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Sample records for c-60 molecule adsorbed

  1. Controlled contact to a C-60 molecule

    DEFF Research Database (Denmark)

    Neel, N.; Kröger, J.; Limot, L.; Frederiksen, Thomas; Brandbyge, Mads

    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 to...

  2. Electronic structure and electrical transport characteristics of C60, 2C60 and 4C60 fullerene molecules

    Institute of Scientific and Technical Information of China (English)

    SHEN Haijun; MU Xiancai

    2007-01-01

    The extended Hückel method and the Green's function method were used to calculate the electronic struc-ture and electrical transport of Au electrode-C60,2C60 or 4C60 fullerene-Au electrode systems.Furthermore,their electronic structure and electrical transport characteristics were com-pared and analyzed.The results show that (I) owing to the contact with the Au electrodes,the C60,2C60 and 4C60 mole-cules change in their electronic structures ignificantly,and their energy gaps between LUMO and HOMO are narrow;(ii) the bonding between C60,2C60 or 4C60 fullerene and Au electrodes is partially covalent and partially electrovalent;and (iii) the conductance of the three fullerenes conforms to the order of C60>2C60>4C60.

  3. Transport properties of individual C60-molecules

    OpenAIRE

    Géranton, G.; Seiler, C.; Bagrets, A.; Venkataraman, L.; Evers, F.

    2012-01-01

    Electrical and thermal transport properties of C60 molecules are investigated with density-functional-theory based calculations. These calculations suggest that the optimum contact geometry for an electrode terminated with a single-Au atom is through binding to one or two C-atoms of C60 with a tendency to promote the sp2-hybridization into an sp3-type one. Transport in these junctions is primarily through an unoccupied molecular orbital that is partly hybridized with the Au, which results in ...

  4. 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

    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...

  5. Transport properties of individual C60-molecules

    International Nuclear Information System (INIS)

    Electrical and thermal transport properties of C60 molecules are investigated with density-functional-theory based calculations. These calculations suggest that the optimum contact geometry for an electrode terminated with a single-Au atom is through binding to one or two C-atoms of C60 with a tendency to promote the  sp2-hybridization into an  sp3-type one. Transport in these junctions is primarily through an unoccupied molecular orbital that is partly hybridized with the Au, which results in splitting the degeneracy of the lowest unoccupied molecular orbital triplet. The transmission through these junctions, however, cannot be modeled by a single Lorentzian resonance, as our results show evidence of quantum interference between an occupied and an unoccupied orbital. The interference results in a suppression of conductance around the Fermi energy. Our numerical findings are readily analyzed analytically within a simple two-level model

  6. 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 mole

  7. 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

    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...

  8. Calculation of images of oriented C_60 molecules using molecular orbital theory

    OpenAIRE

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

    2010-01-01

    Using Hückel molecular-orbital theory, images are created to represent the electron distributions expected for a C60 molecule adsorbed on a substrate. Three different orientations of the C60 molecule on the substrate are considered. The effect of the interaction of the molecule with the substrate is treated purely from the basis of symmetry using group theoretical methods. The resulting electron distributions are then used to generate idealized images which represent how the molec...

  9. Quantum Theory for Large Molecules $C_{60}$ Diffraction

    CERN Document Server

    Wu, Xiang-Yao; Liu, Xiao-Jing; Ba, Nuo; Wu, Yi-Heng; Tang, Hou-Li; Wang, Jing; Zhang, Si-Qi

    2011-01-01

    Diffraction phenomena of large molecules have been studied in many experiments, and these experiments are described by many theoretical works. In this paper, we study $C_{60}$ molecules single and double-slit diffraction with quantum theory approach, and we pay close attention to the $C_{60}$ diffraction experiment carried out by A.Zeilinger et.at in 1999. In double-slit diffraction, we consider the decoherence effect, and find the theoretical results are good agreement with experimental data.

  10. 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.

  11. The nano-science of C60 molecule

    Directory of Open Access Journals (Sweden)

    2002-06-01

    Full Text Available   Over the past few years, nano-science and its associated nano-technology have emerged into prominence in research instiutions 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 C60 molecule, and other cage-like fullerenes, together with carbon nanotubes 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 C60 can also be exploited in designing nano-phase thin films with applications in nanoscopic 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 C60 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.

  12. The nano-science of C60 molecule

    International Nuclear Information System (INIS)

    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 C60 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 C60 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 C60 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

  13. Electronic and vibrational properties of the C60 molecule

    International Nuclear Information System (INIS)

    We have studied the electronic and vibrational properties of the C60 molecule by means of simplified models where only a few parameters are adjusted to experimental data. For the electronic part we use an independent electron model with a central Morse potential corrected by splitting the spherical degeneracy by properly including the icosahedral symmetry given rise to the LUMO and HOMO states. The vibrational spectra is obtained by solving the corresponding secular equation using a Born-Mayer type potential with two parameters adjusted to Raman and IR spectra . The results of our model are compared with some of the best ab initio calculations, phenomenological models and experimental data. We found in general a good agreement for the vibrational spectrum particularly for the high frequency part. Since in our model contains only two parameters we are not able to reproduce accurately the whole spectra. The main contribution of this model is its simplicity to extract most of the gross features of the C60 molecule without cumbersome computation. (Author)

  14. Interfacial and intermolecular interactions determining the rotational orientation of C60 adsorbed on Au(111)

    Science.gov (United States)

    Paßens, Michael; Karthäuser, Silvia

    2015-12-01

    Close-packed monolayers of fullerenes on metallic substrates are very rich systems with respect to their rotational degrees of freedom and possible interactions with different adsorption sites or next neighbours. In this connection, we report in detail on the (2√3 × 2√3)R30°-superstructure of C60 with respect to the Au(111)-surface. We use molecular orbital imaging in systematic UHV-STM studies to reveal the delicate balance of interfacial and intermolecular interactions in this system. Thus, bright C60-molecules in 5:6-top and 6:6-top geometries are observed depending on the respective next neighbours. Moreover, tiny changes in the appearance of the unoccupied molecular orbitals of dim C60-molecules in hex-vac positions are identified which are caused by the respective interaction with the facets surrounding the Au-vacancy.

  15. Electron ionization of superfluid helium nanodroplets doped with C60 and small molecules

    International Nuclear Information System (INIS)

    Helium droplets were co-doped with C60 and ammonia, water or carbon dioxide and the resulting cluster size distributions of the produced cationic complexes are presented. Mass spectra obtained by electron ionization were recorded with high mass resolution of m/Δm ∼ 6000 (FWHM). Series of C60(H2O)n+, C60(NH3)n+ and C60(CO2)n+ complexes for n up to 20 molecules attached to the C60 were observed among other cations. For C60-water cluster ions, the resulting size distribution revealed magic numbers for n=4 and n=7 water molecules attached to the fullerene. Ionic C60-ammonia complexes showed an enhanced stability in the cluster size distribution for n=4 ammonia molecules attached as well. However, no intensity anomalies were observed for larger n. For the nonpolar carbon dioxide, no magic numbers were found in the cluster size distribution of C60(CO2)n+. These findings suggest that single carbon dioxide molecules are homogeneously distributed on the C60; in contrast to ammonia and water, where clusters are attached to the fullerene. In addition, dehydrogenation and protonation reactions of water and ammonia clusters on C60 were observed in the present study.

  16. 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 p

  17. Doubly-charged Negative Ion of C60 Molecule

    CERN Document Server

    Msezane, A Z

    2016-01-01

    Within the Dirac- and Lorentz-bubble potential models an electronic structure of the doubly-charged negative ion has been studied by a variational method. It is shown that even in the first approximation of this method when a trial wave function of the two electrons is represented as a product of one-electron functions the total energy of the system is negative, a manifestation of the existence of a stable state of the doubly-charged negative ion in these models. The second electron affinity of C60 according to estimation is about 1 eV. The photodetachment cross sections of this ion have been calculated as well. Near threshold behavior of cross section is found to exhibit peculiar and interesting behavior. The first cross section accompanied by the transformation of the doubly-charged negative ion into a singly-charged one is exponentially small near the process threshold. The second cross section corresponds to the photodetachment of a singly-charged ion; it increases at the threshold as a power function of ...

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

    Science.gov (United States)

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

    2015-11-01

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

  19. Fluorescence and phosphorescence from individual C$_{60}$ molecules excited by local electron tunneling

    OpenAIRE

    Ćavar, Elizabeta; Blüm, Marie-Christine; Pivetta, Marina; Patthey, François; Chergui, Majed; Schneider, Wolf-Dieter

    2005-01-01

    Using the highly localized current of electrons tunneling through a double barrier Scanning Tunneling Microscope (STM) junction, we excite luminescence from a selected C$_{60}$ molecule in the surface layer of fullerene nanocrystals grown on an ultrathin NaCl film on Au(111). In the observed luminescence fluorescence and phosphorescence spectra, pure electronic as well as vibronically induced transitions of an individual C$_{60}$ molecule are identified, leading to unambiguous chemical recogn...

  20. STM study on one-dimensional cluster formation processes of Y rate at C82 and C60 molecules

    International Nuclear Information System (INIS)

    Using scanning tunneling microscopy (STM), we have studied cluster formation processes of fullerene molecules adsorbed on the Cu(111) 1 x 1 surface. We used two endohedral metallofullerenes; Y rate at C82 and Gd rate at C82, and pristine C60. All adsorbed molecules are observed at step edges of the surface, and thus their processes can be treated with a model of one-dimensional cluster formation. When small amounts of molecules are deposited on the surface, we found that the dimer is most abundant among the clusters of Y rate at C82 while monomers are dominant in the cases of Gd rate at C82 and C60. Since Y rate at C82 has an electronic spin while the others do not, we speculated that the preferred dimer formation of Y rate at C82 is owing to an interaction of the spin. Interaction energies among fullerene molecules were estimated based on a statistical analysis of the STM data. (orig.)

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

    DEFF Research Database (Denmark)

    Danilov, Andrey V.; Hedegård, Per; Golubev, Dimitrii S.; Bjørnholm, Thomas; Kubatkin, Sergey E.

    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 yield...

  2. Effect of doping of N and B atoms on thermoelectric properties of C60 molecule

    Indian Academy of Sciences (India)

    Mojtaba Yaghobi; Fazel Ardeshir Larijani

    2015-01-01

    In this work, the doping effect on the thermoelectric properties of the C60 molecule (fullerene) was studied by considering inelastic electron–phonon interactions. It is seen that the maximum value of thermal conductance (max) with respect to the molecules are max(C59N) < max(C60) < max(C59B). Also, the oscillatory behaviour of thermal conductance is dramatically dependent on the type of molecules. The values of figure of merit (ZT) against energy and with respect to the type of molecules are between 0.25 × 10−5 and 0.194 × 10−3 and effect of the type of molecules is small on the minimum value of ZT.

  3. How Many [2+2] Four-Membered Rings Are Formed on a C60 Molecule when Photopolymerization Is Saturated?

    International Nuclear Information System (INIS)

    The saturation number of the [2+2] four-membered cross-link between adjacent C60 molecules in a photopolymerized C60 film has been determined using the intensity of the C1s shake-up satellite, which originates from the π-π* transition of π electrons of C60 , by x-ray photoelectron spectroscopy. It was found that six [2+2] rings were formed on a C60 molecule when polymerization was saturated. A possible configuration of the C60 polymer was postulated on the basis of the saturation number and the structure of a pristine C60 film. copyright 1997 The American Physical Society

  4. Gate-tunable large negative tunnel magnetoresistance in Ni-C60-Ni single molecule transistors.

    Science.gov (United States)

    Yoshida, Kenji; Hamada, Ikutaro; Sakata, Shuichi; Umeno, Akinori; Tsukada, Masaru; Hirakawa, Kazuhiko

    2013-02-13

    We have fabricated single C(60) molecule transistors with ferromagnetic Ni leads (FM-SMTs) by using an electrical break junction method and investigated their magnetotransport. The FM-SMTs exhibited clear gate-dependent hysteretic tunnel magnetoresistance (TMR) and the TMR values reached as high as -80%. The polarity of the TMR was found to be always negative over the entire bias range studied here. Density functional theory calculations show that hybridization between the Ni substrate states and the C(60) molecular orbitals generates an antiferromagnetic configuration in the local density of states near the Fermi level, which gives a reasonable explanation for the observed negative TMR. PMID:23327475

  5. Temperature dependence of I-V characteristics of C60 molecule

    Directory of Open Access Journals (Sweden)

    SA Ketabi

    2010-06-01

    Full Text Available Making use of a generalized Green’s function technique and Landauer formalism, the temperature depended current-voltage (I-V characteristics of C60 molecule, sandwiched between two metallic electrodes are numerically investigated. In addition, the influence of the electron-phonon coupling strength on the electronic properties of the molecule is studied. The I-V characteristics of the molecule are determined in two temperature limits, T=3K and T=300K. Our results indicate that the molecule primarily acts as a semiconductor in lower temperatures but moves toward becoming an ohmic-like conductor when the temperature increased to the higher magnitudes.

  6. Jahn-Teller effects in molecules on surfaces with specific application to C_60

    OpenAIRE

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

    2010-01-01

    Scanning tunnelling microscopy (STM) is capable of imaging molecules adsorbed onto surfaces with su±cient resolution as to permit intramolecular features to be discerned. Therefore, imaging molecules subject to the Jahn-Teller (JT) effect could, in principle, yield valuable information about the vibronic coupling responsible for the JT effect. However, such an application is not without its complications. For example, the JT effect causes subtle, dynamic distortions of the molecule; but...

  7. Switchable zero-bias anomaly in individual C60 molecules contacted with tunable aluminum electrodes

    International Nuclear Information System (INIS)

    We report the observation of strong resonances at zero bias in the differential conductance through Al-C60-Al junctions with tunable electrode distance, measured above T = 10 K. The conductance value at resonance ranges from a few percent up to eighty percent of the quantum of conductance. The resonances may disappear or reoccur completely and discontinuously upon very small changes of the electrode distance. However, once they are formed they are very robust with respect to changes of the electrode distance. We discuss similarities and differences to the common theories of the Kondo screening of a spontaneous spin polarization of the C60 molecule. We deduce Kondo temperatures in the range from 35 to 160 K and demonstrate that the temperature dependence is in agreement with the scaling behavior of the Kondo effect in the temperature range of our experiment.

  8. Algebraic theory of endohedrally confined diatomic molecules: application to H$_2$@C$_{60}$

    CERN Document Server

    Fortunato, Lorenzo

    2016-01-01

    A simple and yet powerful approach for modeling the structure of endohedrally confined diatomic molecules is introduced. The theory, based on a $u(4)\\oplus u(3)$ dynamical algebra, combines the vibron model with an isotropic three dimensional oscillator. The first describes the internal roto-vibrations degrees of freedom of the molecule, while the second takes into account the confined molecule center-of-mass degrees of freedom. A resulting subalgebra chain is connected to the underlying physics and the model is applied to the prototypical case of H$_2$ caged in a fullerene molecule. The spectrum of the supramolecular complex H$_2$@C$_{60}$ is described with a few parameters and predictions for not yet detected levels are made. Our fits suggest that the quantum numbers of a few lines should be reassigned to obtain better agreement with data.

  9. Electrodynamical Forbiddance of the Strong Quadrupole Light-Molecule Interaction and Its Experimental Manifestation in Fullerene C60

    CERN Document Server

    Chelibanov, V P

    2016-01-01

    It is demonstrated that the forbidden lines, which must be present in the SERS, TERS and SEIRA spectra of molecules with sufficiently high symmetry, associated with a strong quadrupole light-molecule interaction, are absent in the fullerene C60. This result is an experimental manifestation of an electrodynamical forbiddance of the strong quadrupole light-molecule interaction, which must be not only in molecules with cubic symmetry groups, but in the fullerene C60 also.

  10. An NMR study of the occupation of C60 interstitial sites by oxygen molecules

    International Nuclear Information System (INIS)

    The 13C NMR of FCC C60 under magic angle spinning (MAS) conditions yields linewidths on the order of 1 Hz at fields of 4.7 T. The spectrum consists of a primary resonance at 143.7 ppm and a minor peak shifted 0.7 ppm downfield. The intensity of the minor resonance relative to the primary resonance was found to vary from 0.6 to 5.5 % depending on the sample history. The downfield shift obeys Curie's law and is attributed to the Fermi contact coupling interaction between paramagnetic oxygen molecules and all 60 carbon atoms of rapidly rotating adjacent C60 molecules. Exposure of the sample to 1 kbar oxygen for 1 3/4 hours resulted in a spectrum of 7 evenly spaced resonances corresponding to 0 to 6 of the adjacent octahedral interstitial sites being filled with oxygen molecules. At ambient pressure, the oxygen diffused out of the lattice on time scales ranging from hours to days

  11. Specific features of the glass transition in C60 fullerite saturated with carbon monoxide molecules: Photoluminescence studies

    Science.gov (United States)

    Zinoviev, P. V.; Zoryansky, V. N.; Stetsenko, Yu. E.; Danchuk, V. V.

