four disulfides of the native protein were reduced and exposed cysteines were alkylated by 3-bromopropylamine, thus introducing eight additional positive charges. The C60 solubilizing properties of the modified denatured lysozyme proved to be superior to those of the native protein, allowing the preparation of biocompatible highly homogeneous and stable C60 nanoparticles using lower amounts of protein, as demonstrated by dynamic light scattering, transmission electron microscopy and atomic force microscopy studies. This lysozyme derivative could represent an effective tool for the solubilization of other carbon allotropes.

  2. Symmetry-selected spin-split hybrid states in C-60/ferromagnetic interfaces

    DEFF Research Database (Denmark)

    Li, Dongzhe; Barreteau, Cyrille; Kawahara, Seiji Leo

    2016-01-01

    The understanding of orbital hybridization and spin polarization at the organic-ferromagnetic interface is essential in the search for efficient hybrid spintronic devices. Here, using first-principles calculations, we report a systematic study of spin-split hybrid states of C60 deposited on various...

  3. Efficient Energy Sensitization of C 60 and Application to Organic Photovoltaics

    KAUST Repository

    Trinh, Cong

    2013-08-14

    Fullerenes are currently the most popular electron-acceptor material used in organic photovoltaics (OPVs) due to their superior properties, such as good electron conductivity and efficient charge separation at the donor/acceptor interface. However, low absorptivity in the visible spectral region is a significant drawback of fullerenes. In this study, we have designed a zinc chlorodipyrrin derivative (ZCl) that absorbs strongly in the visible region (450-600 nm) with an optical density 7-fold higher than a C60 film. ZCl efficiently transfers absorbed photoenergy to C60 in mixed films. Application of ZCl as an energy sensitizer in OPV devices leads to an increase in the photocurrent from the acceptor layer, without changing the other device characteristics, i.e., open circuit voltage and fill factor. For example, C 60-based OPVs with and without the sensitizer give 4.03 and 3.05 mA/cm2, respectively, while both have VOC = 0.88 V and FF = 0.44. Our ZCl sensitization approach improves the absorbance of the electron-acceptor layer while still utilizing the beneficial characteristics of C60 in OPVs. © 2013 American Chemical Society.

  4. Synthesis of Diads and Triads Derived from Carotenoids and Fullerene C60

    Directory of Open Access Journals (Sweden)

    Devens Gust

    2000-03-01

    Full Text Available A convenient procedure for the synthesis of supramolecules bearing carotenoids and fullerene C60 is reported. The amphipathic nature and the high yield of charge separation of these compounds make them candidates in the formation of transmembrane charge gradients.

  5. Detection of fullerenes (C60 and C70) in commercial cosmetics

    Science.gov (United States)

    Benn, Troy M.; Westerhoff, Paul; Herckes, Pierre

    2013-01-01

    Detection methods are necessary to quantify fullerenes in commercial applications to provide potential exposure levels for future risk assessments of fullerene technologies. The fullerene concentrations of five cosmetic products were evaluated using liquid chromatography with mass spectrometry to separate and specifically detect C60 and C70 from interfering cosmetic substances (e.g., castor oil). A cosmetic formulation was characterized with transmission electron microscopy, which confirmed that polyvinylpyrrolidone encapsulated C60. Liquid-liquid extraction of fullerenes from control samples approached 100% while solid-phase and sonication in toluene extractions yielded recoveries of 27–42%. C60 was detected in four commercial cosmetics ranging from 0.04 to 1.1 μg/g, and C70 was qualitatively detected in two samples. A single-use quantity of cosmetic (0.5 g) may contain up to 0.6 μg of C60, demonstrating a pathway for human exposure. Steady-state modeling of fullerene adsorption to biosolids is used to discuss potential environmental releases from wastewater treatment systems. PMID:21300421

  6. C60 exposure induced tissue damage and gene expression alterations in the earthworm Lumbricus rubellus

    NARCIS (Netherlands)

    Ploeg, van der M.J.C.; Handy, R.D.; Heckmann, L.H.; Hout, van der A.; Brink, van den N.W.

    2013-01-01

    Effects of C60 exposure (0, 15 or 154 mg/kg soil) on the earthworm Lumbricus rubellus were assessed at the tissue and molecular level, in two experiments. In the first experiment, earthworms were exposed for four weeks, and in the second lifelong. In both experiments, gene expression of heat shock

  7. The effects of encapsulating C60 fullerenes on the bending flexibility of carbon nanotubes

    International Nuclear Information System (INIS)

    Zhu, J; Pan, Z Y; Wang, Y X; Zhou, L; Jiang, Q

    2007-01-01

    We investigate the bending flexibility of carbon nanotubes (CNTs) with encapsulated C 60 fullerenes, using molecular dynamics (MD) simulations. Our simulations on the bending of the fully ((C 60 ) 12 -(10,10)) and partially ((C 60 ) 10 -(10,10)) filled peapods show an 18 and 6.3% increase of the flexural rigidity, and a 45 and 11% increase of the buckling strength, respectively, compared to the empty (10, 10) CNT. What is characteristically different for the peapod from the empty CNT is the presence of a transitional region in the loading process that proceeds to the onset of buckling. Within this transitional region, the interaction between the encapsulated fullerenes and the hosting CNT leads to an unusual configuration of the peapod, in which there are ripples along the inner arc of the bent peapod. The transition region in the partially filled peapod is short compared with the fully filled peapod. This is mainly caused by the axial motion of C 60 fullerenes, especially after the appearance of the small ripple. The rippling configuration has been reported previously in the bending of multi-walled CNTs, where it emerges after the critical bending angle. However, in the present case, the peapod remains perfectly elastic in this transitional region until buckling takes place

  8. On the applicability of the Kasha-Vavilov rule to C-60

    NARCIS (Netherlands)

    Williams, R.M.; Verhoeven, J.W.

    1994-01-01

    Via full correction for the instrumental response function, the fluorescence excitation spectrum of C60 in methylcyclohexane between 240 and 580 nm is shown to match the absorption spectrum. This proves that, in contrast to earlier reports, also after UV excitation into higher Sn states,

  9. On the applicability of the Kasha-Vavilov Rule to C-60

    NARCIS (Netherlands)

    Williams, R.M.; Verhoeven, J.W.

    1994-01-01

    Via full correction for the instrumental response function, the fluorescence excitation spectrum of C60 in methylcyclohexane between 240 and 580 nm is shown to match the absorption spectrum. This proves that, in contrast to earlier reports, also after UV excitation into higher S(n) states,

  10. UV/Vis spectroscopy of C60 embedded in water ice

    DEFF Research Database (Denmark)

    Cuylle, Steven; Linnartz, Harold; Thrower, John

    2012-01-01

    Electronic solid state spectra are recorded for C60 embedded in 40 K water ice using broad band direct absorption spectroscopy, and assigned with reference to existing matrix data. The results are interesting in view of the recent gas phase detection of fullerenes in the interstellar medium...

  11. Preparative-scale separation of C60 and C70 on polystyrene gel

    International Nuclear Information System (INIS)

    Guegel, A.; Becker, M.; Hammel, D.; Mindach, L.; Raeder, J.; Simon, T.; Wagner, M.; Muellen, K.

    1992-01-01

    Five grams of a mixture of C 60 /C 70 can be separated in 24 hours by gel permeation chromatography on polystyrene gel. The mobile phase can be completely recovered, and the method can be scaled up by a simple increase in the inner diameter of the column. (orig.) [de

  12. Analytical study of PPV-oligomer- and C-60-based devices for optimising organic solar cells

    NARCIS (Netherlands)

    Geens, W.; Poortmans, J.; Jain, S.C.; Nijs, J.; Mertens, R.; Veenstra, S.C.; Krasnikov, V.V.; Hadziioannou, G

    2000-01-01

    A blend of a 5-ring n-octyloxy-substituted oligo(p-phenylene vinylene) and C60, sandwiched between two electrodes, has been used as the active layer for an organic solar cell. It delivered external quantum efficiencies up to 60% in the visible and 70% in the UV part of the spectrum. To unambiguously

  13. Optical conductivity in A3C60 (A=K, Rb)

    NARCIS (Netherlands)

    Brink, J. van den; Gunnarsson, O.; Eyert, V.

    1997-01-01

    Published in: Phys. Rev. B 57 (1998) 2163-2167 Citing articles (CrossRef) citations recorded in [Science Citation Index] Abstract: We study the optical conductivity in A3C60 (A =K, Rb). The effects of the electron-phonon interaction is included to lowest order in the coupling strength lambda. It is

  14. A BPTTF-based self-assembled electron-donating triangle capable of C60 binding.

    Science.gov (United States)

    Goeb, Sébastien; Bivaud, Sébastien; Dron, Paul Ionut; Balandier, Jean-Yves; Chas, Marcos; Sallé, Marc

    2012-03-25

    A kinetically stable self-assembled redox-active triangle is isolated. The resulting electron-donating cavity, which incorporates three BPTTF units, exhibits a remarkable binding ability for electron-deficient C(60), supported by a favorable combination of structural and electronic features.

  15. C60Recognition from Extended Tetrathiafulvalene Bis-acetylide Platinum(II) Complexes.

    Science.gov (United States)

    Bastien, Guillaume; Dron, Paul I; Vincent, Manon; Canevet, David; Allain, Magali; Goeb, Sébastien; Sallé, Marc

    2016-11-18

    The favorable spatial organization imposed by the square planar 4,4'-di(tert-butyl)-2,2'-bipyridine (dbbpy) platinum(II) complex associated with the electronic and shape complementarity of π-extended tetrathiafulvalene derivatives (exTTF) toward fullerenes is usefully exploited to construct molecular tweezers, which display good affinities for C 60 .

  16. Non conventional screening of the Coulomb interaction in C-60 and in carbon nanotubes

    NARCIS (Netherlands)

    van den Brink, J; Sawatzky, GA; Kuzmany, H; Fink, J; Mehring, M; Roth, S

    1998-01-01

    We study the screening of the Coulomb interaction in C-60 and carbon nanotubes. It is shown that for these systems the screening deviates strongly from the Clausius-Mossotti behavior. The short range interaction is strongly screened and the long range interaction is anti-screened, thereby strongly

  17. Sodium doping in copper-phthalocyanine/C60 heterojunction for organic photovoltaic applications

    International Nuclear Information System (INIS)

    Chen, Hui-Ju; Wu, Hsuan-Ta; Hung, Kuang-Teng; Fu, Sheng-Wen; Shih, Chuan-Feng

    2013-01-01

    Sodium was incorporating at the copper-phthalocyanine (CuPc)/C 60 interface in CuPc/C 60 -based small-molecular solar cells to enhance their power conversion efficiency. C 60 was deposited on slightly sodium-doped CuPc. Post-annealing improved the cell properties. Post-annealing doubled the conversion efficiency of the least sodium-doped devices (75 °C, 40 min). The electron/hole mobility ratio gradually approached unity as the annealing time increased, indicating that a reduction in the space charge accumulation was the main cause of the increase of the short-circuit current. The mechanism of enhancement of carrier transport by annealing was investigated by making capacitance–voltage measurements and performing corresponding depth-profile analyses. - Highlights: • Incorporate Na at copper-phthalocyanine/C 60 interface • Annealing importantly improved the cell efficiency of Na-doped devices. • Change in the carrier mobility and concentration was investigated

  18. Stable aqueous dispersions of C60 fullerene by the use of a block copolymer

    International Nuclear Information System (INIS)

    Mountrichas, G; Pispas, S; Kamitsos, E I; Xenogiannopoulou, E; Couris, S

    2005-01-01

    Stable aqueous solutions of C 60 fullerene have been prepared by the use of a well defined block copolymer, namely poly(styrene-b-ethyleneoxide) (PS-b-PEO). The protocol that has been followed involves, in a first step, the co-dissolution of C 60 fullerene and diblock copolymer in toluene, a solvent where formation of micelles with the PEO as the core block is favored. In the second step evaporation of toluene at room temperature takes place. Finally re-dissolution of the formed film in water, with simultaneous inversion of the micellar structure (PS containing C 60 as the core), is achieved. The aggregates prepared in this way have been characterized by dynamic light scattering as well as scanning electron microscopy. All the applied techniques have indicated the formation of at least two kinds of aggregates, of different sizes, that enclose fullerenes in their cores. This protocol allows the preparation of micellar aggregates, with biocompatible coronas, containing C 60 in 1-20% by weight in respect to the PS component

  19. Intermolecular photoinduced electron-transfer processes between C60 and aniline derivatives in benzonitrile

    International Nuclear Information System (INIS)

    Pan Yang; Tang Wenjian; Yu Tangqin; Wang Jinting; Fu Yao; Wang Guanwu; Yu Shuqin

    2007-01-01

    The quenching behavior of the triplets of C 60 by various aniline derivatives (1a-d and 2a-e) was investigated by means of laser flash photolysis in benzonitrile at 293K. Electron transfer process was proposed to be the main mechanism because of the direct detection of radical ions of aniline derivatives and C 60 in time-resolved transient absorption spectra. The quenching rate constants (k q ) of 3 C 60 * by different substrates determined at 740nm approach or reach the diffusion-controlled limit. DFT method was employed to calculate the unknown oxidation potentials of substrates in solution. With these E ox values, free energy changes (ΔG) were obtained through Rehm-Weller equation. Dependence of observed quenching rate constants on the free energy changes further indicates the photoinduced reactions between 3 C 60 * and substrates proceed through an electron transfer mechanism. Obtained k q values for the aniline derivatives are impacted obviously by ground-state configurations and the kinds substituents quantified by Hammett σ constant. Good correlation between logk q and σ values conforms to the empirical Hammett equation. A more negative ρ value (-3.356) was gained for anilines (2a-e) than that of N,N-dimethylanilines (1a-d) (-1.382), which suggests a more susceptible reactivity for the former substrates. Charge density distribution of reaction center ''N'' originated from quantum calculation supports this suggestion. In addition, a relationship between quenching rate constants and solvent viscosity was gained from C 60 /dimethyl-p-toluidine system in altered mixtures of acetonitrile and toluene

  20. Ecological applications of the irradiated adsorbents

    International Nuclear Information System (INIS)

    Tusseyev, T.

    2004-01-01

    Full text: In our previous works it was shown that after irradiation some adsorbents gain new interesting properties such as increasing (or decreasing) of their adsorption capacity, selectivity in relation to some gases, change of chemical bounds of gas molecules with adsorbent surface as well as other properties. We investigated a lot of adsorbents with semiconducting and dielectric properties. A high temperature superconductor was investigated also. Adsorbents were irradiated by ultraviolet (UV) and gamma - radiation, reactor (n.γ) - radiation, α-particles (E=40-50 MeV), protons ( E=30 MeV), and also He-3 ions (E-29-60 MeV). The following techniques were used: volumetric (manometrical), mass-spectrometer and IR spectroscopic methods, and also method of electronic - paramagnetic resonance (spin paramagnetic resonance) The obtained results allow to speak about creation of new adsorbents for gas purification (clearing) from harmful impurities, gas selection into components, an increasing of adsorbing surface. Thus one more advantage of the irradiated adsorbents is that they have 'memory effect', i.e. they can be used enough long time after irradiation. In laboratory conditions we built the small-sized adsorptive pump on the basis of the irradiated zeolites which are capable to work in autonomous conditions. It was found, that some of adsorbents after irradiation gain (or lose) selectivity in relation to definite gases. So, silica gel, which one in initial state does not adsorb hydrogen, after gamma irradiation it becomes active in relation to hydrogen. Some of rare earths oxides also show selectivity in relation to hydrogen and oxygen depending on a type of irradiation. Thus, it is possible to create different absorbents, depending on a solved problem, using a way or selection of adsorbents, either of radiation type and energy, as a result obtained adsorbents can be used for various ecological purposes

  1. Complementary study of molecular dynamics and domain sizes in heterogenous nanocomposites PBT/DA-C60 and PBT/TCNEO-C60

    International Nuclear Information System (INIS)

    Woźniak-Braszak, A.; Baranowski, M.; Jurga, K.; Hołderna-Natkaniec, K.; Jurga, J.; Brycki, B.; Mikuli, E.

    2014-01-01

    A comprehensive study of molecular dynamics and structure in new heterogenous nanocomposites based on poly(butylene terephthalate) and nanoparticles C 60 modified by n-decylamine or tetracyanoethylene oxide has been performed. The domain structure of new nanocomposites has been investigated by Fourier transform infrared spectroscopy, wide-angle X-ray scattering, and differential scanning calorimetry techniques. Solid-state 1 H NMR techniques were used to study molecular dynamics and domain sizes in new nanocomposites. Information about the electronic properties of these nanocomposites was obtained by means of electron paramagnetic resonance method. It was shown that the structure and molecular dynamics of new nanocomposites were strongly dependent on the properties and concentration of fullerene derivates.

  2. The dynamics and structures of adsorbed surfaces

    International Nuclear Information System (INIS)

    Nielsen, M.; Ellenson, W.D.; McTague, J.P.

    1978-01-01

    This article reviews neutron scattering work performed on films of simple gas atoms and molecules adsorbed primarily on graphite surfaces. Exfoliated graphite substrates such as Grafoil were first used in this kind of measurements about five years ago and new results have been reported at an increasing pace. Elastic neutron diffraction measurements, determining the two-dimensional structural ordering of the adsorbed films, have been performed on layers of N 2 , Ar, H 2 , D 2 , O 2 , Kr, and He. Measurements on layers of larger molecules such as CD 4 and ND 3 have been reported very recently. Inelastic neutron scattering measurements, studying the dynamics of the adsorbed films are only possible in a few especially favourable cases such as 36 Ar and D 2 films, where the coherent phonon scattering cross-sections are very large. In other cases incoherent scattering from hydrogen can give information about e.g. the mobility of molecules such as NH 3 or the internal modes of adsorbed molecules such as C 4 H 10 . Neutron scattering measurements where substrates other than graphite products are used as the adsorbents will not be reviewed here. However, the power of the technique will be demonstrated in an example of H 2 physisorbed to activated alumina and in an example where hydrogen is chemisorbed to Raney nickel. (author)

  3. Ionization, evaporation and fragmentation of C60 in collisions with highly charged C, O and F ions—effect of projectile charge state.

    Science.gov (United States)

    Kelkar, A. H.; Misra, D.; Tribedi, L. C.

    2007-09-01

    We study the various inelastic processes such ionization, fragmentation and evaporation of C60 molecule in collisions with fast heavy ions. We have used 2.33 MeV/u C, O and F projectile ion beams. Various ionization and fragmentation products were detected using time-of-flight mass spectrometer. The multiply charged C60r+ ions were detected for maximum r = 4. The projectile charge state (qp) dependence of the single and double ionization cross sections is well reproduced by a model based on the giant dipole plasmon resonance (GDPR). The qp-dependence of the fragmentation yields, was found to be linear. Variation of relative yields of the evaporation products of C602+ (i.e. C582+, C562+ etc) and C603+ (i.e. C583+, C563+ etc) with qp has also been investigated for various projectiles.

  4. Electrical transport and photovoltaic effects of core-shell CuO/C60 nanowire heterostructure.

    Science.gov (United States)

    Bao, Qiaoliang; Li, Chang Ming; Liao, Lei; Yang, Hongbin; Wang, Wei; Ke, Chang; Song, Qunliang; Bao, Haifeng; Yu, Ting; Loh, Kian Ping; Guo, Jun

    2009-02-11

    An organic/inorganic hybrid heterostructure consisting of p-type CuO nanowire core and n-type C(60) shell was fabricated and its electrical transport properties were studied for the first time. It was found that the devices with contacts on shell-shell show an ohmic behavior but the devices with contacts on core-shell forms a single p-n junction and display a rectifying behavior. Logarithmic current-voltage curves at various temperatures show that the tunneling transport plays a critical role in the electrical transport. Photovoltaic effects were observed in the core-shell contacted CuO/C(60) junctions under illumination. This work demonstrates that an inorganic/organic coaxial nanowire can provide potential in nanoelectronic devices and could further stack high density hybrid nanowires array as a renewable power source.

  5. SiC Formation Through Interface Reaction between C60 and Si in Plasma Environment

    Science.gov (United States)

    Ding, Fang; Meng, Liang; Zhu, Xiaodong

    2007-02-01

    The formation of SiC through the interface reaction between C60 and Si in a plasma-assisted chemical vapour deposition system (PACVD) is investigated with a C60 film previously deposited on Si wafers. The composition and structure of the deposited samples were characterized by micro-Raman spectroscopy and X-ray diffraction (XRD). The results showed that SiC film was formed successfully in hydrogen plasma at a substrate temperature of 800°C. The hydrogen atoms in plasma were found to enhance the production of SiC. Furthermore, the effects of the added CH4 on the formation of film were studied. Introduction of CH4 simultaneously with H2 at the beginning would suppress the formation of the initial layer of SiC due to a carbon-rich environment on the substrate, which would be disadvantageous to the further growth of the SiC film.

  6. Photovoltaic Properties of Solar Cells Based on Poly(methyl phenyl silane) and C60

    Science.gov (United States)

    Mizuno, Toya; Akasaka, Yumeno; Tachibana, Hiroaki

    2012-10-01

    Photovoltaic (PV) devices using blend films of poly(methyl phenyl silane) (PMPS) and fullerene (C60) are fabricated, and the effects of various technical parameters during device fabrication on the PV characteristics under AM 1.5G simulated solar light illumination of 100 mW/cm2 intensity are investigated. The PV performance of the devices depends on the mixing ratio of PMPS:C60, the kind of buffer layer, the thickness of the buffer layer, and the thermal annealing temperature of the devices. The devices optimized for the mixing ratio, kind of buffer layer, and thermal annealing temperature exhibit a short-circuit current density (JSC) of 2.26 mA/cm2, an open circuit voltage (VOC) of 0.71 V, a fill factor (FF) of 0.35, and a power conversion efficiency (PCE) of 0.57%.

  7. Electric field and grain size dependence of Meyer–Neldel energy in C60 films

    Science.gov (United States)

    Ullah, Mujeeb; Pivrikas, A.; Fishchuk, I.I.; Kadashchuk, A.; Stadler, P.; Simbrunner, C.; Sariciftci, N.S.; Sitter, H.

    2011-01-01

    Meyer–Neldel rule for charge carrier mobility measured in C60-based organic field-effect transistors (OFETs) at different applied source drain voltages and at different morphologies of semiconducting fullerene films was systematically studied. A decrease in the Meyer–Neldel energy EMN from 36 meV to 32 meV was observed with changing electric field in the channel. Concomitantly a decrease from 34 meV to 21 meV was observed too by increasing the grain size and the crystallinity of the active C60 layer in the device. These empiric findings are in agreement with the hopping-transport model for the temperature dependent charge carrier mobility in organic semiconductors with a Gaussian density of states (DOS). Experimental results along with theoretical descriptions are presented. PMID:21966084

  8. Electrical transport and photovoltaic effects of core-shell CuO/C60 nanowire heterostructure

    International Nuclear Information System (INIS)

    Bao Qiaoliang; Li Changming; Yang Hongbin; Wang Wei; Song Qunliang; Bao Haifeng; Liao Lei; Yu Ting; Ke Chang; Loh, K P; Guo Jun

    2009-01-01

    An organic/inorganic hybrid heterostructure consisting of p-type CuO nanowire core and n-type C 60 shell was fabricated and its electrical transport properties were studied for the first time. It was found that the devices with contacts on shell-shell show an ohmic behavior but the devices with contacts on core-shell forms a single p-n junction and display a rectifying behavior. Logarithmic current-voltage curves at various temperatures show that the tunneling transport plays a critical role in the electrical transport. Photovoltaic effects were observed in the core-shell contacted CuO/C 60 junctions under illumination. This work demonstrates that an inorganic/organic coaxial nanowire can provide potential in nanoelectronic devices and could further stack high density hybrid nanowires array as a renewable power source.

  9. Photo excitation and laser detachment of C60 − anions in a storage ring

    DEFF Research Database (Denmark)

    Støchkel, Kristian; Andersen, Jens Ulrik

    2013-01-01

    We have studied the photo physics of C60 − anions in the electrostatic storage ring ELISA with ions produced in a plasma source and cooled and bunched in a He filled ion trap. A previous study using delayed electron detachment as a signal of resonance-enhanced multiphoton electron detachment...... from a principal component analysis of these spectra. In good agreement with the earlier REMPED experiment, an origin band for transitions between the two lowest electronic levels of the anion, with t 1u and t 1g symmetry, is observed at 9380 cm−1, with strong sidebands from excitation of the two A g...... level, is much weaker in the new measurements and could be an H g vibrational sideband. Also earlier studies of direct laser detachment from C60 − in the storage ring ASTRID have been revisited, with ions cooled by liquid nitrogen in the ion trap. We confirm the previous measurement with a determination...

  10. High-pressure phase in tetragonal two-dimensional polymeric C60

    International Nuclear Information System (INIS)

    Meletov, K.P.; Rossijskaya Akademiya Nauk, Chernogolovka; Arvanitidis, J.; Ves, S.; Kourouklis, G.A.

    2001-01-01

    The pressure behavior of the phonon modes of tetragonal two-dimensional polymeric C 60 has been studied at pressure up to 27.5 GPa and room temperature by means of Raman spectroscopy. Gradual transformation of the material to a new phase was observed in the pressure region 18.0-22.0 GPa. The Raman spectrum characteristics of the high-pressure phase provide a strong indication that the fullerene molecular cage is retained and the material may be related to a three-dimensionally polymerized C 60 . The new phase remains stable upon pressure decrease down to 9 GPa. Further release of pressure leads to its transformation to a highly disordered structure whose broad features in the Raman spectrum resemble those of amorphous carbon. (orig.)

  11. Low energy ion implantation and high energy heavy ion irradiation in C60 films

    International Nuclear Information System (INIS)

    Narayanan, K.L.; Yamaguchi, M.; Dharmarasu, N.; Kojima, N.; Kanjilal, D.

    2001-01-01

    C 60 films have been bombarded with low energy boron ions and high energy swift heavy ions (SHI) of silver and oxygen at different doses. Raman scattering and Fourier transform infrared (FTIR) studies were carried out on the virgin and irradiated films and the results are in good agreement with each other. The films subject to low energy boron ion implantation showed destruction of the bukky balls whereas the films subject to high energy ion irradiation did not show appreciable effects on their structure. These results indicate that C 60 films are more prone to defects by elastic collision and subsequent implantation at lower energy. Irradiation at higher energy was less effective in creating appreciable defects through electronic excitation by inelastic collisions at similar energy density

  12. Electrical transport and photovoltaic effects of core-shell CuO/C60 nanowire heterostructure

    Science.gov (United States)

    Bao, Qiaoliang; Li, Chang Ming; Liao, Lei; Yang, Hongbin; Wang, Wei; Ke, Chang; Song, Qunliang; Bao, Haifeng; Yu, Ting; Loh, Kian Ping; Guo, Jun

    2009-02-01

    An organic/inorganic hybrid heterostructure consisting of p-type CuO nanowire core and n-type C60 shell was fabricated and its electrical transport properties were studied for the first time. It was found that the devices with contacts on shell-shell show an ohmic behavior but the devices with contacts on core-shell forms a single p-n junction and display a rectifying behavior. Logarithmic current-voltage curves at various temperatures show that the tunneling transport plays a critical role in the electrical transport. Photovoltaic effects were observed in the core-shell contacted CuO/C60 junctions under illumination. This work demonstrates that an inorganic/organic coaxial nanowire can provide potential in nanoelectronic devices and could further stack high density hybrid nanowires array as a renewable power source.

  13. Electronic structure and magnetic properties of 31P@C60-SWCNT as peapods

    Science.gov (United States)

    Suzuki, A.; Oku, T.

    2012-03-01

    Design of the NMR quantum computer of 1D spin chains based on 31P@C60-SWCNT as peapods was studied. Electronic structure and magnetic properties of 31P@C60 encapsulating fullerenes within SWCNT as peapods was investigated by quantum chemical calculation. Characterization of chemical shifts of 13C, principle g-tensor and A-tensor of hyperfine structure for phosphorus atom with electronic spin S = 3/2 and nuclear spin I = 1/2 were studied. The excited energy and wavelength at 1512 nm and 728 nm confirmed assignment of the first and second states as van Hove transitions. Molecular design of carbon peapods is important to control quantum spin qubits, splitting by spin-local interaction and dipole-dipole interaction based on p-orbital spin density distribution under hybrization of molecular orbital at excited state and grand state.

  14. Recent Advances in Electrochemical Biosensors Based on Fullerene-C60 Nano-Structured Platforms.

    Science.gov (United States)

    Pilehvar, Sanaz; De Wael, Karolien

    2015-11-23

    Nanotechnology is becoming increasingly important in the field of (bio)sensors. The performance and sensitivity of biosensors is greatly improved with the integration of nanomaterials into their construction. Since its first discovery, fullerene-C60 has been the object of extensive research. Its unique and favorable characteristics of easy chemical modification, conductivity, and electrochemical properties has led to its tremendous use in (bio)sensor applications. This paper provides a concise review of advances in fullerene-C60 research and its use as a nanomaterial for the development of biosensors. We examine the research work reported in the literature on the synthesis, functionalization, approaches to nanostructuring electrodes with fullerene, and outline some of the exciting applications in the field of (bio)sensing.

  15. An Experimental study of Fullerene (C60) Nano-fluids on Pool Boiling Conditions

    International Nuclear Information System (INIS)

    Melani, Ai; Shin, Byoong Su; Chang, Soon Heung

    2009-01-01

    Critical heat flux (CHF) is directly related to the performance of the system since CHF limits the heat transfer of a heat transfer system. Significant enhancement of CHF allows reliable operation of equipment with more margins to operational limit and more economic cost saving. The previous results show that the nano-fluids significantly enhanced pool boiling CHF compared to pure water. It was supposed that CHF enhancement was due to increased thermal conductivity of fluids, change of bubble shape and behavior, and nano-particle coating of the boiling surface. The previous researches also show that mainly the pool boiling experiment was employed metal particles. Fullerene (C 60 ) is a novel carbon allotrope that was first discovered in 1985 by a winner noble 'Sir Harold W.Kroto, Richard E. Smalley and Robert F.Curl Jr'. In this study we report the first CHF experiment in pool boiling conditions using Fullerene (C 60 ) nanofluids

  16. Substrate templating guides the photoinduced reaction of C60 on calcite.

    Science.gov (United States)

    Lindner, Robert; Rahe, Philipp; Kittelmann, Markus; Gourdon, André; Bechstein, Ralf; Kühnle, Angelika

    2014-07-21

    A substrate-guided photochemical reaction of C60 fullerenes on calcite, a bulk insulator, investigated by non-contact atomic force microscopy is presented. The success of the covalent linkage is evident from a shortening of the intermolecular distances, which is clearly expressed by the disappearance of the moiré pattern. Furthermore, UV/Vis spectroscopy and mass spectrometry measurements carried out on thick films demonstrate the ability of our setup for initiating the photoinduced reaction. The irradiation of C60 results in well-oriented covalently linked domains. The orientation of these domains is dictated by the lattice dimensions of the underlying calcite substrate. Using the lattice mismatch to deliberately steer the direction of the chemical reaction is expected to constitute a general design principle for on-surface synthesis. This work thus provides a strategy for controlled fabrication of oriented, covalent networks on bulk insulators. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Electric and photoelectric properties of n-Si/fullerite C60 isotype heterojunctions

    International Nuclear Information System (INIS)

    Spoyaleh, D.

    2008-01-01

    In this paper the results of the research on electric and photoelectric properties of n-Si/fullerite C 60 isotype heterojunctions are presented. The analysis of dark current-voltage characteristics is performed being taken into account in the equivalent circuit of heterostructures of series and shunt resistances. It is shown that in the range of lower applied voltage U 0,5 V prevails tunneling or multi-step tunneling-recombination mechanisms of charge transfer. (authors)

  18. Desorption of C60 upon thermal decomposition of cesium C58 fullerides.

    Science.gov (United States)

    Ulas, Seyithan; Löffler, Daniel; Weis, Patrick; Böttcher, Artur; Kappes, Manfred M

    2012-03-21

    A monodispersed fullerene material comprising exclusively C(58) cages was doped with Cs to generate Cs(x)C(58) films of various compositions. The resulting modified properties have been studied using a variety of surface analysis methods with emphasis on thermal desorption and ultraviolet photoelectron spectroscopies. Cs doping raises the thermal stability of C(58) films which are characterized by quasi-covalent cage-cage bonds between annelated pentagon sites. Desorption mass spectra show emission of significant amounts of C(60) at elevated temperatures implying that Cs doping can activate C(58)→C(60) conversion in the condensed phase. In the case of saturated Cs(x)C(58) films, up to 4.5% of the initially deposited C(58) can be desorbed as C(60). From the spectroscopic data, we infer that Cs insertion and transport into the interstitial sites of the C(58) solid is accompanied by spontaneous electron transfer to the electronegative fullerene framework-leading to a weakening of intercage carbon-carbon bonds. At the same time, the overall cohesion of the solid film is enhanced by the formation of multiple ionic Cs(+) (β)C(58) (-) (δ) interactions. Near 800 K, Cs(+) activates∕catalyzes concerted disproportionation reactions resulting in the transfer of C(2) from C(58) (-) (δ) to neighbouring cages to yield C(60) (and C(56)). Heating Cs(x)C(58) films to beyond this temperature range yields a (high temperature) stable reaction product with a significantly modified UP spectrum and a finite density of states at the Fermi level. © 2012 American Institute of Physics

  19. Influence of C-60 fullerenes on the glass formation of polystyrene

    OpenAIRE

    Sanz, Alejandro; Wong, Him Cheng; Nedoma, Alisyn J.; Douglas, Jack F.; Cabral, Joao T.

    2015-01-01

    We investigate the impact of fullerene CH on the thermal properties and glass formation of polystyrene (PS) by differential scanning calorimetry (DSC) and dielectric spectroscopy (DS), for CH concentrations up to 30% mass fraction. The miscibility and dispersibility thresholds of PS/C-60 nanocomposites are first estimated by a combination of microscopy, small angle neutron scattering (SANS) and wide-angle X-ray scattering (WAXS) experiments, and these thresholds were found to be similar or eq...

  20. Product Characterization and Headspace Analysis of Solar Irradiated Aqueous C60 Clusters

    OpenAIRE

    Su, Dan

    2013-01-01

    Buckminsterfullerene (C60) is an important fullerene material that has drawn much attention and is currently being applied in many different fields. It was discovered in 1985. As its production has largely increased to meet these industrial needs, it is obvious that its environmental occurrence, especially in aqueous systems, will occur. To further provide information for environmental toxicity studies and for its risk assessment, this thesis focuses on the photo transformation processes of a...

  1. Transformation from C60 fullerene into carbon spheres by shock compression

    International Nuclear Information System (INIS)

    Niwase, K; Nakamura, K G; Homae, T; Kondo, K

    2010-01-01

    Here, we report a partially facetted carbon sphere of about 20 μm in diameter on the outer surface of the recovered sample from C 60 fullerene powder after shock-compression. The sphere has two hexagonal facets locating almost parallel to each other. Spotty contrast is observed on the roundish particle but not on the facetted area. Micro-Raman spectroscopy revealed that the facetted area is in a highly graphitized state but not the roundish area.

  2. Effect of Orbital Hybridization on Spin-Polarized Tunneling across Co/C60 Interfaces.

    Science.gov (United States)

    Wang, Kai; Strambini, Elia; Sanderink, Johnny G M; Bolhuis, Thijs; van der Wiel, Wilfred G; de Jong, Michel P

    2016-10-26

    The interaction between ferromagnetic surfaces and organic semiconductors leads to the formation of hybrid interfacial states. As a consequence, the local magnetic moment is altered, a hybrid interfacial density of states (DOS) is formed, and spin-dependent shifts of energy levels occur. Here, we show that this hybridization affects spin transport across the interface significantly. We report spin-dependent electronic transport measurements for tunnel junctions comprising C 60 molecular thin films grown on top of face-centered-cubic (fcc) epitaxial Co electrodes, an AlO x tunnel barrier, and an Al counter electrode. Since only one ferromagnetic electrode (Co) is present, spin-polarized transport is due to tunneling anisotropic magnetoresistance (TAMR). An in-plane TAMR ratio of approximately 0.7% has been measured at 5 K under application of a magnetic field of 800 mT. The magnetic switching behavior shows some remarkable features, which are attributed to the rotation of interfacial magnetic moments. This behavior can be ascribed to the magnetic coupling between the Co thin films and the newly formed Co/C 60 hybridized interfacial states. Using the Tedrow-Meservey technique, the tunnel spin polarization of the Co/C 60 interface was found to be 43%.

  3. Photoelectron Spectroscopy and Electronic Structures of Fullerene Oxides: C60Ox- (x=1-3)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xue B.; Woo, Hin-koon; Kiran, Boggavarapu; Wang, Lai S.

    2005-12-15

    We report a photoelectron spectroscopy (PES) study on a series of fullerene oxides, C600x- (x = 1-3). The PES spectra reveal one isomer for C600x-, two isomers for C6002-, and multiple isomers for C6003-. Compared to C60, the electronic structures of C600x are only slightly perturbed, resulting in similar anion photoelectron spectra. The electron affinity of C600x was observed to increase only marginally with the number of oxygen atoms, x, from 2.683 eV for C60, to 2.745 eV for C600, and 2.785 eV/2.820 eV for C6002 (two isomers). We also carried out theoretical calculations, which confirmed the observed isomers and showed that all the fullerene oxides are in the form of epoxide. The PES and theoretical calculations, as well as molecular orbital analysis, indicate that addition of oxygen atoms to the C60 cage only modifies the local carbon network and leave the rest of the fullerene cage largely intact geometrically and electronically.

  4. Positron annihilation study of graphite, glassy carbon and C60/C70 fullerene

    International Nuclear Information System (INIS)

    Hasegawa, Masayuki; Kajino, Masahiro; Yamaguchi, Sadae; Iwata, Tadao; Kuramoto, Eiichi; Takenaka, Minoru.

    1992-01-01

    ACAR (Angular Correlation of Annihilation Radiation) and positron lifetime measurements have been made on, HOPG (Highly Oriented Pyrolytic Graphite), isotropic fine-grained graphite, glassy carbons and C 60 /C 70 powder. HOPG showed marked bimodality along the c-axis and anisotropy in ACAR momentum distribution, which stem from characteristic annihilation between 'interlayer' positrons and π-electrons in graphite. ACAR curves of the isotropic graphite and glassy carbons are even narrower than that of HOPG perpendicular to the c-axis. Positron lifetime of 420 and 390 - 480 psec, much longer than that of 221 psec in HOPG, were observed for the isotropic graphite and glassy carbons respectively, which are due to positron trapping in structural voids in them. Positron lifetime and ACAR width (FWHM) can be well correlated to void sizes (1.7 to 5.0 nm) of glassy carbons which have been determined by small angle neutron (SAN) scattering measurements. ACAR curves and positron lifetime of C 60 /C 70 powder agree well with those of glassy carbons. This shows that positron wave functions extend, as in the voids of glassy carbons, much wider than open spaces of the octahedral interstices of the face-centered cubic (FCC) structure of C 60 crystal and strongly suggests positron trapping in the 'soccer ball' vacancy. Possible positron states in the carbon materials are discussed with a simple model of void volume-trapping. Preliminary results on neutron irradiation damage in HOPG are also presented. (author)

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

    Science.gov (United States)

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

    2016-04-01

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

  6. Charge Transport in C60-Based Dumbbell-type Molecules: Mechanically Induced Switching between Two Distinct Conductance States

    Czech Academy of Sciences Publication Activity Database

    Moreno-Garcia, P.; La Rosa, A.; Kolivoška, Viliam; Bermejo, D.; Hong, W.; Yoshida, K.; Baghernejad, M.; Filippone, S.; Broekmann, P.; Wandlowski, T.; Martin, N.

    2015-01-01

    Roč. 137, č. 6 (2015), s. 2318-2327 ISSN 0002-7863 R&D Projects: GA ČR(CZ) GA14-05180S Institutional support: RVO:61388955 Keywords : Atomic force microscopy * Electron tunneling * Fullerenes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 13.038, year: 2015

  7. Quantum Interference of Molecules

    Indian Academy of Sciences (India)

    IAS Admin

    C60, the third allotropic form of carbon was discovered in 1985 by Kroto and colleagues. These carbon mole- cules have a structure of a truncated icosahedron (see. Figure 5). The truncated icosahedron has 12 pentagon and 20 hexagon rings and has 60 vertices { the shape of a soccer ball. These molecules have been ...

  8. Effect of multiple plasmon excitation on single, double and multiple ionizations of C60 in collisions with fast highly charged Si ions

    International Nuclear Information System (INIS)

    Kelkar, A H; Kadhane, U; Misra, D; Kumar, A; Tribedi, L C

    2007-01-01

    We have investigated the single and multiple ionizations of the C 60 molecule in collisions with fast Si q+ projectiles for various projectile charge states (q) between q = 6 and 14. The q-dependence of the ionization cross sections and their ratios is compared with the giant dipole plasmon resonance (GDPR) model. The excellent qualitative agreement with the model in case of single and double ionizations and also a reasonable agreement with the triple (and to some extent with quadruple) ionization (without evaporation) yields signify dominant contributions of the single-, double- and triple-plasmon excitations on the single- and multiple-ionization process

  9. Effect of multiple plasmon excitation on single, double and multiple ionizations of C60 in collisions with fast highly charged Si ions

    Science.gov (United States)

    Kelkar, A. H.; Kadhane, U.; Misra, D.; Kumar, A.; Tribedi, L. C.

    2007-06-01

    We have investigated the single and multiple ionizations of the C60 molecule in collisions with fast Siq+ projectiles for various projectile charge states (q) between q = 6 and 14. The q-dependence of the ionization cross sections and their ratios is compared with the giant dipole plasmon resonance (GDPR) model. The excellent qualitative agreement with the model in case of single and double ionizations and also a reasonable agreement with the triple (and to some extent with quadruple) ionization (without evaporation) yields signify dominant contributions of the single-, double- and triple-plasmon excitations on the single- and multiple-ionization process.

  10. Probing photoelectron multiple interferences via Fourier spectroscopy in energetic photoionization of Xe-C60

    International Nuclear Information System (INIS)

    Potter, Andrea; McCune, Matthew A.; De, Ruma; Chakraborty, Himadri S.; Madjet, Mohamed E.

    2010-01-01

    Considering the photoionization of the Xe-C 60 endohedral compound, we study in detail the ionization cross sections of various levels of the system at energies higher than the plasmon resonance region. Five classes of single-electron levels are identified depending on their spectral character. Each class engenders distinct oscillations in the cross section, emerging from the interference between active ionization modes specific to that class. Analysis of the cross sections based on their Fourier transforms unravels oscillation frequencies that carry unique fingerprints of the emitting level.

  11. Modification of C60/C70+Pd film structure under electric field influence during electron emission

    International Nuclear Information System (INIS)

    Czerwosz, E.; Dluzewski, P.; Kozlowski, M.

    2001-01-01

    We investigated the modification of structure of C 60 /C 70 +Pd films during cold electron emission from these films. Films were obtained by vacuum thermal deposition from two sources and were characterised before and after electron emission measurements by transmission electron microscopy and electron diffraction. Films were composed of nanocrystalline Pd objects dispersed in carbon/fullerenes matrix. I-V characteristics for electron emission were obtained in diode geometry with additionally applied voltage along the film surface. The modification of film structure occurred under applied electric field and the grouping of Pd nano crystals into bigger objects was observed

  12. Probing photoelectron multiple interferences via Fourier spectroscopy in energetic photoionization of Xe@C60

    Science.gov (United States)

    Potter, Andrea; McCune, Matthew A.; de, Ruma; Madjet, Mohamed E.; Chakraborty, Himadri S.

    2010-09-01

    Considering the photoionization of the Xe@C60 endohedral compound, we study in detail the ionization cross sections of various levels of the system at energies higher than the plasmon resonance region. Five classes of single-electron levels are identified depending on their spectral character. Each class engenders distinct oscillations in the cross section, emerging from the interference between active ionization modes specific to that class. Analysis of the cross sections based on their Fourier transforms unravels oscillation frequencies that carry unique fingerprints of the emitting level.

  13. Friction and diffusion dynamics of adsorbates at surfaces

    NARCIS (Netherlands)

    Fusco, C.

    2005-01-01

    A theoretical study of the motion of adsorbates (e. g. atoms, molecules or clusters) on solid surfaces is presented, with a focus on surface diffusion and atomic-scale friction. These two phenomena are inextricably linked, because when an atomic or molecular adsorbate diffuses, or is pulled, it

  14. In Silico Olefin Metathesis with Ru-Based Catalysts Containing N-Heterocyclic Carbenes Bearing C60Fullerenes

    KAUST Repository

    Martínez, Juan Pablo

    2016-04-10

    Density functional theory calculations have been used to explore the potential of Ru-based complexes with 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes) ligand backbone (A) being modified in silico by the insertion of a C60 molecule (B and C), as olefin metathesis catalysts. To this end, we investigated the olefin metathesis reaction catalyzed by complexes A, B, and C using ethylene as the substrate, focusing mainly on the thermodynamic stability of all possible reaction intermediates. Our results suggest that complex B bearing an electron-withdrawing N-heterocyclic carbene improves the performance of unannulated complex A. The efficiency of complex B is only surpassed by complex A when the backbone of the N-heterocyclic carbene of complex A is substituted by two amino groups. The particular performance of complexes B and C has to be attributed to electronic factors, that is, the electronic-donating capacity of modified SIMes ligand rather than steric effects, because the latter are predicted to be almost identical for complexes B and C when compared to those of A. Overall, this study indicates that such Ru-based complexes B and C might have the potential to be effective olefin metathesis catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. In Silico Olefin Metathesis with Ru-Based Catalysts Containing N-Heterocyclic Carbenes Bearing C60 Fullerenes.

    Science.gov (United States)

    Martínez, Juan Pablo; Vummaleti, Sai Vikrama Chaitanya; Falivene, Laura; Nolan, Steven P; Cavallo, Luigi; Solà, Miquel; Poater, Albert

    2016-05-04

    Density functional theory calculations have been used to explore the potential of Ru-based complexes with 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes) ligand backbone (A) being modified in silico by the insertion of a C60 molecule (B and C), as olefin metathesis catalysts. To this end, we investigated the olefin metathesis reaction catalyzed by complexes A, B, and C using ethylene as the substrate, focusing mainly on the thermodynamic stability of all possible reaction intermediates. Our results suggest that complex B bearing an electron-withdrawing N-heterocyclic carbene improves the performance of unannulated complex A. The efficiency of complex B is only surpassed by complex A when the backbone of the N-heterocyclic carbene of complex A is substituted by two amino groups. The particular performance of complexes B and C has to be attributed to electronic factors, that is, the electronic-donating capacity of modified SIMes ligand rather than steric effects, because the latter are predicted to be almost identical for complexes B and C when compared to those of A. Overall, this study indicates that such Ru-based complexes B and C might have the potential to be effective olefin metathesis catalysts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Structural defects and epitaxial rotation of C-60 and C-70(111) films on GeS(001)

    DEFF Research Database (Denmark)

    Bernaerts, D.; Van Tendeloo, G.; Amelinckx, S.

    1996-01-01

    A transmission electron microscopy study of epitaxial C60 and C70 films grown on a GeS (001) surface is presented. The relationship between the orientation of the substrate and the films and structural defects in the films, such as grain boundaries, unknown in bulk C60 and C70 crystals, are studied...

  17. A Journey along the Extruder with Polystyrene : C60 Nanocomposites: Convergence of Feeding Formulations into a Similar Nanomorphology

    NARCIS (Netherlands)

    Gaspar, Hugo; Teixeira, Paulo; Santos, Raquel; Fernandes, Liliana; Hilliou, Loic; Weir, Michael P.; Parnell, Andrew J.; Abrams, Kerry J.; Hill, Christopher J.; Bouwman, W.G.; Parnell, S.R.; King, Stephen M.; Clarke, Nigel; Covas, Jose A.; Bernardo, Gabriel

    2017-01-01

    We investigated the effect of the feeding formulation (premixed powders of pure components versus solvent-blended mixture) of polystyrene–C60 composites on the dispersion and reagglomeration phenomena developing along the barrel of a twin-screw extruder. The dispersion of C60 in the PS matrix is

  18. In silico properties characterization of water-soluble γ-cyclodextrin bi-capped C60 complex

    DEFF Research Database (Denmark)

    Cao, Ruyin; Wu, Shanshan

    2015-01-01

    Cyclodextrin-related host-guest encapsulation is pivotal to modulate the solubility of C60, thereby promoting its potential therapeutic applications. Here we present a computational study on γ-cyclodextrin bi-capped C60 complex, probing characteristics for all the possible stoichiometry in aqueou...

  19. Human serum albumin interactions with C60 fullerene studied by spectroscopy, small-angle neutron scattering, and molecular dynamics simulations

    Science.gov (United States)

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

    2013-07-01

    Concern about the toxicity of engineered nanoparticles, such as the prototypical nanomaterial C60 fullerene, continues to grow. While, evidence continues to mount that C60 and its derivatives may pose health hazards, the specific molecular interactions of these particles with biological macromolecules require further investigation. In this article, we report combined experimental and theoretical studies on the interaction of one of the most prevalent proteins in the human body, human serum albumin (HSA), with C60 in an aqueous environment. The C60-HSA interaction was probed by circular dichroism (CD) spectroscopy, small-angle neutron scattering (SANS), and atomistic molecular dynamics (MD) simulations to understand C60-driven changes in the structure of HSA in solution. The CD spectroscopy demonstrates that the secondary structure of the protein decreases in α-helical content in response to the presence of C60 (0.68 nm in diameter). Similarly, C60 produces subtle changes in the solution conformation of HSA (an 8.0 nm × 3.8 nm protein), as evidenced by the SANS data and MD simulations, but the data do not indicate that C60 changes the oligomerization state of the protein, such as by inducing aggregation. The results demonstrate that the interaction is not highly disruptive to the protein in a manner that would prevent it from performing its physiological function.

  20. Human serum albumin interactions with C60 fullerene studied by spectroscopy, small-angle neutron scattering, and molecular dynamics simulations

    International Nuclear Information System (INIS)

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

    2013-01-01

    Concern about the toxicity of engineered nanoparticles, such as the prototypical nanomaterial C 60 fullerene, continues to grow. While, evidence continues to mount that C 60 and its derivatives may pose health hazards, the specific molecular interactions of these particles with biological macromolecules require further investigation. In this article, we report combined experimental and theoretical studies on the interaction of one of the most prevalent proteins in the human body, human serum albumin (HSA), with C 60 in an aqueous environment. The C 60 –HSA interaction was probed by circular dichroism (CD) spectroscopy, small-angle neutron scattering (SANS), and atomistic molecular dynamics (MD) simulations to understand C 60 -driven changes in the structure of HSA in solution. The CD spectroscopy demonstrates that the secondary structure of the protein decreases in α-helical content in response to the presence of C 60 (0.68 nm in diameter). Similarly, C 60 produces subtle changes in the solution conformation of HSA (an 8.0 nm × 3.8 nm protein), as evidenced by the SANS data and MD simulations, but the data do not indicate that C 60 changes the oligomerization state of the protein, such as by inducing aggregation. The results demonstrate that the interaction is not highly disruptive to the protein in a manner that would prevent it from performing its physiological function

  1. Doping of C60 fullerene peapods with lithium vapor: Raman spectroscopic and spectroelectrochemical studies.

    Science.gov (United States)

    Kalbác, Martin; Kavan, Ladislav; Zukalová, Markéta; Dunsch, Lothar

    2008-01-01

    Raman spectroscopy and in situ Raman spectroelectrochemistry have been applied to the study of the lithium vapor doping of C60@SWCNTs (peapods; SWCNT=single-walled carbon nanotube). A strong degree of doping was proven by the disappearance of the radial breathing mode (RBM) of the SWCNTs and by the attenuation of the tangential (TG) band intensity by two orders of magnitude. The lithium doping causes a downshift of the Ag(2) mode of the intratubular C60 by 27 cm(-1) and changes the resonance condition of the encapsulated fullerene. In contrast to potassium vapor doping, the strong downshift of the TG band was not observed for lithium doping. The peapods treated with lithium vapor remained partially doped even when they were exposed to humid air. This was reflected by a reduction in the intensity of the nanotube and the fullerene modes and by the change in the shape of the RBM band compared with that of the undoped sample. The Ag(2) mode of the intratubular fullerene was not resolved after contact of the lithium-doped sample with water. Lithium insertion into the interior of a peapod and its strong interaction with the intratubular fullerene is suggested to be responsible for the air-insensitive residual doping. This residual doping was confirmed by in situ spectroelectrochemical measurements. The TG band of the lithium-doped peapods did not undergo an upshift during the anodic doping, which points to the formation of a stable exohedral metallofullerene peapod.

  2. SÍNTESIS DE FULLEROLES A PARTIR DE UN DERIVADO BROMADO DE C60

    Directory of Open Access Journals (Sweden)

    Álvaro Duarte

    2009-06-01

    Full Text Available  Se sintetizaron dos fulleroles por hidrólisis básica del compuesto C60Br24 a 60°C, con 22 horas de reacción, en presencia de oxígeno atmosférico y utilizando relaciones molares de KOH/C60Br24 de 109 y 184. La geometría inicial no se mantiene al sustituir los átomos de bromo y los fulleroles obtenidos son de naturaleza aniónica y poseen una estructura compleja que incluye grupos hidroxilo y grupos hemicetal. Se encontró que el tratamiento ácido o el intercambio iónico con resina mixta tipo  H+/OH-, ocasionan la aparición de grupos carbonilos dentro de su estructura. Los productos se caracterizaron por análisis elemental, espectroscopia infrarroja, UV-Vis, 1H-RMN, MALDI-TOF, TGA y DSC.

  3. TEMPO functionalized C60 fullerene deposited on gold surface for catalytic oxidation of selected alcohols

    International Nuclear Information System (INIS)

    Piotrowski, Piotr; Pawłowska, Joanna; Sadło, Jarosław Grzegorz; Bilewicz, Renata; Kaim, Andrzej

    2017-01-01

    C 60 TEMPO 10 catalytic system linked to a microspherical gold support through a covalent S-Au bond was developed. The C 60 TEMPO 10 @Au composite catalyst had a particle size of 0.5–0.8 μm and was covered with the fullerenes derivative of 2.3 nm diameter bearing ten nitroxyl groups; the organic film showed up to 50 nm thickness. The catalytic composite allowed for the oxidation under mild conditions of various primary and secondary alcohols to the corresponding aldehyde and ketone analogues with efficiencies as high as 79–98%, thus giving values typical for homogeneous catalysis, while retaining at the same time all the advantages of heterogeneous catalysis, e.g., easy separation by filtration from the reaction mixture. The catalytic activity of the resulting system was studied by means of high pressure liquid chromatography. A redox mechanism was proposed for the process. In the catalytic cycle of the oxidation process, the TEMPO moiety was continuously regenerated in situ with an applied primary oxidant, for example, O 2 /Fe 3+ system. The new intermediate composite components and the final catalyst were characterized by various spectroscopic methods and thermogravimetry.

  4. Electronic properties of Mn-phthalocyanine–C60 bulk heterojunctions: Combining photoemission and electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Roth, Friedrich; Herzig, Melanie; Knupfer, Martin; Lupulescu, Cosmin; Darlatt, Erik; Gottwald, Alexander; Eberhardt, Wolfgang

    2015-01-01

    The electronic properties of co-evaporated mixtures (blends) of manganese phthalocyanine and the fullerene C 60 (MnPc:C 60 ) have been studied as a function of the concentration of the two constituents using two supplementary electron spectroscopic methods, photoemission spectroscopy (PES) and electron energy-loss spectroscopy (EELS) in transmission. Our PES measurements provide a detailed picture of the electronic structure measured with different excitation energies as well as different mixing ratios between MnPc and C 60 . Besides a relative energy shift, the occupied electronic states of the two materials remain essentially unchanged. The observed energy level alignment is different compared to that of the related CuPc:C 60 bulk heterojunction. Moreover, the results from our EELS investigations show that, despite the rather small interface interaction, the MnPc related electronic excitation spectrum changes significantly by admixing C 60 to MnPc thin films

  5. Solution and solid state NMR studies of the structure and dynamics of C60 and C70

    International Nuclear Information System (INIS)

    Johnson, R.D.; Yannoni, C.S.; Salem, J.; Meijer, G.; Bethune, D.S.

    1991-01-01

    This paper investigates the structure and dynamics of C 60 and C 70 with 13 C NMR spectroscopy. In solution, high-resolution spectra reveal that C 60 has a single resonance at 143 ppm, indicating a strained, aromatic system with high symmetry. This is strong evidence for a C 60 soccer ball geometry. A 2D NMR INADEQUATE experiment on 13 C-enriched C 70 reveals the bonding connectivity to be a linear string, in firm support of the proposed rugby ball structure with D 5h symmetry, and furnishes resonance assignments. Solid state NMR spectra of C 60 at ambient temperatures yield a narrow resonance, indicative of rapid molecular reorientation. Variable temperature T 1 measurements show that the rotational correlation time is ∼ 10 - 9 s at 230 K. At 77 K, this time increases to more than 1 ms, and the 13 C NMR spectrum of C 60 is a powder pattern due to chemical shift anisotropy (tensor components 220, 186, 40 ppm). At intermediate temperatures a narrow peak is superimposed on the powder pattern, suggesting a distribution of barriers to molecular motion in the sample, or the presence of an additional phase in the solid state. A Carr-Purcell dipolar experiment on C 60 in the solid state allows the first precise determination of the C 60 bond lengths: 1.45 and 1.40 Angstrom

  6. Two Positions of Potassium in Chemically Doped C(60) Peapods: An in situ Spectroelectrochemical Study.

    Science.gov (United States)

    Kalbac, Martin; Kavan, Ladislav; Zukalova, Markéta; Dunsch, Lothar

    2004-05-20

    The state of doping of fullerene peapods C60@SWCNT treated with K vapor was studied by in situ Raman spectroelectrochemistry. For all samples under study, a heavy chemical n doping was proved by the vanishing of the radial breathing mode and the downshift of tangential displacement mode. The K-treated peapods remain partly doped even if they are exposed to humid air. The Ag(2) mode of intratubular fullerene in K-doped peapods in contact with air was still redshifted as referred to its position in pristine peapods. Potassium inserted into the peapods is the reason for the air-insensitive residual doping, which can be removed only by electrochemical oxidation. This indicates the presence of two positions of potassium in doped sample.

  7. Triplet-triplet annihilation upconversion kinetics of C60-Bodipy dyads as organic triplet photosensitizers.

    Science.gov (United States)

    Wei, Yaxiong; Zhou, Miaomiao; Zhou, Qiaohui; Zhou, Xiaoguo; Liu, Shilin; Zhang, Song; Zhang, Bing

    2017-08-23

    Three new triplet photosensitizers consisting of a bodipy derivative and C 60 moieties were synthesized for triplet-triplet annihilation upconversion of perylene. With the extension of the π-conjugated structure of the bodipy derivative, the three photosensitizers exhibited different absorption wavelengths, e.g. 517 nm for B-2, 532 nm for B-4, and 557 nm for B-6. The steady-state and transient absorption, steady-state fluorescence, and upconverted fluorescence emission were investigated to reveal step-by-step the dynamic processes of the above systems. The quantum yields of intramolecular energy transfer, intersystem crossing, and triplet-triplet energy transfer were measured. From the upconverted fluorescence emission spectra, the overall quantum yield of the triplet-triplet annihilation upconversion, Φ UC , was determined to be 5.80% for B-2, 7.95% for B-4, and 4.99% for B-6.

  8. Effect of oxygen and iodine on the optical and magnetic properties of fullerite C60

    Science.gov (United States)

    Bagrov, I. V.; Belousova, I. M.; Ermakov, A. V.; Kiselev, V. M.; Kislyakov, I. M.; Sosnov, E. N.

    2009-04-01

    The effect of oxygen and iodine on the optical and magnetic properties of fullerite C60 is studied by luminescence and EPR spectroscopy within widely varied experimental conditions (temperature of the medium, oxygen or buffer gas pressure, concentration of iodine vapor). It is demonstrated that the efficiency of the singlet oxygen formation when a fullerene sample is irradiated by a neodymium laser at a wavelength of 532 nm and the amplitude of the EPR signal emitted from the unirradiated sample are strongly affected by the concentrations of both oxygen and iodine vapor sorbed by the fullerene sample, as well as by its surface temperature. The spin-spin and spin-lattice relaxation times of paramagnetic centers in fullerite samples studied in the presence of molecular oxygen are determined by the method of microwave radiation absorption saturation.

  9. Disordered adsorbate phases

    Science.gov (United States)

    Rys, Franz S.

    1985-04-01

    The occurrence of disordered phases at low temperatures in adsorbed monolayers, as shown recently in a domain wall model, is discussed, the main results are summarized and some relevant experimental systems are mentionned.

  10. Neuronal uptake and intracellular superoxide scavenging of a fullerene (C60)-poly(2-oxazoline)s nanoformulation

    KAUST Repository

    Tong, Jing

    2011-05-01

    Fullerene, the third allotrope of carbon, has been referred to as a "radical sponge" because of its powerful radical scavenging activities. However, the hydrophobicity and toxicity associated with fullerene limits its application as a therapeutic antioxidant. In the present study, we sought to overcome these limitations by generating water-soluble nanoformulations of fullerene (C(60)). Fullerene (C(60)) was formulated with poly(N-vinyl pyrrolidine) (PVP) or poly(2-alkyl-2-oxazoline)s (POx) homopolymer and random copolymer to form nano-complexes. These C(60)-polymer complexes were characterized by UV-vis spectroscopy, infrared spectroscopy (IR), dynamic light scattering (DLS), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Cellular uptake and intracellular distribution of the selected formulations in catecholaminergic (CATH.a) neurons were examined by UV-vis spectroscopy, immunofluorescence and immunogold labeling. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the ability of these C(60)-polymer complexes to scavenge superoxide. Their cytotoxicity was evaluated in three different cell lines. C(60)-POx and C(60)-PVP complexes exhibited similar physicochemical properties and antioxidant activities. C(60)-poly(2-ethyl-2-oxazoline) (PEtOx) complex, but not C(60)-PVP complex, were efficiently taken up by CATH.a neurons and attenuated the increase in intra-neuronal superoxide induced by angiotensin II (Ang II) stimulation. These results show that C(60)-POx complexes are non-toxic, neuronal cell permeable, superoxide scavenging antioxidants that might be promising candidates for the treatment of brain-related diseases associated with increased levels of superoxide.

  11. Impact of electron delocalization on the nature of the charge-transfer states in model pentacene/C60 Interfaces: A density functional theory study

    KAUST Repository

    Yang, Bing

    2014-12-04

    Electronic delocalization effects have been proposed to play a key role in photocurrent generation in organic photovoltaic devices. Here, we study the role of charge delocalization on the nature of the charge-transfer (CT) states in the case of model complexes consisting of several pentacene molecules and one fullerene (C60) molecule, which are representative of donor/acceptor heterojunctions. The energies of the CT states are examined by means of time-dependent density functional theory (TD-DFT) using the long-range-corrected functional, ωB97X, with an optimized range-separation parameter, ω. We provide a general description of how the nature of the CT states is impacted by molecular packing (i.e., interfacial donor/acceptor orientations), system size, and intermolecular interactions, features of importance in the understanding of the charge-separation mechanism.

  12. Molecular Adsorber Coating

    Science.gov (United States)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  13. A comparative study of secondary ion yield from model biological membranes using Au n+ and C60+ primary ion sources

    International Nuclear Information System (INIS)

    Baker, M.J.; Fletcher, J.S.; Jungnickel, H.; Lockyer, N.P.; Vickerman, J.C.