    2016-02-01

    Low temperature (20-230 K) spectral-luminescence studies were conducted on C60 fullerite saturated with carbon monoxide in a physisorption regime. Substantial changes in the photoluminescence characteristics of C60-CO solutions with different impurity concentrations were found already for short intercalation times. Strong dependence of the CO solubility on the saturation temperature was revealed by analyzing the contribution of "deep X-traps" to the luminescence. Furthermore, it was found that filling of the octahedral voids by CO molecules occurs with a lower gradient of the impurity distribution into the bulk C60 crystals as compared with N2. The temperature dependences of the integral emission intensity for the samples with different concentrations of carbon monoxide were studied. For the first time, using the spectral-luminescence method, it was revealed that CO molecules, in contrast to H2 and N2, exhibit a significant effect on the formation of the orientational glass and the rotational dynamics of C60 molecules. Within the model of the transfer of electronic excitation in C60 crystals, the effect of polar CO molecules on the reorientation of C60 molecules and the change in the nature of their rotation in concentrated C60-CO solutions, leading to the observed strong shift of the temperatures of orientational Tc and glass Tg transitions to lower temperatures accompanied by "blurring" of the transition boundaries, were explained.

  12. Peculiarities of glass forming of the fullerite C60 saturated by the carbon monooxide molecules: photoluminescence studies

    International Nuclear Information System (INIS)

    Low temperature (20-230 K) studies were carried out by the spectral-luminescent method of the fullerite C60 saturated by carbon monooxide in the phys-sorption mode. Significant changes of the photoluminescent characteristics of the solutions C60-CO with different concentration of the impurity were found even at small times of intercalation. Strong dependence of CO solubility on the saturation temperature was registered by analyzing the contribution to the luminescence of the ''deep X-traps'', and filling of octahedral voids by CO molecules occurs with smaller gradient of the impurity distribution in depth of C60 crystals in comparison with N2. Temperature dependences of the radiation integral intensity of the samples with different concentration of the carbon monooxide were studied. It was found for the first time that CO molecules have significant influence on the process of orientation glass formation and on the rotational dynamics of the C60 molecules in contrast to H2 and N2. In the framework of the model of electron excitations transfer in C60 crystals, there was explained the influence of the polar CO molecule on the processes of the C60 molecules reorientations and changes of their rotations type in the concentrated C60-CO solutions, which leads to observed strong temperature shift of the orientation Tc and glass Tg transitions to the region of low temperatures, which is accompanied by ''blurring'' of their boundaries.

  13. Hydrophobic Porous Material Adsorbs Small Organic Molecules

    Science.gov (United States)

    Sharma, Pramod K.; Hickey, Gregory S.

    1994-01-01

    Composite molecular-sieve material has pore structure designed specifically for preferential adsorption of organic molecules for sizes ranging from 3 to 6 angstrom. Design based on principle that contaminant molecules become strongly bound to surface of adsorbent when size of contaminant molecules is nearly same as that of pores in adsorbent. Material used to remove small organic contaminant molecules from vacuum systems or from enclosed gaseous environments like closed-loop life-support systems.

  14. Coupling of Surface and Volume Dipole Oscillations in C-60 Molecules

    CERN Document Server

    Brack, M; Murthy, M V N

    2007-01-01

    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''.

  15. Effect of surface temperature on the concentration of C60/C70 molecules in dc arc discharge fullerene generator

    International Nuclear Information System (INIS)

    Synthesis of C60, C70 and higher fullerenes was carried out at Pakistan Institute of Nuclear Science and Technology (PINSTECH) using dc arc discharge technique. High-performance liquid chromatography (HPLC) and UV-vis spectroscopy are employed to characterize the fullerenes. The toluene extracted fullerene solutions of the raw soot collected from four different regions (A-D) of dc arc discharge fullerene generator were compared with pure C60 toluene solution. Due to poor solubility of C60 in HPLC grade methanol, different fractions of methanol as a mobile phase with toluene were tried. The mobile phase composition of 80:20 methanol:toluene was found an optimal ratio to achieve the best separation factor of 1.246 between C60 and C70 fullerenes. Quantitative concentration is calculated from the HPLC and UV-vis spectra. The molarity of C60 carbon molecules for all the regions is calculated from the HPLC spectra by comparing the spectra of known molar solution of C60. The maximum concentration of C70 is found to be 21% in the region B that is nearer the arc zone and at a higher temperature than other regions. Both the techniques confirm the presence of C60, C70 and higher fullerenes in all the four regions with variation in concentration of C60 and C70. UV-vis spectra of the region C show the additional absorption bands at 285 and 305 nm

  16. Force and Conductance during contact formation to a C60 molecule

    OpenAIRE

    Hauptmann N.; Mohn F.; Gross L.; Meyer G.; Frederiksen T.; Berndt R.

    2012-01-01

    Force and conductance were simultaneously measured during the formation of Cu-C60 and C60-C60 contacts using a combined cryogenic scanning tunneling and atomic force microscope. The contact geometry was controlled with submolecular resolution. The maximal attractive forces measured for the two types of junctions were found to differ significantly. We show that the previously reported values of the contact conductance correspond to the junction being under maximal tensile stress.

  17. Interaction of protons with the C60 molecule: calculation of deposited energies and electronic stopping cross sections (v≤5 au)

    International Nuclear Information System (INIS)

    The energy deposited by a proton in a C60 molecule is calculated over a broad collision velocity range from 0.1 to 5 au, using the free-electron gas model of Lindhard and Winther (1964 Mat. Fys. Medd. K Dan. Vidensk. Selsk. 34) and the C60 electron density distribution calculated by Puska and Nieminen. The energy lost by the proton is maximum near 1.8 au collision velocity in contrast with the saturation found in the low-velocity regime, in the 0.25-0.5 au velocity range, by Kunert and Schmidt. From the impact parameter dependence we deduce the distributions of deposited energies, the averaged energy losses and the C60 electronic stopping cross sections. It is found that the C60 molecule behaves as a carbon foil giving very similar absolute stopping cross sections per atom. (author). Letter-to-the-editor

  18. STM-HREELS Investigation of C60 on Cu(111)

    OpenAIRE

    Takaoka, O.; Tindall, C.; Kobayashi, T.; Hasegawa, Y.; T. Sakurai

    1996-01-01

    Using an STM/HREELS system, we have investigated the relationship between the surface morphology and vibrational modes of C60 adsorbed on Cu(111). At 300K, C60 is mobile on the Cu(111) terrace, but is more strongly bound at the step edge. Therefore, any C60 which adsorbs on the terrace will migrate to the step edge where it is immobilized. Thus for very low coverages, the C60 referentially adsorbs at the step edge. Adsorption of the molecule on metal surfaces results in a significant amount o...

  19. Resonant heating and substrate-mediated cooling of a single C60 molecule in a tunnel junction

    OpenAIRE

    Schulze, Gunnar; Franke, Katharina J.; Pascual, Jose Ignacio

    2008-01-01

    We study the influence of different metallic substrates on the electron induced heating and heat dissipation of single C60 molecules in the junction of a low temperature scanning tunneling microscope. The electron current passing through the molecule produces a large amount of heat due to electron-phonon coupling, eventually leading to thermal decomposition of the fullerene cage. The power for decomposition varies with electron energy and reflects the resonance structure participating in the ...

  20. Photoionization of Xe inside a C+60 cage: a single-molecule electron interferometer

    International Nuclear Information System (INIS)

    Absolute cross sections are reported for double photoionization accompanied by loss of n C atoms (n = 0, 2, 4, 6) of endohedral Xe@C+60 molecular ions in the photon energy range 60 − 150 eV. The experimental data show clear evidence of confinement resonances arising from interference of outgoing 4d photoelectron waves.

  1. Simulation of the soft-landing and adsorption of C60 molecules on a graphite substrate and computation of their scanning-tunnelling-microscopy-like images

    International Nuclear Information System (INIS)

    A constant-temperature molecular dynamics (MD) simulation was performed to model the soft-landing and adsorption of C60 molecules on a graphite substrate with the C60s treated as soft molecules and released individually towards the substrate. The intra-molecular and intra-planar covalently bonding interactions were modelled by very accurate many-body potentials, and the non-bonding forces were derived from various pairwise potentials. The simulation extended over 1.6 million time steps covering a significant period of 160 picoseconds. The final alignment of the molecules on the surface agrees closely with that observed in an experiment based on scanning tunnelling microscopy (STM) on the same system, performed at room temperature and under ultrahigh-vacuum (UHV) conditions. Using a tungsten tip in a constant-current mode of imaging, we have also computed the STM-like images of one of the adsorbed molecules using a formulation of the STM tunnelling current based on Keldysh's non-equilibrium Green function formalism. Our aim has been to search for tip-induced states, which were speculated, on the basis of another STM-based experiment, performed in air, to form one of the possible origins of the extra features purported to have been observed in that experiment. We have not obtained any such states. (author)

  2. Size selective hydrophobic adsorbent for organic molecules

    Science.gov (United States)

    Sharma, Pramod K. (Inventor); Hickey, Gregory S. (Inventor)

    1997-01-01

    The present invention relates to an adsorbent formed by the pyrolysis of a hydrophobic silica with a pore size greater than 5 .ANG., such as SILICALITE.TM., with a molecular sieving polymer precursor such as polyfurfuryl alcohol, polyacrylonitrile, polyvinylidene chloride, phenol-formaldehyde resin, polyvinylidene difluoride and mixtures thereof. Polyfurfuryl alcohol is the most preferred. The adsorbent produced by the pyrolysis has a silicon to carbon mole ratio of between about 10:1 and 1:3, and preferably about 2:1 to 1:2, most preferably 1:1. The pyrolysis is performed as a ramped temperature program between about 100.degree. and 800.degree. C., and preferably between about 100.degree. and 600.degree. C. The present invention also relates to a method for selectively adsorbing organic molecules having a molecular size (mean molecular diameter) of between about 3 and 6 .ANG. comprising contacting a vapor containing the small organic molecules to be adsorbed with the adsorbent composition of the present invention.

  3. Preferential adsorption of C60 molecules to step edges of the Si(110)-16 × 2 single domain surface

    International Nuclear Information System (INIS)

    The Si(110) surface has a quite unique one-dimensional (1-D) stable structure with 16 × 2 reconstruction. Since the perfectly straight rows extend over micrometers, the 16 × 2 structure can be a superior template for 1-D nanostructures. However, controlled nanostructures using the Si(110)-16 × 2 template has not been fabricated yet. In this study, we have investigated the adsorption of C60 molecules on the Si(110)-16 × 2 surface at various surface temperatures, and found that the C60 preferable adsorption sites are substantially changed, depending on the surface temperature. The obtained results indicate that the organic 1-D nanostructure can be fabricated on the Si(110)-16 × 2 surface by controlling the surface temperature.

  4. Quick synthesis of highly aligned or randomly oriented nanofibrous structures composed of C60 molecules via self-assembly

    Science.gov (United States)

    Kurosu, Shunji; Fukuda, Takahiro; Maekawa, Toru

    2013-06-01

    Assemblies, which are composed of nanoparticles such as nanofibres, have been intensively studied in recent years. This has particularly been the case in the field of biomedicine, where the aim is to develop efficient methodologies for capturing and separating target biomolecules and cells and/or encouraging bio-chemical reactions, utilizing the extremely high surface area to volume ratio of assemblies. There is an urgent need for the development of a quick synthesis method of forming nanofibrous structures on the surface of biomedical microchips and devices for the investigation of the interactions between biomolecules/cells and the nanostructures. Here, we produce nanofibrous structures composed of C60 molecules, which are aligned in one direction or randomly oriented, by dissolving C60 molecules and sulphur in benzene and evaporating a droplet of the solution on a glass substrate under appropriate conditions. The synthesis time is as short as 30 s. Sulphur is extracted and nanofibres are crystallized by leaving them in supercritical carbon dioxide.

  5. New Volleyballenes: Y20C60, La20C60, and Lu20C60

    OpenAIRE

    Wang, Jing; Liu, Ying(College of Nuclear Science and Technology, Beijing Normal University, 100875, Beijing, China)

    2015-01-01

    New stable Volleyballenes Y20C60, La20C60, and Lu20C60 molecular clusters have been proposed using first-principles density functional theory studies. In conjunction with recent findings for the scandium system, these findings establish Volleyballene M20C60 molecules as a stable general class of fullerene family. All M20C60 (M=Y, La, and Lu) molecules have Th point group symmetries and relatively large HOMO-LUMO gaps.

  6. Rotation dynamics of C60 molecules in a monolayer fullerene film on the WO2/W(110) surface near the rotational phase transition

    International Nuclear Information System (INIS)

    The rotation dynamics of C60 molecules in monolayer fullerene films grown on the WO2/W(110) surface is studied by scanning tunneling microscopy. The formation of molecule clusters, which have a high libron vibration amplitude, is detected near the rotational phase transition temperature. The energy parameters that determine a change in the molecule orientation, namely, the energy difference between the nearest minima of the C60 molecule energy (30 meV) as a function of the molecule orientation and the potential barrier between them (610 meV), are determined. The results are discussed in terms of the mean-field approximation

  7. Dynamic scanning probe microscopy of adsorbed molecules on graphite

    OpenAIRE

    Berdunov, N.; Pollard, A J; Beton, P. H.

    2008-01-01

    We have used a combined dynamic scanning tunneling and atomic force microscope to study the organisation of weakly bound adsorbed molecules on a graphite substrate. Specifically we have acquired images of islands of the perylene derivative molecules. These weakly bound molecules may be imaged in dynamic STM, in which the probe is oscillated above the surface. We show that molecular resolution may be readily attained and that a similar mode of imaging may be realised using conventional STM arr...

  8. 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

  9. Adsorbed molecules in external fields: Effect of confining potential.

    Science.gov (United States)

    Tyagi, Ashish; Silotia, Poonam; Maan, Anjali; Prasad, Vinod

    2016-12-01

    We study the rotational excitation of a molecule adsorbed on a surface. As is well known the interaction potential between the surface and the molecule can be modeled in number of ways, depending on the molecular structure and the geometry under which the molecule is being adsorbed by the surface. We explore the effect of change of confining potential on the excitation, which is largely controlled by the static electric fields and continuous wave laser fields. We focus on dipolar molecules and hence we restrict ourselves to the first order interaction in field-molecule interaction potential either through permanent dipole moment or/and the molecular polarizability parameter. It is shown that confining potential shapes, strength of the confinement, strongly affect the excitation. We compare our results for different confining potentials. PMID:27387127

  10. Charge transport in C60-based dumbbell-type molecules: mechanically induced switching between two distinct conductance states.

    Science.gov (United States)

    Moreno-García, Pavel; La Rosa, Andrea; Kolivoška, Viliam; Bermejo, Daniel; Hong, Wenjing; Yoshida, Koji; Baghernejad, Masoud; Filippone, Salvatore; Broekmann, Peter; Wandlowski, Thomas; Martín, Nazario

    2015-02-18

    Single molecule charge transport characteristics of buckminsterfullerene-capped symmetric fluorene-based dumbbell-type compound 1 were investigated by scanning tunneling microscopy break junction (STM-BJ), current sensing atomic force microscopy break junction (CS-AFM-BJ), and mechanically controlled break junction (MCBJ) techniques, under ambient conditions. We also show that compound 1 is able to form highly organized defect-free surface adlayers, allowing the molecules on the surface to be addressed specifically. Two distinct single molecule conductance states (called high G(H)(1) and low G(L)(1)) were observed, depending on the pressure exerted by the probe on the junction, thus allowing molecule 1 to function as a mechanically driven molecular switch. These two distinct conductance states were attributed to the electron tunneling through the buckminsterfullerene anchoring group and fully extended molecule 1, respectively. The assignment of conductance features to these configurations was further confirmed by control experiments with asymmetrically designed buckminsterfullerene derivative 2 as well as pristine buckminsterfullerene 3, both lacking the G(L) feature. PMID:25651069

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

    Science.gov (United States)

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

    2016-05-01

    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 H2 is lying parallel to lithium adsorbed graphene which is in contrast to its adsorption on pristine graphene (PG) where it prefers perpendicular orientation.