    2006-01-01

    Au n + and C 60 + primary ion sources have been used to acquire spectra from phospholipids, symmetric liposomes and asymmetric liposomes. We demonstrate that when using different ion beams different chemical information can be obtained. Symmetric and asymmetric liposomes, with 95% asymmetry, were produced and analysed with Au + , Au 3 + and C 60 + primary ion beams. C 60 + gave the greatest yield from the symmetric liposome but after correcting for the yield effects on the data obtained from the asymmetric liposome it has been shown that C 60 + is the most surface sensitive, providing the least information from the inner leaflet of the liposome. Au n + provides the greatest amount of information from the inner leaflet. The results present the possibility of designing ToF-SIMS experiments that selectively probe specific regions of a (bio)molecular surface

  14. Photoionization of Xe inside C60: Atom-fullerene hybridization, giant cross-section enhancement, and correlation confinement resonances

    International Nuclear Information System (INIS)

    Madjet, Mohamed E.; Renger, Thomas; Hopper, Dale E.; McCune, Matthew A.; Chakraborty, Himadri S.; Rost, Jan-M.; Manson, Steven T.

    2010-01-01

    A theoretical study of the subshell photoionization of the Xe atom endohedrally confined in C 60 is presented. Powerful hybridization of the Xe 5s state with the bottom edge of C 60 π band is found that induces strong structures in the 5s ionization, causing the cross section to differ significantly from earlier results that omit this hybridization. The hybridization also affects the angular distribution asymmetry parameter of Xe 5p ionization near the Cooper minimum. The 5p cross section, on the other hand, is greatly enhanced by borrowing considerable oscillator strength from the C 60 giant plasmon resonance via the atom-fullerene dynamical interchannel coupling. Beyond the C 60 plasmon energy range the atomic subshell cross sections display confinement-induced oscillations in which, over the large 4d shape resonance region, the dominant 4d oscillations induce their ''clones'' in all degenerate weaker channels known as correlation confinement resonances.

  15. C60@Lysozyme: direct observation by nuclear magnetic resonance of a 1:1 fullerene protein adduct.

    Science.gov (United States)

    Calvaresi, Matteo; Arnesano, Fabio; Bonacchi, Sara; Bottoni, Andrea; Calò, Vincenza; Conte, Stefano; Falini, Giuseppe; Fermani, Simona; Losacco, Maurizio; Montalti, Marco; Natile, Giovanni; Prodi, Luca; Sparla, Francesca; Zerbetto, Francesco

    2014-02-25

    Integrating carbon nanoparticles (CNPs) with proteins to form hybrid functional assemblies is an innovative research area with great promise for medical, nanotechnology, and materials science. The comprehension of CNP-protein interactions requires the still-missing identification and characterization of the 'binding pocket' for the CNPs. Here, using Lysozyme and C60 as model systems and NMR chemical shift perturbation analysis, a protein-CNP binding pocket is identified unambiguously in solution and the effect of the binding, at the level of the single amino acid, is characterized by a variety of experimental and computational approaches. Lysozyme forms a stoichiometric 1:1 adduct with C60 that is dispersed monomolecularly in water. Lysozyme maintains its tridimensional structure upon interaction with C60 and only a few identified residues are perturbed. The C60 recognition is highly specific and localized in a well-defined pocket.

  16. Oxidatively damaged DNA in rats exposed by oral gavage to C60 fullerenes and single-walled carbon nanotubes

    DEFF Research Database (Denmark)

    Folkmann, Janne K; Risom, Lotte; Jacobsen, Nicklas R

    2009-01-01

    BACKGROUND: C60 fullerenes and single-walled carbon nanotubes (SWCNT) are projected to be used in medicine and consumer products with potential human exposure. The hazardous effects of these particles are expected to involve oxidative stress with generation of oxidatively damaged DNA that might......, liver, and lung of rats after intragastric administration of pristine C60 fullerenes or SWCNT (0.064 or 0.64 mg/kg body weight) suspended in saline solution or corn oil. We investigated the regulation of DNA repair systems toward 8-oxodG in liver and lung tissue. RESULTS: Both doses of SWCNT increased...... of genotoxicity, whereas corn oil per se generated more genotoxicity than the particles. Although there was increased mRNA expression of 8-oxoguanine DNA glycosylase in the liver of C60 fullerene-treated rats, we found no significant increase in repair activity. CONCLUSIONS: Oral exposure to low doses of C60...

  17. C60-propylamine adduct monolayers at the gas/water interface: A Brewster angle microscopy and x-ray scattering study

    International Nuclear Information System (INIS)

    Fukuto, M.; Penanen, K.; Heilmann, R.K.; Pershan, P.S.; Vaknin, D.

    1997-01-01

    Brewster angle microscopy (BAM), x-ray specular reflectivity and grazing-incidence x-ray diffraction (GID) studies of C 60 -propylamine adduct monolayers at the gas/water interface as a function of molecular area are reported. At large molecular areas (A>∼150 Angstrom 2 /molecule), BAM images reveal macroscopic heterogeneity in the film, consisting of the coexistence between regions covered with uniform solidlike monolayer and bare water surface. After compression to a limiting molecular area of 150 Angstrom 2 /molecule, the film is observed to be homogeneous, with the uniform monolayer covering the entire available surface. Both the x-ray reflectivity results and the GID patterns are consistent with the formation of a uniform monolayer at A∼150 Angstrom 2 /molecule, while the little dependence that the GID patterns have on the molecular area for A>∼150 Angstrom 2 /molecule is consistent with the heterogeneity in the film. Upon further compression to higher densities (A 2 /molecule), the x-ray reflectivity results suggest the formation of a partial layer either at the molecule/gas interface or at the molecule/water interface. In this high density regime, the shift in the observed GID pattern with molecular area is much smaller than would be expected if the film were to remain a homogeneous monolayer, also consistent with the formation of an inhomogeneous partial layer. The analysis of the broad GID pattern observed from a uniform monolayer in terms of a model 2D radial distribution function, implies a short range positional correlation, extending to only a few molecular distances. The average nearest neighbor distance (d∼13 Angstrom), extracted from the GID analysis, is consistent with the limiting molecular area (A∼150 Angstrom 2 /molecule) assuming local hexagonal packing. (Abstract Truncated)

  18. Electronic excitation induced modifications of structural, electrical and optical properties of Cu-C60 nanocomposite thin films

    Science.gov (United States)

    Inani, H.; Singhal, R.; Sharma, P.; Vishnoi, R.; Ojha, S.; Chand, S.; Sharma, G. D.

    2017-09-01

    High energy ion irradiation significantly affects the size and shape of nanoparticles in composites. Low concentration metal fraction embedded in fullerene matrix in form of nanocomposites was synthesized by thermal co-evaporation method. Swift heavy ion irradiation was performed with 120 MeV Au ion beam on Cu-C60 nanocomposites at different fluences 1 × 1012, 3 × 1012, 6 × 1012, 1 × 1013 and 3 × 1013 ions/cm2. Absorption spectra demonstrated that absorption intensity of nanocomposite thin film was increased whereas absorption modes of fullerene C60 were diminished with fluence. Rutherford backscattering spectroscopy was also performed to estimate the thickness of the film and atomic metal fraction in matrix and found to be 45 nm and 3%, respectively. Transmission electron microscopy was performed for structural and particle size evaluation of Cu nanoparticles (NPs) in fullerene C60 matrix. A growth of Cu nanoparticles is observed at a fluence of 3 × 1013 ions/cm2 with a bi-modal distribution in fullerene C60. Structural evolution of fullerene C60 matrix with increasing fluence of 120 MeV Au ion beam is studied by Raman spectroscopy which shows the amorphization of matrix (fullerene C60) at lower fluence. The growth of Cu nanoparticles is explained using the phenomena of Ostwald ripening.

  19. Geometrical structure and interface dependence of bias stress induced threshold voltage shift in C60-based OFETs.

    Science.gov (United States)

    Ahmed, Rizwan; Kadashchuk, Andrey; Simbrunner, Clemens; Schwabegger, Günther; Baig, Muhammad Aslam; Sitter, Helmut

    2014-09-10

    The influence of the nature of interface between organic semiconductor and gate dielectric on bias stress electrical stability of n-type C60-based organic field effect transistors (OFETs) was studied. The bias stress induced threshold voltage (Vth) shift was found to depend critically on the OFET device structure: the direction of V(th) shift in top-gate OFETs was opposite to that in bottom-gate OFETs, while the use of the dual-gate OFET structure resulted in just very small variations in V(th). The opposite direction of Vth shift is attributed to the different nature of interfaces between C60 semiconductor and Parylene dielectric in these devices. The V(th) shift to more positive voltages upon bias stress in bottom-gate C60-OFET was similar to that observed for other n-type semiconductors and rationalized by electron trapping in the dielectric or at the gate dielectric/C60 interface. The opposite direction of Vth shift in top-gate C60-OFETs is attributed to free radical species created in the course of Parylene deposition on the surface of C60 during device fabrication, which produce plenty of hole traps. It was also realized that the dual-gate OFETs gives stable characteristics, which are immune to bias stress effects.

  20. Robust Inclusion Complexes of Crown Ether Fused Tetrathiafulvalenes with Li+@C-60 to Afford Efficient Photodriven Charge Separation

    DEFF Research Database (Denmark)

    Supur, M.; Kawashima, Y.; Larsen, K. R.

    2014-01-01

    ) obtained by UV/Vis titrations in benzonitrile (PhCN) at room temperature. On the basis of DFT studies at the B3LYP/6-311G(d,p) level, the orbital interactions between the crown ether moieties and the p surface of the fullerene together with the endohedral Li+ have a crucial role in robust complex formation....... Interestingly, complexation of Li+@C-60 with crown ethers accelerates the intersystem crossing upon photoexcitation of the complex, thereby yielding 3(Li+@C-60)*, when no charge separation by means of 1Li(+)@C-60* occurs. Photoinduced charge separation by means of 3Li(+)@C-60* with lifetimes of 135 and 120 ms...... for 1 center dot Li+@C-60 and 2 center dot Li+@C-60, respectively, and quantum yields of 0.82 in PhCN have been observed by utilizing time-resolved transient absorption spectroscopy and then confirmed by electron paramagnetic resonance measurements at 4 K. The difference in crown ether structures...

  1. Immunotoxicity of nanoparticles: a computational study suggests that CNTs and C60 fullerenes might be recognized as pathogens by Toll-like receptors

    Science.gov (United States)

    Turabekova, M.; Rasulev, B.; Theodore, M.; Jackman, J.; Leszczynska, D.; Leszczynski, J.

    2014-03-01

    Over the last decade, a great deal of attention has been devoted to study the inflammatory response upon exposure to multi/single-walled carbon nanotubes (CNTs) and different fullerene derivatives. In particular, carbon nanoparticles are reported to provoke substantial inflammation in alveolar and bronchial epithelial cells, epidermal keratinocytes, cultured monocyte-macrophage cells, etc. We suggest a hypothetical model providing the potential mechanistic explanation for immune and inflammatory responses observed upon exposure to carbon nanoparticles. Specifically, we performed a theoretical study to analyze CNT and C60 fullerene interactions with the available X-ray structures of Toll-like receptors (TLRs) homo- and hetero-dimer extracellular domains. This assumption was based on the fact that similar to the known TLR ligands both CNTs and fullerenes induce, in cells, the secretion of certain inflammatory protein mediators, such as interleukins and chemokines. These proteins are observed within inflammation downstream processes resulted from the ligand molecule dependent inhibition or activation of TLR-induced signal transduction. Our computational studies have shown that the internal hydrophobic pockets of some TLRs might be capable of binding small-sized carbon nanostructures (5,5 armchair SWCNTs containing 11 carbon atom layers and C60 fullerene). High binding scores and minor structural alterations induced in TLR ectodomains upon binding C60 and CNTs further supported our hypothesis. Additionally, the proposed hypothesis is strengthened by the indirect experimental findings indicating that CNTs and fullerenes induce an excessive expression of specific cytokines and chemokines (i.e. IL-8 and MCP1).Over the last decade, a great deal of attention has been devoted to study the inflammatory response upon exposure to multi/single-walled carbon nanotubes (CNTs) and different fullerene derivatives. In particular, carbon nanoparticles are reported to provoke

  2. Decomposition of palladium acetate and C60 fullerite during thermal evaporation in PVD process

    Directory of Open Access Journals (Sweden)

    Rymarczyk Joanna

    2017-10-01

    Full Text Available The mechanisms of thermal decomposition of evaporated material during Physical Vapor Deposition (PVD process depend on the kind of evaporated material. Such parameters of PVD process as deposition rate, source temperature and deposition time should be carefully selected taking into account the properties of material. Deposited films can span the range of chemical compositions based on the source materials. The nanostructural carbon films in form of palladium nanograins embedded in various carbonaceous matrixes were obtained by thermal evaporation during PVD process from two separated sources containing C60 fullerite and palladium acetate, both in a form of powder. The evaporation was realized by resistive heating of sources under a dynamic vacuum of 10-3 Pa. The influence of decomposition path of evaporated materials on the film structure has been discussed. Prepared C-Pd films were characterized using thermo-gravimetric method, differential thermal analysis, infrared spectroscopy and X-ray diffraction. The influence of decomposition of Pd acetate and fullerite on the final film structure was also shown.

  3. Analysis of loads on the SDC at Paktoa C-60 during an ice creep buckling event

    Energy Technology Data Exchange (ETDEWEB)

    Sudom, D.; Timco, G. [National Research Council of Canada, Ottawa, ON (Canada). Canadian Hydraulics Centre

    2008-07-01

    During the winter of 2005-2006, an exploratory well was drilled using the steel drilling caisson (SDC) at Devon Canada's Paktoa C-60 site in the Beaufort Sea. Three major storms occurred during deployment. This paper focused on the final storm in late February, 2006. Although the ice surrounding the SDC was landfast and 1 metre thick, it buckled overnight. This paper examined the available data and utilized four separate approaches to estimate the ice force on the SDC during this loading event. A sketch of the ice buckling near the SDC on the during the event was presented along with load calculations. Ice creep buckling force calculations were also explained. Two methods were presented to calculate ice creep buckling force, notably buckle wavelength and time constant. The paper also presented suggestions that should be addressed to make this approach more reliable for load predictions. It was concluded that the load prediction using the geotechnical response was especially interesting as it gave reasonable agreement with other predictive approaches. It also pointed to important questions that should be addressed to further develop this approach. 11 refs., 4 figs.

  4. AC electric field assisted orientational photorefractive effect in C60-doped nematic liquid crystal

    International Nuclear Information System (INIS)

    Sun Xiudong; Pei Yanbo; Yao Fengfeng; Zhang Jianlong; Hou Chunfeng

    2007-01-01

    Photorefractive gratings were produced in a C 60 -doped nematic liquid crystal cell under the application of two coherent beams and a nonbiased sinusoidal ac electric field. The beam coupling and diffraction of the ac electric field assisted gratings were studied systematically. A stable asymmetric energy transference was obtained. Diffraction was observed when the angle (between the normal of the cell and the bisector of the writing beams) was 0 0 , and the dependence of diffraction efficiency on the peak-to-peak value of the ac voltage was similar to that at an incidence angle of 45 0 , suggesting that the role of the ac field was to facilitate the charge separation, and the space-charge field (SCF) originated predominantly from the diffusion of the ac electric field assisted photo-induced carriers under the application of nonuniform illumination and an applied ac field. The grating was produced by director reorientation induced by the cooperation of the SCF and the applied ac electric field. A self-erasing phenomenon was observed in this cell. An explanation in terms of the movement of two kinds of carriers with opposite signs was proposed

  5. The Effect of Highly Hydroxylated Fullerenol C60(OH36 on Human Erythrocyte Membrane Organization

    Directory of Open Access Journals (Sweden)

    Jacek Grebowski

    2015-01-01

    Full Text Available The mechanism of the interaction of highly hydroxylated fullerenol C60(OH36 with erythrocyte membranes was studied by electron spin resonance spectroscopy (ESR of stearic acid derivatives labeled with a nitroxyl radical at C-12 or C-16 and with a nitroxyl derivative of maleimide covalently attached to sulfhydryl groups of membrane proteins. A significant increase in membrane fluidity in the hydrophobic region of the lipid bilayer was observed for 12-doxylstearic acid at fullerenol concentrations of 100 mg/L or 150 mg/L, while for 16-doxylstearic acid significant increase in fluidity was only observed at 150 mg/L. Fullerenol at 100 mg/L or 150 mg/L caused conformational changes in membrane proteins, expressed as an increase in the hw/hs parameter, when fullerenol was added before the maleimide spin label (MSL to the membrane suspension. The increase of the hw/hs parameter may be caused by changes in lipid-protein or protein-protein interactions which increase the mobility of the MSL label and as a result increase the membrane fluidity. Incubation of the membranes with the MSL before the addition of fullerenol blocked the available membrane protein –SH groups and minimized the interaction of fullerenol with them. This confirms that fullerenol interacts with erythrocyte membrane proteins via available protein –SH groups.

  6. Toxicity and bioaccumulation of xenobiotic organic compounds in the presence of aqueous suspensions of aggregates of nano-C(60).

    Science.gov (United States)

    Baun, A; Sørensen, S N; Rasmussen, R F; Hartmann, N B; Koch, C B

    2008-02-18

    The potential of C(60)-nanoparticles (Buckminster fullerenes) as contaminant carriers in aqueous systems was studied in a series of toxicity tests with algae (Pseudokirchneriella subcapitata) and crustaceans (Daphnia magna). Four common environmental contaminants (atrazine, methyl parathion, pentachlorophenol (PCP), and phenanthrene) were used as model compounds, representing different physico-chemical properties and toxic modes of action. The aggregates of nano-C(60) formed over 2 months of stirring in water were mixed with model compounds 5 days prior to testing. Uptake and excretion of phenanthrene in 4-days-old D. magna was studied with and without addition of C(60) in aqueous suspensions. It was found that 85% of the added phenanthrene sorbed to C(60)-aggregates >200 nm whereas about 10% sorption was found for atrazine, methyl parathion, and pentachlorophenol. In algal tests, the presence of C(60)-aggregates increased the toxicity of phenanthrene with 60% and decreased toxicity of PCP about 1.9 times. Addition of C(60)-aggregates reduced the toxicity of PCP with 25% in tests with D. magna, whereas a more than 10 times increase in toxicity was observed for phenanthrene when results were expressed as water phase concentrations. Thus, results from both toxicity tests show that phenanthrene sorbed to C(60)-aggregates is available for the organisms. For atrazine and methyl parathion no statistically significant differences in toxicities could be observed in algal and daphnid tests as a result of the presence of C(60)-aggregates. In bioaccumulation studies with phenanthrene in D. magna it was found that the uptake of phenanthrene was faster when C(60) was present in suspension and that a 1.7 times higher steady-state concentration was reached in the animals. However, a very fast clearance took place when animals were transferred to clean water resulting in no accumulation of phenanthrene. This study is the first to demonstrate the influence of C(60)-aggregates on

  7. Computer simulations of adsorbed liquid crystal films

    Science.gov (United States)

    Wall, Greg D.; Cleaver, Douglas J.

    2003-01-01

    The structures adopted by adsorbed thin films of Gay-Berne particles in the presence of a coexisting vapour phase are investigated by molecular dynamics simulation. The films are adsorbed at a flat substrate which favours planar anchoring, whereas the nematic-vapour interface favours normal alignment. On cooling, a system with a high molecule-substrate interaction strength exhibits substrate-induced planar orientational ordering and considerable stratification is observed in the density profiles. In contrast, a system with weak molecule-substrate coupling adopts a director orientation orthogonal to the substrate plane, owing to the increased influence of the nematic-vapour interface. There are significant differences between the structures adopted at the two interfaces, in contrast with the predictions of density functional treatments of such systems.

  8. Zero-charged catanionic lamellar liquid crystals doped with fullerene C60 for potential applications in tribology.

    Science.gov (United States)

    Chen, Mengjun; Liu, Baoyong; Wang, Xiaolin; Fu, Yanxu; Hao, Jingcheng; Li, Hongguang

    2017-09-20

    The formation of lamellar liquid crystals (LLCs) has been demonstrated in a few salt-free catanionic surfactant systems and their properties have been well documented. However, examples of their combination with other materials are relatively rare. Herein, a salt-free zero-charged catanionic surfactant with low chain melting temperature was prepared by mixing equimolar tetradecyltrimethylammonium oxide (TTAOH) and oleic acid (OA) in water, and its concentration-dependent aggregate transition was investigated. In the dilute region (c TTAO ≤ 5 wt%), fluorescence microscopy observations revealed the formation of vesicles (the L αv phase). Further increasing c TTAO induced a transition from the L αv phase to LLCs via a region where vesicles and lamellae coexist. With ordered hydrophobic domains, the LLCs can be used as hosts for the doping of fullerene C 60 (refers to C 60 hereafter) with the highest C 60 /TTAO weight ratio of 0.04. The doping of C 60 effectively improves the viscoelasticity of the LLCs confirmed by rheological characterization while only slight modifications on their matrixes have been detected using small angle X-ray scattering measurements. The LLC/C 60 hybrids with c TTAO = 80 wt% were then subjected to tribological measurements, and an obvious reduction in their friction coefficients and wear volumes was observed. The C 60 /TTAO weight ratio at which the best tribological performance appears was determined to be 0.01. Our results indicate that the combination of C 60 and catanionic LLCs could lead to the appearance of a new generation of environmentally-benign lubricants.

  9. C60-fullerenes as Drug Delivery Carriers for Anticancer Agents: Promises and Hurdles.

    Science.gov (United States)

    Kumar, Manish; Raza, Kaisar

    2017-01-01

    C60-fullerenes (CFs) constitute a carbon-allotropic family with cage-like fused-ring structure, comprising of 20 hexagons and 12 pentagons. Since discovery in 1985, CFs attracted the scientists from various strata for unique properties like tensile strength, nanometeric size, symmetric nature, thermal and photo conductivity, chemical tailoring opportunities and drug loading capabilities. Surprisingly, CFs are also established to possess antiviral, neuroprotective, antiinflammatory, MRI contrast and antioxidant properties. Though extensively explored for chemical modifications and therapeutic benefits, CFs and derivatives also offer immense promises in drug delivery, especially to the cancerous cells. The present review is an attempt to highlight the promises of CFs in drug delivery, esp. of anticancer agents. The review also analyzes the safety concerns of CF-based drug delivery and attempts to discuss the promises and challenges in the light of preclinical and clinical data. The raw material (research/review articles) for the manuscript was collected from Pubmed, Google scholar and Scopus and the keywords used were fullerenes, nanotechnology, nanomedicine, functionalization, safety, drug delivery and biomedical applications. The drug release rate controlling behavior, higher drug loading, immuno-neutrality, substantial biocompatibility, capability to bypass mononuclear phagocytic system, long circulating nature and tissue extraction by virtue of enhanced permeability and retention effect are the major promises of these nanocarriers. On the other hand, the concerns like elimination from the biological system, anticipated tissue toxicity, stability of the final product, sterility issues and commercial viability pose challenges in proper utilization of CFs as ideal drug delivery carriers. However, a few commercial products based on CFs with human safety evidences provide a ray of hope. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. Application of C60, C72 and carbon nanotubes as anode for lithium-ion batteries: A DFT study

    International Nuclear Information System (INIS)

    Najafi, Meysam

    2017-01-01

    The application of C 60 , C 72 , CNT (8, 0) and CNT (10, 0) as anode materials for Lithium-ion batteries were investigated by density functional theory (DFT) calculations. Results show that the average values of voltage cell (V cell ) and adsorption energy (E ad ) of CNT (8, 0) and CNT (10, 0) were higher than C 60 and C 72 ca 0.327 V and 6.52 kcal/mol, respectively. The NH 2 functionalization of studied nanostructures as a strategy to improve the performance of these systems as anode materials of Lithium-ion batteries were investigated. Results show that, NH 2 functionalization of studied nanostructures increase the average values of voltage cell and adsorption energy ca 0.197 V and 8.20 kcal/mol, respectively. Obtained results propose that NH 2 functionalized C 72 and CNT (10, 0) have larger V cell and E ad values and therefore these nanostructures have higher potential as anode material for Lithium-ion battery. - Highlights: • C 60 and CNT (10, 0) as anode materials for Lithium-ion batteries were investigated. • V cell and E ad of CNT (8, 0) and CNT (10, 0) were higher than C 60 and C 72 ca. • NH 2 functionalization of C 60 improve the performance of it as anode materials of Lithium-ion batteries.

  11. The effect of gate voltage on the electrical transport properties in the contacts of C60 to carbon nano tube leads

    International Nuclear Information System (INIS)

    Shokri, A. A.; Nikzad, Sh.

    2012-01-01

    In this paper, we examined the effect of gate voltage, bias voltage, contact geometries and the different bond lengths on the electrical transport properties in a nano structure consisting of C 60 molecule attached to two semi-infinite leads made of single wall carbon nano tubes in the coherent regime. Our calculation was based on the Green's function method within nearest-neighbour tight-binding approximation. After the calculation was of transmission, the electrical current was obtained by the Landauer-Buttiker formula. Next, the effect of the mentioned factors was investigated in the nano structure. The application of the present results may be useful in designing devices based on molecular electronics in nano scale.

  12. Sputtered neutral SinCm clusters as a monitor for carbon implantation during C60 bombardment of silicon

    International Nuclear Information System (INIS)

    Wucher, A.; Kucher, A.; Winograd, N.; Briner, C.A.; Krantzman, K.D.

    2011-01-01

    The incorporation of carbon atoms into a silicon surface under bombardment with 40-keV C 60 + ions is investigated using time-of-flight mass spectrometry of sputtered neutral and ionized Si n C m clusters. The neutral particles emitted from the surface are post-ionized by strong field infrared photoionization using a femtosecond laser system operated at a wavelength of 1400/1700 nm. From the comparison of secondary ion and neutral spectra, it is found that the secondary ion signals do not reflect the true partial sputter yields of the emitted clusters. The measured yield distribution is interpreted in terms of the accumulating carbon surface concentration with increasing C 60 fluence. The experimental results are compared with those from recent molecular dynamics simulations of C 60 bombardment of silicon.

  13. (RbxK1-x)3C60 superconductors: Formation of a continuous series of solid solutions

    International Nuclear Information System (INIS)

    Chia-Chun Chen; Kelty, S.P.; Lieber, C.M.

    1991-01-01

    By means of an approach that employs alkali-metal alloys, bulk single-phase (Rb x K 1-x ) 3 C 60 superconductors have been prepared for all x between 0 and 1. For x = 1 it is shown that the maximum superconducting fraction, which approaches 100% in sintered pellets, occurs at a Rb to C 60 ratio of 3:1. More importantly, single-phase superconductors are formed at all intermediate values of x, and it is shown that the transition temperature (T c ) increases linearly with x in the series of materials. The formation of a continuous range of solid solutions demonstrates that the rubidium- and potassium-doped C 60 superconducting phases must be isostructural, and furthermore, suggests that the linear increase in T c with x results from a chemical pressure effect

  14. Toxicity and bioaccumulation of xenobiotic organic compounds in the presence of aqueous suspensions of aggregates of nano-C60

    DEFF Research Database (Denmark)

    Baun, Anders; Sørensen, Sara Nørgaard; Rasmussen, R.F.

    2008-01-01

    as water phase concentrations. Thus, results from both toxicity tests show that phenanthrene sorbed to C60-aggregates is available for the organisms. For atrazine and methyl parathion no statistically significant differences in toxicities could be observed in algal and daphnid tests as a result...... animals were transferred to clean water resulting in no accumulation of phenanthrene. This study is the first to demonstrate the influence of C60-aggregates on aquatic toxicity and bioaccumulation of other environmentally relevant contaminants. The data provided underline that not only the inherent......, pentachlorophenol (PCP), and phenanthrene) were used as model compounds, representing different physico-chemical properties and toxic modes of action. The aggregates of nano-C60 formed over 2 months of stirring in water were mixed with model compounds 5 days prior to testing. Uptake and excretion of phenanthrene...

  15. Hybrids of copolymers of fluorene and C60 -carrying-carbazole with semiconducting single-walled carbon nanotubes.

    Science.gov (United States)

    Toshimitsu, Fumiyuki; Ozawa, Hiroaki; Nakashima, Naotoshi

    2015-02-16

    Three different copolymers of C60 -carrying-carbazole and fluorene units with different copolymer composition ratios were designed and synthesized. On the basis of photoluminescence, atomic force microscopy, and Vis-NIR and Raman spectroscopic analysis, we found that these copolymers solubilize only semiconducting single-walled carbon nanotubes (sem-SWNTs) to form copolymer/sem-SWNT hybrids, in which energy transfer from the copolymer/C60 moieties to the SWNTs was revealed. By comparing two possible hybrid structures with molecular-mechanics simulations, the greatest stabilization was found when the C60 moieties lay on the sem-SWNT surfaces. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weinelt, M.; Nilsson, A.; Wassdahl, N. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

  17. Possible magnetic states in buckybowl molecules

    OpenAIRE

    Harigaya, Kikuo

    2011-01-01

    Possible magnetic properties are studied in the buckybowl molecules: the sumanene and a part of C_60. The Hubbard model is applied to the systems. We find that the molecular structure determines the magnetism in the sumanene. On the other hand, the edge state is found along the zigzag edge of a part of C_60. Therefore, the novel property, transition from molecular magnetism to the magnetism like in nanographene, is found.

  18. Modeling New Adsorbents for Ethylene/Ethane Separations by Adsorption via {Pi}-Complexation

    Energy Technology Data Exchange (ETDEWEB)

    Blas, F. J.; Vega, L. F.; Gubbins, K. E.

    1998-01-01

    The adsorption of olefins and paraffins in a novel model porous adsorbent is studied by means of molecular simulations. The adsorbents are synthesized by effective dispersion of CuCI on substrates with hydrocarbon-phobic surfaces, such as {gamma}-A1{sub 2}O{sub 3}. The Cu(I) cations are able to undergo {pi}-complexation with olefin molecules. Ethane and ethylene are studied as adsorbents, and the molecules are modeled as having two Lennard-Jones sites. Ethylene molecules have two additional associating square-well sites placed in the line perpendicular to the symmetry axis of the molecules in order to reproduce the {pi}-complexation.

  19. Strong antiferromagnetic coupling of spins in the (MDABCO+)(C60·-) salt with 3D close packing of the C60·- radical anions (MDABCO+: N-methyldiazabicyclooctanium cation).

    Science.gov (United States)

    Konarev, Dmitri V; Khasanov, Salavat S; Otsuka, Akihiro; Yamochi, Hideki; Saito, Gunzi; Lyubovskaya, Rimma N

    2014-06-01

    A new salt, (MDABCO(+))(C60(·-)) (1; MDABCO(+) = N-methyldiazabicyclooctanium cation), was obtained as single crystals. The crystal structure of 1 determined at 250 and 100 K showed 3D close packing of fullerenes with eight fullerene neighbors for each C60(·-). These neighbors are located at 10.01-10.11 Å center-to-center distances (250 K) and van der Waals interfullerene C⋅⋅⋅C contacts are formed with four fullerene neighbors arranged in the bc plane. Fullerene ordering observed below 160 K is accompanied by the appearance of one and a half independent C60(·-) and trebling of the unit cell along the b axis. Fullerenes are packed closer to each other at 100 K. As a result, fullerenes are located in the three-dimensional packing at 9.91-10.12 Å center-to-center distances and 18 short interfullerene C⋅⋅⋅C contacts are formed for each C60(·-). Although they are closed packed, fullerenes are not dimerized down to 1.9 K. Magnetic data indicate strong antiferromagnetic coupling of spins in the 70-300 K range with a Weiss temperature of Θ = -118 K. Magnetic susceptibility shows a round maximum at 46 K. Such behavior can be described well by the Heisenberg model for square two-dimensional antiferromagnetic coupling of spins with an exchange interaction of J/kB = -25.3 K. This magnetic coupling is one of the strongest observed for C60(·-) salts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Fluorine containing C(60) derivatives for high-performance electron transporting field-effect transistors and integrated circuits

    NARCIS (Netherlands)

    Wobkenberg, Paul H.; Ball, James; Bradley, Donal D. C.; Anthopoulos, Thomas D.; Kooistra, Floris; Hummelen, Jan C.; de Leeuw, Dago M.; Wöbkenberg, Paul H.

    2008-01-01

    We report on electron transporting organic transistors and integrated ring oscillators based on four different solution processible fluorine containing C(60) derivatives. Electron mobilities up to 0.15 cm(2)/V s are obtained from as-prepared bottom-gate, bottom-contact transistors utilizing gold

  1. A first-principle investigation into effect of B-and BN-doped C60 in ...

    Indian Academy of Sciences (India)

    Annual Meetings · Mid Year Meetings · Discussion Meetings · Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 40; Issue 7. A first-principle investigation into effect of B- and BN-doped C 60 in lowering dehydrogenation of MXH 4 ...

  2. AC/DC electrical conduction and dielectric properties of PMMA/PVAc/C60 down-shifting nanocomposite films

    Science.gov (United States)

    El-Bashir, S. M.; Alwadai, N. M.; AlZayed, N.

    2018-02-01

    Polymer nanocomposite films were prepared by doping fullerene C60 in polymer blend composed of polymethacrylate/polyvinyl acetate blends (PMMA/PVAc) using solution cast technique. The films were characterized by differential scanning calorimeter (DSC), Transmission electron microscope (TEM), DC/AC electrical conductivity and dielectric measurements in the frequency range (100 Hz- 1 MHz). The glass transition temperature, Tg, was increased by increasing the concentration of fullerene C60; this property reflects the increase of thermal stability by increasing the nanofiller content. The DC and AC electrical conductivities were enhanced by increasing C60 concentration due to the electron hopping or tunneling between filled and empty localized states above Tg. The relaxation time was determined from the αβ -relaxations and found to be attenuated by increasing the temperature as a typical behavior of amorphous polymers. The calculated values of thermodynamic parameters revealed the increase of molecular stability by increasing the doping concentration; this feature supports the application of PMMA/PVAc/C60 nanocomposite films in a wide scale of solar energy conversion applications such as luminescent down-shifting (LDS) coatings for photovoltaic cells.

  3. On the possibility of the electron polarization to be the driving force for the C60-TMB nanowire growth

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Geng, Junfeng; Solov'yov, Andrey V.

    2009-01-01

    The effect of electron polarization has been suggested to explain the exceptionally large length-to width aspect ratio (more than 3000) in recently observed C_60-based nanowires. The theoretical estimates performed in the present Letter show that at room temperature the effect of electron polariz...

  4. Photo-assisted electrochemical abatement of trifluralin using a cathode containing a C60-carbon nanotubes composite.

    Science.gov (United States)

    Hasanzadeh, Aliyeh; Khataee, Alireza; Zarei, Mahmoud; Joo, Sang Woo

    2018-05-01

    This work reports the potential application of modified gas-diffusion electrode (GDE) with C 60 -CNT composite, as a stable and efficient cathode material for degradation of trifluralin (TRL) pesticide by photo-assisted electrochemical (PE) process. C 60 -CNT composite was prepared and characterized. Subsequently, a novel C 60 -CNT composite modified GDE cathode was developed and the electrochemical and physical characteristics of the modified GDEs were studied. C 60 -CNT composite/GDE showed great efficiencies for electro-generating H 2 O 2 , owing to huge surface area and high conductivity. Afterwards, a comparative study of TRL oxidation via photolysis, anodic oxidation (AO) and PE processes using C 60 -CNT composite/GDE revealed the degradation percentages of 42.2, 48.5 and 93.4%, respectively, after 180 min of treatment. The TRL degradation followed a pseudo-first-order kinetics, being faster in the order: photolysis composite/GDE exhibited great performance for the degradation of TRL (20 mg L -1 ) under its original pH, Na 2 SO 4 electrolyte concentration of 0.05 mol L -1 , applied current intensity of 300 mA, and flow rate of 12.5 L h -1 . TOC results displayed that 92.8% of TRL was mineralized after 8 h of PE process. In addition, a plausible pathway for mineralization of TRL was proposed according to the identified by-products detected by means of gas chromatography-mass spectroscopy (GC-MS), High-performance liquid chromatography (HPLC) and ion chromatography analyses. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Zeolites as alcohol adsorbents from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Cekova Blagica

    2006-01-01

    Full Text Available The potential usage of zeolites as adsorbents for the removal of organic molecules from water was investigated in a series of experiments with aqueous solutions of lower alcohols. This could represent a simple solution to the problem of cleaning up industrial wastewater as well as recovering valuable chemicals at relatively low costs. Adsorption isotherms of the Langmuir type were applied, and calculations showed that the amount of propanol adsorbed on silicalite corresponded to approximately 70% of the pore volume. The adsorption process is simple, and recovery of the more concentrated products is easily done by heat treatment and/or at lowered pressures. Adsorption experiments with aqueous acetone showed that silicalite had approximately the same adsorption capacity for acetone as for n-propanol. Heats of adsorption were determined calorimetrically.

  6. Relative ion yields in mammalian cell components using C60 SIMS

    Science.gov (United States)

    Keskin, Selda; Piwowar, Alan; Hue, Jonathan; Shen, Kan; Winograd, Nicholas

    2013-01-01

    Time of flight secondary ion mass spectrometry has been used to better understand the influence of molecular environment on the relative ion yields of membrane lipid molecules found in high abundance in a model mammalian cell line, RAW264.7. Control lipid mixtures were prepared to simulate lipid–lipid interactions in the inner and outer leaflet of cell membranes. Compared with its pure film, the molecular ion yields of 1,2-dioleoyl-sn-glycero-3-phosphocholine and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine are suppressed when mixed with 2-dipalmitoyl-sn-glycero-3-phosphocholine. In the mixture, proton competition between 1,2-dioleoyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, and 2-dipalmitoyl-sn-glycero-3-phosphocholine led to lower ionization efficiency. The possible mechanism for ion suppression was also investigated with 1H and 13C nuclear magnetic resonance spectroscopy. The formation of a hydroxyl bond in lipid mixtures confirms the mechanism involving proton exchange with the surrounding environment. Similar effects were observed for lipid mixtures mimicking the composition of the inner leaflet of cell membranes. The secondary molecular ion yield of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine was observed to be enhanced in the presence of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine. PMID:25140069

  7. Predicting the properties of a new class of host-guest complexes: C60 fullerene and CB[9] cucurbituril.

    Science.gov (United States)

    Fileti, Eudes; Colherinhas, Guilherme; Malaspina, Thaciana

    2014-11-07

    DFT, semi-empirical and classical molecular dynamics methods were used to describe the structure and stability of the inclusion complex formed by the fullerene C60 and the cucurbituril CB[9]. Our results indicate a high structural compatibility between the two monomers, which is evident from the potential energy curve for the inclusion process of the C60 into the CB[9] cavity. The interaction between the two monomers is mainly of the van der Waals type and leads to a highly stable complex. Thermal contributions and environmental interaction are taken into account by the free energy of binding of -224 kJ mol(-1), indicating that even in aqueous medium the complex remains very stable.

  8. Enhanced performance of C60 organic field effect transistors using a tris(8-hydroxyquinoline) aluminum buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Hong; Cheng Xiaoman; Tian Haijun [Institute of Material Physics, Key Laboratory of Display Material and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); Zhao Geng, E-mail: zheng_033@163.com [School of Science, Tianjin University of Technology, Tianjin 300384 (China)

    2011-09-15

    We have investigated the properties of C60-based organic field effect transistors (OFETs) with a tris(8-hydroxyquinoline) aluminum (Alq3) buffer layer inserted between the source/drain electrodes and the active material. The electrical characteristics of OFETs are improved with the insertion of Alq3 film. The peak field effect mobility is increased to 1.28 x 10{sup -2} cm{sup 2}/(V{center_dot}s) and the threshold voltage is decreased to 10 V when the thickness of the Alq3 is 10 nm. The reason for the improved performance of the devices is probably due to the prevention of metal atoms diffusing into the C60 active layer and the reduction of the channel resistance in Alq3 films. (semiconductor devices)

  9. Size-exclusive nanosensor for quantitative analysis of fullerene C60.

    Science.gov (United States)

    Kikandi, Samuel N; Okello, Veronica A; Wang, Qiong; Sadik, Omowunmi A; Varner, Katrina E; Burns, Sarah A

    2011-06-15

    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 (β-CD-NH₂) was synthesized and confirmed by ¹HNMR as the host molecule to isolate the desired fullerene C₆₀. This was subsequently assembled onto the surfaces of gold-coated quartz crystal microbalance (QCM) electrodes using N-dicyclohexylcarbodiimide/N-hydroxysuccinimide (DCC/NHS) surface immobilization chemistry to create a selective molecular configuration described as (Au)-S-(CH₂)²-CONH-beta-CD sensor. The mass change on the sensor configuration on the QCM was monitored for selective quantitative analysis of fullerene C₆₀ from a C₆₀/C₇₀ mixture and soil samples. About ~10¹⁴-10¹⁶ C₆₀ particles/cm² were successfully quantified by QCM measurements. Continuous spike of 200 μL of 0.14 mg C₆₀ /mL produced changes in frequency (-Δf) that varied exponentially with concentration. FESEM and time-of-flight secondary-ion mass spectrometry confirmed the validity of sensor surface chemistry before and after exposure to fullerene C₆₀. The utility of this sensor for spiked real-world soil samples has been demonstrated. Comparable sensitivity was obtained using both the soil and purified toluene samples. This work demonstrates that the sensor has potential application in complex environmental matrices.

  10. Growth of Fullerene Fragments Using the Diels-Alder Cycloaddition Reaction: First Step towards a C60 Synthesis by Dimerization

    Directory of Open Access Journals (Sweden)

    Julio A. Alonso

    2013-02-01

    Full Text Available Density Functional Theory has been used to model the Diels-Alder reactions of the fullerene fragments triindenetriphenilene and pentacyclopentacorannulene with ethylene and 1,3-butadiene. The purpose is to prove the feasibility of using Diels-Alder cycloaddition reactions to grow fullerene fragments step by step, and to dimerize fullerene fragments, as a way to obtain C60. The dienophile character of the fullerene fragments is dominant, and the reaction of butadiene with pentacyclopentacorannulene is favored.

  11. Tunability of RF-Responses by Plasmonic Dielectric Amplification Using Branched e- -Polarizable C60-Adducts on Magnetic (Postprint)

    Science.gov (United States)

    2016-07-18

    energy can lead to the formation of polarizations at the surface region. Polarizability of this particular type of NPs, as a function of the size...Soumekh, M. Synthetic Aperture Radar Signal Processing with MATLAB Algorithms ; John Wiley & Sons: New York, 1999. (16) Kong, J. A. Electromagnetic Wave...FeOx NP core, was effectively released at the light-off stage to induce the intramolecular polarization of C60-DPAF adducts. Resulting charged

  12. High performance Mo adsorbent PZC

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1998-10-01

    We have developed Mo adsorbents for natural Mo(n, {gamma}){sup 99}Mo-{sup 99m}Tc generator. Among them, we called the highest performance adsorbent PZC that could adsorb about 250 mg-Mo/g. In this report, we will show the structure, adsorption mechanism of Mo, and the other useful properties of PZC when you carry out the examination of Mo adsorption and elution of {sup 99m}Tc. (author)

  13. Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

    KAUST Repository

    Mahfouz, Remi

    2015-09-18

    We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C60 encapsulated inside carbon nanotubes called peapods can be derived from 13C nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to −68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shift anisotropy and spin-lattice relaxation (T1) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C60 that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C60 at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(EF).

  14. COMBINED EFFECT OF ELECTROMAGNETIC RADIATION, DNA-INTERCALATORS, C60-FULLERENE AND CAFFEINE ON HUMAN BUCCAL EPITHELIUM CELLS

    Directory of Open Access Journals (Sweden)

    G. B. Skamrova

    2014-04-01

    Full Text Available Now the number of physical and chemical biologically active damage factors dramatically increased. The ways to neutralize such effects have not been studied enough. In this work the techniques of visual assessment of chromatin granulation and of electronegativity of human buccal epithelium cell nuclei were used in order to study the combined effects of the exposure to low-intensity electromagnetic radiation of the millimeter range electromagnetic radiation and to the DNA-binding compounds, such as: antibiotic doxorubicin, mutagens ethidium bromide and proflavine, as well as to caffeine and C60 -fullerene which are not directly interact with DNA. When the action of electromagnetic radiation and DNA-binding compounds is combined, a synergistic effect of reducing the cell response was observed in contrast to the effects caused by electromagnetic radiation and drugs separately. When cells were irradiated in the presence of C60 -fullerene or caffeine, a protective effect of compounds against electromagnetic radiation influence was observed. The obtained results may provide perspectives in the use of the C60 fullerene and caffeine as DNA-protectors under the action of electromagnetic radiation.

  15. Plasticization effect of C60 on the fast dynamics of polystyrene and related polymers: an incoherent neutron scattering study

    International Nuclear Information System (INIS)

    Sanz, Alejandro; Ruppel, Markus; Cabral, Joao T; Douglas, Jack F

    2008-01-01

    We utilize inelastic incoherent neutron scattering (INS) to quantify how fullerenes affect the 'fast' molecular dynamics of a family of polystyrene related macromolecules. In particular, we prepared bulk nanocomposites of (hydrogenous and ring-deuterated) polystyrene and poly(4-methyl styrene) using a rapid precipitation method where the C 60 relative mass fraction ranged from 0% to 4%. Elastic window scan measurements, using a high resolution (0.9 μeV) backscattering spectrometer, are reported over a wide temperature range (2-450 K). Apparent Debye-Waller (DW) factors 2 >, characterizing the mean-square amplitude of proton displacements, are determined as a function of temperature, T. We find that the addition of C 60 to these polymers leads to a progressive increase in 2 > relative to the pure polymer value over the entire temperature range investigated, where the effect is larger for larger nanoparticle concentration. This general trend seems to indicate that the C 60 nanoparticles plasticize the fast (∼10 -15 s) local (∼1 A) dynamics of these polymer glasses. Generally, we expect nanoparticle additives to affect polymer dynamics in a similar fashion to thin films in the sense that the high interfacial area may cause both a speeding up and slowing down of the glass state dynamics depending on the polymer-surface interaction

  16. Kinetics of conformational changes of fibronectin adsorbed onto model surfaces.

    Science.gov (United States)

    Baujard-Lamotte, L; Noinville, S; Goubard, F; Marque, P; Pauthe, E

    2008-05-01

    Fibronectin (FN), a large glycoprotein found in body fluids and in the extracellular matrix, plays a key role in numerous cellular behaviours. We investigate FN adsorption onto hydrophilic bare silica and hydrophobic polystyrene (PS) surfaces using Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) in aqueous medium. Adsorption kinetics using different bulk concentrations of FN were followed for 2h and the surface density of adsorbed FN and its time-dependent conformational changes were determined. When adsorption occurs onto the hydrophilic surface, FN molecules keep their native conformation independent of the adsorption conditions, but the amount of adsorbed FN increases with time and the bulk concentration. Although the protein surface density is the same on the hydrophobic PS surface, this has a strong impact on the average conformation of the adsorbed FN layer. Indeed, interfacial hydration changes induced by adsorption onto the hydrophobic surface lead to a decrease in unhydrated beta-sheet content and cause an increase in hydrated beta-strand and hydrated random domain content of adsorbed FN. This conformational change is mainly dependent on the bulk concentration. Indeed, at low bulk concentrations, the secondary structures of adsorbed FN molecules undergo strong unfolding, allowing an extended and hydrated conformation of the protein. At high bulk concentrations, the molecular packing reduces the unfolding of the stereoregular structures of the FN molecules, preventing stronger spreading of the protein.

  17. Positronium chemistry in porous adsorbents

    International Nuclear Information System (INIS)

    Foti, G.; Nagy, L.G.; Moravcsik, G.; Schay, G.

    1981-01-01

    Kinetic studies on the annihilation of orthopositronium in porous adsorbents have been performed using lifetime spectroscopy. The positron source applied was 22 Na with 0.2 MBq activity. The adsorbents investigated were silica gels of different particle size and pore structure. The appearance of the long-lived component in the lifetime spectra can be explained by the diffusion of the orthopositronium into the pores affected by the particle size and the pore size of the adsorbent, the coverage on it and the chemical nature of the adsorbate. The long-term aim of the work is to determine and to explain these effects. (author)

  18. Modeling adsorption and reactions of organic molecules at metal surfaces.

    Science.gov (United States)

    Liu, Wei; Tkatchenko, Alexandre; Scheffler, Matthias

    2014-11-18

    response effects enables reliable modeling of structure and stability for a broad class of organic molecules adsorbed on metal surfaces. This method was demonstrated to achieve quantitative accuracy for aromatic hydrocarbons (benzene, naphthalene, anthracene, and diindenoperylene), C60, and sulfur/oxygen-containing molecules (thiophene, NTCDA, and PTCDA) on close-packed and stepped metal surfaces, leading to an overall accuracy of 0.1 Å in adsorption heights and 0.1 eV in binding energies with respect to state-of-the-art experiments. An unexpected finding is that vdW interactions contribute more to the binding of strongly bound molecules on transition-metal surfaces than for molecules physisorbed on coinage metals. The accurate inclusion of vdW interactions also significantly improves tilting angles and adsorption heights for all the studied molecules, and can qualitatively change the potential-energy surface for adsorbed molecules with flexible functional groups. Activation barriers for molecular switches and reaction precursors are modified as well.

  19. Vibrational spectra of C60C8H8 and C70C8H8 in the rotor-stator and polymer phases

    OpenAIRE

    Klupp, G.; Borondics, F.; Kováts, É.; Pekker, Á.; Bényei, G.; Jalsovszky, I.; Hackl, R.; Pekker, S.; Kamarás, K.

    2007-01-01

    C60-C8H8 and C70-C8H8 are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C60C8H8) and poly(C70C8H8) resulting from a solid state reaction occurring on heating. Based on the spectra we propose a connection pattern for the fullerene in poly(C60C8H8), where the symmetry of the C60 is D2h. On illuminating...

  20. Conceptual modeling for identification of worst case conditions in environmental risk assessment of nanomaterials using nZVI and C60 as case studies

    DEFF Research Database (Denmark)

    Grieger, Khara Deanne; Hansen, Steffen Foss; Sørensen, Peter B.

    2011-01-01

    response mechanisms such as reactive oxygen species (ROS) production and cell membrane damage or disruption, iv) surface properties of nZVI and C60, and v) acute exposure tolerance of organisms. Additional estimates of worst-case conditions for C60 also include the physical location of C60...... of nZVI and C60 and ecotoxicological response end-points and response mechanisms including ROS production and cell membrane damage, full nanomaterial characterization taking into account detailed information on nanomaterial surface properties, and investigations of dose–response relationships...

  1. A Saturn-Like Complex Composed of Macrocyclic Oligothiophene and C60 Fullerene: Structure, Stability, and Photophysical Properties in Solution and the Solid State.

    Science.gov (United States)

    Shimizu, Hideyuki; Park, Kyu Hyung; Otani, Hiroyuki; Aoyagi, Shinobu; Nishinaga, Tohru; Aso, Yoshio; Kim, Dongho; Iyoda, Masahiko

    2018-03-12

    A Saturn-like 1:1 complex composed of macrocyclic oligothiophene E-8T7A and C 60 fullerene (C 60 ) was synthesized to investigate the interaction between macrocyclic oligothiophenes and C 60 in solution and the solid state. Because the Saturn-like 1:1 complex E-8T7A⋅C 60 is mainly stabilized by van der Waals interactions between C 60 and the sulfur atoms of the E-8T7A macrocycle, C 60 is rather weakly incorporated inside the macro-ring in solution. However, in the solid state the Saturn-like 1:1 complex preferentially formed single crystals or nanostructured polymorphs. Interestingly, X-ray analysis and theoretical calculations exhibited hindered rotation of C 60 in the Saturn-like complex due to interactions between C 60 and the sulfur atoms. Furthermore, the photoinduced charge transfer (CT) interaction between E-8T7A and C 60 in solution was investigated by using femtosecond transient absorption (TA) spectroscopy. The ultrafast TA spectral changes in the photoinduced absorption bands were attributed to the CT process in the Saturn-like structure. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Catalytic reduction of 1,2-dihaloethanes by electrochemically generated C60n- (n=2 and 3)

    Science.gov (United States)

    D'Souza, F.; Choi, J.-P.; Hsieh, Y. Y.; Shriner, K.; Kutner, W.

    1998-08-01

    1,2-Dihaloethanes were catalytically reduced by electrochemically generated C60n- (n=2 or 3) anions in 0.1 M tetrabutlammonium hexafluorophosphate in benzonitrile under cyclic voltammetry and rotating disk electrode (RDE) voltammetry conditions at platinum electrodes. The second-order catalytic rate constants, determined by the RDE voltammetry under pseudo-first-order conditions against the 1,2-dihaloethanes, largely increase in the order: 1,2-dichloroethane1,2-dibromoethane<1,2-diiodoethane. Alkanes, alkenes and monohalogenated alkanes were products of the electrocatalyses.

  3. Fourier photospectroscopy of Xe-C60 through a Xe 4d resonance window: theory versus recent experiment

    International Nuclear Information System (INIS)

    Patel, Aakash B; Chakraborty, Himadri S

    2011-01-01

    The photoionization cross section of endohedral Xe-C 60 over a Xe 4d giant resonance energy region, calculated in the time-dependent local density approximation, is compared with recent measurements (Kilcoyne et al 2010 Phys. Rev. Lett. 105 213001). An analysis based on the Fourier transforms of oscillatory cross sections is performed to derive a number of inherent similarities between the prediction and the data, including a large beating-type oscillation and several others of intermediate size. Results stress the need for more accurate measurements to access the wealth of information about the geometry of the system. (fast track communication)

  4. Calculations of the thermal expansion, cohesive energy and thermodynamic stability of a Van der Waals crystal - fullerene C60

    International Nuclear Information System (INIS)

    Zubov, V.I.; Tretiakov, N.P.; Teixeira Rabelo, J.N.; Sanchez Ortiz, J.F.

    1994-01-01

    The temperature dependence of the intermolecular distance and the cohesive energy in the high-temperature modification of C 60 solid fullerene was studied on basis of the correlative method of unsymmetrized self-consistent field. The central intermolecular potential of Girifalco and its approximation by Yakub were used. We conclude about the decisive role of anharmonic effects at high temperatures. The discrepancy between the calculated and experimental values of intermolecular distance does not exceed 0.8% on the whole temperature interval. The temperature of loss of thermodynamic stability was obtained (∼1915 K) and a possible melting temperature was estimated (∼1400 K). ((orig.))

  5. Effect of giant plasmon excitations in single and double ionization of C60 in fast heavy-ion collisions

    Science.gov (United States)

    Kadhane, Umesh; Kelkar, A.; Misra, D.; Kumar, Ajay; Tribedi, Lokesh C.

    2007-04-01

    Single and multiple ionization of C60 in collisions with highly charged fast oxygen ions have been studied using the recoil-ion time-of-flight technique. The dependence of multiple-ionization cross sections on projectile charge state (qp) was found to be drastically different from those for an atomic target, such as Ne. A model based on the giant dipole plasmon resonance explains quite well the observed qp dependence for the single- and-double-ionization cross sections. But the same model deviates for triple and quadruple ionizations.

  6. The absorption spectrum of C60 in n-hexane solution revisited: Fitted experiment and TDDFT/PCM calculations

    Science.gov (United States)

    Menéndez-Proupin, E.; Delgado, Alain; Montero-Alejo, Ana L.; García de la Vega, J. M.

    2014-02-01

    The UV absorption spectrum of C60 in n-hexane solvent has been revised by means of numerical analysis and time-dependent density functional theory (TDDFT). The absorption spectrum in the range 3-7 eV has been fitted by a spectral function that includes fourteen transitions with Gaussian lineshape, providing reference transition energies and intensities. The agreement between the experimental and theoretical UV absorption intensities has been considerably improved with respect to previous calculations, by including the solvent dielectric response via the polarizable continuum model (PCM).

  7. Structure of Irreversibly Adsorbed Star Polymers

    Science.gov (United States)

    Akgun, Bulent; Aykan, Meryem Seyma; Canavar, Seda; Satija, Sushil K.; Uhrig, David; Hong, Kunlun

    Formation of irreversibly adsorbed polymer chains on solid substrates have a huge impact on the wetting, glass transition, aging and polymer chain mobility in thin films. In recent years there has been many reports on the formation, kinetics and dynamics of these layers formed by linear homopolymers. Recent studies showed that by varying the number of polymer arms and arm molecular weight one can tune the glass transition temperature of thin polymer films. Using polymer architecture as a tool, the behavior of thin films can be tuned between the behavior of linear chains and soft colloids. We have studied the effect of polymer chain architecture on the structure of dead layer using X-ray reflectivity (XR) and atomic force microscopy. Layer thicknesses and densities of flattened and loosely adsorbed chains has been measured for linear, 4-arm, and 8-arm star polymers with identical total molecular weight as a function of substrate surface energy, annealing temperature and annealing time. Star polymers have been synthesized using anionic polymerization. XR measurements showed that 8-arm star PS molecules form the densest and the thickest dead layers among these three molecules.

  8. Adsorbate-induced lifting of substrate relaxation is a general mechanism governing titania surface chemistry.

    Science.gov (United States)

    Silber, David; Kowalski, Piotr M; Traeger, Franziska; Buchholz, Maria; Bebensee, Fabian; Meyer, Bernd; Wöll, Christof

    2016-09-30

    Under ambient conditions, almost all metals are coated by an oxide. These coatings, the result of a chemical reaction, are not passive. Many of them bind, activate and modify adsorbed molecules, processes that are exploited, for example, in heterogeneous catalysis and photochemistry. Here we report an effect of general importance that governs the bonding, structure formation and dissociation of molecules on oxidic substrates. For a specific example, methanol adsorbed on the rutile TiO 2 (110) single crystal surface, we demonstrate by using a combination of experimental and theoretical techniques that strongly bonding adsorbates can lift surface relaxations beyond their adsorption site, which leads to a significant substrate-mediated interaction between adsorbates. The result is a complex superstructure consisting of pairs of methanol molecules and unoccupied adsorption sites. Infrared spectroscopy reveals that the paired methanol molecules remain intact and do not deprotonate on the defect-free terraces of the rutile TiO 2 (110) surface.

  9. The synthesis of a new type adsorbent for the removal of toxic gas by radiation-induced graft polymerization

    International Nuclear Information System (INIS)

    Okamoto, Jiro; Sugo, Takanobu

    1990-01-01

    A new type of adsorbent containing sulfuric acid group for the removal of ammonia gas was synthesized by radiation-induced graft polymerization of styrene onto fibrous and nonwoven type polypropylene followed by sulufonation with chlorosulfonic acid. The rate of the adsorption of ammonia gas by H-type adsorbent is independent of the ion-exchange capacity. The amount of ammonia gas adsorbed by the chemical adsorption was dependent on the ion-exchange capacity of H-type fibrous adsorbent and was kept constant value in spite of the equilibrium pressure of ammonia gas. Cu(II)- and Ni(II)-types fibrous adsorbent were prepared by the ion exchange reaction of Na-type fibrous adsorbent with metal nitrate solutions. Although, the rate of adsorption of ammonia gas by metal-type fibrous adsorbent is lower than that of H-type adsorbent, the amount of ammonia gas adsorbed increases compared to H-type adsorbent with the same ion exchange capacity. It was related to the highest coordination number of metal ion. The ratio of the number of ammonia molecules adsorbed chemically and the number of metal ion adsorbed in fibrous adsorbent was 4 for Cu-type and 6 for Ni-type fibrous adsorbent, respectively. (author)

  10. Thermal-induced changes on the properties of spin-coated P3HT:C60 thin films for solar cell applications

    CSIR Research Space (South Africa)

    Motaung, DE

    2009-09-01

    Full Text Available The thermal transition behaviour, optical and structural properties of spin-coated P3HT:C60 blended films with different C60 ratios were investigated using differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), ultraviolet...

  11. Progress in Development of C60 Nanoparticle Plasma Jet for Diagnostic of Runaway Electron Beam-Plasma Interaction and Disruption Mitigation Study for ITER

    Science.gov (United States)

    Bogatu, I. N.; Thompson, J. R.; Galkin, S. A.; Kim, J. S.

    2013-10-01

    We produced a C60 nanoparticle plasma jet (NPPJ) with uniquely fast response-to-delivery time (~ 1 - 2 ms) and unprecedentedly high momentum (~ 0 . 6 g .km/s). The C60 NPPJ was obtained by using a solid state TiH2/C60 pulsed power cartridge producing ~180 mg of C60 molecular gas by sublimation and by electromagnetic acceleration of the C60 plasma in a coaxial gun (~35 cm length, 96 kJ energy) with the output of a high-density (>1023 m-3) hyper-velocity (>4 km/s) plasma jet. The ~ 75 mg C60/C plasma jet has the potential to rapidly and deeply deliver enough mass to significantly increase electron density (to ne ~ 2 . 4 ×1021 m-3, i.e. ~ 60 times larger than typical DIII-D pre-disruption value, ne 0 ~ 4 ×1019 m-3), and to modify the 'critical electric field' and the runaway electrons (REs) collisional drag during different phases of REs dynamics. The C60 NPPJ, as a novel injection technique, allows RE beam-plasma interaction diagnostic by quantitative spectroscopy of C ions visible/UV line intensity. The system is scalable to ~ 1 - 2 g C60/C plasma jet output and technology is adaptable to ITER acceptable materials (BN and Be) for disruption mitigation. Work supported by US DOE DE-FG02-08ER85196 grant.

  12. Relaxation and crystallization phenomena of water adsorbed to cellulose

    International Nuclear Information System (INIS)

    Czihak, Ch.; Mueller, M.; Schober, H.; Vogl, G.

    1999-01-01

    Complete text of publication follows. Cellulose, the most abundant biopolymer whose unit is D-anhydroglucose pyranose, has a tendency to adsorb water due to unsaturated hydroxyl groups in low ordered regions. This adsorbed water is present in the temperature range of 200 K < T < 273 K in different modifications. Due to voids and pores within and between the cellulose fibers, water molecules are able to build crystalline aggregations. Beyond that, water is able to penetrate the low ordered regions [1] and it adsorbs to cellulose chains. As introduced earlier in [2], the adsorbed water freezes to an amorphous like ice, while above T = 200 K an onset of relaxational motion on different time-scales (ns, ps) occurs. Recent neutron diffraction and INS data of water adsorbed to amorphous cellulose are shown as a new model system. Together with earlier experiments, the characteristics of relaxational motions are summarized and similarities to a glass transition of adsorbed water are discussed. (author) [1] J.M. Ioelovits and M. Gordeev, Acta Polymer. 45, 121-123 (1994); [2] J.C. Czihak, M. Mueller, H. Schober, L. Heux, G. Vogl, Physica B 266, 878-91. (1999)

  13. Fullerenol C60(OH)24 nanoparticles decrease relaxing effects of dimethyl sulfoxide on rat uterus spontaneous contraction

    International Nuclear Information System (INIS)

    Slavic, Marija; Djordjevic, Aleksandar; Radojicic, Ratko; Milovanovic, Slobodan; Orescanin-Dusic, Zorana; Rakocevic, Zlatko; Spasic, Mihajlo B.; Blagojevic, Dusko

    2013-01-01

    Dimethyl sulfoxide (DMSO) is a widely used solvent and cryoprotectant that can cause impaired blood flow, reduction in intracranial pressure, tissue edema, inflammatory reactions, inhibition of vascular smooth muscle cell migration and proliferation, processes which can lead to atherosclerosis of the coronary, peripheral and cerebral circulation. Although the adverse effects are rare when DMSO is administered in clinically established concentrations, there is no safe antagonist for an overdose. In this work, we treated isolated spontaneous and calcium-induced contractile active rat uteri (Wistar, virgo intacta), with DMSO and fullerenol C 60 (OH) 24 nanoparticle (FNP) in DMSO. FNP is a water-soluble derivative of fullerene C 60 . Its size is a 1.1 nm in diameter and is a very promising candidate for a drug carrier in nanomedicine. FNP also displays free radical scavenging activity. DMSO decreased both spontaneous and calcium-induced contractions. In contrast, FNP only decreased spontaneous contraction. FNP decreased copper–zinc superoxide dismutase activity and prevented the DMSO-induced increase in glutathione reductase activity. Atomic force microscopy detected that FNP aggregated with calcium ions. Our results indicate that FNP has properties that make it a good candidate to be a modulator of DMSO activity which could minimize side effects of the latter.