  12. Adsorption of PTCDA and C60 on KBr(001): electrostatic interaction versus electronic hybridization

    OpenAIRE

    Jia, Q.; Ji, W.; Burke, S. A.; Gao, H. J.; Grutter, P.; Guo, H

    2013-01-01

    The adsorption of functional molecules on insulator surfaces is of great importance to molecular electronics. We present a systematical investigation of geometric and electronic properties of PTCDA and C60 on KBr(001) using DFT and non-contact atomic force microscopy. It was found that electrostatics is the primary interaction mechanism for PTCDA and C60 adsorbed on KBr. It was thus concluded that alkali-halides is a competitive candidate to be adopted to support low polarizability molecules,...

  13. Dynamics of different molecules adsorbed in porous media

    Indian Academy of Sciences (India)

    S Mitra; V S Kamble; A K Tripathi; N M Gupta; R Mukhopadhyay

    2004-08-01

    We present in this paper a comparative study on the dynamics of benzene, cyclohexane, and methanol molecules, confined in the pores of MCM-41 molecular sieve and HZSM-5 zeolite. The quasi-elastic neutron scattering (QENS) measurements revealed that the physical state of these adsorbed molecules depended not only on the structural characteristics of the host matrix but also on the chemical properties, such as dipole moment, of the guest molecules. Thus, while no motion was observed in the time-scale of 10−10 –10−12 s in the case of methanol, the larger size benzene and cyclohexane molecules are found to perform six-fold and three-fold jump rotation, respectively, when adsorbed inside the cages of HZSM-5 at room temperature. At the same time, all the three molecules are found to undergo a translational motion inside the pores of MCM-41 molecular sieves, the value of diffusion constant being the lowest in case of methanol because of its higher polarity. Translationl motion of the guest molecules inside the pores of MCM-41 can be satisfactorily described by Chudley–Eliott fixed jump length diffusion and accordingly the residence time, jump length and diffusion constant are estimated.

  14. 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.

  15. STM topographical images of C60

    International Nuclear Information System (INIS)

    In this paper STM topographical images of C60 are reported. The images are consistent with a molecule approximately 9 Angstrom in diameter possessing the now-famous soccer ball structure. With the molecule deposited on gold, its atomic structure is not resolved. On graphite the structure of the within the borders of the C60 molecule is dominated by that of the graphite forming a moire-like pattern. Some evidence of atomic structure is seen in multilayers of C60 where some five- and six-membered rings are visible. These may, however, be features of fragments of the fullerene rather than whole molecules

  16. Interstellar C60+

    CERN Document Server

    Berne, Olivier; Joblin, Christine

    2012-01-01

    Buckminsterfullerene (C60) was recently detected through its infrared emission bands in the interstellar medium (ISM), including in the proximity of massive stars, where physical conditions could favor the formation of the cationic form, C60+. In addition, C60+ was proposed as the carrier of two diffuse interstellar bands in the near-IR, although a firm identification still awaits for gas-phase spectroscopic data. We examined in details the Spitzer IRS spectra of the NGC 7023 reflection nebula, at a position close (7.5") to the illuminating B star HD 200775, and found four previously unreported bands at 6.4, 7.1, 8.2 and 10.5 \\mu m in addition to the classical bands attributed to Polycylic Aromatic Hydrocarbons (PAHs) and neutral C60. These 4 bands are observed only in this region of the nebula, while C60 emission is still present slightly further away from the star, and PAH emission even further away. Based on this observation, on theoretical calculations we perform, and on laboratory studies, we attribute t...

  17. Strong-field above-threshold ionization in laser-irradiated C60 molecule: The signatures of orbital symmetry and intramolecular quantum interference

    International Nuclear Information System (INIS)

    The strong-field (multiphoton) process of above-threshold ionization (ATI) in laser-irradiated fullerene C60 is addressed theoretically within molecular strong-field approximation (SFA) applied in the so-called velocity-gauge (VG) formulation with respect to a strong electromagnetic interaction with incident laser field. The applied VG-SFA approach also essentially exploits the density-functional-theory (DFT) method for numerical composition of initial (laser-free) molecular wavefunction and respective the highest-occupied molecular orbital (HOMO) using the model LBα (van Leu wen-Baerends) intramolecular binding potential, which incorporates both the exchange and correlation model LSDA-potentials. According to the results of our DFT-SFA based numerical simulations (calculated for Ti:Sapphire laser radiation of wavelength λ = 800 nm and 35 fs pulse duration), the ionization of C60 reaches saturation at laser peak intensity I ≅ 2x1014 W/cm2, that is fairly well consistent with relevant experimental value. In addition, our findings proved to demonstrate at least two pronounced interference-related minima arising both in low-energy and high-energy domains of numerically calculated C60 photoelectron energy spectra (PES) due to destructive intramolecular (multislit) laser field-induced quantum interference, In particular, due to destructive interference in low-energy domain, the respective low-energy ATI photoelectron peaks are always highly suppressed that explains a high suppression in strong-field ionization of C60, thereby providing quite a clear and transparent physical interpretation within the molecular DFT-SFA presently applied. Whereas, the location of the high-energy interference minimum proved to be strongly dependent on the laser wavelength λ, in a full accordance with the theory prediction. (authors)

  18. On the fluorescence of C60 at room temperature

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The fluorescence properties of C 60 in different organic solvents have been investigated at room temperature. Three fluorescence emission centers are discovered and ascribed to different aggregations of C 60 in solvent. A series of blue fluorescence peaks centered at 440 nm derive from C 60 nanoparticles; a distinctive yellow-green fluorescence band in 575 nm region arises from the aggregates of C 60 nanoparticles; a more informative salmon fluorescence band around 700 nm originates from C 60 microcrystals. And the distinct configurations of C 60 aggregations are closely associated with the characteristic interaction between C 60 and solvent molecules.

  19. Adsorption of PTCDA and C60 on KBr(001): electrostatic interaction versus electronic hybridization.

    Science.gov (United States)

    Jia, Qian; Hu, Zhi-Xin; Ji, Wei; Burke, Sarah A; Gao, Hong-Jun; Grütter, Peter; Guo, Hong

    2016-04-20

    The adsorption of functional molecules on insulator surfaces is of great interest to molecular and organic electronics. Here, we present a systematic investigation of the geometric and electronic properties of perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA) and C60 on KBr(001) using density functional theory and non-contact atomic force microscopy to reveal the interplay of interactions between aromatic molecules and insulating substrates. Energetic and structural details are discussed, as well as electronic structures, e.g. local electronic density of states, (differential) charge density, and Bader charge analysis, were inspected. Electrostatics was found to be the primary interaction mechanism for systems of PTCDA and C60 adsorbed on KBr, which can be further promoted by electronic hybridizations of non-polar, but polarizable, molecules with substrates, e.g. C60/KBr(001). Electronic hybridization, depending on the polarizability of the π-system, may be suppressed by introducing high electron affinity atoms, e.g. O, into the molecule. Besides, we investigate molecules adsorbed on two-layer KBr(001) covered Cu(001), in which no hybridisation was found between PTCDA and the metal underneath, but a C-Br-Cu hybridized state in C60/KBr(001)/Cu(001). Since the interaction mechanism is dominated by electrostatics, it is concluded that alkali-halides are interesting and important materials for investigation, due to the minor influence on the molecular electronic structure, which may inspire new research fields of electronics. PMID:27045440

  20. Electronic Structure Calculation of Adsorbate Gas Molecules on an Armchair Graphene Nanoribbon

    OpenAIRE

    Khadije Imani; Gholamhossein Jafari; Mohammad Reza Abolhasani

    2012-01-01

    By using the first-principle methods, we have investigated the adsorption of the CO, CO2, NO, and NH3 molecules on an armchair graphene nanoribbon (AGNR). The optimal adsorption positions and orientations of these molecules on AGNR are determined. The adsorption energies, the charge transfer, and the density of states (DOS) are obtained. The NO, CO, and CO2 adsorbed molecules act as an acceptor, and the NH3 adsorbed molecule acts as a donor. The NO and CO molecules contributed with localized ...

  1. Synthesis, Crystal Structure and Characterization of a Novel Super Molecule [Na(C60H80O12)]+[Au(SCN)4]%金(Ⅲ)与杯[4]乙酯合钠(Ⅰ)超分子化合物:[Na(C60H80O12)]+[Au(SCN)4]-的合成、结构及性能

    Institute of Scientific and Technical Information of China (English)

    付勇; 徐琰; 宋毛平; 吴养洁

    2005-01-01

    A novel super molecule [Na(C60H80O12)]+[Au(SCN)4]- was obtained by extraction of calix[4] arene (L) for an aqueous solution containing [AuCl4]-, and NaCl into CH2Cl2. The crystal structure and properties of the title super molecule were characterized by single-crystal X-ray diffraction, IR and 1H NMR spectra. The X-ray single crystal structure analysis shows that the crystal was Tetragonal system with space group P4/n and the unit cell parameters were as follows: a=2.880 8(18) nm, b=2.880 8(18) nm, c=2.2924(5) nm, and final R indices [I>2σ(I)]:R1=0.0485, wR2=0.1061. CCDC: 243229.

  2. 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)

    A quantitative study of the C60 fullerenes fragmentation in collision with light ions (Hn+ with n=1,2,3, Heq+ 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)

  3. Collision studies involving C60 (Buckminsterfullerene) ions

    International Nuclear Information System (INIS)

    The discovery of the exceptional stability of C60 (Buckminsterfullerene) and its ions has prompted a large number of experimental and theoretical investigations concerning this soccerball-shaped molecule. After the discovery of a method, by which macroscopic quantities of C60 are available, this molecule has become an obvious candidate for structural and dynamic investigations by atomic-collision experiments. In our experiments, the fragment distributions suggest a mechanism where fragmentation occurs by sequential loss of 'pairs' of carbon atoms. We have continued the C+60 fragmentation studies and also included negative and multiply charged as well as other fullerene ions besides C60. In the case of positive fullerenes, only even-numbered molecules were observed, but for the negative fullerenes, also odd-numbered molecules were recorded on the ∼ 0.5% level relative to the even-numbered components. This finding indicates that the electron structure also plays an important role for the stability of fullerene ions, or perhaps that negative molecules can exist in some isomeric form. The total destruction cross sections for fullerene ions have been measured in several target gases. We are planning to continue with collisional studies of various fullerene ions with special emphasis on a better understanding of the collisionally induced fragmentation for ions in well prepared states, and also endohedral complexes and fusion will be investigated in collision studies. (EG) (8 refs.)

  4. Auger electron spectroscopy as a tool for measuring intramolecular charges of adsorbed molecules

    Science.gov (United States)

    Magkoev, T. T.

    1993-10-01

    A way for the determination of the values of intramolecular charges of adsorbed molecules of some binary dielectrics, based on Auger electron spectroscopy (AES), is proposed. These values can be obtained from the coverage dependences of the ratios of intensities of anion KL 23L 23 and KL 1L 1 Auger transitions, which are sensitive to the amount of charge at the 2p-orbitals. As an example, MgO adsorbed on Mo(110) is presented.

  5. Photoionization dynamics of C60

    International Nuclear Information System (INIS)

    Photoionization of C60 by means of synchrotron radiation is reported. The present investigation covers an energy range of 15 - 120 eV. The findings are compared with other recent reports focusing on the ionization and fragmentation behaviour of C60 as a result of certain energy transfer processes to the cluster. The actual ionization mechanism, the temperature dependence on the ion yield curve and the fragmentation behaviour of ionic C60 are discussed. (orig.)

  6. LACTOFERRIN ADSORBED ONTO BIOMIMETIC HYDROXYAPATITE: A MULTIFUNCTIONAL ANTIMICROBIAL MOLECULE

    OpenAIRE

    Fulgione, Andrea

    2015-01-01

    Lactoferrin (LF), is an iron-binding protein, belonging to transferrin family. It is found in the mucosal secretions (tears, saliva, milk, and colostrums) of the majority of mammalian species, including humans. LF is a multitask molecule: it partecipates to iron absorption and distribution, but also displays anti-inflammatory, antioxidant, anticarcinogenic, and antimicrobial properties. Hydroxyapatite (HA) plays an important role in the formation of the bony skeleton and bone remodeling. A...

  7. Rotational Spectromicroscopy: Imaging the Orbital Interaction between Molecular Hydrogen and an Adsorbed Molecule

    Science.gov (United States)

    Li, Shaowei; Yuan, Dingwang; Yu, Arthur; Czap, Gregory; Wu, Ruqian; Ho, W.

    2015-05-01

    A hydrogen molecule can diffuse freely on the surface and be trapped above an adsorbed molecule within the junction of a scanning tunneling microscope. The trapped dihydrogen exhibits the properties of a free rotor. Here we show that the intermolecular interaction between dihydrogen and Mg-porphyrin (MgP) can be visualized by imaging j =0 to 2 rotational excitation of dihydrogen. The interaction leads to a weakened H-H bond and modest electron donation from the dihydrogen to the lowest unoccupied molecular orbital of MgP, a process similarly observed for the interaction between dihydrogen and an adsorbed Au atom.

  8. Rotational Spectromicroscopy: Imaging the Orbital Interaction between Molecular Hydrogen and an Adsorbed Molecule.

    Science.gov (United States)

    Li, Shaowei; Yuan, Dingwang; Yu, Arthur; Czap, Gregory; Wu, Ruqian; Ho, W

    2015-05-22

    A hydrogen molecule can diffuse freely on the surface and be trapped above an adsorbed molecule within the junction of a scanning tunneling microscope. The trapped dihydrogen exhibits the properties of a free rotor. Here we show that the intermolecular interaction between dihydrogen and Mg-porphyrin (MgP) can be visualized by imaging j=0 to 2 rotational excitation of dihydrogen. The interaction leads to a weakened H-H bond and modest electron donation from the dihydrogen to the lowest unoccupied molecular orbital of MgP, a process similarly observed for the interaction between dihydrogen and an adsorbed Au atom. PMID:26047242

  9. Local field distribution and configuration of CO molecules adsorbed on the nanostructure platinum surface

    Institute of Scientific and Technical Information of China (English)

    Huang Xiao-Jing; He Su-Zhen; Wu Chen-Xu

    2006-01-01

    This paper shows that the local electric field distribution near the nanostructure metallic surface is obtained by solving the Laplace equation, and furthermore, the configuration of CO molecules adsorbed on a Pt nanoparticle surface is obtained by using Monte Carlo simulation. It is found that the uneven local electric field distribution induced by the nanostructure surface can influence the configuration of carbon monoxide (CO) molecules by a force, which drags the adsorbates to the poles of the nanoparticles. This result, together with our results obtained before, may explain the experimental results that the nanostructure metallic surface can lead to abnormal phenomena such as anti-absorption infrared effects.

  10. 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.

  11. Thermionic Emission and Fragmentation of C60

    International Nuclear Information System (INIS)

    We analyze the rate of delayed (thermionic) ionization of photoexcited C60 molecules. The rate has a power-law dependence, indicating the presence of a continuum of rate constants. The value of the exponent provides information about the competition between delayed ionization and unimolecular fragmentation; it is equal to the ratio of the ionization energy and the activation energy for fragmentation. This result provides a novel method to measure the controversial bond dissociation energy of neutral C60. We obtain a value of 11.9±1.9eV. copyright 1997 The American Physical Society

  12. Molecular simulation of C60 adsorption onto a TiO2 rutile (1 1 0) surface

    International Nuclear Information System (INIS)

    A Monte Carlo molecular simulation study is presented on the adsorption and growth of C60 films on the surface of the (1 1 0) face of rutile. Simulations are performed for a temperature of 600 K using atomistic models both for the fullerene molecules and the TiO2 surface. It is found in this work that C60 is adsorbed preferably in an ordered arrangement along the surface depressions over the exposed undercoordinated Ti cations. At low densities adsorption occurs preferably at alternate rows, with locations in consecutive rows being occupied appreciably only at higher C60 densities. At low densities, the fullerene molecules tend to aggregate into islands in the surface plane. Additional layers of C60 form only as the density increases, and do so before a monolayer is completed in all consecutive rows. Full monolayer capacity obtained at the highest densities is about 0.9 C60 molecules per nm2, but this is only achieved by completing the packing of molecules in interstices at a slightly upper level. The fraction of the molecules that lie closest to the surface only amounts to 0.6 molecules per nm2.

  13. Surface-enhanced Raman Scattering from Molecules Adsorbed on Mixed Silver/Gold Nanoparticle Surfaces

    Institute of Scientific and Technical Information of China (English)

    FANG Jing-huai; HUANG Yun-xia; LI Xia; DOU Xiao-ming

    2004-01-01

    @@ Introduction Since the first discovery of Surface-Enhanced Raman Scattering(SERS) from pyridine molecules adsorbed at roughened silver electrodes in 1974 by Fleischmann et al.[1],the research of SERS has made tremendous progress in applications of it to various fields of science and technology[2-8].