  14. The role of attached phase soil and sediment organic matter physicochemical properties on fullerene (nC60) attachment.

    Science.gov (United States)

    McNew, Coy P; LeBoeuf, Eugene J

    2015-11-01

    Attached phase soil and sediment organic matter is ubiquitous in the subsurface environment, with a tendency to strongly sorb contaminants, and therefore it may play an important role in contaminant transport. In this study, the deposition of C60 nanoparticles onto attached phase Harpeth Humic Acid and Harpeth Fulvic Acid (HHA and HFA) is explored by using a quartz crystal microbalance with dissipation monitoring and systematically varying thermal energy. By comparing the C60 attachment onto HHA and HFA surfaces to that of bare silica and DLVO predictions, we find that the HHA and HFA layers hinder attachment at low temperatures, while HHA enhances attachment at higher temperatures. Based on thermal characterization of the HHA and HFA layers compared to the corresponding attachment trends, the attachment efficiency is strongly correlated with hydration of the layer. Possible mechanisms explaining this phenomenon include water-assisted disruption of polar SOM contacts and hydration-induced swelling of the AP-SOM matrix. Since humic substances typically dominate subsurface organic matter, these results may prove crucial to understanding the complex interactions of engineered nanomaterials in both the natural and engineered environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Fullerenol C60(OH)24 nanoparticles decrease relaxing effects of dimethyl sulfoxide on rat uterus spontaneous contraction

    Science.gov (United States)

    Slavic, Marija; Djordjevic, Aleksandar; Radojicic, Ratko; Milovanovic, Slobodan; Orescanin-Dusic, Zorana; Rakocevic, Zlatko; Spasic, Mihajlo B.; Blagojevic, Dusko

    2013-05-01

    Dimethyl sulfoxide (DMSO) is a widely used solvent and cryoprotectant that can cause impaired blood flow, reduction in intracranial pressure, tissue edema, inflammatory reactions, inhibition of vascular smooth muscle cell migration and proliferation, processes which can lead to atherosclerosis of the coronary, peripheral and cerebral circulation. Although the adverse effects are rare when DMSO is administered in clinically established concentrations, there is no safe antagonist for an overdose. In this work, we treated isolated spontaneous and calcium-induced contractile active rat uteri (Wistar, virgo intacta), with DMSO and fullerenol C60(OH)24 nanoparticle (FNP) in DMSO. FNP is a water-soluble derivative of fullerene C60. Its size is a 1.1 nm in diameter and is a very promising candidate for a drug carrier in nanomedicine. FNP also displays free radical scavenging activity. DMSO decreased both spontaneous and calcium-induced contractions. In contrast, FNP only decreased spontaneous contraction. FNP decreased copper-zinc superoxide dismutase activity and prevented the DMSO-induced increase in glutathione reductase activity. Atomic force microscopy detected that FNP aggregated with calcium ions. Our results indicate that FNP has properties that make it a good candidate to be a modulator of DMSO activity which could minimize side effects of the latter.

  16. Spontaneous Orbital-Selective Mott Transitions and the Jahn-Teller Metal of A3C60

    Science.gov (United States)

    Hoshino, Shintaro; Werner, Philipp

    2017-04-01

    The alkali-doped fullerides A3C60 are half-filled three-orbital Hubbard systems which exhibit an unconventional superconducting phase next to a Mott insulator. While the pairing is understood to arise from an effectively negative Hund coupling, the highly unusual Jahn-Teller metal near the Mott transition, featuring both localized and itinerant electrons, has not been understood. This property is consistently explained by a previously unrecognized phenomenon: the spontaneous transition of multiorbital systems with negative Hund coupling into an orbital-selective Mott state. This symmetry-broken state, which has no ordinary orbital moment, is characterized by an orbital-dependent two-body operator (the double occupancy) or an orbital-dependent kinetic energy and may be regarded as a diagonal-order version of odd-frequency superconductivity. We propose that the recently discovered Jahn-Teller metal phase of Rbx Cs3 -xC60 is an experimental realization of this novel state of matter.

  17. Uptake, transportation, and accumulation of C60fullerene and heavy metal ions (Cd, Cu, and Pb) in rice plants grown in an agricultural soil.

    Science.gov (United States)

    Liang, Chuanzhou; Xiao, Haijun; Hu, Ziqi; Zhang, Xu; Hu, Jun

    2018-04-01

    The mutual influences of C 60 fullerene (C 60 ) and heavy metal ions (Cd, Cu, and Pb) on the uptake, transportation, and accumulation of these coexisting pollutants in four rice cultivars planted in agricultural soil were investigated during the whole life cycle of rice. The biomass of the rice plants was not affected significantly by the presence of C 60 . C 60 exposure exerted different impacts on the bioaccumulation of Cd, Cu, and Pb in various rice tissues. For example, the bioaccumulation of Cd in rice 9311 panicles was significantly decreased (p concentrations in the roots, stems, and panicles of the four rice cultivars that were harvested after a 130-day exposure to 600 mg/kg C 60 were 40-292, 4.4-24.5 and 0.077-1.2 mg/kg (dry weight), respectively. C 60 and heavy metal ions exhibited different uptake and transportation mechanisms, which depended on the rice cultivar, soil heavy metal ion concentration, and C 60 exposure time and concentration. For example, the average C 60 in the four rice cultivars was increased sharply, from 47.4 to 196.3 mg/kg from the tillering to booting stages, whereas Cd levels increased only slightly, from 23.1 to 25.9 mg/kg. The study demonstrated that the bioaccumulation of C 60 and heavy metal ions under co-contamination scenario differs from under single contaminant. The accumulation of C 60 in rice panicles may increase the concern of food safety. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. First determination of C 60 and C 70 fullerenes and N-methylfulleropyrrolidine C 60 on the suspended material of wastewater effluents by liquid chromatography hybrid quadrupole linear ion trap tandem mass spectrometry

    Science.gov (United States)

    Farré, Marinella; Pérez, Sandra; Gajda-Schrantz, Krisztina; Osorio, Victoria; Kantiani, Lina; Ginebreda, Antoni; Barceló, Damià

    2010-03-01

    SummaryThe increasing use and production of carbon-based nanoparticles demands for new analytical approaches able to achieve sensitivities in the low ng/L range in order to assess their presence in environmental samples. This paper describes development, optimization and validation of a novel method for the analysis of C 60 and, C 70 fullerenes and N-methylfulleropyrrolidine C 60 in the environment. The method relies on ultrasonication extraction from suspended solids in wastewater, followed by liquid chromatography (LC) coupled to a hybrid triple quadrupole linear ion trap mass spectrometry (QqLIT-MS) for trace quantification. Recoveries obtained were generally higher than 60% for both surface water and wastewaters. The overall variability of the method was below 15%, for the three fullerenes and all tested matrices: ultra-pure water, surface water and wastewater. For the effluents of wastewater treatment plants the method quantification limits (MQL) ranged from 0.2 to 1 ng/L. The precision of the method, calculated as relative standard deviation (RSD), ranged from 1% to 2% and from 5% to 9% for intra and inter-day analysis, respectively. The developed analytical method was applied to the analysis of fullerenes in the effluents of 22 wastewater treatment plants in Catalonia (NE of Spain). 50% of the analyzed samples contained fullerenes, nine of them in the μg/L concentration range. This work constitutes the first report on the occurrence of fullerenes in suspended solids of wastewater effluents highlighting the need of nanotechnologies residues assessment for risk evaluation of nanoparticles in the environment.

  19. Black Sprayable Molecular Adsorber Coating

    Data.gov (United States)

    National Aeronautics and Space Administration — The main objective of this technology project is to develop, optimize, and flight qualify a black version of the molecular adsorber coating and a conductive version...

  20. The amorphous nature of C60 hard carbon manifested in its specific heat, sound velocity and heat conduction

    International Nuclear Information System (INIS)

    Biljakovic, K.; Kozlov, M.; Staresinic, D.; Saint-Paul, M.

    2002-01-01

    Detailed measurements of the specific heat, thermal conductivity and relative variation of the sound velocity in the temperature range 2-280 K for hard fullerene-based carbon are reported. The novel material was obtained from pressure-temperature treatment of C 60 fullerene and is known for a unique combination of its diamond-like hardness and high electrical conductivity. The substance was found to possess an unconventional, close-to-linear temperature dependence of the thermal conductivity over almost the entire temperature range. The specific heat of hard carbon exhibited a very large linear contribution to the specific heat at low temperatures, but no excess contribution to C p /T 3 , and a deviation from the Debye dependence above 6 K. The sound velocity decreased linearly from 4 up to 120 K. These results are consistent with the concept of a glassy solid formed by polymerized and partially transformed fullerene clusters. (author)

  1. Complete assignment of the vibrational modes of C60 by inelastic neutron scattering spectroscopy and periodic-DFT.

    Science.gov (United States)

    Parker, Stewart F; Bennington, Stephen M; Taylor, Jon W; Herman, Henryk; Silverwood, Ian; Albers, Peter; Refson, Keith

    2011-05-07

    In this paper we exploit the complementarity of inelastic neutron scattering (INS), infrared and Raman spectroscopies with ab initio calculations to generate an updated assignment of the vibrational modes of C(60). We have carried out periodic-DFT calculations of the high temperature face centred cubic phase modelled as the standard structure and also of the low temperature simple cubic phase, the latter for the first time. Our assignment differs from all previous work, however, it is the only one that is able to successfully reproduce the INS spectrum in terms of both transition energies and intensities. In addition to the INS spectrum we are also able to quantitatively simulate the major features of the infrared and Raman spectra in the high temperature phase and the infrared spectrum in the low temperature phase. This journal is © the Owner Societies 2011

  2. Static and Dynamic Energetic Disorders in the C 60 , PC 61 BM, C 70 , and PC 71 BM Fullerenes

    KAUST Repository

    Tummala, Naga Rajesh

    2015-09-17

    We use a combination of molecular dynamics simulations and density functional theory calculations to investigate the energetic disorder in fullerene systems. We show that the energetic disorder evaluated from an ensemble average contains contributions of both static origin (time-independent, due to loose packing) and dynamic origin (time-dependent, due to electron-vibration interactions). In order to differentiate between these two contributions, we compare the results obtained from an ensemble average approach with those derived from a time average approach. It is found that in both amorphous C60 and C70 bulk systems, the degrees of static and dynamic disorder are comparable, while in the amorphous PC61BM and PC71BM systems, static disorder is about twice as large as dynamic disorder. © 2015 American Chemical Society.

  3. Neuroprotective effects of hydrated fullerene C60: cortical and hippocampal EEG interplay in an amyloid-infused rat model of Alzheimer's disease.

    Science.gov (United States)

    Vorobyov, Vasily; Kaptsov, Vladimir; Gordon, Rita; Makarova, Ekaterina; Podolski, Igor; Sengpiel, Frank

    2015-01-01

    We studied the effects of fullerene C60 nanoparticles, namely hydrated fullerene C60 (C60HyFn), on interrelations between EEG frequency spectra from the frontal cortex and the dorsal hippocampus (CA1) on an amyloid-β (Aβ) rat model of Alzheimer's disease (AD). Infusion of Aβ1-42 protein (1.5 μl) into the CA1 region two weeks before EEG testing diminished hippocampal theta (3.8-8.4 Hz) predominance and eliminated cortical beta (12.9-26.2 Hz) predominance observed in baseline EEG of rats infused with saline (control) or with C60HyFn alone. In contrast, these Aβ1-42 effects were abolished in rats pretreated with C60HyFn, 30 min apart. Dopaminergic mediation in AD has been shown to be involved in neuronal plasticity and Aβ transformation in different ways. To clarify its role in the cortex-hippocampus interplay in the Aβ model of AD, we used peripheral injection of a dopamine agonist, apomorphine (APO), at a low dose (0.1 mg/kg). In rats infused with C60HyFn or Aβ1-42 alone, APO attenuated the cortical beta predominance, with immediate and delayed phases evident in the Aβ1-42-rats. Pretreatment with C60HyFn diminished the APO effect in the Aβ1-42-treated rats. Thus, we show that intrahippocampal injection of Aβ1-42 dramatically disrupts cortical versus hippocampal EEG interrelations and that pretreatment with the fullerene eliminates this abnormality. We suggest that some effects of C60HyFn may be mediated through presynaptic dopamine receptors and that water-soluble C60 fullerenes have a neuroprotective potential.

  4. 5-nm LiF as an Efficient Cathode Buffer Layer in Polymer Solar Cells Through Simply Introducing a C60 Interlayer

    Science.gov (United States)

    Liu, Xiaodong; Guo, L. Jay; Zheng, Yonghao

    2017-09-01

    Lithium fluoride (LiF) is an efficient and widely used cathode buffer layer (CBL) in bulk heterojunction polymer solar cells (PSCs). The LiF thickness is normally limited to 1 nm due to its insulting property. Such small thickness is difficult to precise control during thermal deposition, and more importantly, 1-nm-thick LiF cannot provide sufficient protection for the underlying active layer. Herein, we demonstrated the application of a very thick LiF as CBL without sacrificing the device efficiency by simply inserting a C60 layer between the active layer and LiF layer. The devices with the C60/LiF (5 nm) double CBLs exhibit a peak power conversion efficiency (PCE) of 3.65%, which is twofold higher than that (1.79%) of LiF (5 nm)-only device. The superior performance of the C60/LiF (5 nm)-based devices is mainly attributed to the good electrical conductivity of the C60/LiF (5 nm) bilayer, arising from the intermixing occurred at the C60/LiF interface. Besides, the formation of a P3HT/C60 subcell and the optical spacer effect of C60 also contribute to the increase in short-circuit current density ( J sc) of the device. With further increase of LiF thickness to 8 nm, a PCE of 1.10% is attained for the C60/LiF-based device, while the negligible photovoltaic performance is observed for the LiF-only device. All in all, our results show that C60/LiF bilayer is a promising alternative to LiF single layer due to its high tolerance to the LiF thickness variations.

  5. Dynamics of different molecules adsorbed in porous media

    Indian Academy of Sciences (India)

    linear behaviour suggesting that simple Fick's law is not adequate in describing the experimental data. A more elaborate model was formulated by Chudley and Elliott. [5]. This model assumes that for a time interval τ, an atom remains on a given site, vibrating about a centre of equilibrium, building up a thermal cloud. After.

  6. Distribution of adsorbed molecules in electronic nose sensors

    DEFF Research Database (Denmark)

    Swann, M.J.; Glidle, A.; Gadegaard, Nikolaj

    2000-01-01

    Neutron reflectivity measurements of thin films of electropolymerised poly(pyrrole) show that swelling of these insoluble polymers does occur following vapour adsorption. The variation in swelling found for different vapours is correlated with corresponding changes in polymer conductivity and mass...

  7. Multiple ionization of C60 in collisions with 2.33MeV/u O-ions and giant plasmon excitation

    International Nuclear Information System (INIS)

    Kelkar, A.H.; Kadhane, U.; Misra, D.; Kumar, Ajay; Tribedi, L.C.

    2007-01-01

    Single and multiple ionization of C 60 in collisions with fast (v=9.7a.u.) O q+ ions have been studied. Relative cross sections for production of C 60 1+ to C 60 4+ have been measured. The intensity ratios of double-to-single ionization agree very well with a model based on giant dipole plasmon resonance (GDPR). Almost linear increasing trend of the yields of single and double ionizations with projectile charge state is well reproduced by the single and double plasmon excitation mechanisms. The observed charge state independence of triple and quadruple ionization is in sharp contrast to the GDPR model

  8. Quantitative relationship between adsorbed amount of solute and solvent composition

    International Nuclear Information System (INIS)

    Wang Yan; Geng Xindu; Zebolsky, Don M.

    2003-01-01

    A new adsorption isotherm that relates the amount of solute adsorbed to the solvent concentration is proposed. The new equation is derived from Geng and Shi's stoichiometric displacement model for adsorption (SDM-A). The obtained equation may be simplified to an expression containing two parameters. The equation with two parameters, valid for low concentrations of solute, is a logarithmically linear relationship. The intercept contains a thermodynamic equilibrium constant of the solute displacing solvent from the adsorbent. The slope is the negative value of the stoichiometric displacement parameter (Z), the average total number of solvent molecules displaced from an active site on the adsorbent and from the solute. Tests with a homologous series of aromatic alcohols by frontal analysis in reversed phase liquid chromatography demonstrate that experimental results fit the equation well

  9. Transport through a Single Octanethiol Molecule

    NARCIS (Netherlands)

    Kockmann, D.; Poelsema, Bene; Zandvliet, Henricus J.W.

    2009-01-01

    Octanethiol molecules adsorbed on Pt chains are studied with scanning tunneling microscopy and spectroscopy at 77 K. The head of the octanethiol binds to a Pt atom and the tail is lying flat down on the chain. Open-loop current time traces reveal that the molecule wags its tail and attaches to the

  10. Preparation and Preliminary Dielectric Characterization of Structured C60-Thiol-Ene Polymer Nanocomposites Assembled Using the Thiol-Ene Click Reaction

    OpenAIRE

    Ahmed, Hanaa M.; Windham, Amber D.; Al-Ejji, Maryam M.; Al-Qahtani, Noora H.; Hassan, Mohammad K.; Mauritz, Kenneth A.; Buchanan, Randy K.; Buchanan, J. Paige

    2015-01-01

    Fullerene-containing materials have the ability to store and release electrical energy. Therefore, fullerenes may ultimately find use in high-voltage equipment devices or as super capacitors for high electric energy storage due to this ease of manipulating their excellent dielectric properties and their high volume resistivity. A series of structured fullerene (C60) polymer nanocomposites were assembled using the thiol-ene click reaction, between alkyl thiols and allyl functionalized C60 deri...

  11. A large-scale association study for nanoparticle C60 uncovers mechanisms of nanotoxicity disrupting the native conformations of DNA/RNA.

    Science.gov (United States)

    Xu, Xue; Wang, Xia; Li, Yan; Wang, Yonghua; Yang, Ling

    2012-09-01

    Nano-scale particles have attracted a lot of attention for its potential use in medical studies, in particular for the diagnostic and therapeutic purposes. However, the toxicity and other side effects caused by the undesired interaction between nanoparticles and DNA/RNA are not clear. To address this problem, a model to evaluate the general rules governing how nanoparticles interact with DNA/RNA is demanded. Here by, use of an examination of 2254 native nucleotides with molecular dynamics simulation and thermodynamic analysis, we demonstrate how the DNA/RNA native structures are disrupted by the fullerene (C60) in a physiological condition. The nanoparticle was found to bind with the minor grooves of double-stranded DNA and trigger unwinding and disrupting of the DNA helix, which indicates C60 can potentially inhibit the DNA replication and induce potential side effects. In contrast to that of DNA, C60 only binds to the major grooves of RNA helix, which stabilizes the RNA structure or transforms the configuration from stretch to curl. This finding sheds new light on how C60 inhibits reverse transcription as HIV replicates. In addition, the binding of C60 stabilizes the structures of RNA riboswitch, indicating that C60 might regulate the gene expression. The binding energies of C60 with different genomic fragments varies in the range of -56 to -10 kcal mol(-1), which further verifies the role of nanoparticle in DNA/RNA damage. Our findings reveal a general mode by which C60 causes DNA/RNA damage or other toxic effects at a systematic level, suggesting it should be cautious to handle these nanomaterials in various medical applications.

  12. Modest vasomotor dysfunction induced by low doses of C60 fullerenes in apolipoprotein E knockout mice with different degree of atherosclerosis

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Folkmann, Janne K; Jacobsen, Nicklas R

    2009-01-01

    ABSTRACT: BACKGROUND: Exposure to small size particulate matter in urban air is regarded as a risk factor for cardiovascular effects, whereas there is little information about the impact on the cardiovascular system by exposure to pure carbonaceous materials in the nano-size range. C60 fullerenes...... treatment. These findings represent an important step in the hazard characterization of C60 fullerenes by showing that intraperitoneal administration is associated with a moderate decrease in the vascular function of mice with atherosclerosis....

  13. Effects of aqueous stable fullerene nanocrystals (nC60) on the food conversion from Daphnia magna to Danio rerio in a simplified freshwater food chain.

    Science.gov (United States)

    Tao, Xianji; Li, Cuilan; Zhang, Bo; He, Yiliang

    2016-02-01

    Understanding the nanomaterial potential to the food conversion of two food chain levels is important in the ecosystem assessment as manufactured nanomaterials are being released into the environment. In this investigation, the food conversion from Daphnia magna (D. magna) (prey) to Danio rerio (D. rerio) (predator) was used as the study object of aqueous stable fullerene nanocrystals (nC60). Accumulated nC60 of D. magna was determined as the nominal initial exposure concentration for D. rerio. The results of 21-d dietary exposure experiment demonstrate that nC60 in D. magna decreased the body weight growths and condition factors of D. rerio, and reduced the food conversion ratio by 20% (from D. magna to D. rerio). Further, the experiments present that nC60 decrease three digestive enzymes activities of trypsinase, lipase, and amylase by 30, 29, and 55% in vivo, and by 60, 90, and 42% in vitro, respectively. Both in vivo and in vitro experiments indicated that nC60 was involved with the decrements of digestive enzymes activities. These decrements in digestive enzymes activities may be due to the deactivation caused by the adsorption of nC60 particles onto the surface or active center of digestive enzymes. Sum up, these results not only describe the nC60 deleterious effects on the food conversion from D. magna to D. rerio, but also provide some information regarding a probable food conversion inhibition mechanism of nC60. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. An experimental study on pool boiling characteristics of carbon nano tube (CNT) and fullerene (C-60) nanofluids

    International Nuclear Information System (INIS)

    Ai, Melani

    2009-02-01

    In recent years, it was found that pool boiling critical heat flux (CHF) increases in nanofluids. The CHF conditions are important for safe and economic design of many heat transfer units including nuclear reactor. In this study, our objective is to evaluate the impact of Carbone Nano Tubes (Singlewalled CNTs and Multiwalled CNTs) and Fullerene (C-60) nanofluids at different particle concentration on pool boiling critical heat flux experimentally at saturated conditions. Multiwalled CNT and fullerene (C-60) added in the pure water at three volume concentrations (0.01%, 0.001%, and 0.0001%). Singlewalled CNT nanoparticles added in the pure water at two volume concentrations (0.0005%, and 0.0001%). For the dispersion of nanoparticles in pure water, several treatments were performed. Multiwalled CNTs and Fullerene (C-60) prepared using acid treatment, meanwhile two treatment are using for Singlewalled CNTs: (1)Singlewalled CNTs prepared using polymer treatment, (2)Singlewalled CNTs prepared using pre polymerization of micelle treatment. The zeta potential of CNTs and Fullerene nanofluids were in the range of 13-71 mV. The zeta potential of nanofluids was constant for more than one month. It concludes that the treatment has been succeeded produces water dispersible CNTs and Fullerene nanofluids with good stability. The critical heat flux (CHFs) of the solution is enhanced greatly for all nanofluids. Enhanced (∼167.9%) CHF was observed for solutions with Multiwalled CNT nanoparticles with concentration 0.01 vol%. Enhanced (∼109.4%) CHF was observed for solutions with Singlewalled CNT nanoparticles with concentration 0.0005 vol%. Enhanced (∼108.9%) CHF was observed for solutions with Fullerene nanoparticles with concentration 0.01 vol%. The pool boiling Heat Transfer Coefficient (HTCs) of the CNTs nanofluids are lower than those of pure water in the entire nucleate boiling regime. On the other hand, the pool boiling HTCs of Fullerene nanofluids are higher than

  15. Membrane adsorber for endotoxin removal

    Directory of Open Access Journals (Sweden)

    Karina Moita de Almeida

    Full Text Available ABSTRACT The surface of flat-sheet nylon membranes was modified using bisoxirane as the spacer and polyvinyl alcohol as the coating polymer. The amino acid histidine was explored as a ligand for endotoxins, aiming at its application for endotoxin removal from aqueous solutions. Characterization of the membrane adsorber, analysis of the depyrogenation procedures and the evaluation of endotoxin removal efficiency in static mode are discussed. Ligand density of the membranes was around 7 mg/g dry membrane, allowing removal of up to 65% of the endotoxins. The performance of the membrane adsorber prepared using nylon coated with polyvinyl alcohol and containing histidine as the ligand proved superior to other membrane adsorbers reported in the literature. The lack of endotoxin adsorption on nylon membranes without histidine confirmed that endotoxin removal was due to the presence of the ligand at the membrane surface. Modified membranes were highly stable, exhibiting a lifespan of approximately thirty months.

  16. Evolution of lone pair of excess electrons inside molecular cages with the deformation of the cage in e2@C60F60 systems.

    Science.gov (United States)

    Wang, Yin-Feng; Chen, Wei; Yu, Guang-Tao; Li, Zhi-Ru; Wu, Di; Sun, Chia-Chung

    2011-07-15

    For unusual e(2)@C(60)F(60)(I(h), D(6h), and D(5d)) cage structures with two excess electrons, it is reported that not only the lone pair in singlet state but also two single excess electrons in triplet state can be encapsulated inside the C(60)F(60) cages to form single molecular solvated dielectrons. The interesting relationship between the shape of the cage and the spin state of the system has revealed that ground states are singlet state for spherical shaped e(2)@C(60)F(60)(I(h)) and triplet states for short capsular shaped e(2)@C(60)F(60)(D(6h)) and long capsular shaped e(2)@C(60)F(60)(D(5d)), which shows a spin evolution from the singlet to triplet state with the deformation of the cage from spherical to capsular shape. For these excess electron systems, the three ground state structures have large vertical electron detachment energies (VDEs (I) of 1.720-2.283 eV and VDEs (II) of 3.959-5.288 eV), which shows their stabilities and suggests that the large C(60)F(60) cage is the efficient container of excess electrons. Copyright © 2011 Wiley Periodicals, Inc.

  17. Modification of antioxidative and antiapoptotic genes expression in irradiated K562 cells upon fullerenol C60(OH)24 nanoparticle treatment.

    Science.gov (United States)

    Stankov, Karmen; Borisev, Ivana; Kojic, Vesna; Rutonjski, Lazar; Bogdanovic, Gordana; Djordjevic, Aleksandar

    2013-01-01

    Recent data established the prospective applications for fullerenol (C60(OH)24) nanoparticle (FNP) in many fields, such as antioxidants, neuroprotective agents, and potential anti-radiation drugs. Leukemia cell sensitization to apoptosis induced by ionizing radiation is achieved by upregulation of ROS production and/or downregulation of antioxidative enzymes. Therefore, our aim was to analyze the potential role of fullerenol nanoparticle in modulation of the leukemic cellular response to irradiation. We used the qRT-PCR to analyze the expression level of mRNA for 11 genes in irradiated and FNP pre-treated irradiated K562 cells, and compared the gene expression level with the overall cell survival. Our results of the improved cell survival in FNP-treated irradiated cells and significant overexpression of anti-apoptotic Bcl-2 and Bcl-xL and cytoprotective genes such as GSTA4, MnSOD, NOS, CAT and HO-1 genes, may indicate that FNP exerts cytoprotective function in K562 leukemic cells, rendering K562 cells more tolerant to radiotherapy.

  18. Fullerol C60(OH)24 nanoparticles and mycotoxigenic fungi: a preliminary investigation into modulation of mycotoxin production.

    Science.gov (United States)

    Kovač, Tihomir; Šarkanj, Bojan; Klapec, Tomislav; Borišev, Ivana; Kovač, Marija; Nevistić, Ante; Strelec, Ivica

    2017-07-01

    Increased use of fullerols in various fields and expected increase of their environmental spread impose the necessity for testing fullerol nanoparticles (FNP) effects on microbiota. There is little information available on the interaction of mycotoxigenic fungi and FNP, despite FNP having a great potential of modifying mycotoxin production. Namely, FNP exhibit both ROS-quenching and ROS-producing properties, while oxidative stress stimulates mycotoxin synthesis in the fungi. In order to shed some light on the extent of interaction between FNP and mycotoxigenic fungi, the effects of fullerol C 60 (OH) 24 nanoparticles (10, 100, 1000 ng/mL) on mycelial growth, aflatoxin production and oxidative stress modulation in an aflatoxigenic strain of Aspergillus flavus (NRRL 3251) during 168 h of incubation in a liquid culture medium were examined. FNP slightly reduced mycelial biomass weight, but significantly decreased aflatoxin concentration in media. Lipid peroxide content, superoxide dismutase, catalase and glutathione peroxidase activities suggest that FNP treatments hormetically reduced oxidative stress within fungal cells in turn suppressing aflatoxin production. These findings contribute to the assessment of environmental risk and application potential of fullerols.

  19. Ion-Regulated Allosteric Binding of Fullerenes (C-60 and C-70) by Tetrathiafulvalene-Calix[4]pyrroles

    DEFF Research Database (Denmark)

    Davis, C. M.; Lim, J. M.; Larsen, K. R.

    2014-01-01

    The effect of ionic species on the binding of fullerenes (C-60 and C-70) by tetrathiafulvalene-calix[4]pyrrole (TTF-C4P) receptors and the nature of the resulting supramolecular complexes (TTF-C4P + fullerene + halide anion + tetraalkylammonium cation) was studied in the solid state through single...... of the C4P in a ball-and-socket binding mode. The interactions between the TTF-C4P receptors and the fullerene guests are highly influenced by both the nature of halide anions and their counter tetraalkylammonium cations. Three halides (F-, Cl-, and Br-) were studied. All three potentiate the binding...... of the two test fullerenes by inducing a conformational change from the 1,3-alternate to the cone conformer of the TTF-C4Ps, thus acting as positive heterotropic allosteric effectors. For a particular halide anion, the choice of tetraalkylammonium salts serves to modulate the strength of the TTF-C4P...

  20. Degradation of C60 Fullerol by White-Rot Basidiomycete Fungi: Implications for Environmental Release of Nanomaterials

    Science.gov (United States)

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

    2008-12-01

    Industrially produced carbon-based nanomaterials, including fullerenes and fullerols, will be introduced into the environment in increasing amounts over the next century. Oxygenated fullerenes are likely to be produced in the environment through both biotic and abiotic weathering, and yet the environmental fate of compounds like hydroxylated fullerenes are almost unknown. This study examines the ability of two white rot basidiomycete fungi (Phlebia tremellosa and Trametes versicolor) to metabolize and degrade 13C-labeled C60 fullerol. Both of these fungi were shown to degrade fullerol to CO2 both in the presence of wood tissue and without, and incorporate trace amounts of the carbon into fungal biomass. Absorbance data also indicate that a significant portion of the original fullerol was broken down into small molecular weight metabolites. Phlebia tremellosa proved to be, in general, more aggressive towards fullerol degradation than Trametes versicolor. These findings represent the report of fungal degradation of this important nanomaterial and also provide valuable information about the possible environmental fates of this compound.

  1. Fragment ion distribution in charge-changing collisions of 2-MeV Si ions with C60

    Science.gov (United States)

    Itoh, A.; Tsuchida, H.; Miyabe, K.; Majima, T.; Nakai, Y.

    2001-09-01

    We have measured positive fragment ions produced in collisions of 2 MeV Siq+ (q=0, 1, 2, 4) projectiles with a C60 molecular target. The measurement was performed with a time-of-flight coincidence method between fragment ions and charge-selected outgoing projectiles. For all the charge-changing collisions investigated here, the mass distribution of small fragment ions C+n (n=1-12) can be approximated fairly well by a power-law form of n-λ as a function of the cluster size n. The power λ derived from each mass distribution is found to change strongly according to different charge-changing collisions. As a remarkable experimental finding, the values of λ(loss) in electron loss collisions are almost the same for the same final charge states k irrespective of the initial charge q, exhibiting a nearly perfect linear relationship with k. We also performed calculations of the projectile ionization on the basis of the semiclassical approximation and obtained inelastic energy deposition for individual collision processes. The estimated energy deposition is found to have a simple correlation with the experimentally determined values of λ(loss).

  2. Mott Transition in the A 15 Phase of Cs3 C60 : Absence of a Pseudogap and Charge Order

    Science.gov (United States)

    Alloul, H.; Wzietek, P.; Mito, T.; Pontiroli, D.; Aramini, M.; Riccò, M.; Itie, J. P.; Elkaim, E.

    2017-06-01

    We present a detailed NMR study of the insulator-to-metal transition induced by an applied pressure p in the A 15 phase of Cs3 C60 . We evidence that the insulating antiferromagnetic (AFM) and superconducting (SC) phases coexist only in a narrow p range. At fixed p , in the metallic state above the SC transition Tc, the 133Cs and 13C NMR spin-lattice relaxation data are seemingly governed by a pseudogaplike feature. We prove that this feature, also seen in the 133Cs NMR shift data, is rather a signature of the Mott transition which broadens and smears out progressively for increasing (p ,T ). The analysis of the variation of the quadrupole splitting νQ of the 133Cs NMR spectrum precludes any cell symmetry change at the Mott transition and only monitors a weak variation of the lattice parameter. These results open an opportunity to consider theoretically the Mott transition in a multiorbital three-dimensional system well beyond its critical point.

  3. The fabrication and analysis of a PbS nanocrystal:C(60) bilayer hybrid photovoltaic system.

    Science.gov (United States)

    Dissanayake, D M N M; Hatton, R A; Lutz, T; Curry, R J; Silva, S R P

    2009-06-17

    A near-infrared sensitive hybrid photovoltaic system between PbS nanocrystals (PbS-NCs) and C(60) is demonstrated. Up to 0.44% power conversion efficiency is obtained under AM1.5G with a short circuit current density (J(sc)) of 5 mA cm(-2) when the PbS-NC layer is treated in anhydrous methanol. The observed J(sc) is found be approximately one-third of the maximum expected from this hybrid configuration, indicating the potential for further optimization. Crucial for device operation, a smooth film of nanocrystals is seen to form on the hole transporting poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer deposited on the transparent electrode, facilitated through an ionic interaction between nanocrystal capping ligands and the PEDOT:PSS. The formation of the open circuit voltage in this system is seen to be influenced by an interfacial dipole formed at the hole-extracting electrode, providing insights for further optimization.

  4. Application of ESR to the study of adsorbed species

    International Nuclear Information System (INIS)

    Naccache, C.

    1975-01-01

    Electron spin resonance (ESR) enables the defects and paramagnetic species present at the surface of solids to be studied. The informations obtained from these studies lead to a better knowledge of the activation process of certain adsorbed molecules. A brief review is given of ESR principles. Some experimental results are described concerning the adsorption of monoatomic ions and atoms, the inorganic radicals, the reactivity of the O - and O 2 - ions and the adsorption of transition ions [fr

  5. Effect of the Co-C(C60(-)) bond formation on magnetic properties of the ionic complex {cryptand[2,2,2] x (Na+)} x {Co(II)TPP x (C60(-))} x (C6H4Cl2)2.

    Science.gov (United States)

    Konarev, Dmitri V; Khasanov, Salavat S; Otsuka, Akihiro; Saito, Gunzi; Lyubovskaya, Rimma N

    2009-08-28

    A new ionic complex {cryptand[2,2,2] x (Na(+))} x {Co(II)TPP x (C(60)(-))} x (C(6)H(4)Cl(2))(2) has been obtained as single crystals by a diffusion technique. It involves coordination {Co(II)TPP x u(C(60)(-))} units and bulky {cryptand[2,2,2] x (Na(+))} cations. The Co-C(C(60)(-)) coordination bond is short (2.262(2) A at 100 K) which provides ordering in the C(60)(-) anions. This is the first ordered structure of {Co(II)TPP x (C(60)(-))}. The coordination bonds weaken upon heating to be 2.316(4) A at 250 K. As a result, the C(60)(-) anions begin to rotate at 250 K about the Co-C bond between two orientations. The complex is diamagnetic from 4 up to 320 K. The Co-C bonds dissociate above 320 K only to form unbound paramagnetic Co(II)TPP and C(60)(*-) species. The process is accompanied by the reversible increase in magnetic susceptibility of the complex and the appearance of a new broad EPR signal with g = 2.1187 and a linewidth of approximately 120 mT (350 K). The signal was attributed to both paramagnetic Co(II)TPP and C(60)(*-), which showed strong exchange interaction.

  6. The influence of frequency on fractal dimension of adsorbed layers

    International Nuclear Information System (INIS)

    Gasparovic, B.; Risovic, D.; Cosovic, B.; Nelson, A.

    2007-01-01

    Alternating current (AC) voltammetry and electrochemical impedance spectroscopy are often the methods of choice for use in study of adsorption of organic molecules. The adsorption of organic molecules on interface may result in the formation of fractal structures, whose fractal dimension can be estimated using the method of scaling the hanging mercury drop electrode (HMDE). The aim of present study was to check whether the estimated fractal dimension, D (or for that matter the fractal ordering of the adsorbed layer) shows any correlation (dependence) with change of applied frequency, and second, to check the possibility to extend the method to broad frequency spectrum compatible with impedance spectroscopy. The investigation included two surfactants nonionic Triton-X-100 (T-X-100) and anionic sodium dodecyl sulfate (SDS) and alcohol tert-butanol. All measurements were performed on HMDE at thermodynamic equilibrium employing broad frequency spectrum. The validity of the approach was checked by measurements on pure electrolyte and by comparison with previously obtained results for fractal layers. The results of the investigations show that: (1) the method of scaling the HMDE to obtain the fractal dimension of adsorbed layer is compatible with impedance spectroscopy and the combination of these methods can be used as a powerful tool to investigate fractal aspect of adsorption of organic molecules; (2) fractal ordering of adsorbed layer and the value of fractal dimension is not influenced by the frequency of applied sinusoidal voltage perturbations

  7. A theoretical study of the interaction of hydrogen and oxygen with palladium or gold adsorbed on pyridine-like nitrogen-doped graphene.

    Science.gov (United States)

    Rangel, Eduardo; Magana, Luis Fernando; Sansores, Luis Enrique

    2014-12-15

    The interaction of H2 and O2 molecules in the presence of nitrogen-doped graphene decorated with either a palladium or gold atom was investigated by using density functional theory. It was found that two hydrogen molecules were adsorbed on the palladium atom. The interaction of these adsorbed hydrogen molecules with two oxygen molecules generates two hydrogen peroxide molecules first through a Eley-Rideal mechanism and then through a Langmuir-Hinshelwood mechanism. The barrier energies for this reaction were small; therefore, we expect that this process may occur spontaneously at room temperature. In the case of gold, a single hydrogen molecule is adsorbed and dissociated on the metal atom. The interaction of the dissociated hydrogen molecule on the surface with one oxygen molecule generates a water molecule. The competitive adsorption between oxygen and hydrogen molecules slightly favors oxygen adsorption. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Investigation and Control of "Sphere-Like" Buckminsterfullerene C60 and "Disk-Like" Copper(II) Phthalocyanine

    Science.gov (United States)

    McAfee, Terry Richard

    Due to the growing global need for cheap, flexible, and portable electronics, numerous research groups from mechanical and electrical engineering, material science, chemistry, and physics have increasingly turned to organic electronics research over the last ˜5--10 years. Largely, the focus of researchers in this growing field have sought to obtain the next record holding device, allowing a heuristic approach of trial and error to become dominant focus of research rather than a fundamental understanding. Rather than working with the latest high performance organic semiconducting materials and film processing techniques, I have chosen to investigate and control the fundamental self-assembly interactions of organic photovoltaic thin films using simplified systems. Specifically, I focus on organic photovoltaic research using two of the oldest and well studies semiconducting materials, namely "sphere-like" electron donor material Buckminsterfullerene C60 and "disklike" electron acceptor material Copper(II) Phthalocyanine. I manufactured samples using the well-known technique of physical vapor deposition using a high vacuum chamber that I designed and built to accommodate my need of precise material deposition control, with codeposition capability. Films were characterized using microscopy and spectroscopy techniques locally at NCSU, including Atomic Force Microscopy, scanning tunneling microscopy, X-ray photoelectron spectroscopy, and Ultraviolet-visible spectroscopy, as well as at National Laboratory based synchrotron x-ray techniques, including Carbon and Nitrogen k-edge Total Electron Yield and Transmission Near Edge X-ray absorption fine structure spectroscopy, Carbon k-edge Resonant Soft x-ray Microscopy, Resonant Soft x-ray reflectivity, and Grazing Incidence Wide-Angle X-ray scattering.

  9. Bicarbonate Elution of Uranium from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Kuo, Li-Jung [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Gill, Gary [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Tian, Guoxin [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Rao, Linfeng [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Das, Sadananda [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Mayes, Richard T. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Janke, Christopher J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA

    2017-05-02

    Uranium adsorbed on amidoxime-based polyethylene fibers in simulated seawater can be quantitatively eluted using 3 M KHCO3 at 40°C. Thermodynamic calculations are in agreement with the experimental observation that at high bicarbonate concentrations (3 M) uranyl ions bound to amidoxime molecules are converted to uranyl tris-carbonato complex in the aqueous solution. The elution process is basically the reverse reaction of the uranium adsorption process which occurs at a very low bicarbonate concentration (~10-3 M) in seawater. In real seawater experiments, the bicarbonate elution is followed by a NaOH treatment to remove natural organic matter adsorbed on the polymer adsorbent. Using the sequential bicarbonate and NaOH elution, the adsorbent is reusable after rinsing with deionized water and the recycled adsorbent shows no loss of uranium loading capacity based on real seawater experiments.

  10. Molecule Matters

    Indian Academy of Sciences (India)

    is a very stable and inert molecule due to the formation of a triple bond between the two atoms. Surpris- ingly isoelectronic molecules are quite reactive making dinitrogen very useful and unique. Dinitrogen (N. 2. ) is such an innocuous molecule that you might not think it worthy of special attention. We take this molecule for.

  11. Electronic properties of NH4-adsorbed graphene nanoribbon as a promising candidate for a gas sensor

    Directory of Open Access Journals (Sweden)

    Naoki Harada

    2016-05-01

    Full Text Available The electronic properties of NH4-adsorbed N = 7 armchair graphene nanoribbons (AGNRs were theoretically investigated using self-consistent atomistic simulations to explore the feasibility of AGNRs as a gas sensing material. Whereas a pristine AGNR has a finite band gap and is an intrinsic semiconductor, an NH4-adsorbed AGNR exhibits heavily doped n-type properties similar to a graphene sheet with the molecules adsorbed. The electric characteristics of a back-gated AGNR gas sensor were also simulated and the drain current changed exponentially with increasing number of adsorbed molecules. We may conclude that an AGNR is promising as a highly sensitive gas-sensing material with large outputs.

  12. Photoinduced electron transfer in a Watson-Crick base-paired, 2-aminopurine:uracil-C60 hydrogen bonding conjugate.

    Science.gov (United States)

    D'Souza, Francis; Gadde, Suresh; Islam, D-M Shafiqul; Pang, Siew-Cheng; Schumacher, Amy Lea; Zandler, Melvin E; Horie, Rumiko; Araki, Yasuyaki; Ito, Osamu

    2007-02-07

    A fluorescent reporter molecule, 2-aminopurine was self-assembled via Watson-Crick base-pairing to a uracil appended fullerene to form a donor-acceptor conjugate; efficient photoinduced charge separation was confirmed by time-resolved emission and transient absorption spectral studies.

  13. Intraperitoneal Exposure to Nano/Microparticles of Fullerene (C60 Increases Acetylcholinesterase Activity and Lipid Peroxidation in Adult Zebrafish (Danio rerio Brain

    Directory of Open Access Journals (Sweden)

    Gonzalo Ogliari Dal Forno

    2013-01-01

    Full Text Available Even though technologies involving nano/microparticles have great potential, it is crucial to determine possible toxicity of these technological products before extensive use. Fullerenes C60 are nanomaterials with unique physicochemical and biological properties that are important for the development of many technological applications. The aim of this study was to evaluate the consequences of nonphotoexcited fullerene C60 exposure in brain acetylcholinesterase expression and activity, antioxidant responses, and oxidative damage using adult zebrafish as an animal model. None of the doses tested (7.5, 15, and 30 mg/kg altered AChE activity, antioxidant responses, and oxidative damage when zebrafish were exposed to nonphotoexcited C60 nano/microparticles during 6 and 12 hours. However, adult zebrafish exposed to the 30 mg/kg dose for 24 hours have shown enhanced AChE activity and augmented lipid peroxidation (TBARS assays in brain. In addition, the up-regulation of brain AChE activity was neither related to the transcriptional control (RT-qPCR analysis nor to the direct action of nonphotoexcited C60 nano/microparticles on the protein (in vitro results but probably involved a posttranscriptional or posttranslational modulation of this enzymatic activity. Taken together these findings provided further evidence of toxic effects on brain after C60 exposure.

  14. Preparation and Preliminary Dielectric Characterization of Structured C60-Thiol-Ene Polymer Nanocomposites Assembled Using the Thiol-Ene Click Reaction.

    Science.gov (United States)

    Ahmed, Hanaa M; Windham, Amber D; Al-Ejji, Maryam M; Al-Qahtani, Noora H; Hassan, Mohammad K; Mauritz, Kenneth A; Buchanan, Randy K; Buchanan, J Paige

    2015-11-18

    Fullerene-containing materials have the ability to store and release electrical energy. Therefore, fullerenes may ultimately find use in high-voltage equipment devices or as super capacitors for high electric energy storage due to this ease of manipulating their excellent dielectric properties and their high volume resistivity. A series of structured fullerene (C 60 ) polymer nanocomposites were assembled using the thiol-ene click reaction, between alkyl thiols and allyl functionalized C 60 derivatives. The resulting high-density C 60 -urethane-thiol-ene (C 60 -Thiol-Ene) networks possessed excellent mechanical properties. These novel networks were characterized using standard techniques, including infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermal gravimetric analysis (TGA). The dielectric spectra for the prepared samples were determined over a broad frequency range at room temperature using a broadband dielectric spectrometer and a semiconductor characterization system. The changes in thermo-mechanical and electrical properties of these novel fullerene-thiol-ene composite films were measured as a function of the C 60 content, and samples characterized by high dielectric permittivity and low dielectric loss were produced. In this process, variations in chemical composition of the networks were correlated to performance characteristics.

  15. Preparation and Preliminary Dielectric Characterization of Structured C60-Thiol-Ene Polymer Nanocomposites Assembled Using the Thiol-Ene Click Reaction

    Directory of Open Access Journals (Sweden)

    Hanaa M. Ahmed

    2015-11-01

    Full Text Available Fullerene-containing materials have the ability to store and release electrical energy. Therefore, fullerenes may ultimately find use in high-voltage equipment devices or as super capacitors for high electric energy storage due to this ease of manipulating their excellent dielectric properties and their high volume resistivity. A series of structured fullerene (C60 polymer nanocomposites were assembled using the thiol-ene click reaction, between alkyl thiols and allyl functionalized C60 derivatives. The resulting high-density C60-urethane-thiol-ene (C60-Thiol-Ene networks possessed excellent mechanical properties. These novel networks were characterized using standard techniques, including infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, dynamic mechanical analysis (DMA, and thermal gravimetric analysis (TGA. The dielectric spectra for the prepared samples were determined over a broad frequency range at room temperature using a broadband dielectric spectrometer and a semiconductor characterization system. The changes in thermo-mechanical and electrical properties of these novel fullerene-thiol-ene composite films were measured as a function of the C60 content, and samples characterized by high dielectric permittivity and low dielectric loss were produced. In this process, variations in chemical composition of the networks were correlated to performance characteristics.

  16. Intraperitoneal Exposure to Nano/Microparticles of Fullerene (C60) Increases Acetylcholinesterase Activity and Lipid Peroxidation in Adult Zebrafish (Danio rerio) Brain

    Science.gov (United States)

    Dal Forno, Gonzalo Ogliari; Kist, Luiza Wilges; de Azevedo, Mariana Barbieri; Fritsch, Rachel Seemann; Pereira, Talita Carneiro Brandão; Britto, Roberta Socoowski; Guterres, Sílvia Stanisçuaski; Külkamp-Guerreiro, Irene Clemes; Bonan, Carla Denise; Monserrat, José María; Bogo, Maurício Reis

    2013-01-01

    Even though technologies involving nano/microparticles have great potential, it is crucial to determine possible toxicity of these technological products before extensive use. Fullerenes C60 are nanomaterials with unique physicochemical and biological properties that are important for the development of many technological applications. The aim of this study was to evaluate the consequences of nonphotoexcited fullerene C60 exposure in brain acetylcholinesterase expression and activity, antioxidant responses, and oxidative damage using adult zebrafish as an animal model. None of the doses tested (7.5, 15, and 30 mg/kg) altered AChE activity, antioxidant responses, and oxidative damage when zebrafish were exposed to nonphotoexcited C60 nano/microparticles during 6 and 12 hours. However, adult zebrafish exposed to the 30 mg/kg dose for 24 hours have shown enhanced AChE activity and augmented lipid peroxidation (TBARS assays) in brain. In addition, the up-regulation of brain AChE activity was neither related to the transcriptional control (RT-qPCR analysis) nor to the direct action of nonphotoexcited C60 nano/microparticles on the protein (in vitro results) but probably involved a posttranscriptional or posttranslational modulation of this enzymatic activity. Taken together these findings provided further evidence of toxic effects on brain after C60 exposure. PMID:23865059

  17. Perturbed Angular Correlation Study of the Static and Dynamic Aspects of Cadmium and Mercury Atoms Inside and Attached to a C60 Fullerene Cage

    CERN Document Server

    Das, Satyendra K; Banerjee, Debasish; Johnston, Karl; Das, Parnika; Butz, Tilman; Amaral, Vitor S; Correia, Joao G; Barbosa, Marcelo B

    2014-01-01

    30 keV Cd-111m and 50 keV Hg-199m beams from ISOLDE were used to implant on preformed targets of C-60 with a thickness of 1 mg cm(-2). Endofullerene compounds, viz. Cd-111m@C-60 and Hg-199m@C-60 formed during implantation were separated by filtration through micropore filter paper followed by solvent extraction. Dried samples of the endofullerene compounds were counted for the time differential perturbed angular correlation (TDPAC) measurement using the coincidence of the 151-245 keV cascade of Cd-111m and the 374 158 keV cascade of Hg-199m on a six LaBr3(Ce) detector system coupled with digital electronics. The results for 111mCd@C60 indicate a single static component (27\\%) and a fast relaxing component (73\\%), the latter implying that the cadmium atom moves rapidly inside the cage at room temperature. The quadrupole interaction frequency and asymmetry parameter of the cadmium atom occupying the static site in C60 are omega(Q) = 8.21(36) Mrad s(-1) and eta = 0.41(9), respectively. The fast relaxation con...

  18. Black Sprayable Molecular Adsorber Coating Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This novel molecular adsorber coating would alleviate the size, weight, and complexity issues of traditional molecular adsorber puck.  A flexible tape version...

  19. A direct investigation of photocharge transfer across monomolecular layer between C60 and CdS quantum dots by photoassisted conductive atomic force microscopy

    Directory of Open Access Journals (Sweden)

    Xiaohong Jiang

    2016-04-01

    Full Text Available The composite assembly of C60 and CdS Quantum Dots (QDs on ITO substrate was prepared by Langmuir-Blodgett (LB technique using arachic acid (AA, stearic acid (SA and octadecanyl amine (OA as additives. Photoassisted conductive atomic force microscopy was used to make point contact current-voltage (I-V measurements on both the CdS QDs and the composite assembly of C60/CdS. The result make it clear that the CdS, C60/CdS assemblies deposited on ITO substrate showed linear characteristics and the current increased largely under illumination comparing with that in the dark. The coherent, nonresonant tunneling mechanism was used to explain the current occurrence. It is considered that the photoinduced carriers CdS QDs tunneled through alkyl chains increased the current rapidly.

  20. Genotoxicity, cytotoxicity, and reactive oxygen species induced by single-walled carbon nanotubes and C(60) fullerenes in the FE1-Mutatrade markMouse lung epithelial cells

    DEFF Research Database (Denmark)

    Jacobsen, Nicklas Raun; Pojana, Giulio; White, Paul

    2008-01-01

    Viability, cell cycle effects, genotoxicity, reactive oxygen species production, and mutagenicity of C(60) fullerenes (C(60)) and single-walled carbon nanotubes (SWCNT) were assessed in the FE1-Mutatrade markMouse lung epithelial cell line. None of these particles induced cell death within 24 hr...... at doses between 0 and 200 microg/ml or during long-term subculture exposure (576 hr) at 100 microg/ml, as determined by two different assays. However, cell proliferation was slower with SWCNT exposure and a larger fraction of the cells were in the G1 phase. Exposure to carbon black resulted...... by the comet assay. The mutant frequency in the cII gene was unaffected by 576 hr of exposure to either 100 microg/ml C(60) or SWCNT when compared with control incubations, whereas we have previously reported that carbon black and diesel exhaust particles induce mutations using an identical exposure scenario...

  1. Enhancement of photovoltaic efficiency of phosphor doped organic solar cell by energy and electron transfer from the phosphor to C60 acceptor

    Science.gov (United States)

    Yang, Dongfang; Li, Wenlian; Chu, Bei; Su, Zisheng; Wang, Junbo; Zhang, Guang; Zhang, Feng

    2011-11-01

    About 67% increase in power conversion efficiency (PCE) of copper phthalocyanine/C60 based organic solar cells was demonstrated by doping 4 wt % iridium(III)bis(3-(2-benzothiazolyl)-7-(diethylamino)-2H-1-benzopyran-2-onato-N',C4)(acetyl acetonate) (IrC6) into C60 acceptor layer. The raised PCE was proved to result from the efficient photo absorption of IrC6 followed by the energy and electron transfer from IrC6 to C60 due to the matched energy level alignment between these two species. Besides, IrC6 could also increase the exciton dissociation efficiency at the active interface of the solar cells. The more detail improvement mechanisms were also discussed.

  2. Synthesis and photoisomerization study of new aza-crown macrocyclic tweezer tethered through an azobenzene linker: The first report on supramolecular interaction of azobenzene moiety with C60

    Science.gov (United States)

    Ghanbari, Bahram; Mahdavian, Mahsa; García-Deibe, A. M.

    2017-09-01

    In the present communication, three bimacrocyclic tweezers linked through azobenzene moiety, Ln (n = 1-3) were synthesized in a multistep route and characterized by x-ray crystallography, IR, 1H and 13C NMR, UV-vis spectroscopy as well as CHN microanalysis. UV-visible spectroscopy established that the irradiation of L1 and L3 with UV light promoted the trans to cis isomerization. Irradiating the reaction mixtures with Hg lamp, significant supramolecular interactions between L1 and L3 with C60 were also found in terms of the association constants calculated by UV-visible spectroscopy, denoting on more pronounced interaction with C60 that in the absence of UV light. The molecular structures of L1-L3 calculated by using DFT method suggested a novel unprecedented interaction between the HOMO's of azobenzene moiety on the tweezer instead of the aromatic groups with C60.

  3. Modest vasomotor dysfunction induced by low doses of C60 fullerenes in apolipoprotein E knockout mice with different degree of atherosclerosis

    Directory of Open Access Journals (Sweden)

    Loft Steffen

    2009-02-01

    Full Text Available Abstract Background Exposure to small size particulate matter in urban air is regarded as a risk factor for cardiovascular effects, whereas there is little information about the impact on the cardiovascular system by exposure to pure carbonaceous materials in the nano-size range. C60 fullerenes are nano-sized particles that are expected to have a widespread use, including cosmetics and medicines. Methods We investigated the association between intraperitoneal injection of pristine C60 fullerenes and vasomotor dysfunction in the aorta of 11–13 and 40–42 weeks old apolipoprotein E knockout mice (apoE-/- with different degree of atherosclerosis. Results The aged apoE-/-mice had lower endothelium-dependent vasorelaxation elicited by acetylcholine in aorta segments mounted in myographs and the phenylephrine-dependent vasoconstriction response was increased. One hour after an intraperitoneal injection of 0.05 or 0.5 mg/kg of C60 fullerenes, the young apoE-/- mice had slightly reduced maximal endothelium-dependent vasorelaxation. A similar tendency was observed in the old apoE-/- mice. Hampered endothelium-independent vasorelaxation was also observed as slightly increased EC50 of sodium nitroprusside-induced vasorelaxation response in young apoE-/- mice. Conclusion Treatment with C60 fullerenes affected mainly the response to vasorelaxation in young apoE-/- mice, whereas the vasomotor dysfunction in old apoE-/- mice with more advanced atherosclerosis was less affected by acute C60 fullerene treatment. These findings represent an important step in the hazard characterization of C60 fullerenes by showing that intraperitoneal administration is associated with a moderate decrease in the vascular function of mice with atherosclerosis.

  4. Atomic-Scale Control of Electron Transport through Single Molecules

    DEFF Research Database (Denmark)

    Wang, Y. F.; Kroger, J.; Berndt, R.

    2010-01-01

    Tin-phthalocyanine molecules adsorbed on Ag(111) were contacted with the tip of a cryogenic scanning tunneling microscope. Orders-of-magnitude variations of the single-molecule junction conductance were achieved by controllably dehydrogenating the molecule and by modifying the atomic structure...

  5. Fullerene-Based Macro-Heterocycle Prepared through Selective Incorporation of Three N and Two O Atoms into C60.

    Science.gov (United States)

    Li, Yanbang; Zhang, Gaihong; Wang, Dian; Xu, Beidi; Xu, Dan; Lou, Ning; Gan, Liangbing

    2016-11-14

    A 14-membered heterocycle is created on the C 60 cage skeleton through a multistep procedure. Key steps involve repeated PCl 5 -induced hydroxylamino N-O bond cleavage leading to insertion of nitrogen atoms, and also piperidine-induced peroxo O-O bond cleavage leading to insertion of oxygen atoms. The hetero atoms form one pyrrole, two pyran, and one diazepine rings in conjunction with the C 60 skeleton carbon atoms. The fullerene-based macrocycle showed unique reactivities towards fluoride ion and copper salts. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Low energy electron spectroscopy of C60 in collisions with fast bare ions: Observation of GDPR peak and its angular distribution

    Science.gov (United States)

    Kelkar, A. H.; Misra, D.; Chatterjee, S.; Kasthurirangan, S.; Agnihotri, A.; Tribedi, L. C.

    2009-11-01

    We report the first direct measurement of GDPR peak in heavy ion (4 MeV/u F9+) induced secondary electron DDCS (double differential cross section) spectrum of C60 fullerene. A peak corresponding to GDPR is seen at all angles and the angular distribution, showing a dip at 90°, is in contrast with ion-atom collisions, indicating plasmon oscillations along beam direction. A comparison has also been done between C60 and other gaseous targets as well as with state-of-the art theoretical models, based on density functional methods.

  7. Low energy electron spectroscopy of C60 in collisions with fast bare ions: Observation of GDPR peak and its angular distribution

    International Nuclear Information System (INIS)

    Kelkar, A H; Misra, D; Chatterjee, S; Kasthurirangan, S; Agnihotri, A; Tribedi, L C

    2009-01-01

    We report the first direct measurement of GDPR peak in heavy ion (4 MeV/u F''9''+) induced secondary electron DDCS (double differential cross section) spectrum of C 60 fullerene. A peak corresponding to GDPR is seen at all angles and the angular distribution, showing a dip at 90''0, is in contrast with ion-atom collisions, indicating plasmon oscillations along beam direction. A comparison has also been done between C 60 and other gaseous targets as well as with state-of-the art theoretical models, based on density functional methods.

  8. Electronic Spectroscopy of Organic Cations in Gas-Phase at 6 K:IDENTIFICATION of C60/^+ in the Interstellar Medium

    Science.gov (United States)

    Maier, John P.

    2016-06-01

    After the discovery of C60, the question of its relevance to the diffuse interstellar bands was raised. In 1987 H. W. Kroto wrote: ``The present observations indicate that C60 might survive in the general interstellar medium (probably as the ion C60/^+)''. In 1994 two diffuse interstellar bands (DIBs) at 9632 and 9577 Å/ were detected and proposed to be the absorption features of C60/^+. This was based on the proximity of these wavelengths to the two prominent absorption bands of C60/^+ measured by us in a neon matrix in 1993. Confirmation of the assignment required the gas phase spectrum of C60/^+ and has taken 20 years. The approach which succeeded confines C60/^+ ions in a radiofrequency trap, cools them by collisions with high density helium allowing formation of the weakly bound C60/^+--He complexes below 10 K. The photofragmentation spectrum of this mass-selected complex is then recorded using a cw laser. In order to infer the position of the absorption features of the bare C60/^+ ion, measurements on C60/^+--He_2 were also made. The spectra show that the presence of a helium atom shifts the absorptions by less than 0.2 Å, much less than the accuracy of the astronomical measurements. The two absorption features in the laboratory have band maxima at 9632.7(1) and 9577.5(1) Å, exactly the DIB wavelengths, and the widths and relative intensities agree. This leads to the first definite identification of now five bands among the five hundred or so DIBs known and proves the presence of gaseous C60/^+ in the interstellar medium. The absorption of cold C70/^+ has also been obtained by this approach. In addition the electronic spectra of a number of cations of astrophysical interest ranging from those of carbon chains including oxygen to larger polycyclic aromatic hydrocarbon could be measured in the gas phase at around 10 K in the ion trap but using an excitation-dissociation approach. The implications of these laboratory spectra in relation to the diffuse

  9. Adsorption of diclofenac and nimesulide on activated carbon: Statistical physics modeling and effect of adsorbate size

    Science.gov (United States)

    Sellaoui, Lotfi; Mechi, Nesrine; Lima, Éder Cláudio; Dotto, Guilherme Luiz; Ben Lamine, Abdelmottaleb

    2017-10-01

    Based on statistical physics elements, the equilibrium adsorption of diclofenac (DFC) and nimesulide (NM) on activated carbon was analyzed by a multilayer model with saturation. The paper aimed to describe experimentally and theoretically the adsorption process and study the effect of adsorbate size using the model parameters. From numerical simulation, the number of molecules per site showed that the adsorbate molecules (DFC and NM) were mostly anchored in both sides of the pore walls. The receptor sites density increase suggested that additional sites appeared during the process, to participate in DFC and NM adsorption. The description of the adsorption energy behavior indicated that the process was physisorption. Finally, by a model parameters correlation, the size effect of the adsorbate was deduced indicating that the molecule dimension has a negligible effect on the DFC and NM adsorption.

  10. Distribution of metal and adsorbed guest species in zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes {sup 129}Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of {sup 129}Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, {sup 129}Xe NMR is insensitive to fine structural details at room temperature.

  11. Distribution of metal and adsorbed guest species in zeolites

    International Nuclear Information System (INIS)

    Chmelka, B.F.