  14. On stabilization of free radicals under γ-irradiation of molecules adsorbed by zeolites

    International Nuclear Information System (INIS)

    Investigated are ESR spectra and stability of free radicals forming as a result of γ-irradiation at -196 deg of triethylbenzol, diethyl spirit of dimethylmalon acid and tret butylbenzol, sorbed by NaX and CaX zeolites at room and increased temperatures. Anomalously high stability is characteristic only of radicals formed of γ-irradiated molecules, traversing close to the diameter of zeolite entry windows. The obtained data testifies to the effect that radiospectroscopy in combination with radiation effect on the adsorbed substances can successfully be used as the most sensitive method for porous structure characteristic of mineral adsorbents, in particular, for direct investigation of activized physical adsorption processes

  15. Relaxation of C60 after excitation by electron impact

    International Nuclear Information System (INIS)

    The photons and electrons emission (thermoemission, break-off of the electron with C60- and delayed ionization by the C60 impact on the surface) is studied in the C60 + e- crossing beams by the electron energy Ee up to 100 eV. The radiation (300 ≤ λ nm ≤ 800) was of a thermal character and increased after the e- thermoemission. The radioactive temperature C60+* reached T = 3150 K, the radiative efficiency coefficient equaled 6; the C60+* formation cross section - 2x10-20 m2; the C60+* ion energy radiation losses velocity by T = 3150 K = 5.5 x 105 eV s-1. It is shown, that the C60 cluster due to its unique stability to fragmentation displays both the molecule and particle properties of solid substance

  16. 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.

  17. On-surface magnetochemistry: controlling spins in adsorbed molecules by a chemical switch

    International Nuclear Information System (INIS)

    Full text: We are interested in controlling the magnetic properties of paramagnetic molecules adsorbed on ferromagnetic substrates. The transition-metal ions in the surface-adsorbed porphyrins / phthalocyanines have a free top site for an additional ligand to bind and to control the magnetic properties of the on-surface complex. We show switching-off, tuning and switching-on the magnetic moments in the adsorbed complexes. Because of the interaction with the surface, the exact outcome of those reactions can be different. The axial-ligand allows to modify this interaction and can thus be used to control the exchange-interaction with the substrate. We combine element specific x-ray magnetic circular dichroism (XMCD) with STM and DFT+U. (author)

  18. Superconductivity at 45 K in Rb/Tl codoped C60 and C60/C70 mixtures

    Science.gov (United States)

    Iqbal, Zafar; Baughman, Ray H.; Khare, Sandeep; Murthy, N. S.; Ramakrishna, B. L.; Bornemann, Hans J.; Morris, Donald E.

    1991-11-01

    The appearance of superconductivity at relatively high temperatures in alkali metal-doped C60 fullerene provides the challenge to both understand the nature and origin of the superconductivity and to determine the upper limit of the superconducting transition temperature (Tc). Toward the latter goal, it is shown that doping with potassium-thallium and rubidium-thallium alloys in the 400 to 430 C temperature range increases the Tc of C60/C70 mixtures to 25.6 K and above 45 K, respectively. Similar increases in Tc were also observed on analogous doping of pure C60. Partial substitution of potassium with thallium in interstitial sites between C60 molecules is suggested by larger observed unit cell parameters than for the K3C60 and K4C60 phases. Contrary to previous results for C60 doped with different alkali metals, such expansion does not alone account for the changes in critical temperature.

  19. Fabrication of C60/amorphous carbon superlattice structures

    International Nuclear Information System (INIS)

    The nitrogen doping effects in C60 films by RF plasma source was investigated, and it was found that the nitrogen ion bombardment broke up C60 molecules and changed them into amorphous carbon. Based on these results, formation of C60/amorphous carbon superlattice structure was proposed. The periodic structure of the resulted films was confirmed by XRD measurements, as the preliminary results of fabrication of the superlattice structure

  20. Rod-like cyanophenyl probe molecules nanoconfined to oxide particles: Density of adsorbed surface species

    Science.gov (United States)

    Frunza, Stefan; Frunza, Ligia; Ganea, Constantin Paul; Zgura, Irina; Brás, Ana Rita; Schönhals, Andreas

    2016-02-01

    Surface layers have already been observed by broadband dielectric spectroscopy for composite systems formed by adsorption of rod-like cyanophenyl derivates as probe molecules on the surface of oxide particles. In this work, features of the surface layer are reported; samples with different amounts of the probe molecules adsorbed onto oxide (nano) particles were prepared in order to study their interactions with the surface. Thermogravimetric analysis (TGA) was applied to analyze the amount of loaded probe molecules. The density of the surface species ns was introduced and its values were estimated from quantitative Fourier transform infrared spectroscopy (FTIR) coupled with TGA. This parameter allows discriminating the composites into several groups assuming a similar interaction of the probe molecules with the hosts of a given group. An influence factor H is further proposed as the ratio of the number of molecules in the surface layer showing a glassy dynamics and the number of molecules adsorbed tightly on the surface of the support: It was found for aerosil composites and used for calculating the maximum filling degree of partially filled silica MCM-41 composites showing only one dielectric process characteristic for glass-forming liquids and a bulk behavior for higher filling degrees.

  1. 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.

  2. 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)

  3. 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(+) b

  4. Kondo effect of an adsorbed cobalt phthalocyanine (CoPc) molecule: the role of quantum interference

    OpenAIRE

    Chiappe, G.; Louis, E.

    2006-01-01

    A recent experimental study showed that, distorting a CoPc molecule adsorbed on a Au(111) surface, a Kondo effect is induced with a temperature higher than 200 K. We examine a model in which an atom with strong Coulomb repulsion (Co) is surrounded by four atoms on a square (molecule lobes), and two atoms above and below it representing the apex of the STM tip and an atom on the gold surface (all with a single, half-filled, atomic orbital). The Hamiltonian is solved exactly for the isolated cl...

  5. Sc20C60: a volleyballene

    Science.gov (United States)

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

    2016-06-01

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

  6. A New Approach to C60-Containing Polyphosphazenes by Polymerization of Phosphonitrile Chloride Trimer in the Presence of C60

    Institute of Scientific and Technical Information of China (English)

    LI Zhen; ZENG Qi; ZHU Zhi-Chao; LI Qian-Qian; LI Zhong-An; QIN Jin-Gui

    2007-01-01

    A novel synthetic strategy was developed to prepare polyphosphazenes containing C60 moieties. Thus, the phosphonitrile chloride trimer underwent thermal ring-opening polymerization (ROP) in the presence of C60 molecules to yield the reactive macromolecular intermediate, C60-containing poly(dichlorophosphazene). And then, the other groups could be linked to the phosphazene backbone by nucleophilic substitution reaction of the chlorine atoms in this intermediate to produce a series of C60-containing polyphosphazene. The polymer exhibits good solubility in common organic solvents and is thermally stable.

  7. Can circular dichroism in core-level photoemission provide a spectral fingerprint of adsorbed chiral molecules?

    Energy Technology Data Exchange (ETDEWEB)

    Allegretti, F [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Polcik, M [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D 14195 Berlin (Germany); Sayago, D I [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D 14195 Berlin (Germany); Demirors, F [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D 14195 Berlin (Germany); O' Brien, S [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Nisbet, G [Centre for Applied Catalysis, Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH (United Kingdom); Lamont, C L A [Centre for Applied Catalysis, Department of Chemical and Biological Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH (United Kingdom); Woodruff, D P [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2005-04-01

    The results of experimental measurements and theoretical simulations of circular dichroism in the angular distribution (CDAD) of photoemission from atomic core levels of each of the enantiomers of a chiral molecule, alanine, adsorbed on Cu(1 1 0) are presented. Measurements in, and out of, substrate mirror planes allow one to distinguish the CDAD due to the chirality of the sample from that due to a chiral experimental geometry. For these studies of oriented chiral molecules, the CDAD is seen not only in photoemission from the molecular chiral centre, but also from other atoms which have chiral geometries as a result of the adsorption. The magnitude of the CDAD due to the sample chirality differs for different adsorption phases of alanine, and for different emission angles and energies, but is generally small compared with CDAD out of the substrate mirror planes which is largely unrelated to the molecular chirality. While similar measurements of other molecules may reveal larger CDAD due to molecular chirality, the fact that the results for one chiral molecule show weak effects means that such CDAD is unlikely to provide a simple and routine general spectral fingerprint of adsorbed molecular chirality.

  8. High-resolution scanning tunneling microscopy for molecules

    International Nuclear Information System (INIS)

    Scanning tunneling microscopy (STM) can detect individual molecular configuration with its high spatial resolution ability, but some intrinsical and extrinsic factors result in the complexities of STM imaging of single molecules. By combining STM experimental work and theoretical simulation with the local density approximation based on Bardeen perturbation method, we have explored the atomic-scale configuration of the following molecular systems: C60 molecules adsorbed on Si(1 1 1)-(7x7); alkanethiol self-assembly monolayers on Au(1 1 1); C60 molecule imaged by STM tip adsorbed with another C60 molecule; O2 molecule adsorbed on Ag(1 1 0) and CO molecule adsorbed on Cu(1 1 1) imaged by CO chemically modified STM tip. Some related problems including: molecule-substrate interactions, STM imaging mechanism, chemically modified STM tip, etc., are discussed

  9. STM studies of the epitaxial growth of C_(60) molecules on Si(111)-7 ×7 surface%C_(60)分子在Si(111)-7×7表面分子束外延生长的STM研究

    Institute of Scientific and Technical Information of China (English)

    赵明海; 孙静静; 王丹; 邹志强; 梁齐

    2010-01-01

    在超高真空中采用分子束外延(molecular beam epitaxial)技术进行C_(60)分子在硅(111)-7×7表面的生长,并利用扫描隧道显微镜进行原位研究.室温下,相对于无层错半胞(unfaulted half unit cell),C_(60)更易于吸附在有层错半胞(faulted half unit cell).表面台阶处的电子悬挂键密度最高,通过控制温度和时间进行退火处理后,C_(60)分子会向着台阶的方向扩散并聚集.测量分子在不同吸附位置的直径和高度,发现由于不同位置分子与衬底的相互作用强度的不同,其分子直径和高度也存在一定差异.还研究了C_(60)分子在Si(111)-7×7表面的多层生长模式,并且通过600℃退火处理在硅表面形成了有序的单层结构,从而实现了C_(60)分子在硅表面从Stanski-Krastanov三维岛状模式到Frank-van der Merwe层状生长模式的转变.

  10. Diffusive motion of C60 on a graphene sheet

    OpenAIRE

    Neek-Amal, M.; Abedpour, N.; Rasuli, S. N.; Naji, A; Ejtehadi, M.R.

    2009-01-01

    The motion of a C60 molecule over a graphene sheet at finite temperature is investigated both theoretically and computationally. We show that a graphene sheet generates a van der Waals laterally periodic potential, which directly influences the motion of external objects in its proximity. The translational motion of a C60 molecule near a graphene sheet is found to be diffusive in the lateral directions. While, in the perpendicular direction, the motion may be described as diffusion in an effe...

  11. Ultra-sensitive fluorescence spectroscopy of isolated surface-adsorbed molecules using an optical nanofiber.

    Science.gov (United States)

    Stiebeiner, A; Rehband, O; Garcia-Fernandez, R; Rauschenbeutel, A

    2009-11-23

    The strong radial confinement and the pronounced evanescent field of the guided light in optical nanofibers yield favorable conditions for ultra-sensitive surface spectroscopy of molecules deposited on the fiber. Using the guided mode of the nanofiber for both excitation and fluorescence collection, we present spectroscopic measurements on 3,4,9,10-perylenetetracarboxylic dianhydride molecules (PTCDA) at ambient conditions. Surface coverages as small as 1 per thousand of a compact monolayer still give rise to fluorescence spectra with a good signal to noise ratio. Moreover, we analyze and quantify the self-absorption effects due to reabsorption of the emitted fluorescence light by circumjacent surface-adsorbed molecules distributed along the fiber waist. PMID:19997412

  12. Homeotropic orientation of a nematic liquid crystal by bent-core molecules adsorbed on its surface

    Science.gov (United States)

    Hwang, Jiyong; Yang, Seungbin; Lee, Hyojin; Kim, Jongyoon; Lee, Ji-Hoon; Kang, Shin-Woong; Choi, E.-Joon

    2015-06-01

    We reported the promotion of a homeotropic alignment of a nematic liquid crystal (NLC) by bent-core liquid-crystal (BLC) Molecules adsorbed its surface. The BLC was mixed at various concentrations with the NLC, and the mixtures were injected into an empty cell with a cell gap of 13 μm. Although the pure NLC showed a heterogeneous orientation, the BLC-NLC mixture was gradually transformed to a homeotropic alignment with increasing concentration of the BLC. We investigated the surface topography of the samples by using an atomic force microscopy (AFM) and found that the BLC molecules were segregated into a polyimide (PI) surface and formed protrusion domains with diameters of 50-100 nm. The BLC protrusions might promote the homeotropic orientation of the NLC molecules.

  13. Directed motion of C60 on a graphene sheet subjected to a temperature gradient

    OpenAIRE

    Lohrasebi, A.; Neek-Amal, M.; Ejtehadi, M. R.

    2011-01-01

    Nonequilibrium molecular dynamics simulations is used to study the motion of a C60 molecule on a graphene sheet subjected to a temperature gradient. The C60 molecule is actuated and moves along the system while it just randomly dances along the perpendicular direction. Increasing the temperature gradient increases the directed velocity of C60. It is found that the free energy decreases as the C60 molecule moves toward the cold end. The driving mechanism based on the temperature gradient sugge...

  14. Junction characteristics of C60/polycarbonate blend on Si substrate

    International Nuclear Information System (INIS)

    We report a study of the interface between fullerene (C60) doped polycarbonate (PC) blends and n-type Si substrate. C60 is usually an electron acceptor in interpenetrated networks and an electron transport in photovoltaic cells. We have studied that the guest-host approach to prepare C60 doped polycarbonate blend. In this article, we report the I-V characteristics of C60 doped polycarbonate/n-type Si junction and the annealing effect on these characteristics. In this junction, a nanocomposite of organic semiconductor fullerene (C60), used as the active medium, with an inert polycarbonate matrix was spin coated on n-type Si substrate. We found that the C60 shows the junction characteristics with n-type Si substrate. The knee voltage and dynamic resistance varies with concentration of C60 as well as temperature. Ellipsometry studies showed the annealing effect on the refractive index and thickness of C60 doped polycarbonate blend on n-type Si substrate. The optical micrographs show that fullerene (C60) is spherical molecule and it is blend in the form of crystallites having size of micron order.

  15. Redox transformations of adsorbed NO molecules on a Pt(100) electrode

    OpenAIRE

    Molodkina, E.B.; Botryakova, I.G.; Danilov, A.I.; Souza-Garcia, Janaina; Figueiredo, Marta C.; Feliu, Juan M.

    2014-01-01

    The electrochemical behavior of adsorbed NO molecules on a Pt(100) electrode has been studied in perchloric acid solutions by means of cyclic voltammetry. According to the literature data, a saturated NO adlayer with a coverage of ∼0.5 monolayers (MLs) is formed under open circuit conditions in an acidic nitrite solution as a result of a disproportionation reaction. The saturated adlayer is stable in the potential range of 0.4–0.9 V vs. a reversible hydrogen electrode in 0.1 M HClO4. NO molec...

  16. Thermal and Electronic Fluctuations of Flexible Adsorbed Molecules: Azobenzene on Ag(111)

    Science.gov (United States)

    Maurer, Reinhard J.; Liu, Wei; Poltavsky, Igor; Stecher, Thomas; Oberhofer, Harald; Reuter, Karsten; Tkatchenko, Alexandre

    2016-04-01

    We investigate the thermal and electronic collective fluctuations that contribute to the finite-temperature adsorption properties of flexible adsorbates on surfaces on the example of the molecular switch azobenzene C12 H10 N2 on the Ag(111) surface. Using first-principles molecular dynamics simulations, we obtain the free energy of adsorption that accurately accounts for entropic contributions, whereas the inclusion of many-body dispersion interactions accounts for the electronic correlations that govern the adsorbate binding. We find the adsorbate properties to be strongly entropy driven, as can be judged by a kinetic molecular desorption prefactor of 1024 s-1 that largely exceeds previously reported estimates. We relate this effect to sizable fluctuations across structural and electronic observables. A comparison of our calculations to temperature-programed desorption measurements demonstrates that finite-temperature effects play a dominant role for flexible molecules in contact with polarizable surfaces, and that recently developed first-principles methods offer an optimal tool to reveal novel collective behavior in such complex systems.