    1989-12-01

    Because of their high internal surface areas and molecular-size cavity dimensions, zeolites are used widely as catalysts, shape- selective supports, or adsorbents in a variety of important chemical processes. For metal-catalyzed reactions, active metal species must be dispersed to sites within the zeolite pores that are accessible to diffusing reactant molecules. The distribution of the metal, together with transport and adsorption of reactant molecules in zeolite powders, are crucial to ultimate catalyst performance. The nature of the metal or adsorbed guest distribution is known, however, to be dramatically dependent upon preparatory conditions. Our objective is to understand, at the molecular level, how preparatory treatments influence the distribution of guest species in zeolites, in order that macroscopic adsorption and reaction properties of these materials may be better understood. The sensitivity of xenon to its adsorption environment makes 129 Xe NMR spectroscopy an important diagnostic probe of metal clustering and adsorbate distribution processes in zeolites. The utility of 129 Xe NMR depends on the mobility of the xenon atoms within the zeolite-guest system, together with the length scale of the sample heterogeneity being studied. In large pore zeolites containing dispersed guest species, such as Pt--NaY, 129 Xe NMR is insensitive to fine structural details at room temperature

  12. Functionalization, self-assembly, and photoswitching quenching for azobenzene derivatives adsorbed on Au(111).

    Science.gov (United States)

    Cho, Jongweon; Berbil-Bautista, L; Levy, Niv; Poulsen, Daniel; Fréchet, Jean M J; Crommie, Michael F

    2010-12-21

    We have used scanning tunneling microscopy to investigate the structure and photoswitching behavior of azobenzene molecules functionalized with bulky spacer groups and adsorbed onto Au(111). We find that positioning tert-butyl "legs" in a canted arrangement on the azobenzene phenyl rings quenches photoisomerizability of the molecule on Au(111). Addition of cyano groups at the para positions changes the molecular self-assembly significantly, but does not alter the quenched photoisomerizability. This behavior likely arises from a combination of molecule-surface interactions, molecule-molecule interactions, and alteration of azobenzene electronic structure resulting from the position-specific addition of tert-butyl groups.

  13. Molecule nanoweaver

    Science.gov (United States)

    Gerald, II; Rex, E [Brookfield, IL; Klingler, Robert J [Glenview, IL; Rathke, Jerome W [Homer Glen, IL; Diaz, Rocio [Chicago, IL; Vukovic, Lela [Westchester, IL

    2009-03-10

    A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

  14. Single Electron Transfer-Promoted Photochemical Reactions of Secondary N-Trimethylsilylmethyl-N-benzylamines Leading to Aminomethylation of Fullerene C60.

    Science.gov (United States)

    Lim, Suk Hyun; Jeong, Ho Cheol; Sohn, Youngku; Kim, Young-Il; Cho, Dae Won; Woo, Hee-Jae; Shin, Ik-Soo; Yoon, Ung Chan; Mariano, Patrick S

    2016-03-18

    Photoreactions between C60 and secondary N-trimethylsilylmethyl-N-benzylamines were explored to evaluate the feasibility of a new method for secondary aminomethylation of electron acceptors. The results show that photoreactions of C60 with these secondary amines in 10% EtOH-toluene occur to form aminomethyl-1,2-dihydrofullerenes predominantly through a pathway involving single electron transfer (SET)-promoted formation of secondary aminium radicals followed by preferential loss of the α-trimethylsilyl group. The aminomethyl radicals formed in this manner then couple with C60 or C60(•-) to form radical or anion precursors of the aminomethyl-1,2-dihydrofullerenes. In contrast to thermal and photochemical strategies developed previously, the new SET photochemical approach using α-trimethylsilyl-substituted secondary amines is both mild and efficient, and as a result, it should be useful in broadening the library of substituted fullerenes. Moreover, the results should have an impact on the design of SET-promoted C-C bond forming reactions. Specifically, introduction of an α-trimethylsilyl group leads to a change in the chemoselectivity of SET-promoted reactions of secondary amines with acceptors that typically favor aminium radical N-H deprotonation, leading to N-C bond formation. Finally, symmetric and unsymmetric fulleropyrrolidines are also generated in yields that are highly dependent on the electronic properties of arene ring substituents in amines, irradiation time, and solvent.

  15. Quantum plasmon and Rashba-like spin splitting in self-assembled Co x C60 composites with enhanced Co content (x > 15)

    Science.gov (United States)

    Lavrentiev, Vasily; Chvostova, Dagmar; Stupakov, Alexandr; Lavrentieva, Inna; Vacik, Jiri; Motylenko, Mykhaylo; Barchuk, Mykhailo; Rafaja, David; Dejneka, Alexandr

    2018-04-01

    Driving by interplay between plasmonic and magnetic effects in organic composite semiconductors is a challenging task with a huge potential for practical applications. Here, we present evidence of a quantum plasmon excited in the self-assembled Co x C60 nanocomposite films with x > 15 (interval of the Co cluster coalescence) and analyse it using the optical absorption (OA) spectra. In the case of Co x C60 film with x = 16 (LF sample), the quantum plasmon generated by the Co/CoO clusters is found as the 1.5 eV-centred OA peak. This finding is supported by the establishment of four specific C60-related OA lines detected at the photon energies E p > 2.5 eV. Increase of the Co content up to x = 29 (HF sample) leads to pronounced enhancement of OA intensity in the energy range of E p > 2.5 eV and to plasmonic peak downshift of 0.2 eV with respect to the peak position in the LF spectrum. Four pairs of the OA peaks evaluated in the HF spectrum at E p > 2.5 eV reflect splitting of the C60-related lines, suggesting great change in the microscopic conditions with increasing x. Analysis of the film nanostructure and the plasmon-induced conditions allows us to propose a Rashba-like spin splitting effect that suggests valuable sources for spin polarization.

  16. Comment on "Atomic force microscopy characterization of stable faces in cubic C60 single crystals": possible evidence for growth-promoting cross-twinning

    NARCIS (Netherlands)

    van de Waal, B.W.

    1994-01-01

    An explanation is given for a molecular arrangement on a face of a C60 fcc single crystal as observed recently with atomic force microscopy (B. Keita et al., Chem. Phys. 179 (1994) 595). The explanation relies on a cross-twinning model of fcc crystal growth, and involves local fivefold symmetry.

  17. Structural and electrochemical characterization of fullerene-based surfaces of C-60 mono- or bis-adducts grafted onto self-assembled monolayers

    NARCIS (Netherlands)

    Cecchet, Francesca; Rapino, Stefania; Margotti, Massimo; Da Ros, Tatiana; Prato, Maurizio; Paolucci, Francesco; Rudolf, Petra

    2006-01-01

    Single layers Of C-60 mono- and bis-adducts have been obtained by functionalizing an acid-terminated self-assembled monolayer (SAM) of thiols on gold. X-ray photoelectron spectroscopy demonstrated the grafting onto the SAM by covalent bonding, via the formation of an amide bond, while cyclic

  18. Incorporating C60 as Nucleation Sites Optimizing PbI2 Films To Achieve Perovskite Solar Cells Showing Excellent Efficiency and Stability via Vapor-Assisted Deposition Method.

    Science.gov (United States)

    Chen, Hai-Bin; Ding, Xi-Hong; Pan, Xu; Hayat, Tasawar; Alsaedi, Ahmed; Ding, Yong; Dai, Song-Yuan

    2018-01-24

    To achieve high-quality perovskite solar cells (PSCs), the morphology and carrier transportation of perovskite films need to be optimized. Herein, C 60 is employed as nucleation sites in PbI 2 precursor solution to optimize the morphology of perovskite films via vapor-assisted deposition process. Accompanying the homogeneous nucleation of PbI 2 , the incorporation of C 60 as heterogeneous nucleation sites can lower the nucleation free energy of PbI 2 , which facilitates the diffusion and reaction between PbI 2 and organic source. Meanwhile, C 60 could enhance carrier transportation and reduce charge recombination in the perovskite layer due to its high electron mobility and conductivity. In addition, the grain sizes of perovskite get larger with C 60 optimizing, which can reduce the grain boundaries and voids in perovskite and prevent the corrosion because of moisture. As a result, we obtain PSCs with a power conversion efficiency (PCE) of 18.33% and excellent stability. The PCEs of unsealed devices drop less than 10% in a dehumidification cabinet after 100 days and remain at 75% of the initial PCE during exposure to ambient air (humidity > 60% RH, temperature > 30 °C) for 30 days.

  19. Diels-Alders adducts of C-60 and esters of 3-(1-indenyl)-propionic acid : alternatives for [60]PCBM in polymer:fullerene solar cells

    NARCIS (Netherlands)

    Sieval, Alexander B.; Treat, Neil D.; Rozema, Desiree; Hummelen, Jan C.; Stingelin, Natalie

    2015-01-01

    A series of new, easily synthesized C-60-fullerene derivatives is introduced that allow for optimization of the interactions between rr-P3HT and the fullerene by systematic variation of the size of the ester group. Two compounds gave overall cell efficiencies of 4.8%, clearly outperforming [60]PCBM

  20. The influence hydrogen atom addition has on charge switching during motion of the metal atom in endohedral Ca@C60H4 isomers

    Science.gov (United States)

    Raggi, G.; Besley, E.; Stace, A. J.

    2016-01-01

    Density functional theory has been applied in a study of charge transfer between an endohedral calcium atom and the fullerene cage in Ca@C60H4 and [Ca@C60H4]+ isomers. Previous calculations on Ca@C60 have shown that the motion of calcium within a fullerene is accompanied by large changes in electron density on the carbon cage. Based on this observation, it has been proposed that a tethered endohedral fullerene might form the bases of a nanoswitch. Through the addition of hydrogen atoms to one hemisphere of the cage it is shown that, when compared with Ca@C60, asymmetric and significantly reduced energy barriers can be generated with respect to motion of the calcium atom. It is proposed that hydrogen atom addition to a fullerene might offer a route for creating a bi-stable nanoswitch that can be fine-tuned through the selection of an appropriate isomer and number of atoms attached to the cage of an endohedral fullerene. This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’. PMID:27501967

  1. Structural, electronic and magnetic properties of Fen-C60 and Fen-C80 (n=2-7) endohedral metallofullerene nano-cages: First principles study

    International Nuclear Information System (INIS)

    Bezi Javan, M.; Tajabor, N.

    2012-01-01

    We studied the structural, electronic and magnetic properties of small Fe n clusters (n=2-7) endohedrally doped in icosahedral C 60 and C 80 fullerenes using first principles calculations based on the density functional theory. It is found that the encapsulated Fe n clusters inside icosahedral C 80 are energetically favorable while Fe n -C 60 metallofullerene nano-cages are not. The binding energies of the Fe n encapsulated in C 60 are positive and increase with the number of iron atoms (n) while those of the Fe n -C 80 are negative and their absolute values increase up to n=6. The encapsulation does not significantly change the enclosed cluster structure, but the total magnetic moment of the larger clusters reduces due to a stronger Fe-C hybridization. - Highlights: → Encapsulated Fe n clusters inside C 80 cage are energetically favorable while Fe n -C 60 nano-cages are not. → Encapsulation does not significantly change the enclosed cluster structure. → Total magnetic moment of the larger clusters reduces due to a stronger Fe-C hybridization.

  2. Selective electrolytic removal of bis(alkoxycarbonyl)methano addends from C60 bis-adducts and electrochemical stability of C70 derivatives

    Science.gov (United States)

    Kessinger; Fender; Echegoyen; Thilgen; Echegoyen; Diederich

    2000-06-16

    The novel mixed bis-adducts of C60, (+/-)-4-(+/-)-8 and 9, with a bis(ethoxycarbonyl)methano addend (Bingel addend) and a second addend ([1,2]benzeno, but[2]eno, methaniminomethano, or diarylmethano) bridging 6,6-closed bonds of the carbon sphere were synthesized in two-step reactions. Each bis-adduct was exhaustively electrolyzed at the potential of the second fullerene-centered reduction step, resulting in the selective removal of the Bingel addend (retro-Bingel reaction) to produce the corresponding mono-adducts, which were isolated in yields of over 60%. These results open up the possibility of using the Bingel addend as a temporary protecting and directing group in the construction of multiple adducts of C60 with unusual addition patterns. The Bingel-type mono-adduct of C70 10 and the constitutionally isomeric bis-adducts 11, (+/-)-12, and (+/-)-13 were also included in this investigation. A large difference in the electrochemical behavior between C70 bis-adducts and the corresponding C60 derivatives was observed. Thus, the intramolecular "walk-on-the-sphere" isomerization which occurs readily with Bingel-type bis-adducts of C60 under the conditions of two-electron controlled potential electrolysis (CPE) is only a minor reaction pathway in the series of C70 derivatives. The latter preferentially undergo retro-Bingel reaction.

  3. DFT and TD-DFT theoretical studies on photo-induced electron transfer process on [Cefamandole].C60 nano-complex.

    Science.gov (United States)

    Taherpour, Avat Arman; Jamshidi, Morteza; Rezaei, Omid

    2017-08-01

    The C 60 fullerene displays a considerable electronegativity. It has a unique photophysical and electrochemical behavior that can be used as a suitable drug carrier. In the present study, the interaction of C 60 fullerene as an electron recipient with the Cefamandole antibiotic was investigated in both ground and excited states using DFT and TD-DFT methods. The study of the interaction of C 60 and Cefamandole via electron localization function (ELF) and reduced density gradient (RDG) revealed that the complex formation is of van der Waals type. The data from natural bonding orbitals (NBO) analysis also confirmed the interaction type. The study of absorption and emission spectrum via CAM-B3LYP in the TD-SCF state showed that the emission peak of C 60 fullerene in the 591.73nm after the complex formation results in the extinction of this emission spectrum due to charge transfer (CT) from chelator to fluorophore. The photoinduced electron transfer (PET) process was investigated using the electron hole theory. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Dynamics of copper-phthalocyanine molecules on Au/Ge(001)

    NARCIS (Netherlands)

    Sotthewes, Kai; Heimbuch, Rene; Zandvliet, Henricus J.W.

    2015-01-01

    Spatially resolved current-time scanning tunneling spectroscopy combined with current-distance spectroscopy has been used to characterize the dynamic behavior of copper-phthalocyanine (CuPc) molecules adsorbed on a Au-modified Ge(001) surface. The analyzed CuPc molecules are adsorbed in a “molecular

  5. Resonant-Gravimetric Identification of Competitive Adsorption of Environmental Molecules.

    Science.gov (United States)

    Xu, Pengcheng; Xu, Tao; Yu, Haitao; Li, Xinxin

    2017-07-05

    Understanding competitive adsorption relationship among various ambient gases is important in adsorbing-material development for capturing environmentally harmful gas. For example, environmental interfering factors (e.g., moisture) can affect the competitive gas-molecule adsorption that needs to be clarified. Due to a lack of method to quantitatively study the dynamic adsorbing process (e.g., real-time-counting adsorbed molecule number), it is difficult to reveal the competitive adsorption mechanism. Still using conventional "trial-and-error" method hinders the development of high-performance adsorbing materials; thereby new technology is in high demand to address the issue. This study opens up a three-step resonant-gravimetric analysis method by using ultrasensitive resonant cantilevers. The three experimental steps are sequentially for qualitative analysis, quantitative determination, and thermodynamic-level identification about the competitive adsorption relationship among the environmental gas molecules. Previous studies indicate that the zeolitic-imidazolate framework (ZIF) of ZIF-8 nanocrystals has a low affinity to environmental CO 2 . This conclusion is confirmed in this study by evaluating ZIF-8 with the three experimental steps, sequentially for qualitative judgment of adsorbability, quantitative determination of hydrous molecule structure in real air, and quantitative extraction of thermodynamic enthalpy, ΔH°. By figuring out the competitive interface-adsorption relationship, we verified that ZIF-8 cannot adsorb CO 2 in real air. However, for the first time, ZIF-8 is identified as an excellent adsorbent to environmental NO 2 .

  6. Liquid-Cell Electron Microscopy of Adsorbed Polymers.

    Science.gov (United States)

    Nagamanasa, Kandula Hima; Wang, Huan; Granick, Steve

    2017-11-01

    Individual macromolecules of polystyrene sulfonate and poly(ethylene oxide) are visualized with nanometer resolution using transmission electron microscopy (TEM) imaging of aqueous solutions with and without added salt, trapped in liquid pockets between creased graphene sheets. Successful imaging with 0.3 s per frame is enabled by the sluggish mobility of the adsorbed molecules. This study finds, validating others, that an advantage of this graphene liquid-cell approach is apparently to retard sample degradation from incident electrons, in addition to minimizing background scattering because graphene windows are atomically thin. Its new application here to polymers devoid of metal-ion labeling allows the projected sizes and conformational fluctuations of adsorbed molecules and adsorption-desorption events to be analyzed. Confirming the identification of the observed objects, this study reports statistical analysis of datasets of hundreds of images for times up to 100 s, with variation of the chemical makeup of the polymer, the molecular weight of the polymer, and the salt concentration. This observation of discrete polymer molecules in solution environment may be useful generally, as the findings are obtained using an ordinary TEM microscope, whose kind is available to many researchers routinely. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Ultrahigh-density data storage into thin films of fullerene molecules

    Science.gov (United States)

    Nakaya, Masato; Aono, Masakazu; Nakayama, Tomonobu

    2016-11-01

    Recording nonvolatile digital data with an aerial density above terabit per square inch (Tbits/in.2), the so-called ultrahigh-density data storage, is one of the key technologies toward a sophisticated information-oriented society in the near future. To overcome the limitation of conventional magnetic data storage, one proposed solution is the use of thin films of functional molecules as recording media, in which each nonvolatile digital datum is stored into a single molecule by controlling its chemical reaction. Here, we show the recent progress in ultrahigh-density data storage using ultrathin films of C60 molecules. In this data storage, binary digits (1 and 0) are stored with an aerial density up to 180 Tbits/in.2 by controlling the bound and unbound states of C60 molecules in the films. Writing and erasing bit data have been carried out by selectively inducing the formation and annihilation of a covalent bond between neighboring C60 molecules, respectively, which are precisely controlled for a designated C60 molecule on the surface of a C60 film using the metal tip of a scanning tunneling microscopy (STM) system. It has also been shown that quantum efficiencies of STM-induced intermolecular reactions between C60 molecules are a key factor in determining the speeds of data writing and erasing as well as the reliability of these operations. Controlling the quantum efficiencies of intermolecular reactions by electrostatic charge injection from the conductive substrate to the surface layer of C60 films results in data writing with an operating speed of ∼363 bits/s.

  8. Spin-dependent rectification in the C59N molecule

    Indian Academy of Sciences (India)

    2013-02-05

    Feb 5, 2013 ... organic semiconductors, is placed as a bridge in magnetic tunnel junctions, because its lowest unoccupied molecular orbital (LUMO) is located at relatively lower energies. The spin-dependent transport in FM/C60/FM junction was studied [26], but spin-dependent transport through a single C59N molecule, ...

  9. Equilibrium and heat of adsorption of diethyl phthalate on heterogeneous adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W.M.; Xu, Z.W.; Pan, B.C.; Hong, C.H.; Jia, K.; Jiang, P.J.; Zhang, Q.J.; Pan, B.J. [Nanjing University, Nanjing (China)

    2008-09-15

    Removal of phthalate esters from water has been of considerable concern recently. In the present study, the adsorptive removal performance of diethyl phthalate (DEP) from water was investigated with the aminated polystyrene resin (NDA-101) and oxidized polystyrene resin (NDA-702). In addition, the commercial homogeneous polystyrene resin (XAD-4) and acrylic ester resin (Amberlite XAD-7) as well as coal-based granular activated carbon (AC-750) were chosen for comparison. The corresponding equilibrium isotherms are well described by the Freundlich equation and the adsorption capacities for DEP followed the order NDA-702 > NDA-101 > AC-750 > XAD-4 > XAD-7. Analysis of adsorption mechanisms suggested that these adsorbents spontaneously adsorb DEP molecules driven mainly by enthalpy change, and the adsorption process was derived by multiple adsorbent-adsorbate interactions such as hydrogen bonding, {pi}-{pi} stacking, and micropore filling. The information related to the adsorbent surface heterogeneity and the adsorbate-adsorbate interaction was obtained by Do's model. All the results indicate that heterogeneous resins NDA-702 and NDA-101 have excellent potential as an adsorption material for the removal of DEP from the contaminated water.

  10. A machine learning approach to graph-theoretical cluster expansions of the energy of adsorbate layers

    Science.gov (United States)

    Vignola, Emanuele; Steinmann, Stephan N.; Vandegehuchte, Bart D.; Curulla, Daniel; Stamatakis, Michail; Sautet, Philippe

    2017-08-01

    The accurate description of the energy of adsorbate layers is crucial for the understanding of chemistry at interfaces. For heterogeneous catalysis, not only the interaction of the adsorbate with the surface but also the adsorbate-adsorbate lateral interactions significantly affect the activation energies of reactions. Modeling the interactions of the adsorbates with the catalyst surface and with each other can be efficiently achieved in the cluster expansion Hamiltonian formalism, which has recently been implemented in a graph-theoretical kinetic Monte Carlo (kMC) scheme to describe multi-dentate species. Automating the development of the cluster expansion Hamiltonians for catalytic systems is challenging and requires the mapping of adsorbate configurations for extended adsorbates onto a graphical lattice. The current work adopts machine learning methods to reach this goal. Clusters are automatically detected based on formalized, but intuitive chemical concepts. The corresponding energy coefficients for the cluster expansion are calculated by an inversion scheme. The potential of this method is demonstrated for the example of ethylene adsorption on Pd(111), for which we propose several expansions, depending on the graphical lattice. It turns out that for this system, the best description is obtained as a combination of single molecule patterns and a few coupling terms accounting for lateral interactions.

  11. Recovery of Th(IV) from aqueous solution by reassembled collagen-tannin fiber adsorbent

    International Nuclear Information System (INIS)

    Yunhang Zeng; Xuepin Liao; Qiang He; Bi Shi

    2009-01-01

    A novel adsorbent, collagen immobilized tannin adsorbent (CITA), was prepared and its adsorption behaviors to Th(IV) were investigated. CITA was n fibrous state due to the reassembly of collagen molecules by the inducement of tannin. This adsorbent loaded a greater amount of tannin and exhibited higher adsorption capacity to Th(IV) than the tannin immobilized adsorbent prepared from collagen fiber. The adsorption of CITA to Th(IV) is mainly attributed to surface complexation, which is a pH- rather than an ionic strength-dependent process. The adsorption kinetics and isotherms were described by pseudo-second-order rate model and Freundlich equation, respectively. Column adsorption studies indicated that CITA is available for effectively recovering Th(IV) from aqueous solution. (author)

  12. Magnetic susceptibility of oxygen adsorbed on the surface of spherical and fibrous activated carbon.

    Directory of Open Access Journals (Sweden)

    Kiyoshi Kawamura

    2009-02-01

    Full Text Available The magnetic susceptibilities of oxygen adsorbed on the surface of bead-shaped activated carbon and activated carbon fibers were evaluated as a function of temperature between 4.2 K and 300 K, and found to exhibit a sharp peak at around 50 K. This implies that the adsorbed oxygen molecules form an antiferromagnetic state. The relation between the susceptibility and the adsorbed mass suggest that the thickness of the adsorbed oxygen is thin enough to consider a two-dimensional structure for bead–shaped activated carbon and carbon fibers across the fiber axis but thick enough to regard it as three-dimensional along the fiber axis. The result is discussed with reference to the study on one-dimensional oxygen array.

  13. Corrected electrostatic model for dipoles adsorbed on a metal surface

    Energy Technology Data Exchange (ETDEWEB)

    Maschhoff, B.L.; Cowin, J.P. (Enviornmental and Molecular Science Laboratory, Pacific Northwest Laboratories Box 999 MS K2-14, Richland, Washington 99352 (United States))

    1994-11-01

    We present a dipole--dipole interaction model for polar molecules vertically adsorbed on a idealized metal surface in an approximate analytic form suitable for estimating the coverage dependence of the work function, binding energies, and thermal desorption activation energies. In contrast to previous treatments, we have included all contributions to the interaction energy within the dipole model, such as the internal polarization energy and the coverage dependence of the self-image interaction with the metal. We show that these can contribute significantly to the total interaction energy. We present formulae for both point and extended dipole cases.

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

    Science.gov (United States)

    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.

  15. Structure formation in bis(terpyridine) derivative adlayers: molecule-substrate versus molecule-molecule interactions.

    Science.gov (United States)

    Hoster, Harry E; Roos, Matthias; Breitruck, Achim; Meier, Christoph; Tonigold, Katrin; Waldmann, Thomas; Ziener, Ulrich; Landfester, Katharina; Behm, R Jürgen

    2007-11-06

    The influence of the substrate and the deposition conditions-vapor deposition versus deposition from solution-on the structures formed upon self-assembly of deposited bis(terpyridine) derivative (2,4'-BTP) monolayers on different hexagonal substrates, including highly oriented pyrolytic graphite (HOPG), Au(111), and (111)-oriented Ag thin films, was investigated by high-resolution scanning tunneling microscopy and by model calculations of the intermolecular energies and the lateral corrugation of the substrate-adsorbate interaction. Similar quasi-quadratic network structures with almost the same lattice constants obtained on all substrates are essentially identical to the optimum configuration expected from an optimization of the adlayer structure with C-H...N-type bridging bonds as a structure-determining factor, which underlines a key role of the intermolecular interactions in adlayer order. Slight distortions from the optimum values to form commensurate adlayer structures on the metal substrates and the preferential orientation of the adlayer with respect to the substrate are attributed to the substrate-adsorbate interactions, specifically, the lateral corrugation in the substrate-adsorbate interaction upon lateral displacement and rotation of the adsorbed BTP molecules. The fact that similar adlayer structures are obtained on HOPG under ultrahigh vacuum conditions (solid|gas interface) and on HOPG in trichlorobenzene (solid|liquid interface) indicates that the intermolecular interactions are not severely affected by the solvent.

  16. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 4. Molecule Matters – van der Waals Molecules - History and Some Perspectives on Intermolecular Forces ... Author Affiliations. E Arunan1. Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India.

  17. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 4. Molecule Matters – van der Waals Molecules - History and Some Perspectives on Intermolecular Forces. E Arunan. Feature Article Volume 14 Issue 4 April 2009 pp 346-356 ...

  18. Single-crystal C60 needle/CuPc nanoparticle double floating-gate for low-voltage organic transistors based non-volatile memory devices.

    Science.gov (United States)

    Chang, Hsuan-Chun; Lu, Chien; Liu, Cheng-Liang; Chen, Wen-Chang

    2015-01-07

    Low-voltage organic field-effect transistor memory devices exhibiting a wide memory window, low power consumption, acceptable retention, endurance properties, and tunable memory performance are fabricated. The performance is achieved by employing single-crystal C60 needles and copper phthalocyanine nanoparticles to produce an ambipolar (hole/electron) trapping effect in a double floating-gate architecture. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Ambipolar blends of CuPc and C60: charge carrier mobility, electronic structure and its implications for solar cell applications

    OpenAIRE

    Bruetting, W.; Bronner, M.; Goetzenbrugger, M.; Opitz, A.

    2007-01-01

    Ambipolar transport has been realised in blends of the molecular hole conductor Cu-phthalocyanine (CuPc) and the electron conducting fullerene C60. Charge carrier mobilities and the occupied electronic levels have been analyzed as a function of the mixing ratio using field-effect transistor measurements and photoelectron spectroscopy. These results are discussed in the context of photovoltaic cells based on these materials.

  20. Organic adsorbates on metal surfaces. PTCDA and NTCDA on AG(110)

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, Afshin

    2010-02-22

    Polyaromatic molecules functionalized with carboxylic groups have served as model systems for the growth of organic semiconducting films on a large variety of substrates. Most non-reactive substrates allow for a growth mode compatible with the bulk phase of the molecular crystal with two molecules in the unit cell, but some more reactive substrates including Ag(111) and Ag(110) can induce substantial changes in the first monolayer (ML). In the specific case of Ag(110), the adsorbate unit cell of both NTCDA and PTCDA resembles a brickwall structure, with a single molecule in the unit cell. From this finding, it can be concluded that the adsorbate-substrate interaction is stronger than typical inter-molecular binding energies in the respective bulk phases. In the present work, the interactions between small Ag(110) clusters and a single NTCDA or PTCDA molecule are investigated with different ab initio techniques. Four major ingredients contribute to the binding between adsorbate and substrate: Directional bonds between Ag atoms in the topmost layer and the oxygen atoms of the molecule, Pauli repulsion between filled orbitals of molecule and substrate, an attractive van-der-Waals interaction, and a negative net charge on the molecule inducing positive image charges in the substrate, resulting therefore in an attractive Coulomb interaction between these opposite charges. As both Hartree-Fock theory and density functional theory with typical gradient-corrected density functional do not contain any long range correlation energy required for dispersion interactions, we compare these approaches with the fastest numerical technique where the leading term of the van-der-Waals interaction is included, i.e. second order Moeller-Plesset theory (MP2). Both Hartree-Fock and density functional theory result in bended optimized geometries where the adsorbate is interacting mainly via the oxygen atoms, with the core of the molecule repelled from the substrate. Only at the MP2 level

  1. Filter-adsorber aging assessment

    Energy Technology Data Exchange (ETDEWEB)

    Winegardner, W.K. [Pacific Northwest Laboratory, Richland, WA (United States)

    1995-02-01

    An aging assessment of high-efficiency particulate (HEPA) air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the U.S. Nuclear Regulatory Commission`s (USNRC) Nuclear Plant Aging Research (NPAR) Program. This evaluation of the general process in which characteristics of these two components gradually change with time or use included the compilation of information concerning failure experience, stressors, aging mechanisms and effects, and inspection, surveillance, and monitoring methods (ISMM). Stressors, the agents or stimuli that can produce aging degradation, include heat, radiation, volatile contaminants, and even normal concentrations of aerosol particles and gasses. In an experimental evaluation of degradation in terms of the tensile breaking strength of aged filter media specimens, over forty percent of the samples did not meet specifications for new material. Chemical and physical reactions can gradually embrittle sealants and gaskets as well as filter media. Mechanisms that can lead to impaired adsorber performance are associated with the loss of potentially available active sites as a result of the exposure of the carbon to airborne moisture or volatile organic compounds. Inspection, surveillance, and monitoring methods have been established to observe filter pressure drop buildup, check HEPA filters and adsorbers for bypass, and determine the retention effectiveness of aged carbon. These evaluations of installed filters do not reveal degradation in terms of reduced media strength but that under normal conditions aged media can continue to effectively retain particles. However, this degradation may be important when considering the likelihood of moisture, steam, and higher particle loadings during severe accidents and the fact it is probable that the filters have been in use for an extended period.

  2. Unraveling the Charge Extraction Mechanism of Perovskite Solar Cells Fabricated with Two-Step Spin Coating: Interfacial Energetics between Methylammonium Lead Iodide and C60.

    Science.gov (United States)

    Shin, Dongguen; Kang, Donghee; Jeong, Junkyeong; Park, Soohyung; Kim, Minju; Lee, Hyunbok; Yi, Yeonjin

    2017-11-02

    In organolead halide perovskite solar cells (PSCs), interfacial properties between the perovskite and charge transport layers are the critical factors governing charge extraction efficiency. In this study, the effect of interfacial energetics between two-step spin-coated methylammonium lead iodide (MAPbI 3 ) with different methylammonium iodide (MAI) concentrations and C 60 on the charge extraction efficiency is investigated. The electronic structures of perovskite films are significantly varied by the MAI concentrations due to the changes in the residual precursor and MA + defect content. As compared to the optimum PSCs with 25 mg mL -1 MAI, PSCs with other MAI concentrations show significantly lower power conversion efficiencies and severe hysteresis. The energy level alignment at the C 60 /MAPbI 3 interface determined by ultraviolet and inverse photoelectron spectroscopy measurements reveals the origin of distinct differences in device performances. The conduction band offset at the C 60 /MAPbI 3 interface plays a crucial role in efficient charge extraction in PSCs.

  3. Structure and electronic properties of the nanopeapods—One dimensional C60O polymer encapsulated in single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Qiao Weiye; Li Xinqian; Bai Hongcun; Zhu Ying; Huang Yuanhe

    2012-01-01

    The structure–property relationship of the nanopeapods—one dimensional (1D) C 60 O polymer encapsulated in single-walled carbon nanotubes (SWCNTs)—is studied by means of the self-consistent field crystal orbital method. The calculations show that the nearest distance between the two constituents is within Van der Waals interaction scope in the most stable two peapods. The SWCNT sizes affect not only the stability but also the electronic structures of the peapods. The peapods with larger tube diameters keep the semiconductive and metallic properties of the corresponding pristine SWCNTs. These combination systems are stiffer than the corresponding SWCNTs due to larger Young's moduli. The magnitude order of the calculated mobility of charge carriers is in the range of 10 2 –10 5 cm 2 V −1 s −1 for the peapods, indicating that the combined systems may be good high-mobility electronic materials. - Graphical abstract: Formation of the novel peapod—1D C 60 O polymer encapsulated inside single-walled carbon nanotube. Highlights: ► Several novel peapods encapsulating one dimensional C 60 O polymers are constructed. ► Interwall distance of the two most stable peapods is in the Van der Waals scope. ► All peapods studied are stiffer than the corresponding SWCNTs. ► These peapods have high mobilies—in the order of 10 2 –10 5 cm 2 V −1 s −1 .