  17. Molecular resonant dissociation of surface-adsorbed molecules by plasmonic nanoscissors

    Science.gov (United States)

    Zhang, Zhenglong; Sheng, Shaoxiang; Zheng, Hairong; Xu, Hongxing; Sun, Mengtao

    2014-04-01

    The ability to break individual bonds or specific modes in chemical reactions is an ardently sought goal by chemists and physicists. While photochemistry based methodologies are very successful in controlling e.g. photocatalysis, photosynthesis and the degradation of plastic, it is hard to break individual molecular bonds for those molecules adsorbed on the surface because of the weak light-absorption in molecules and the redistribution of the resulting vibrational energy both inside the molecule and to its surrounding environment. Here we show how to overcome these obstacles with a plasmonic hot-electron mediated process and demonstrate a new method that allows the sensitive control of resonant dissociation of surface-adsorbed molecules by `plasmonic' scissors. To that end, we used a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) setup to dissociate resonantly excited NC2H6 fragments from Malachite green. The surface plasmons (SPs) excited at the sharp metal tip not only enhance the local electric field to harvest the light incident from the laser, but crucially supply `hot electrons' whose energy can be transferred to individual bonds. These processes are resonant Raman, which result in some active chemical bonds and then weaken these bonds, followed by dumping in lots of indiscriminant energy and breaking the weakest bond. The method allows for sensitive control of both the rate and probability of dissociation through their dependence on the density of hot electrons, which can be manipulated by tuning the laser intensity or tunneling current/bias voltage in the HV-TERS setup, respectively. The concepts of plasmonic scissors open up new versatile avenues for the deep understanding of in situ surface-catalyzed chemistry.The ability to break individual bonds or specific modes in chemical reactions is an ardently sought goal by chemists and physicists. While photochemistry based methodologies are very successful in controlling e.g. photocatalysis

  18. Uenbinding'' an adsorbed organic molecule: K plus PTCDA on Ag(110)

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Oliver; Schmitz, Christoph H.; Fiedler, Benjamin; Sokolowski, Moritz [Institut fuer Physikalische und Theoretische Chemie, Universitaet Bonn (Germany); Mercurio, Giuseppe; Subach, Sergey; Tautz, Frank Stefan [Institut fuer Bio- und Nanosysteme 3, Forschungszentrum Juelich (Germany)

    2010-07-01

    We have doped the well-known brick-wall structure of pristine PTCDA which is present in the monolayer on the Ag(110) surface with potassium (K) and investigated the induced structural and electronic changes at the interface. SPA-LEED measurements reveal that the structural order of the PTCDA molecules is strongly altered upon K dosing: A variety of co-existing binary phases is observed within the monolayer. In addition we have conducted XPS and NIXSW measurements on K+PTCDA/Ag(110). The photoemission experiments indicate that the K atoms preferentially interact with the carboxylic groups of the co-adsorbed PTCDA molecules. This interpretation is further supported by the NIXSW results: The adsorption geometries of the carboxylic and the anhydride oxygen (O) atoms are highly influenced by the presence of K on the surface, the bonding distances are extended. The adsorption height of the perylene core is also increased by K doping. Hence we conclude that the local Ag-O bonds at the interface are partially lifted by the co-adsorbed K and that K and Ag atoms compete for the interaction with the carboxylic groups of PTCDA while the bonding across the interface is weakened.

  19. The formation of buckminsterfullerene (C$_{60}$) in interstellar space

    CERN Document Server

    Berné, Olivier

    2011-01-01

    Buckminsterfullerene (C$_{60}$) was recently confirmed to be the largest molecule identified in space. However, it remains unclear how, and where this molecule is formed. It is generally believed that C$_{60}$ is formed from the build up of small carbonaceous compounds, in the hot and dense envelopes of evolved stars. Analyzing infrared observations, obtained by Spitzer and Herschel, we found that C$_{60}$ 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 C$_{60}$, under UV irradiation from massive stars. This shows that alternative - top-down - routes are key to understanding the organic inventory in space.

  20. Symmetry-selected spin-split hybrid states in C60/ferromagnetic interfaces

    Science.gov (United States)

    Li, Dongzhe; Barreteau, Cyrille; Kawahara, Seiji Leo; Lagoute, Jérôme; Chacon, Cyril; Girard, Yann; Rousset, Sylvie; Repain, Vincent; Smogunov, Alexander

    2016-02-01

    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 ferromagnetic surfaces: bcc-Cr(001), bcc-Fe(001), bcc-Co(001), fcc-Co(001), and hcp-Co(0001). We show that the adsorption geometry of the molecule with respect to the surface crystallographic orientation of the magnetic substrate as well as the strength of the interaction play a crucial role in the spin polarization of the hybrid orbitals. We find that a large spin polarization in vacuum above the buckyball can only be achieved if the molecule is adsorbed upon a bcc-(001) surface by its pentagonal ring. Therefore, bcc-Cr(001), bcc-Fe(001), and bcc-Co(001) are the optimal candidates. Spin-polarized scanning tunneling spectroscopy measurements on single C60 adsorbed on Cr(001) and Co/Pt(111) also confirm that the symmetry both of the substrate and of the molecular conformation has a strong influence on the induced spin polarization. Our finding may give valuable insights for further engineering of spin filtering devices through single molecular orbitals.

  1. Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS2

    International Nuclear Information System (INIS)

    Density functional theory calculations were performed to assess changes in the geometric and electronic structures of monolayer WS2 upon adsorption of various gas molecules (H2, O2, H2O, NH3, NO, NO2, and CO). The most stable configuration of the adsorbed molecules, the adsorption energy, and the degree of charge transfer between adsorbate and substrate were determined. All evaluated molecules were physisorbed on monolayer WS2 with a low degree of charge transfer and accept charge from the monolayer, except for NH3, which is a charge donor. Band structure calculations showed that the valence and conduction bands of monolayer WS2 are not significantly altered upon adsorption of H2, H2O, NH3, and CO, whereas the lowest unoccupied molecular orbitals of O2, NO, and NO2 are pinned around the Fermi-level when these molecules are adsorbed on monolayer WS2. The phenomenon of Fermi-level pinning was discussed in light of the traditional and orbital mixing charge transfer theories. The impacts of the charge transfer mechanism on Fermi-level pinning were confirmed for the gas molecules adsorbed on monolayer WS2. The proposed mechanism governing Fermi-level pinning is applicable to the systems of adsorbates on recently developed two-dimensional materials, such as graphene and transition metal dichalcogenides

  2. Electrical conductivity of reconstructed Si(111) surface with sodium-doped C60 layers

    International Nuclear Information System (INIS)

    Electrical conductance of sodium-doped C60 ultra-thin layers (1–6 monolayers) grown on the Na-adsorbed Si(111)√3 × √3-Au surface has been studied in situ by four-point probe technique, combined with low-energy electron diffraction observations. Evidence of conductance channel formation through the C60 ultrathin layer is demonstrated as a result of Na dosing of 3 and 6 monolayers thick C60 layers. The observed changes in surface conductivity can be attributed to the formation of fulleride-like NaC60 and Na2C60 compound layers

  3. Cross-sectional scanning probe microscopy on GaAs: Tip-induced band bending, buried acceptors and adsorbed molecules

    OpenAIRE

    Münnich, Gerhard

    2014-01-01

    This thesis presents low temperature scanning probe experiments performed in the cross-sectional geometry (X-SPM) on GaAs samples. In particular, three topics have been addressed. First, the GaAs(110) surface has been utilized as a substrate to adsorb iron-II-phthalocyanine molecules. The molecules were probed from scanning tunneling microscopy (STM) and spectroscopy (STS) and were found to be only weakly perturbed by the substrate. This is in analogy to molecules decoupled from a metalli...

  4. Imaging the wave functions of adsorbed molecules using angle-resolved photoemmision data

    Science.gov (United States)

    Lüftner, Daniel; Ules, Thomas; Reinisch, Eva Maria; Koller, Georg; Soubatch, Serguei; Tautz, F. Stefan; Ramsey, Michael G.; Puschnig, Peter

    2014-03-01

    The frontier electronic orbitals of molecules are the prime determinants of the respective compounds' chemical, electronic, and optical properties. Although orbitals are very powerful concepts, experimentally only the electron densities and energy levels are directly observable. As has been shown in recent publications, angle-resolved photoemission (ARPES) intensity maps of organic molecular layers are related to the absolute value of the Fourier transform of the initial state molecular orbital. However, the lost phase information impedes the back-transformation of the orbital into real space. Here, we show how molecular orbital images as well as the absent phase information can be retrieved by applying an iterative procedure which takes experimental ARPES maps as input and only assumes spatial confinement of the orbital. The method is demonstrated for several molecular orbitals of two proto-typical pi-conjugated molecules: the LUMO, HOMO, and HOMO-1 of pentacene, and the LUMO and HOMO of PTCDA. The technique is simple and robust and further emphasizes the capabilities of ARPES looking at spatial distributions of wave functions of adsorbed molecules thereby complementing data obtained from scanning probe methods.

  5. Room temperature differential conductance measurements of triethylamine molecules adsorbed on Si(001).

    Science.gov (United States)

    Naitabdi, Ahmed; Rochet, François; Carniato, Stéphane; Bournel, Fabrice; Gallet, Jean-Jacques

    2016-08-17

    We have measured the differential conductance of the triethylamine molecule (N(CH2CH3)3) adsorbed on Si(001)-2 × 1 at room temperature using scanning tunneling spectroscopy. Triethylamine can be engaged in a dative bonding with a silicon dimer, forming a Si-Si-N(CH2CH3)3 unit. We have examined the datively bonded adduct, either as an isolated molecule, or within an ordered molecular domain (reconstructed 4 × 2). The differential conductance curves, supported by DFT calculations, show that in the explored energy window (±2.5 near the Fermi level) the main features stem from the uncapped dangling bonds of the reacted dimer and of the adjacent unreacted ones that are electronically coupled The formation of a molecular domain, in which one dimer in two is left unreacted, is reflected in a shift of the up dimer atom occupied level away from the Fermi level, likely due to an increased π-bonding strength. In stark contrast with the preceding, pairs of dissociated molecule (a minority species) are electronically decoupled from the dimer dangling bond states. DFT calculation show that the lone-pair of the Si-N(CH2CH3)2 is a shallow level, that is clearly seen in the differential conductance curve. PMID:27499070

  6. Effect of resonance dipole-dipole interaction on spectra of adsorbed SF6 molecules.

    Science.gov (United States)

    Dobrotvorskaia, Anna N; Kolomiitsova, Tatiana D; Petrov, Sergey N; Shchepkin, Dmitriy N; Smirnov, Konstantin S; Tsyganenko, Alexey A

    2015-09-01

    Adsorption of SF6 on zinc oxide and on silicalite-1 was investigated by a combination of IR spectroscopy with the calculations of spectra by means of a modernized model, developed previously for liquids. Comparison of the experimental spectra and the results of modeling shows that the complex band shapes in spectra of adsorbed molecules with extremely high absorbance are due to the strong resonance dipole-dipole interaction (RDDI) rather that the surface heterogeneity or the presence of specific surface sites. Perfect agreement between calculated and observed spectra was found for ZnO, while some dissimilarity in band intensities for silicalite-1 was attributed to complicated geometry of molecular arrangement in the channels. PMID:25897721

  7. C60 as a Probe for Astrophysical Environments

    Science.gov (United States)

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

    2016-08-01

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

  8. Electronic structure and binding geometry of tetraphenylporphyrin-derived molecules adsorbed on metal and metal oxide surfaces

    Science.gov (United States)

    Coh, Senia

    Tetraphenylporphyrin (TPP)-derived molecules have been studied extensively as efficient photosensitizers when chemisorbed on the metal oxide substrates in dye-sensitized solar cells. Still, many fundamental electronic properties of the dye/oxide interface are not understood and need careful consideration. In this thesis we present a comprehensive study of the electronic structure, energy level alignment and the adsorption geometry of the TPP-derived dye molecules adsorbed on TiO2(110), ZnO(1120) and Ag(100) single crystal surfaces using ultra-high vacuum (UHV) based surface sensitive techniques. The alignment of the molecular energy levels with respect to the TiO 2 and ZnO band edges for all TPP-derived molecules we studied was found to be insensitive to either the nature of the functional groups located on the phenyl rings, presence of zinc as a central metal ion and different binding geometry of the molecules. Binding geometry, molecule-molecule interaction and the aggregation effects in the adsorbed layer, that were observed in the UV-visible spectra of the molecules adsorbed on ZnO substrate were not observed in the ultraviolet photoemission (UPS) and inverse photoemission (IPS) spectra of the occupied and unoccupied molecular states. Using near edge X-ray absorption fine structure (NEXAFS) and scanning tunneling microscopy (STM), binding geometry of the two representative TPP-derivatives was directly determined to be upright, with the porphyrin ring under large angle with respect to the surface for the p-ZnTCPP molecules and with the porphyrin ring parallel to the surface for the m-ZnTCPP molecules. We observe that the energies and the energy level alignment of the ZnTPP molecular levels measured in UPS and IPS depend on the substrate on which the molecules are adsorbed (Ag(100) or TiO2(110) single crystal surfaces). The differences are attributed to different charge screening properties of these two materials. Image charges created in the substrates during

  9. Biological applications of hydrophilic C60 derivatives (hC60s)- a structural perspective.

    Science.gov (United States)

    Zhu, Xiaolei; Sollogoub, Matthieu; Zhang, Yongmin

    2016-06-10

    Reactive oxygen species (ROS) generation and radical scavenging are dual properties of hydrophilic C60 derivatives (hC60s). hC60s eliminate radicals in dark, while they produce reactive oxygen species (ROS) in the presence of irradiation and oxygen. Compared to the pristine C60 suspension, the aqueous solution of hC60s is easier to handle in vivo. hC60s are diverse and could be placed into two general categories: covalently modified C60 derivatives and pristine C60 solubilized non-covalently by macromolecules. In order to present in detail, the above categories are broken down into 8 parts: C60(OH)n, C60 with carboxylic acid, C60 with quaternary ammonium salts, C60 with peptide, C60 containing sugar, C60 modified covalently or non-covalently solubilized by cyclodextrins (CDs), pristine C60 delivered by liposomes, functionalized C60-polymer and pristine C60 solubilized by polymer. Each hC60 shows the propensity to be ROS producer or radical scavenger. This preference is dependent on hC60s structures. For example, major application of C60(OH)n is radical scavenger, while pristine C60/γ-CD complex usually serves as ROS producer. In addition, the electron acceptability and innate hydrophobic surface confer hC60s with O2 uptake inhibition, HIV inhibition and membrane permeability. In this review, we summarize the preparation methods and biological applications of hC60s according to the structures. PMID:27049677

  10. Observation and analysis of Fano-like lineshapes in the Raman spectra of molecules adsorbed at metal interfaces

    OpenAIRE

    Dey, S; Banik, M; Hulkko, E.; Rodriguez, K.; Apkarian, V. A.; Galperin, M.; Nitzan, A.

    2015-01-01

    Surface enhanced Raman spectra from molecules (bipyridyl ethylene) adsorbed on gold dumbells are observed to become increasingly asymmetric (Fano-like) at higher incident light intensity. The electronic temperature (inferred from the anti-Stokes (AS) electronic Raman signal increases at the same time while no vibrational AS scattering is seen. These observations are analyzed by assuming that the molecule-metal coupling contains an intensity dependent contribution (resulting from light-induced...

  11. Iron ion implantation into C60 layer

    International Nuclear Information System (INIS)

    Complete text of publication follows. The soccer ball shaped carbon molecule consisting of 60 carbon atoms (C60, fullerene) was discovered in 1985. Since that time the fullerene has become intensively studied. This special molecule has much potential in medical care, biotechnology and nanotechnology. We are motivated to produce special type fullerenes, so called endohedral fullerenes (some alien atoms are encapsulated inside the fullerene cage). The spring of our motivation is that the Fe at C60 could be applied as a contrast material for MRI (Magnetic Resonance Imaging) or microwave heat therapy. One way to make X at C60 is the surface production using an ECRIS (Electron Cyclotron Resonance Ion Source). An evaporated or preprepared fullerene layer is irradiated by ions to form a new material during the implantation. By this method several kinds of atomic species, such as Li, Na, K, Rb, Xe were encapsulated into the fullerenes. However evidence for the Fe at C60 has not been found yet. During the analysis of the irradiated samples three questions must be answered. 1. Are there iron atoms in the layer and where? 2. Does the iron bond to the fullerene? 3. How does the iron bond to the fullerene, inside or outside? Using different investigation tools, SNMS (Secondary Neural Mass Spectrometer), MALDI-TOF (Matrix Assisted Laser Desorption Ionization Time of Flight), XPS (Xray Photoelectron Spectroscopy) or HPLC (High-Performance Liquid Chromatography), all these questions could be clarified step by step. In this paper we made the first steps to answer the first question: fullerene layers irradiated by iron ion beam delivered by the ATOMKI-ECRIS have been analyzed by the ATOMKI-SNMS. The evaporated 90 - 120 nm thick fullerene layers on Si holder were irradiated by Fe5+ and Fe+ ion beams produced from Ferrocene vapor. Samples were irradiated with two different doses (5 1018 ion/cm3 and 1022 ion/cm3) at four ion energies (65 keV, 6.5 keV, 0.2 keV and two of these samples

  12. Superconductivity in alkali-doped C60

    International Nuclear Information System (INIS)

    Highlight: • Superconductivity in alkali-doped C60 (A3C60) 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 A3C60 offers a paradigm for the development of new superconducting materials. - Abstract: Superconductivity in alkali-doped C60 (A3C60, 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 (Tc) up to 33 K in single-phase material. The good understanding of pairing in A3C60 offers a paradigm for the development of new superconducting materials

  13. Nature of free-electron-like states in PTCDA molecules adsorbed on an Ag(111) surface

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Mats; Dyer, Matthew [Surface Science Research Centre, University of Liverpool, L69 3BX Liverpool (United Kingdom)

    2009-07-01

    Advances in molecular assembly experiments on metal surfaces and potential applications arising from them call for a better understanding of the electronic structure at the interface of metals and organic systems. There is a high interest in delocalized electronic states, because of their potential use in molecular and opto-electronics applications. Recently, unoccupied, free-electron-like states arising in mono layers of 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) molecules adsorbed on an Ag(111) surface at energies close to the Fermi energy have been observed by scanning tunneling and photoemission spectroscopies. So as to reveal the nature of these delocalized states we have carried out a density functional study of the electronic structure and local density of states of these systems. We show that the observed free-electron state originates from a Shockley surface state (SS) at the zone centre of the bare surface. The SS is shifted up by the interaction with the organic overlayer.

  14. Barriers to intramolecular rotation determined from the temperature dependence of the Henry constant in the region of adsorbed molecule rigidity failure

    Science.gov (United States)

    Dolgonosov, A. M.; Prudkovskii, A. G.

    2008-05-01

    A distribution for the rigid and nonrigid adsorbed molecule forms was found. Adsorbed molecule rigidity failure was shown to be accompanied by a weak nonlinear effect, which manifested itself as a temperature dependence of the Henry constant. A method for the determination of the barrier to intramolecular rotation from the temperature dependence of the molecule adsorption constant was suggested. Barriers to rotation about the C-C and C-O bonds were determined for several molecules.

  15. Structural and Electrical Investigation of C60-Graphene Vertical Heterostructures.

    Science.gov (United States)

    Kim, Kwanpyo; Lee, Tae Hoon; Santos, Elton J G; Jo, Pil Sung; Salleo, Alberto; Nishi, Yoshio; Bao, Zhenan

    2015-06-23

    Graphene, with its unique electronic and structural qualities, has become an important playground for studying adsorption and assembly of various materials including organic molecules. Moreover, organic/graphene vertical structures assembled by van der Waals interaction have potential for multifunctional device applications. Here, we investigate structural and electrical properties of vertical heterostructures composed of C60 thin film on graphene. The assembled film structure of C60 on graphene is investigated using transmission electron microscopy, which reveals a uniform morphology of C60 film on graphene with a grain size as large as 500 nm. The strong epitaxial relations between C60 crystal and graphene lattice directions are found, and van der Waals ab initio calculations support the observed phenomena. Moreover, using C60-graphene heterostructures, we fabricate vertical graphene transistors incorporating n-type organic semiconducting materials with an on/off ratio above 3 × 10(3). Our work demonstrates that graphene can serve as an excellent substrate for assembly of molecules, and attained organic/graphene heterostructures have great potential for electronics applications. PMID:26027690

  16. Nuclear magnetic resonance study of the structure of simple molecules adsorbed on metal surfaces: acetylene on platinum

    International Nuclear Information System (INIS)

    We have used NMR to determine the structure of acetylene (HC - CH) adsorbed at room temperature on small platinum particles by studying the 13C-13C, 13C-1H, and 1H-1H dipolar interactions among the nuclei in the adsorbed molecules. We find a model of 77% CCH2 and 23% HCCH to be the only one consistent with all of our data. The C-C bond length of the majority species, CCH2, is determined as 1.44 +- 0.02 A, midway between a single and double bond, suggesting that both carbon atoms bond to the surface. 36 references, 29 figures, 1 table

  17. Magnetic transitions induced by tunneling electrons in individual adsorbed M-phthalocyanine molecules (M=Fe and Co)

    OpenAIRE

    Gauyacq, J. P.; Novaes, Frederico D; Lorente, N.

    2010-01-01

    We report on a theoretical study of magnetic transitions induced by tunnelling electrons in individual adsorbed M-Phthalocyanine (M-Pc) molecules where M is a metal atom: Fe-Pc on a Cu(110)(2$\\times$1)-O surface and Co-Pc layers on Pb(111) islands. The magnetic transitions correspond to the change of orientation of the spin angular momentum of the metal ion with respect to the surroundings and possibly an applied magnetic field. The adsorbed Fe-Pc system is studied with a Density Functional T...

  18. Properties of ferrocene derivative C60 adduct

    International Nuclear Information System (INIS)

    Properties of ferrocene derivative C60 adduct were investigated by thermal analyses, x-ray diffraction, 57Fe Moessbauer spectroscopy in order to examine interaction of iron with fullerene. Thermal treatment may be applied to remove organic groups to obtain sample containing C60Fe with C60 arranged in the fcc lattice and iron dispersed between fullerenes. We performed calculations based on the semi-empirical quantum chemistry model P M3 for a few exohedral complexes with Fe at various sites relatively to C60

  19. Photosensitization of Nanocrystalline TiO2 Electrode Modifiedwith C60 Carboxylic Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    张文; 史亚茹; 甘良兵; 黄春辉; 王艳琴; 虎民

    2001-01-01

    C60 carboxylic acid derivatives can be readily adsorbed on the surface of nanocrystalline TiO2 films act as charge-transfer sensitizer. The electron transport from TiO2 to the C60 derivatives results in the generation of the cathodic photocurrent. The short-circuit photocurrent of a C60 tetracarboxylic acid is 0.45 μA/cm2 under 464 um light illumination. The photoelectric behaviour of ITO electrodes modified by the same C60 carboxylic acids is different from that of the modified TiO2 electrodes, and shows anodic photocurrent.

  20. Direct comparison of the electronic coupling efficiency of sulfur and selenium alligator clips for molecules adsorbed onto gold electrodes

    International Nuclear Information System (INIS)

    Scanning tunneling microscopy experiments have been performed to compare the electronic coupling provided by S and by Se used as alligator clips for bisthiol- and biselenol-terthiophene molecules adsorbed onto gold. The molecules were inserted in a dodecanethiol (DT) self-assembled monolayer. Their apparent height above the dodecanethiol matrix was used as a measure of the electronic coupling strength corresponding to S and Se, respectively. We show that the insertion behaviors of the two molecules are qualitatively the same, and that Se provides systematically a better coupling link than S, whatever the tunneling conditions

  1. 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....

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

    Science.gov (United States)

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

    2016-06-01

    We recently reported (Song Y-D et al., 2016, J Mol Model 22:50) that doping with Li greatly affects the static first hyperpolarizability of C60Cl2. In this work, with a view to creating nonlinear optical materials with high thermodynamic stability and wide transparent regions, a series of Li@C60Cl n (n = 4, 6, 8, 10) were designed. The structures, electrostatic potentials, electronic structures, absorption spectra, and linear and nonlinear optical properties of C60Cl n and Li@C60Cl n were systematically investigated using density functional theory (DFT) methods. The results of our calculations indicated that the stability of these molecules decreases in the order Li@C60Cl10 > Li@C60Cl8 > Li@C60Cl6 > Li@C60Cl4. It is clear that the number of Cl atoms greatly influences the stability of Li@C60Cl n . Li@C60Cl n showed greater thermodynamic stability than Li@C60Cl2. We also investigated the first hyperpolarizabilities of Li@C60Cl n and found them to be 2973, 3640, 4307, and 2627 au for n = 4, 6, 8, and 10, respectively-higher than that of Li@C60Cl2. Finally, we noted that the transparent region could be modulated by increasing the number of Cl atoms: Li@C60Cl n possess wider transparent regions than that of Li@C60Cl2. We therefore believe that this study has highlighted an effective method for designing nonlinear optical materials with high thermodynamic stability and wide transparent regions. PMID:27188724

  3. 15 CFR 8c.60 - Communications.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Communications. 8c.60 Section 8c.60 Commerce and Foreign Trade Office of the Secretary of Commerce ENFORCEMENT OF NONDISCRIMINATION ON THE... Communications. (a) The agency shall take appropriate steps to ensure effective communication with...

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

    International Nuclear Information System (INIS)

    The behavior of C60 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 C60 is of considerable interest in itself and needs to be understood in detail if C60 cluster ion beams are to be fully exploited technologically. In addition, one may anticipate that an understanding of C60 fragmentation will contribute mutatis mutandis to an elucidation of the elementary steps leading to the assembly of C60 from smaller carbon clusters

  5. 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

    2001-01-01

    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

  6. Effects of molecule-insulator interaction on geometric property of a single phthalocyanine molecule adsorbed on an ultrathin NaCl film

    Science.gov (United States)

    Miwa, Kuniyuki; Imada, Hiroshi; Kawahara, Shota; Kim, Yousoo

    2016-04-01

    The adsorption structure and orientation of a metal-free phthalocyanine (H2Pc ) and a magnesium phthalocyanine (MgPc) on a bilayer of NaCl films were investigated both theoretically and experimentally by means of first-principles calculations based on density functional theory and by scanning tunneling microscopy. H2Pc is adsorbed with its center over the sodium cation, and H-N bonds in the molecule are aligned with the [100] or [010] surface direction of a bilayer (001)-terminated NaCl film. The most stable structures of MgPc on the NaCl film show two kinds of orientations corresponding to the molecule rotated by ±7∘ relative to the [110] surface direction, with the Mg cation positioned over the chlorine anion in both cases. The energetic barrier for switching between these orientations is as low as 9.0 meV, and during an STM measurement, an orientational change of MgPc can be observed. The interaction between the adsorbed molecule and the NaCl film were analyzed in terms of dispersion interaction, Mg-Cl chemical bonding, and electrostatic interaction. It is found that the small electrostatic interaction between the molecule and the film gives a dominant contribution to determining the molecular orientation. Our detailed and comprehensive studies of the molecule-insulator interaction will provide knowledge to understand and control the properties of molecules on an insulating material.

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

    International Nuclear Information System (INIS)

    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

  8. Thermal expansion of C60 single crystals under pressure

    International Nuclear Information System (INIS)

    The thermal expansion and compressibility of C60 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 C60-samples was measured with a resolution of ΔL/L∼10-9. The crystals consist of weakly bonded C60-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 C60-molecules. (orig.)

  9. Photoionization of the fullerene ion C60+

    OpenAIRE

    Polozkov, R. G.; Ivanov, V. K.; Solov'yov, A. V.

    2004-01-01

    Photoionization cross section of the fullerene ion C60+ has been calculated within a single-electron approximation and also by using a consistent many-body theory accounting for many-electron correlations.

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

    Science.gov (United States)

    Qian, Xiaofeng; Umari, Paolo; Marzari, Nicola

    2015-06-01

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

  11. Preparation of theoretical scanning tunneling microscope images of adsorbed molecules: a theoretical study of benzene on the Cu(110) surface

    International Nuclear Information System (INIS)

    Full text: Since its development in 1982, the Scanning Tunneling Microscope (STM) has developed into a powerful tool for the study of surfaces and adsorbates. However, the utility of the technique can be further enhanced through the development of techniques for generating theoretical STM images. This is particularly true when studying molecules adsorbed on a substrate, as the results are often interpreted superficially due to an inadequate understanding of the orbital overlap probed in the experiment. A method of preparing theoretical scanning tunneling microscope (STM) images using comparatively inexpensive desktop computers and the commercially available CRYSTAL98 package is presented through a study of benzene adsorbed on the Cu(110) surface. Density Functional Theory (DFT) and Hartree-Fock (HF) methods are used to model clean Cu(110) slabs of various thicknesses and to simulate the adsorption of benzene onto these slabs. Eight possible orientations of benzene on the Cu(110) surface are proposed, and the optimum orientation according to the calculations is presented. Theoretical STM images of the Cu(110) surface and benzene adsorbed on the Cu(110) surface are compared with experimental STM images of the system from a published study. Significant differences are observed and are examined in detail

  12. James C. McGroddy Prize Talk: What Was New About C60

    Science.gov (United States)

    Haddon, Robert

    2008-03-01

    C60 was named molecule of the year by Science in 1991, and in this talk I will discuss what I consider to be the most novel features of the molecule. In some ways C60 is truly unique and the discovery of the molecule in 1985 and its subsequent synthesis in 1990 blazed a trail of new chemical and physical properties that is unlikely to be surpassed by any other molecule. I will discuss the electronic structure of C60, its magnetism, and the conductivity and superconductivity shown by the alkali metal-doped phases.

  13. Adsorption energy and geometry of adsorbed organic molecules on Au(111) probed by surface-state photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Ziroff, Johannes; Forster, Frank [Universitaet Wuerzburg, Experimentelle Physik II, D-97074 Wuerzburg (Germany); Reinert, Friedrich [Universitaet Wuerzburg, Experimentelle Physik II, D-97074 Wuerzburg (Germany); Forschungszentrum Karlsruhe, Gemeinschaftslabor fuer Nanoanalytik, D-76021 Karlsruhe (Germany)

    2009-07-01

    The modification of the Au(111) surface states by an adsorbed monolayer of large {pi}-conjugated molecules (PTCDA, NTCDA, CuPc) was investigated by high-resolution angle-resolved photoelectron spectroscopy. We determined binding energy, band mass, and Rashba-splitting and discuss the results in the context of rare-gas adsorption on noble metals. This comparison allows the determination of the bonding strength of the adsorbates, found to be physisorptive with derived binding energies per molecule of 2.0 eV for PTCDA and 1.5 eV for NTCDA. We will also present a superstructure model for the NTCDA/Au(111) system, deduced from low energy electron diffraction images in combination with band-backfolding of the Tamm and Shockley states. The coverage dependent evolution of the surface states was also investigated for the three molecules, giving evidence for a dilute-phase growth of the CuPc molecule on the Au(111) surface.

  14. Charge-transfer photodissociation of adsorbed molecules via electron image states

    CERN Document Server

    Jensen, E T

    2007-01-01

    The 248nm and 193nm photodissociation of submonolayer quantities of CH$_3$Br and CH$_3$I adsorbed on thin layers of n-hexane indicate that the dissociation is caused by dissociative electron attachment from sub-vacuum level photoelectrons created in the copper substrate. The characteristics of this photodissociation-- translation energy distributions and coverage dependences show that the dissociation is mediated by an image potential state which temporarily traps the photoelectrons near the n-hexane--vacuum interface, and then the charge transfers from this image state to the affinity level of a co-adsorbed halomethane which then dissociates.

  15. Molecule-solid interaction: Electronic states of anthracene-9-carboxylic acid adsorbed on the surface of TiO2

    International Nuclear Information System (INIS)

    Electronic excited states of athracene-9-carboxylic acid chemisorbed on the surface of TiO2 nanoparticles were investigated by means of the electroabsorption (Stark effect) spectroscopy at low temperature. In addition to a fraction of molecules adsorbed with no significant spectral changes, two forms absorbing at lowered energy (25,600 cm-1 and 24,900 cm-1) were observed, that exhibit a large increase in the excited-minus-ground state dipole moments, 2.7 D and 9.5 D, respectively, as well as changed molecular polarizabilities. The dipole moments are interpreted as indicators of partial charge-transfer character of the excited state, corresponding to the optical electron transfer from the adsorbate onto TiO2 concomitantly with the photon absorption. Consequences of these observations are shortly discussed in the context of the electron transfer process in dye-sensitized solar cells.

  16. Carbonization process and SiC formation at C60/Si(111) interface studied by SRPES

    International Nuclear Information System (INIS)

    Carbonization process and SiC formation upon annealing the Si(111) surface covered by C60 molecules with the thickness of 1.3 nm have been investigated by using synchrotron radiation photoelectron spectroscopy (SRPES), X-ray photoemission (XPS) and reflection high energy electron diffraction (RHEED) in NSRL. C60 molecules are chemisorbed on the Si(111) surface at room temperature, via Si-C60 hybridization to form covalent bonds, which can be explained by adsorption model including two adsorption configurations S3 and L With annealing the sample, the Si-C60 hybridization weakened C-C bonds internally in C60 molecules and enhanced the formation of SixC60, an intermediate species. Further annealing the sample to 650 deg. C will lead to the decomposition of C60 molecules, the released carbon fragment will bond with external silicon atoms to form SiC. While annealing the sample to 850 deg. C, decomposition of all C60 molecules was accomplished, and only a SiC film was left on the surface

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

    International Nuclear Information System (INIS)

    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 4He adsorbed on metallic films. In contrast to measurements of 4He adsorbed on all other insulating substrates, we have shown that 4He 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, 4He adsorbed on sapphire and on Ag films and H2 adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs

  18. 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.