  4. Passivating ZnO Surface States by C60 Pyrrolidine Tris-Acid for Hybrid Solar Cells Based on Poly(3-hexylthiophene/ZnO Nanorod Arrays

    Directory of Open Access Journals (Sweden)

    Peng Zhong

    2017-12-01

    Full Text Available Construction of ordered electron acceptors is a feasible way to solve the issue of phase separation in polymer solar cells by using vertically-aligned ZnO nanorod arrays (NRAs. However, the inert charge transfer between conducting polymer and ZnO limits the performance enhancement of this type of hybrid solar cells. In this work, a fullerene derivative named C60 pyrrolidine tris-acid is used to modify the interface of ZnO/poly(3-hexylthiophene (P3HT. Results indicate that the C60 modification passivates the surface defects of ZnO and improves its intrinsic fluorescence. The quenching efficiency of P3HT photoluminescence is enhanced upon C60 functionalization, suggesting a more efficient charge transfer occurs across the modified P3HT/ZnO interface. Furthermore, the fullerene modified hybrid solar cell based on P3HT/ZnO NRAs displays substantially-enhanced performance as compared to the unmodified one and the devices with other modifiers, which is contributed to retarded recombination and enhanced exciton separation as evidenced by electrochemical impedance spectra. Therefore, fullerene passivation is a promising method to ameliorate the connection between conjugated polymers and metal oxides, and is applicable in diverse areas, such as solar cells, transistors, and light-emitting dioxides.

  5. Electronic Structure of C60/Zinc Phthalocyanine/V2O5 Interfaces Studied Using Photoemission Spectroscopy for Organic Photovoltaic Applications

    Directory of Open Access Journals (Sweden)

    Chang Jin Lim

    2018-02-01

    Full Text Available The interfacial electronic structures of a bilayer of fullerene (C60 and zinc phthalocyanine (ZnPc grown on vanadium pentoxide (V2O5 thin films deposited using radio frequency sputtering under various conditions were studied using X-ray and ultraviolet photoelectron spectroscopy. The energy difference between the highest occupied molecular orbital (HOMO level of the ZnPc layer and the lowest unoccupied molecular orbital (LUMO level of the C60 layer was determined and compared with that grown on an indium tin oxide (ITO substrate. The energy difference of a heterojunction on all V2O5 was found to be 1.3~1.4 eV, while that on ITO was 1.1 eV. This difference could be due to the higher binding energy of the HOMO of ZnPc on V2O5 than that on ITO regardless of work functions of the substrates. We also determined the complete energy level diagrams of C60/ZnPc on V2O5 and ITO.

  6. Complete braided adsorbent for marine testing to demonstrate 3g-U/kg-adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Janke, Chris [ORNL; Yatsandra, Oyola [ORNL; Mayes, Richard [ORNL; none,; Gill, Gary [PNNL; Li-Jung, Kuo [PNNL; Wood, Jordana [PNNL; Sadananda, Das [ORNL

    2014-04-30

    ORNL has manufactured four braided adsorbents that successfully demonstrated uranium adsorption capacities ranging from 3.0-3.6 g-U/kg-adsorbent in marine testing at PNNL. Four new braided and leno woven fabric adsorbents have also been prepared by ORNL and are currently undergoing marine testing at PNNL.

  7. Immunoreactivity of adsorbed anti human chorionic gonadotropin studied with an optical waveguide interferometric sensor

    NARCIS (Netherlands)

    Heideman, Rene; Kooyman, R.P.H.; Greve, Jan

    1994-01-01

    A study on the immunoreactivity of adsorbed αhCG molecules as a function of substrate hydrophobicity and protein coverage is presented. The experiments were performed with a planar waveguide interferometrical immunosensor. The substrate hydrophobicity and the antibody density were found to be of

  8. Thermodynamics of gas adsorption on solid adsorbents

    International Nuclear Information System (INIS)

    Budrugeac, P.

    1979-01-01

    Starting with several hypotheses about the adsorbtion system and the adsorption phenomenon, a thermodynamic treatment of gas adsorption on solid adsorbants is presented. The relationships for determination from isotherms and calorimetric data of thermodynamic functions are derived. The problem of the phase changes in adsorbed layer is discussed. (author)

  9. adsorbent for defluoridation of drinking water

    African Journals Online (AJOL)

    2014-12-17

    Dec 17, 2014 ... In this study, the performance of different aluminium hydroxide–based adsorbents was compared in terms of fluoride adsorption capacity, potential for repetitive regeneration, surface acidity and surface site concentrations. The adsorbents were aluminium hydro(oxide) (AO), activated alumina (AA), and ...

  10. Extraction of uranium from seawater by the fibrous composite adsorbent

    International Nuclear Information System (INIS)

    Katoh, Shunsaku; Sugasaka, Kazuhiko; Nogi, Tatsuo; Yoshizumi, Nobuo; Mima, Kooji.

    1986-01-01

    The fibrous composite adsorbents consisting of hydrous titanium oxide and activated carbon were prepared with hydrophilic polyacrylonitrile system polymer as a binder under various conditions, and the adsorptive property of the fibrous composite adsorbents for uranium from seawater was examined. The fibrous composite adsorbents which spun under high pressure (10 kg/cm 2 ) was the finest having the largest pore volume. In addition, the amount of uranium adsorbed of the fibrous adsorbent was the largest. The rate of uranium adsorption by the fibrous adsorbent was the same as the rate of uranium adsorption by the powdery adsorbent. The excellent fibrous adsorbent adsorbed 0.23 mg U/g adsorbent for 10 d and 0.65 mg U/g adsorbent for 100 d. The rate of uranium desorption from the fibrous adsorbent by alkali carbonate solution was large, and the uranium in the fibrous adsorbent desorbed 75 % for 8 h and about 100 % for 24 h. (author)

  11. The interaction of linear and ring forms of DNA molecules with nanodiamonds synthesized by detonation

    International Nuclear Information System (INIS)

    Purtov, K V; Burakova, L P; Puzyr, A P; Bondar, V S

    2008-01-01

    Nanodiamonds synthesized by detonation have been found not to immobilize the ring form of pUC19 plasmid DNA. Linear pUC19 molecules with blunt ends, prepared by restriction of the initial ring form of pUC19 DNA, and linear 0.25-10 kb DNA fragments are adsorbed on nanodiamonds. The amount of adsorbed linear DNA molecules depends on the size of the molecules and the size of the nanodiamond clusters

  12. Atkins' molecules

    CERN Document Server

    Atkins, Peters

    2003-01-01

    Originally published in 2003, this is the second edition of a title that was called 'the most beautiful chemistry book ever written'. In it, we see the molecules responsible for the experiences of our everyday life - including fabrics, drugs, plastics, explosives, detergents, fragrances, tastes, and sex. With engaging prose Peter Atkins gives a non-technical account of an incredible range of aspects of the world around us, showing unexpected connections, and giving an insight into how this amazing world can be understood in terms of the atoms and molecules from which it is built. The second edition includes dozens of extra molecules, graphical presentation, and an even more accessible and enthralling account of the molecules themselves.

  13. Interstellar Molecules

    Science.gov (United States)

    Solomon, Philip M.

    1973-01-01

    Radioastronomy reveals that clouds between the stars, once believed to consist of simple atoms, contain molecules as complex as seven atoms and may be the most massive objects in our Galaxy. (Author/DF)

  14. Imaging and manipulation of a polar molecule oil Ag(111)

    DEFF Research Database (Denmark)

    Lin, Rong; Braun, K.F.; Tang, H.

    2001-01-01

    A scanning tunneling microscope (STM) was applied to image and laterally manipulate isolated phosphangulene molecules on Ag(111) at 6 K. Atomic-resolution images clearly revealed three characteristic types of appearances (three-lobed, fish and bump shape) for the adsorbed molecules, which could...

  15. sup(60)Co hot atom chemistry of tris(acetylacetonato) cobalt(III) adsorbed on silica gel

    International Nuclear Information System (INIS)

    Nishioji, H.; Sakai, Y.; Tominaga, T.

    1985-01-01

    The sup(60)Co hot atom reactions were studied in tris(acetylacetonato)cobalt(III) adsorbed on silica gel surface. sup(57)Fe Moessbauer spectra of tris(acetylacetonato)iron(III) in the corresponding system were also measured in order to examine the state of dispersion of complex molecules on silica gel. The retention formation processes were discussed in terms of the dependence of sup(60)Co retention on the adsorbed amount (concentration) of cobalt(III) complexes. (author)

  16. Heat transfer to the adsorbent in solar adsorption cooling device

    Science.gov (United States)

    Pilat, Peter; Patsch, Marek; Papucik, Stefan; Vantuch, Martin

    2014-08-01

    The article deals with design and construction of solar adsorption cooling device and with heat transfer problem in adsorber. The most important part of adsorption cooling system is adsorber/desorber containing adsorbent. Zeolith (adsorbent) type was chosen for its high adsorption capacity, like a coolant was used water. In adsorber/desorber occur, at heating of adsorbent, to heat transfer from heat change medium to the adsorbent. The time required for heating of adsorber filling is very important, because on it depend flexibility of cooling system. Zeolith has a large thermal resistance, therefore it had to be adapted the design and construction of adsorber. As the best shows the tube type of adsorber with double coat construction. By this construction is ensured thin layer of adsorbent and heating is quick in all volume of adsorbent. The process of heat transfer was experimentally measured, but for comparison simulated in ANSYS, too.

  17. New development of large-area direct conversion detector for digital radiography using amorphous selenium with a C60-doped polymer layer

    Science.gov (United States)

    Nariyuki, F.; Imai, S.; Watano, H.; Nabeta, T.; Hosoi, Y.

    2010-04-01

    We have developed a novel direct conversion detector for digital radiography by using a fullerene (C60)-doped polymer layer added on a thick amorphous selenium (a-Se) layer coupled to an amorphous silicon thin-film transistor (a-Si TFT) array. This detector exhibits considerable improvement in the lag characteristics and durability in high ambient temperatures. The C60-doped polymer layer, which is directly and uniformly solution cast on the a-Se layer and followed by an inorganic electron-transporting layer, smoothly changes the electronic junction between the a-Se layer and the inorganic layer. It lubricates the emission of photocurrents from the a-Se photo-conversion layer and leads to the improved lag characteristics. Another merit of using a C60-doped polymer is that it is stabile in high-temperature ambient conditions and is not degraded by humidity or a large amount of X-ray exposure. The polymer layer prevents the crystallization of a-Se, which otherwise occurs on exposure of a-Se to high temperature not only during the deposition of the inorganic layer or the metal electrode layer in the manufacturing process but also in actual use. A prototype detector, with a size of 17 in × 17 in and a pixel pitch of 150 μm, exhibited a good resolution; its DQE is approximately 48% at 1 cy/mm in 258 μC/kg (RQA5). This new development can simplify cooling apparatus and detector modules and also make a wide range of operational environments available. In addition, the improved lag characteristics make it possible to reduce the exposure intervals for static imaging, tomosynthesis, and other various exposure techniques.

  18. Activity of catalase adsorbed to carbon nanotubes: effects of carbon nanotube surface properties.

    Science.gov (United States)

    Zhang, Chengdong; Luo, Shuiming; Chen, Wei

    2013-09-15

    Nanomaterials have been studied widely as the supporting materials for enzyme immobilization. However, the interactions between enzymes and carbon nanotubes (CNT) with different morphologies and surface functionalities may vary, hence influencing activities of the immobilized enzyme. To date how the adsorption mechanisms affect the activities of immobilized enzyme is not well understood. In this study the adsorption of catalase (CAT) on pristine single-walled carbon nanotubes (SWNT), oxidized single-walled carbon nanotubes (O-SWNT), and multi-walled carbon nanotubes (MWNT) was investigated. The adsorbed enzyme activities decreased in the order of O-SWNT>SWNT>MWNT. Fourier transforms infrared spectroscopy (FTIR) and circular dichrois (CD) analyses reveal more significant loss of α-helix and β-sheet of MWNT-adsorbed than SWNT-adsorbed CAT. The difference in enzyme activities between MWNT-adsorbed and SWNT-adsorbed CAT indicates that the curvature of surface plays an important role in the activity of immobilized enzyme. Interestingly, an increase of β-sheet content was observed for CAT adsorbed to O-SWNT. This is likely because as opposed to SWNT and MWNT, O-SWNT binds CAT largely via hydrogen bonding and such interaction allows the CAT molecule to maintain the rigidity of enzyme structure and thus the biological function. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Imaging prototypical aromatic molecules on insulating surfaces: a review

    Science.gov (United States)

    Hoffmann-Vogel, R.

    2018-01-01

    Insulating substrates allow for in-plane contacted molecular electronics devices where the molecule is in contact with the insulator. For the development of such devices it is important to understand the interaction of molecules with insulating surfaces. As substrates, ionic crystals such as KBr, KCl, NaCl and CaF2 are discussed. The surface energies of these substrates are small and as a consequence intrinsic properties of the molecules, such as molecule–molecule interaction, become more important relative to interactions with the substrates. As prototypical molecules, three variants of graphene-related molecules are used, pentacene, C60 and PTCDA. Pentacene is a good candidate for molecular electronics applications due to its high charge carrier mobility. It shows mainly an upright standing growth mode and the morphology of the islands is strongly influenced by dewetting. A new second flat-lying phase of the molecule has been observed. Studying the local work function using the Kelvin method reveals details such as line defects in the center of islands. The local work function differences between the upright-standing and flat-lying phase can only be explained by charge transfer that is unusual on ionic crystalline surfaces. C60 nucleation and growth is explained by loosely bound molecules at kink sites as nucleation sites. The stability of C60 islands as a function of magic numbers is investigated. Peculiar island shapes are obtained from unusual dewetting processes already at work during growth, where molecules ‘climb’ to the second molecular layer. PTCDA is a prototypical semiconducting molecule with strong quadrupole moment. It grows in the form of elongated islands where the top and the facets can be molecularly resolved. In this way the precise molecular arrangement in the islands is revealed.

  20. Structural effects of C60+ bombardment on various natural mineral samples-Application to analysis of organic phases in geological samples

    International Nuclear Information System (INIS)

    Siljestroem, S.; Lausmaa, J.; Hode, T.; Sundin, M.; Sjoevall, P.

    2011-01-01

    Organic phases trapped inside natural mineral samples are of considerable interest in astrobiology, geochemistry and geobiology. Examples of such organic phases are microfossils, kerogen and oil. Information about these phases is usually retrieved through bulk crushing of the rock which means both a risk of contamination and that the composition and spatial distribution of the organics to its host mineral is lost. An attractive of way to retrieve information about the organics in the rock is depth profiling using a focused ion beam. Recently, it was shown that it is possible to obtain detailed mass spectrometric information from oil-bearing fluid inclusions, i.e. small amounts of oil trapped inside a mineral matrix, using ToF-SIMS. Using a 10 keV C 60 + sputter beam and a 25 keV Bi 3 + analysis beam, oil-bearing inclusions in different minerals were opened and analysed individually. However, sputtering with a C 60 + beam also induced other changes to the mineral surface, such as formation of topographic features and carbon deposition. In this paper, the cause of these changes is explored and the consequences of the sputter-induced features on the analysis of organic phases in natural mineral samples (quartz, calcite and fluorite) in general and fluid inclusions in particular are discussed. The dominating topographical features that were observed when a several micrometers deep crater is sputtered with 10 keV C 60 + ions on a natural mineral surface are conical-shaped and ridge-like structures that may rise several micrometers, pointing in the direction of the incident C 60 + ion beam, on an otherwise flat crater bottom. The sputter-induced structures were found to appear at places with different chemistry than the host mineral, including other minerals phases and fluid inclusions, while structural defects in the host material, such as polishing marks or scratches, did not necessarily result in sputter-induced structures. The ridge-like structures were often covered

  1. Linear-dendritic supramolecular complexes as nanoscale reaction vessels for "green" chemistry. Diels-Alder reactions between fullerene C60 and polycyclic aromatic hydrocarbons in aqueous medium.

    Science.gov (United States)

    Simonyan, Arsen; Gitsov, Ivan

    2008-10-21

    This study describes the first Diels-Alder (DA) reaction performed in aqueous medium with highly hydrophobic compounds-fullerene (C 60) as the dienophile and anthracene (An) or tetracene (Tet) as the dienes, respectively. The reactions are performed in nanocontainers, constructed by self-assembly of linear-dendritic amphiphilic copolymers with poly(ethylene glycol), PEG or poly(ethylene oxide), PEO as the hydrophilic blocks and poly(benzyl ether) monodendrons as the hydrophobic fragments: G3PEO13k, dG3 and dG2. Comparative studies under identical conditions are carried out with an amphiphilic linear-linear copolymer, poly(styrene)1800- block-PEO2100, PSt-PEO, and the nonionic surfactant Igepal CO-720, IP720. The binding affinity of supermolecules built of these amphiphiles toward the DA reagents decreases in the following order: G3PEO13k > dG3 > PSt-PEO > dG2 > IP720. The kinetic constant of binding is evaluated for tetracene and decreases in a similar fashion: 5 x 10 (-7) M/min (G3PEO13k), through 4 x 10 (-7) M/min (PSt-PEO) down to 1.5 x 10 (-7) M/min for IP720. The mobility of substrates encapsulated in the micellar core, estimated by pyrene fluorescence decay, is 95-121 ns for the micelles of the linear-dendritic copolymers and notably higher for PSt-PEO (152 ns), revealing the much denser interior of the linear analogue. The apparent kinetic constant for the DA reaction of C 60 and Tet within the G3PEO13k supermolecule in aqueous medium is markedly higher than in organic solvent (toluene), 208 vs 1.82 M /min. With G3PEO13k the conversions reach 49% for the DA reaction between C 60 and An, and 55% for C 60 and Tet. Besides the monoadduct (26.5% yield) the reaction with An produces exclusively increasing amounts of D 2 h -symmetric antipodal bis-adduct, whose yield reaches up to 22.5% after 48 h. In addition to the environmentally friendly conditions notable advantages of the synthetic strategy described are the extended stability of the linear

  2. Multiple ionization of C 60 in collisions with 2.33 MeV/u O-ions and giant plasmon excitation

    Science.gov (United States)

    Kelkar, A. H.; Kadhane, U.; Misra, D.; Kumar, Ajay; Tribedi, L. C.

    2007-03-01

    Single and multiple ionization of C60 in collisions with fast (v = 9.7 a.u.) Oq+ ions have been studied. Relative cross sections for production of C 601+ to C 604+ have been measured. The intensity ratios of double-to-single ionization agree very well with a model based on giant dipole plasmon resonance (GDPR). Almost linear increasing trend of the yields of single and double ionizations with projectile charge state is well reproduced by the single and double plasmon excitation mechanisms. The observed charge state independence of triple and quadruple ionization is in sharp contrast to the GDPR model.

  3. Hypercrosslinked poly(styrene-co-divinylbenzene) resin as a specific polymeric adsorbent for purification of berberine hydrochloride from aqueous solutions.

    Science.gov (United States)

    Li, Yin; Cao, Ruofan; Wu, Xiaofei; Huang, Jianhan; Deng, Shuguang; Lu, Xiuyang

    2013-06-15

    A hypercrosslinked poly(styrene-co-divinylbenzene) resin (TEPA) was synthesized and characterized as a specific polymeric adsorbent for concentrating berberine hydrochloride from aqueous solutions. Three organic molecules of different sizes (2-naphthol, berberine hydrochloride, and Congo red) were used as target molecules to elucidate the molecular sieving effect of the TEPA adsorbent. Because the TEPA adsorbent has a pore structure consisting mainly of micropores and mesopores, the adsorption of 2-naphthol from aqueous solutions is very efficient due to the micropore filling effect. The adsorption of berberine hydrochloride mostly takes place in the mesopores as well as macropores, while the adsorption of Congo red mainly occurs in the macropores. The smaller adsorbate molecule (2-naphthol) reaches the adsorption equilibrium much faster than the larger ones (berberine hydrochloride and Congo red). An adsorption breakthrough experiment with an aqueous solution containing 2-naphthol and berberine hydrochloride demonstrated that the TEPA adsorbent could effectively remove 2-naphthol from berberine hydrochloride at 0-107 BV (bed volume, 1 BV=10 ml), and the berberine hydrochloride concentration was increased from 66.7% to 99.4%, suggesting that this polymeric adsorbent is promising for purifying berberine hydrochloride and similar alkaloids from herbal plant extracts. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Adhesion molecules

    CERN Document Server

    Preedy, Victor R

    2016-01-01

    This book covers the structure and classification of adhesion molecules in relation to signaling pathways and gene expression. It discusses immunohistochemical localization, neutrophil migration, and junctional, functional, and inflammatory adhesion molecules in pathologies such as leukocyte decompression sickness and ischemia reperfusion injury. Highlighting the medical applications of current research, chapters cover diabetes, obesity, and metabolic syndrome; hypoxia; kidney disease; smoking, atrial fibrillation, and heart disease, the brain and dementia; and tumor proliferation. Finally, it looks at molecular imaging and bioinformatics, high-throughput technologies, and chemotherapy.

  5. Asymmetric Flow Field Flow Fractionation of Aqueous C60 Nanoparticles with Size Determination by Dynamic Light Scattering and Quantification by Liquid Chromatography Atmospheric Pressure Photo-Ionization Mass Spectrometry

    Science.gov (United States)

    A size separation method was developed for aqueous C60 fullerene aggregates (aqu/C60) using asymmetric flow field flow fractionation (AF4) coupled to a dynamic light scattering detector in flow through mode. Surfactants, which are commonly used in AF4, were avoided as they may al...

  6. XPS and XAS investigation of condensed and adsorbed n-octane on a Cu(110) surface

    International Nuclear Information System (INIS)

    Weiss, K.; Oestroem, H.; Triguero, L.; Ogasawara, H.; Garnier, M.G.; Pettersson, L.G.M.; Nilsson, A.

    2003-01-01

    The electronic structure of n-octane adsorbed on Cu(110) is studied by using X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) in combination with cluster model calculations in the framework of density functional theory (DFT). The molecule is found to be well oriented on the surface, which is seen from the high degree of XAS dichroism. Saturated hydrocarbons are commonly considered to physisorb on metals such as Cu(110), but still the C 1s XAS spectra reveal large changes in the electronic structure of the adsorbed octane relative to the free molecule. We find that the XAS resonances corresponding to the molecular Rydberg-valence states are strongly quenched upon adsorption and that there is a significant hybridization of the molecular valence orbitals with the metal bands. In addition to a precise interpretation of the XAS spectra, we present details on the molecular orbital structure of the adsorbed octane molecule. We also discuss shifts in the relative binding energies of the chemically inequivalent carbon atoms in octane upon adsorption, which lead to a narrower XPS spectrum for the adsorbate than the condensed phase spectrum due to the existence of a new relaxation channel

  7. Configuration of bovine serum albumin adsorbed on polymer particles with grafted dextran corona.

    Science.gov (United States)

    Vauthier, Christine; Lindner, Peter; Cabane, Bernard

    2009-03-01

    The configuration of BSA macromolecules adsorbed on the surfaces of poly(alkylcyanoacrylate) nanoparticles has been determined using small angle neutron scattering (SANS). The nanoparticles were made by anionic emulsion polymerization (AEP) and self-assembly of dextran-poly(isobutylcyanoacrylate) (PICBA) copolymers. They have a hydrophobic PICBA core and a hydrophilic dextran corona. In vivo, they are recognized by the macrophages of the mononuclear phagocyte system. The amount of BSA bound to the particles, at adsorption equilibrium, has been determined through immunodiffusion, immunoelectrophoresis, and SANS. For particles with a radius of 25.3nm, the adsorption was found to saturate at 64 adsorbed BSA molecules per particle. The configuration of the adsorbed BSA molecules was determined from the SANS scattering curves, first at full contrast, and then at contrast match. Both experiments indicate that the BSA molecules are adsorbed on the PICBA core, in a flat configuration. This result may be important for understanding the in vivo opsonization mechanisms of nanoparticles and their resulting biodistribution.

  8. Alkali metal adsorbate sputtering by molecular impact

    International Nuclear Information System (INIS)

    Moran, J.P.; Wachman, H.Y.; Trilling, L.

    1974-01-01

    An exploratory study of the sputtering by a krypton molecular beam of rubidium adsorbed at low coverage on a tungsten substrate has been described in a previous paper. An extension of this work is reported now

  9. Black Sprayable Molecular Adsorber Coating Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The main objective of this technology project is to develop, optimize, and flight qualify a black version of the molecular adsorber coating and a conductive version...

  10. PERVAPORATION USING ADSORBENT-FILLED MEMBRANES

    Science.gov (United States)

    Membranes containing selective fillers, such as zeolites and activated carbon, can improve the separation by pervaporation. Applications of adsorbent-filled membranes in pervaporation have been demonstrated by a number of studies. These applications include removal of organic co...

  11. New liquid waste control with tannin adsorbent

    International Nuclear Information System (INIS)

    Nakamura, Yoshinobu; Shirato, Wataru; Nakamura, Yasuo

    1998-01-01

    Since 1971, the Mitsubishi Nuclear Fuel Co., Ltd. (MNF) has been fabricating PWR fuels and developing related technology and processes. In the UF 6 reconversion lines of MNF, the ammonium diuranate (ADU) process has been operating and the newly developed process of liquid waste treatment was installed last year. The characteristic of this process is to use insoluble tannin adsorbent which has been developed by MNF. The tannin adsorbent is not only an effective means to adsorb heavy metals such as uranium and plutonium but is also easy to incinerate at low temperature. Control of radioactive liquid waste from nuclear facilities is generally implemented by co-precipitation. However, it produces secondary wastes such as noncombustible materials which include radionuclides and it is anticipated that the storage and disposal of those wastes will be at high cost. Those are the reasons why tannin adsorbent has an advantage, and why MNF develops it. (author)

  12. Robust Cross-Linked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization.

    Science.gov (United States)

    Vidal, Fernando; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y-X

    2016-08-03

    The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust cross-linked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site-controlled propagation mechanism. Postfunctionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible cross-linked thin-film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Cross-linking of such complexes affords robust cross-linked stereocomplexes that are solvent-resistant and also exhibit considerably enhanced thermal and mechanical properties compared with the un-cross-linked stereocomplexes.

  13. Angle-differential observation of plasmon electrons in the double-differential cross-section spectra of fast-ion-induced electron ejection from C60

    Science.gov (United States)

    Kelkar, A. H.; Gulyás, L.; Tribedi, Lokesh C.

    2015-11-01

    We report on the measurement of double-differential distribution of soft electron emission from C60 fullerene, induced by a fast-moving Coulomb field of 76 MeV energy bare fluorine ions. A broad "plasmon-electron" peak, riding on the Coulomb-ionization continuum, is observed due to the deexcitation of the giant dipole plasmon resonance state in C60. The angular distribution of the plasmon electrons goes through a dip around 90°, which is contrary to that observed in ion-atom collisions measured in situ, indicating the alignment of the induced dipole moment along the projectile beam direction. A model based on the photoelectron angular distribution which is modified due to the ion-induced postcollisional interaction provides an excellent agreement with the observed asymmetric distribution. The distribution smoothly changes from a dip at 90° to a peak with the variation of ejected electron energy indicating transition from a collective plasmon behavior of the whole system to a single ion-atom interaction. The single-differential cross section was also derived, which preserves the signature of the collective excitation.

  14. Robust Crosslinked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization

    KAUST Repository

    Vidal, Fernando

    2016-07-07

    The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust crosslinked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site controlled propagation mechanism. Post-functionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible crosslinked thin film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Crosslinking of such complexes afforded robust crosslinked stereocomplexes that are solvent resistant and also exhibit considerably enhanced thermal and mechanical properties as compared to the uncrosslinked stereocompexes.

  15. NOx Removal and Effect of Adsorbate-Adsorbate Interactions

    DEFF Research Database (Denmark)

    Khan, Tuhin Suvra

    to obtain more accurate catalytic rates than with the commonly used non-interacting mean field model. I then applied the proposed adsorbate-adsorbate interaction model to three important catalytic reactions, the direct NO decomposition, CO methanation, and steam reforming of methane, and analyzed the effect...... these challenges systematically and have developed some new methods and models to counter those challenges and obtain some general understanding of the catalytic process. I have developed an adsorbate-adsorbate interaction model to include the coverage dependency of the adsorption energy in kinetic models...... of adsorbate-adsorbate interactions on their catalytic rates. An alloy screening method has also been developed to screen for the industrially most promising alloy catalysts for any catalytic reaction. I have also studied the structure sensitivity of the rates of catalytic direct NO decomposition on different...

  16. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Molecule Matters - Dinitrogen. A G Samuelson J Jabadurai. Volume 16 Issue 12 ... Author Affiliations. A G Samuelson1 J Jabadurai1. Department of Inroganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India.

  17. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 5. Molecule Matters - N-Heterocyclic Carbenes - The Stable Form of R2 C: Anil J Elias. Feature Article Volume 13 Issue 5 May 2008 pp 456-467. Fulltext. Click here to view fulltext PDF. Permanent link:

  18. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 9. Molecule Matters - A Chromium Compound with a Quintuple Bond. K C Kumara Swamy. Feature Article Volume 11 Issue 9 September 2006 pp 72-75. Fulltext. Click here to view fulltext PDF. Permanent link:

  19. Dissolved Air Flotation of arsenic adsorbent particles

    Directory of Open Access Journals (Sweden)

    Mario Enrique Santander Muñoz

    2015-01-01

    Full Text Available The removal of arsenic from synthetic effluent was studied using the adsorbent particle flotation technique (APF and dissolved air flotation (DAF. A sample of an iron mineral was used as adsorbent particles of arsenic, ferric chloride as coagulant, cationic poly-acrylamide (NALCO 9808 as flocculants, and sodium oleate as collector. Adsorption studies to determine the pH influence, contact time, and adsorbent particles concentration on the adsorption of arsenic were carried out along with flotation studies to determine the removal efficiency of adsorbents particles. The results achieved indicate that the adsorption kinetic of arsenic is very rapid and that in range of pH’s from 2 to 7 the adsorption percentages remain constant. The equilibrium conditions were achieved in 60 minutes and about 95% of arsenic was adsorbed when used an adsorbent concentration of 2 g/L and pH 6.3. The maximum adsorption capacity of adsorbent particles was 4.96 mg/g. The mean free energy of adsorption (E was found to be 2.63 kJ/mol, which suggests physisorption. The results of the flotation studies demonstrated that when synthetic effluents with 8.9 mg/L of arsenic were treated under the following experimental conditions; 2 g/L of adsorbent particles, 120 mg/L of Fe(III, 2 mg/L of Nalco 9808, 20 mg/L of sodium oleate, and 40% of recycle ratio in the DAF, it was possible to reach 98% of arsenic removal and 6.3 NTU of residual turbidity in clarified synthetic effluent.

  20. Mesoporous Silica: A Suitable Adsorbent for Amines

    Directory of Open Access Journals (Sweden)

    Abdollahzadeh-Ghom Sara

    2009-01-01

    Full Text Available Abstract Mesoporous silica with KIT-6 structure was investigated as a preconcentrating material in chromatographic systems for ammonia and trimethylamine. Its adsorption capacity was compared to that of existing commercial materials, showing its increased adsorption power. In addition, KIT-6 mesoporous silica efficiently adsorbs both gases, while none of the employed commercial adsorbents did. This means that KIT-6 Mesoporous silica may be a good choice for integrated chromatography/gas sensing micro-devices.