  19. C60 as a probe for astrophysical environments

    CERN Document Server

    Brieva, Abel; Jaeger, Cornelia; Huisken, Friedrich; Henning, Thomas

    2016-01-01

    The C60 molecule has been recently detected in a wide range of astrophysical environments through its four active intramolecular vibrational modes (T1u) near 18.9 {\\mu}m, 17.4 {\\mu}m, 8.5 {\\mu}m, and 7.0 {\\mu}m. The strengths of the mid-infrared emission bands have been used to infer astrophysical conditions in the fullerene-rich regions. Widely varying values of the relative intrinsic strengths (RIS) of these four bands are reported in laboratory and theoretical papers, which impedes the derivation of the excitation mechanism of C60 in the astrophysical sources. The spectroscopic analysis of the C60 samples produced with our method delivers highly reproducible RIS values of 100, 25 +- 1, 26 +- 1 and 40 +- 4. A comparison of the inferred C60 emission band strengths with the astrophysical data shows that the observed strengths cannot be explained in terms of fluorescent or thermal emission alone. The large range in the observed 17.4 {\\mu}m/18.9 {\\mu}m emission ratios indicates that either the emission bands co...

  20. Dynamical fragmentation of C60 ions

    International Nuclear Information System (INIS)

    The distribution of fragments resulting from collisions between 50--200-keV C60+ ions and H2 and He is found to follow approximately a simple power law I(m)=cpm where p is a constant depending on both energy and target gas, and m is the number of missing ''pairs'' of carbon atoms. Based on this observation, a new dynamical fragmentation model involving the ratio of two characteristic times is proposed. In collisions by 300-keV C60++ ions, the singly charged products are distributed quite differently, which implies the first evidence of the presence of charge-separation reactions

  1. Luminescence of 2,5-bis(2-benzoxazolylhydroquinone Molecules Adsorbed on Copper Island Film

    Directory of Open Access Journals (Sweden)

    Chayka K.

    2005-12-01

    Full Text Available Characteristics of photoluminescence spectra of polycrystalline 2,5-bis(2-benzoxazolylhydroquinone (BBHQ adsorbed on a copper island film have been studied in the conditions of laser excitation. The reflectivity, transmission and luminescence spectra have been measured in the temperature range of 600 – 800 K for a number of film thicknesses and annealing conditions. It has been found that annealing of the films induces changes in the islands’ morphologies. The spectral luminescence characteristics have been compared with those peculiar for the BBHQ solution in 3-metylpentan, for the BBHQ samples adsorbed on pure plane-parallel quartz plates and for the samples contained in quartz glass cell. The results have been used for interpretation of the spectra and estimation of the average amplification factor and the characteristics of molecular excitons in the crystals under investigation.

  2. 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

    Inclusion complexes of benzo-and dithiabenzocrown ether functionalized monopyrrolotetrathiafulvalene (MPTTF) molecules were formed with Li+@C-60 (1 center dot Li+@C-60 and 2 center dot Li+@C-60). The strong complexation has been quantified by high binding constants that exceed 10(6) (-1)(M) obtai...

  3. Theoretical Study of the Ozonolysis of C60: Primary Ozonide Formation, Dissociation, and Multiple Ozone Additions

    OpenAIRE

    Chapleski, Robert C., Jr.; Morris, John R.; Troya, Diego

    2014-01-01

    We present an investigation of the reaction of ozone with C60 fullerene using electronic structure methods. Motivated by recent experiments of ozone exposure to a C60 film, we have characterized stationary points in the potential energy surface for the reactions of O3 with C60 that include both the formation of primary ozonide and subsequent dissociation reactions of this intermediate that lead to C_C bond cleavage. We have also investigated the addition of multiple O3 molecules to the C60 ca...

  4. STM/STS observation of ferrocene derivative adduct to C60 on HOPG

    International Nuclear Information System (INIS)

    The C60ONCFn cycloadduct (Fn=ferrocene) was prepared in the reaction between C60 and ferrocene oxime, the ferrocene derivative was bound to C60 at the 6-6 bond by a heterocyclic oxygen-nitrogen-carbon ring; the compound was stable in air. The compound dissolved in dichloroethane was deposited on HOPG and observed by UHV STM/STS methods. The molecules of C60ONCFn formed several-microns-long straight chains with clearly visible adducted groups pointing to one side of the chain. The STM/STS observations are discussed within the terms of semiempirical quantum chemical molecular modeling

  5. Charge transfer and formation of conducting C60 monolayers at C60/noble-metal interfaces

    Science.gov (United States)

    Nouchi, Ryo; Kanno, Ikuo

    2005-05-01

    The resistance of a conducting C60 monolayer formed on a polycrystalline Ag film was found to be 0.7±0.1kΩ by in situ resistance measurements. By another series of in situ resistance measurements, the surface scattering cross sections, whose magnitude represents the relative amount of transferred charge, were evaluated as 100Å2 for C60/Au, and 150Å2 for C60/Cu and C60/Ag systems. However, comparison with previous results obtained for monolayers formed on Au and Cu films showed that the resistances of conducting C60 monolayers do not show a simple dependence on the transferred charge. Atomic force microscopy measurements revealed that the grain size of the underlying noble metals also plays an important role.

  6. Electric-field-dependent empirical potentials for molecules and crystals: a first application to flexible water molecule adsorbed in zeolites

    OpenAIRE

    Cicu, P.; Demontis, Pierfranco; Spanu, Silvano; Suffritti, Giuseppe Baldovino; Tilocca, Antonio

    2000-01-01

    A general method to include electric-field-dependent terms in empirical potential functions representing interatomic interactions is proposed. It is applied to derive an intramolecular potential model for the water molecule able to reproduce the effects of an electric field on its geometry and dynamics: to enlarge the HOH angle, to increase slightly the OH bond lengths, to red-shift the stretching vibrational frequencies, and to blue-shift slightly the bending mode frequency. These effects ha...

  7. Tailorable acceptor ${\\rm C}_{60-n}{\\rm B}_{n}$ and donor ${\\rm C}_{60-m}{\\rm N}_{m}$ pairs for molecular electronics

    OpenAIRE

    Xie, Rui-Hua; Bryant, Garnett W.; Zhao, Jijun; Smith Jr, Vedene H.; Di Carlo, Aldo; Pecchia, Alessandro

    2003-01-01

    Our first-principles calculations demonstrate that ${\\rm C}_{60-n}{\\rm B}_{n}$ and ${\\rm C}_{60-m}{\\rm N}_{m}$ molecules can be engineered as the acceptors and donors, respectively, which are needed for molecular electronics, by properly controlling the number $n$ and $m$ of the substitutional dopants in ${\\rm C}_{60}$. As an example, we show that acceptor ${\\rm C}_{48}{\\rm B}_{12}$ and donor ${\\rm C}_{48}{\\rm N}_{12}$ are promising components for molecular rectifiers, carbon nanotube-based $...

  8. The metrics of surface adsorbed small molecules on the Young's fringe dual-slab waveguide interferometer

    International Nuclear Information System (INIS)

    A method for analysing thin films using a dual-waveguide interferometric technique is described. Alternate dual polarization addressing of the interferometer sensor using a ferroelectric liquid crystal polarization switch allowed the opto-geometrical properties (density and thickness) of adsorbed layers at a solid-liquid interface to be determined. Differences in the waveguide mode dispersion between the transverse electric and transverse magnetic modes allowed unique combinations of layer thickness and refractive index to be determined at all stages of the layer formation process. The technique has been verified by comparing the analysis of the surface adsorption of surfactants with data obtained using neutron scattering techniques, observing their behaviour on trimethylsilane coated silicon oxynitride surfaces. The data obtained were found to be in excellent agreement with analogous neutron scattering experiments and the precision of the measurements taken to be of the order of 40 pm with respect to adsorbed layer thicknesses. The study was extended to a series of surfactants whose layer morphology could be correlated with their hydrophilicity/lipophilicity balance. Those in the series with longer alkyl chains were observed to form thinner, denser layers at the hydrophobic solid/aqueous liquid interface and the degree of order attained at sub-critical micelle concentrations to be correlated with molecular fluidity. The technique is expected to find utility with those interested in thin film analysis. An important and growing area of application is within the life sciences, especially in the field of protein structure and function

  9. Adsorbed states of chlorophenol on Cu(110) and controlled switching of single-molecule junctions

    Science.gov (United States)

    Okuyama, H.; Kitaguchi, Y.; Hattori, T.; Ueda, Y.; Ferrer, N. G.; Hatta, S.; Aruga, T.

    2016-06-01

    A molecular junction of substituted benzene (chlorophenol) is fabricated and controlled by using a scanning tunneling microscope (STM). Prior to the junction formation, the bonding geometry of the molecule on the surface is characterized by STM and electron energy loss spectroscopy (EELS). EELS shows that the OH group of chlorophenol is dissociated on Cu(110) and that the molecule is bonded nearly flat to the surface via an O atom, with the Cl group intact. We demonstrate controlled contact of an STM tip to the "available" Cl group and lift-up of the molecule while it is anchored to the surface via an O atom. The asymmetric bonding motifs of the molecule to the electrodes allow for reversible control of the junction.

  10. A study on quantum mechanical approach for $C_{60}$ diffraction analysis

    OpenAIRE

    Wu, Xiang-Yao; Zhang, Bo-Jun; Liu, Xiao-Jing; Ba, Nuo; Wu, Yi-Heng; Tang, Hou-Li; Wang, Jing; Zhang, Si-Qi

    2011-01-01

    Diffraction phenomena of large molecules have been studied in many experiments, and these experiments are described by many theoretical works. In this paper, we study $C_{60}$ molecules single and double-slit diffraction with quantum theory approach, and we pay close attention to the $C_{60}$ diffraction experiment carried out by A.Zeilinger et.at in 1999. In double-slit diffraction, we consider the decoherence effect, and find the theoretical results are good agreement with experimental data.

  11. Structure of film compositions C60-Bi

    International Nuclear Information System (INIS)

    The structure of film compositions C60-Bi on fluorineflogopite substrates were investigated at the relation of density of fluxes of Bi atoms and C60 moleculas from 0 to 1 over the temperature range 400 - 500 K. The quality model of bismuth segregation in the composite films is studied. In our study fullerite and composite C60-Bi are considered as a model object (for the data on possible practical application of fullerite see, e.g. [1]). The special consideration in the study is given to the investigation of deposition conditions of perfect fullerite films on orienting substrates and to the processes of metal-fulleren composition formation in the absence of a chemical bond among the elements of the starting components. High-resolution electron microscopy (direct resolution of crystallographic planes, microdifraction) and X-ray diffractometry method (0 - 20) of scanning in Cu-Kα1 radiation) were used in the study to examine the structure of pure fullerite and fulleren-bismuth composite. The composite was formed at the thermal evaporation of the components from two Knudsen cells. The density of the flux of Bi atoms varied from 0 to 1 with respect to a cluster C60 flux. The quantity of the substance being evaporated was controlled with a quartz microbalance. The plane (001) of artificial mice - fluorineflogopite (ff) was chosen as substrates. The applying process was performed in the substrate holder temperature range Tn = 400 - 500 K in vacuum approx. 10-3 Pa condensed to be examined with electronic microscope PEM-U; X-ray study of the films approx. 500 nm thick was made with the help of a diffractometer DRON-3M. The microscope resolution was 0.2 nm and this was confirmed by direct resolution of (200) planes of atoms of thin monocrystalline films of gold. In the study we used the substrate holders with either constant temperature or temperature gradient held in the plane

  12. Mechanism of charge transfer and its impacts on Fermi-level pinning for gas molecules adsorbed on monolayer WS{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Changjie; Zhu, Huili, E-mail: hlzhu@jmu.edu.cn [Department of Physics, School of Science, Jimei University, Xiamen 361021 (China); Yang, Weihuang [Division of Physics and Applied Physics, School of Physical and Mathematical Science, Nanyang Technological University, Singapore 637371 (Singapore)

    2015-06-07

    Density functional theory calculations were performed to assess changes in the geometric and electronic structures of monolayer WS{sub 2} upon adsorption of various gas molecules (H{sub 2}, O{sub 2}, H{sub 2}O, NH{sub 3}, NO, NO{sub 2}, and CO). The most stable configuration of the adsorbed molecules, the adsorption energy, and the degree of charge transfer between adsorbate and substrate were determined. All evaluated molecules were physisorbed on monolayer WS{sub 2} with a low degree of charge transfer and accept charge from the monolayer, except for NH{sub 3}, which is a charge donor. Band structure calculations showed that the valence and conduction bands of monolayer WS{sub 2} are not significantly altered upon adsorption of H{sub 2}, H{sub 2}O, NH{sub 3}, and CO, whereas the lowest unoccupied molecular orbitals of O{sub 2}, NO, and NO{sub 2} are pinned around the Fermi-level when these molecules are adsorbed on monolayer WS{sub 2}. The phenomenon of Fermi-level pinning was discussed in light of the traditional and orbital mixing charge transfer theories. The impacts of the charge transfer mechanism on Fermi-level pinning were confirmed for the gas molecules adsorbed on monolayer WS{sub 2}. The proposed mechanism governing Fermi-level pinning is applicable to the systems of adsorbates on recently developed two-dimensional materials, such as graphene and transition metal dichalcogenides.

  13. Radioiodination of C60 derivative C60(OH)xOy

    International Nuclear Information System (INIS)

    Water-soluble fullerene derivative C60(OH)xOy was radioiodinated with the iodogen method. The labeling yield was determined by radio-TLC. The effects of pH value, reaction time, temperature and amount of the iodogen on the labeling yield were studied. The labeled product was purified by Sephadex G-25 column chromatography and then stability of 125I-C60(OH)xOy was examined. The results showed that the radiochemical purity of 125I-C60(OH)xOy solution with benzylalcohol remained 82.7% after 43 hours. (author)

  14. Electronic Structure of Crystalline Buckyballs: fcc-C60

    Science.gov (United States)

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

    2016-01-01

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

  15. C60-derived nanobaskets: stability, vibrational signatures, and molecular trapping.

    Science.gov (United States)

    dos Santos, S G; Pires, M S; Lemos, V; Freire, V N; Caetano, E W S; Galvão, D S; Sato, F; Albuquerque, E L

    2009-09-30

    C(60)-derived nanobaskets, with chemical formulae (symmetry point group) C(40)H(10) (C(5v)), C(39)H(12) (C(3v)), C(46)H(12) (C(2v)), were investigated. Molecular dynamic simulations (MDSs) indicate that the molecules preserve their bonding frame for temperatures up to 300 K (simulation time 100 ps), and maintain atomic cohesion for at least 4 ps at temperatures up to 3500 K. The infrared spectra of the C(60)-derived nanobaskets were simulated through density functional theory (DFT) calculations, allowing for the attribution of infrared signatures specific to each carbon nanobasket. The possibility of using C(60)-derived nanobaskets as molecular containers is demonstrated by performing a DFT study of their bonding to hydrogen, water, and L-alanine. The carbon nanostructures presented here show a higher bonding energy (approximately 1.0 eV), suggesting that a family of nanostructures, C(n)-derived (n = 60,70,76,80, etc) nanobaskets, could work as molecular containers, paving the way for future developments such as tunable traps for complex molecular systems. PMID:19724106

  16. CO molecular impurity influence on fullerite C60 structural and thermodynamical properties in a wide range of sorption temperatures

    International Nuclear Information System (INIS)

    The influence of CO sorption at pressure P = 30 atm in temperature range 150-600 C on fullerite C60 structural and thermodynamical properties re-searched by powder x-ray diffraction methods. Sorption kinetics investigated by construction of C60 lattice parameter dependences of CO molecules sorption time. At temperature T > 300C CO molecules dissociation detected, which accompanied by carbonic powder precipitation and chemical interaction of atomic oxygen with C60 molecules, with CO and, probably, with carbonic condensate. These processes have a strong in-fluence on fullerite C60 structural characteristics, that leads, particularly, to nonmonotonic lattice parameter and volume of matrix dependences from the impurity sorption temperature. At the physical sorption area a solid solutions concentrations established for C60(CO)x poly- and monocrystalline samples at two sorption regimes (150 and 250 C). The character of CO molecules influence on lattice parameter and orientational transition temperature of fullerite C60 defined to be linear.

  17. Preparation and surface enhanced Raman scattering behavior of Ag-coated C60 nanoclusters

    International Nuclear Information System (INIS)

    Ag-coated C60 nanoclusters were prepared and characterized with X-ray diffraction, transmission electron microscopy and nitrogen adsorption–desorption isotherm measurement. The Ag-coated C60 nanoclusters were assembled on the glass substrate to form a thin film using the layer-by-layer technique. Meanwhile, the surface enhanced Raman scattering (SERS) of musk xylene adsorbed on the film of Ag-coated C60 nanoclusters was explored. The results indicated that the film of Ag-coated C60 nanoclusters was a unique SERS-active substrate with a detection limit of 10−9 mol L−1 for musk xylene. Furthermore, the surface enhanced mechanisms were discussed preliminarily.

  18. Laser deposition, vibrational spectroscopy, NMR spectroscopy and STM imaging of C60 and C70

    International Nuclear Information System (INIS)

    The authors of this paper demonstrated that C60 and C70, as well as other fullerenes, can be deposited and accumulated on surfaces using laser ablation of graphite in an inert gas atmosphere. Indicating the presence of C60 in carbon soot, the authors showed that samples consisting exclusively of C60 and C70 can be sublimed from such soot. Vibrational Raman spectra of C60 and C70 were obtained from these samples. The C60 spectrum is consistent with the calculated spectrum of Buckminsterfullerene, and the strongest three lines can be assigned on the basis of frequency and polarization. The NMR spectrum of dissolved C60 was then obtained, and found to consist of a single resonance, establishing the Icosahedral symmetry of this molecule. STM images of the C60 molecules on a Au(111) crystal face show that these clusters form hexagonal arrays with an intercluster spacing of 11.0 Angstrom and are mobile at ambient temperature. Distinctly taller species evident in the arrays are believed to be C70 clusters. Vibrational Raman and infrared spectra have also been obtained for separated C60 and C70

  19. Some Features of Raman Scattering by Molecules Adsorbed on Metal Crystal Faces and a Fine Light Structure

    CERN Document Server

    Polubotko, A M

    2013-01-01

    The paper analyzes some experiments on Raman scattering by molecules adsorbed on the face (111) of silver monocrystals performed by A. Campion et al. From the existence of the forbidden line of benzene, the conclusion about existence of the surface field, caused by atomic structure of the surface is made. The relatively large intensity of this line allows to make a conclusion about large influence of the electromagnetic field spatial inhomogeneity in crystals on their optical properties. The difference between this field and a regular plane wave, which usually describes propagation of electromagnetic field in solids is named as a fine light structure. The influence of this structure on optical properties of solids is pointed out.

  20. Effects of non-local exchange on core level shifts for gas-phase and adsorbed molecules

    International Nuclear Information System (INIS)

    Density functional theory calculations are often used to interpret experimental shifts in core level binding energies. Calculations based on gradient-corrected (GC) exchange-correlation functionals are known to reproduce measured core level shifts (CLS) of isolated molecules and metal surfaces with reasonable accuracy. In the present study, we discuss a series of examples where the shifts calculated within a GC-functional significantly deviate from the experimental values, namely the CLS of C 1s in ethyl trifluoroacetate, Pd 3d in PdO and the O 1s shift for CO adsorbed on PdO(101). The deviations are traced to effects of the electronic self-interaction error with GC-functionals and substantially better agreements between calculated and measured CLS are obtained when a fraction of exact exchange is used in the exchange-correlation functional

  1. Density Functional Theory and Grand Canonical Monte Carlo Simulations of the Hydrogen Storage Properties of Partially Truncated and Open Cage C60 Fullerenes

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Dong; TANG Yong-Jian; CHENG Xin-Lu; ZHANG Hong

    2011-01-01

    The potential energies of H2 molecules with partially truncated and open cage C6o fullerenes,including Css,C55,C54(Ⅰ),C54(Ⅱ) and C46,are investigated by means of the density functional theory method.The energy barrier for one H2 molecule (with two postures) entering into the nanocage decreases from 435.59 (513.45)kcal/mol to 3.64 (-2.06) kcal/mol with the increase of the truncated pore.The grand canonical Monte Carlo simulations reveal that each nanocage can accommodate only one H2 molecule inside its cavity at both 77K and 298K.All the other H2 molecules are adsorbed round the truncated pores outside the nanocages.Exceptionally,the truncated C46 can store 2.28wt% H2 molecules at 77K.Therefore,the truncating part of the C60 molecule may be a novel idea to explore C60 fullerene as a hydrogen storage material.Hydrogen is one of the clean and renewable energy carriers used to replace traditional fossil fuels,which have caused great negative effects on the environment.However,the main obstacle for the wide use of hydrogen is its dense and safe storage.[1-3] One proposed method is to physisorbe molecular hydrogen on porous materials.[4-6] Some studies found that metal organic frameworks have the potential to satisfy the goal of gravimetric density of 6wt% hydrogen,[6-9]as set by the U.S.Department of Energy in 2010.However,it is unfortunate that the synthesis of these artificially designed frames is a tremendous obstacle.%The potential energies of H2 molecules with partially truncated and open cage C60 fullerenes, including C58, C55, C54(I), C54(I) and C46, are investigated by means of the density functional theory method. The energy barrier for one H2 molecule (with two postures) entering into the nanocage decreases from 435.59 (513.45) kcal/mol to 3.64 (-2.06) kcal/mol with the increase of the truncated pore. The grand canonical Monte Carlo simulations reveal that each nanocage can accommodate only one H2 molecule inside its cavity at both 77 K and 298 K. All

  2. Doubly-charged Negative Ion of C60 Molecule

    OpenAIRE

    Msezane, A. Z.; Baltenkov, A S

    2016-01-01

    Within the Dirac- and Lorentz-bubble potential models an electronic structure of the doubly-charged negative ion has been studied by a variational method. It is shown that even in the first approximation of this method when a trial wave function of the two electrons is represented as a product of one-electron functions the total energy of the system is negative, a manifestation of the existence of a stable state of the doubly-charged negative ion in these models. The second electron affinity ...

  3. Fullerene C60 in Aqueous Medium

    Czech Academy of Sciences Publication Activity Database

    Kocábová, Jana; Gál, Miroslav; Hromadová, Magdaléna; Kavan, Ladislav; Pospíšil, Lubomír; Sokolová, Romana

    Ústí nad Labem: BEST servis, 2010 - (Navrátil, T.; Barek, J.), s. 15-18 ISBN 978-80-254-6710-7. [Modern Electroanalytical Methods /30./. Jetřichovice (CZ), 24.05.2010-28.05.2010] R&D Projects: GA ČR GA203/09/0705; GA ČR GA203/08/1157; GA ČR GP203/09/P502; GA MŠk LC510; GA MŠk OC 140 Institutional research plan: CEZ:AV0Z40400503 Keywords : fullerene C60 * aqueous solution * electron transfer Subject RIV: CG - Electrochemistry

  4. Energy spectrum of C60 fullerene

    Science.gov (United States)

    Mironov, G. I.; Murzashev, A. I.

    2011-11-01

    The energy spectrum of the C60 fullerene has been calculated in terms of the Shubin-Vonsovskii-Hubbard model using an approximation of static fluctuations. Based on the spectrum, the optical absorption bands at 4.84, 5.88, and 6.30 eV observed experimentally have been successfully explained. It has been concluded that the model used is applicable for the calculation of the energy spectrum and the energy properties of other nanosystems, such as fullerenes of higher orders, carbon nanotubes, and grafen planes.

  5. 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 calculation...

  6. Random phase approximation with exchange for the photoionization of confined atoms: Xe in C_{60} fullerene

    CERN Document Server

    Chen, Zhifan

    2008-01-01

    Photoionization of a Xe atom confined inside C$_{60}$ has been studied using the random phase approximation with exchange (RPAE) method. The C$_{60}$ fullerene has been descr ibed by an attractive short range spherical well with potential $V(r)$, given by $V(r)=-V_ 0$ for $r_ir_0$ have been obtained by solving the Schr\\"{o}dinger equation using both regular and irregular solutions and the continuous boundary conditions at $r_i$ and $r_0$. The photoionization cross sections for the Xe 4d, $5s$ and $5p$ ele ctrons in the Xe@C$_{60}$ endohedral molecule have been evaluated and compared with those of the photoionization for the free Xe atom and other previo us calculations for the Xe@C$_{60}$ fullerene. Our method surmounted the weaknesses of the previous model potential calculation s and demonstrated significantly stronger correlated confinement resonances for the Xe@C$_{60}$ photoionization.

  7. The development of a range of C60 ion beam systems

    International Nuclear Information System (INIS)

    C60 ion beams are being used in a widening variety of analytical applications. The interaction of the C60 molecule with most sample surfaces differs markedly from that of an atomic ion beam, leading to elevated sputter yields and ion yields. A further important consequence of C60 bombardment is very low residual damage after sputtering of surface layers. We have developed a range of C60 ion beam systems for use in static SIMS, dynamic SIMS, SIMS imaging, including intracellular imaging of biological compounds, and in surface cleaning and depth profiling in electron spectroscopy. We describe the design criteria for the C60 range and illustrate the performance of these systems with recent applications data

  8. 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)-...

  9. 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...

  10. Identification of more interstellar C60+ bands

    CERN Document Server

    Walker, Gordon; Maier, John; Campbell, Ewen

    2015-01-01

    Based on gas-phase laboratory spectra at 6 K, Campbell et al. (2015) confirmed that the diffuse interstellar bands (DIBs) at 9632.7 and 9577.5A are due to absorption by the fullerene ion C60+. They also reported the detection of two other, weaker bands at 9428.5 and 9365.9A. These lie in spectral regions heavily contaminated by telluric water vapour lines. We acquired CFHT ESPaDOnS spectra of HD183143 close to the zenith and chopped with a nearby standard to correct for the telluric line absorption which enabled us to detect a DIB at 9365.9A of relative width and strength comparable to the laboratory absorption. There is a DIB of similar strength and FWHM at 9362.5A. A stellar emission feature at 9429A prevented detection of the 9428.5A band. However, a CFHT archival spectrum of HD169454, where emission is absent at 9429A, clearly shows the 9428.5A DIB with the expected strength and width. These results further confirm C60+ as a DIB carrier.

  11. Identification of More Interstellar C60+ Bands

    Science.gov (United States)

    Walker, G. A. H.; Bohlender, D. A.; Maier, J. P.; Campbell, E. K.

    2015-10-01

    Based on gas-phase laboratory spectra at 6 K, Campbell et al. confirmed that the diffuse interstellar bands (DIBs) at 9632.7 and 9577.5 Å are due to absorption by the fullerene ion {{{C}}}60+. They also reported the detection of two other, weaker bands at 9428.5 and 9365.9 Å. These lie in spectral regions heavily contaminated by telluric water vapor lines. We acquired CFHT ESPaDOnS spectra of HD 183143 close to the zenith and chopped with a nearby standard to correct for the telluric line absorption which enabled us to detect a DIB at 9365.9 Å of relative width and strength comparable to the laboratory absorption. There is a DIB of similar strength and FWHM at 9362.5 Å. A stellar emission feature at 9429 Å prevented detection of the 9428.5 Å band. However, a CFHT archival spectrum of HD 169454, where emission is absent at 9429 Å, clearly shows the 9428.5 Å DIB with the expected strength and width. These results further confirm {{{C}}}60+ as a DIB carrier. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  12. Switching orientation of adsorbed molecules: Reverse domino on a metal surface

    Science.gov (United States)

    Braatz, C. R.; Esat, T.; Wagner, C.; Temirov, R.; Tautz, F. S.; Jakob, P.

    2016-01-01

    A thus far unknown phase of 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) on Ag(111), characterized by an all perpendicular orientation of the planar molecules and bound to the Ag substrate through the carboxyl oxygen atoms has been identified using infrared absorption spectroscopy and scanning tunneling microscopy. Its formation process requires second layer NTCDA to squeeze into empty spaces between relaxed monolayer NTCDA molecules. Remarkably, this process causes initially parallel oriented NTCDA to likewise adopt the new, highly inclined adsorption geometry. According to our SPA-LEED and STM findings, the new phase displays a distinct long range order and shows a pronounced tendency to form 1D rows or narrow islands. We suggest that extra NTCDA preferentially transforms into the upright configuration close to existing islands and attaches to them, i.e. the transformation process proceeds in a directed and recurrent manner (reverse domino scenario). Identical processing starting with a compressed NTCDA/Ag(111) monolayer leads to a purely parallel oriented bilayer, that is, the NTCDA monolayer phase is retained and merely acts as a passive template for bilayer NTCDA. The new vertical NTCDA phase represents an unusual molecular system with π-orbitals oriented parallel to a metal surface. A substantially reduced coupling of these orbitals to Ag(111) electronic levels is conjectured, which will have a major impact on intermolecular couplings and electronically excited state lifetimes.

  13. Tribochemical synthesis of nano-lubricant films from adsorbed molecules at sliding solid interface: Tribo-polymers from α-pinene, pinane, and n-decane

    Science.gov (United States)

    He, Xin; Barthel, Anthony J.; Kim, Seong H.

    2016-06-01

    The mechanochemical reactions of adsorbed molecules at sliding interfaces were studied for α-pinene (C10H16), pinane (C10H18), and n-decane (C10H22) on a stainless steel substrate surface. During vapor phase lubrication, molecules adsorbed at the sliding interface could be activated by mechanical shear. Under the equilibrium adsorption condition of these molecules, the friction coefficient of sliding steel surfaces was about 0.2 and a polymeric film was tribochemically produced. The synthesis yield of α-pinene tribo-polymers was about twice as much as pinane tribo-polymers. In contrast to these strained bicyclic hydrocarbons, n-decane showed much weaker activity for tribo-polymerization at the same mechanical shear condition. These results suggested that the mechanical shear at tribological interfaces could induce the opening of the strained ring structure of α-pinene and pinane, which leads to polymerization of adsorbed molecules at the sliding track. On a stainless steel surface, such polymerization reactions of adsorbed molecules do not occur under typical surface reaction conditions. The mechanical properties and boundary lubrication efficiency of the produced tribo-polymer films are discussed.

  14. Two-dimensional van der Waals C60 molecular crystal

    Science.gov (United States)

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

    2015-07-01

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

  15. DFT study of hydrogen storage in Pd-decorated C60 fullerene

    Science.gov (United States)

    El Mahdy, A. M.

    2015-11-01

    Hydrogen storage reactions on Pd-doped C60 fullerene are investigated by using the state-of-the-art density functional theory calculations. The Pd atom prefers to bind at the bridge site between two hexagonal rings, and can bind up to four hydrogen molecules with average adsorption energies of 0.61, 0.45, 0.32, and 0.21 eV per hydrogen molecule. With no metal clustering, the system gravimetric capacities are expected to be as large as 5.8 wt%. While the desorption activation barriers of the complexes nH2 + Pd-C60 with n = 1 are outside the department of energy (DOE) domain (-0.2 to -0.6 eV), the desorption activation barriers of the complexes nH2 + Pd-C60 with n = 2-4 are inside this domain. While the interaction of 1H2 with Pd + C60 is irreversible at 459 K, the interaction of 2H2 with Pd + C60 is reversible at 529 K. The hydrogen storage of the irreversible 1H2 + Pd-C60 and reversible 2H2 + Pd-C60 interactions are characterised in terms of densities of states, infrared, Raman, and proton magnetic resonance spectra, electrophilicity, and statistical thermodynamic stability.

  16. Modulation of nanocavity plasmonic emission by local molecular states of C60 on Au(111).

    Science.gov (United States)

    Geng, Feng; Zhang, Yang; Yu, Yunjie; Kuang, Yanmin; Liao, Yuan; Dong, Zhenchao; Hou, Jianguo

    2012-11-19

    We investigate the modulation of C60 monolayers on the nanocavity plasmonic (NCP) emission on Au(111) by tunneling electron excitation from a scanning tunneling microscope (STM) tip. STM induced luminescence spectra show not only suppressed emission, but also significant redshift of NCP emission bands on the C60 molecules relative to the bare metal surface. The redshift, together with the bias- and coverage-dependent emission feature, indicates that the C60 molecules act beyond a pure dielectric spacer, their electronic states are heavily involved in the inelastic tunneling process for plasmonic emission. A modified quantum cutoff relation is proposed to explain qualitatively the observed emission feature at both bias polarities. We also demonstrate molecularly resolved optical contrast on the C60 monolayer and discuss the contrast mechanism briefly. PMID:23187525

  17. Environmental effects on electron spin relaxation in N@C60

    CERN Document Server

    Morton, J J L; Ardavan, A; Porfyrakis, K; Lyon, S A; Briggs, G A D; Morton, John J. L.; Tyryshkin, Alexei M.; Ardavan, Arzhang; Porfyrakis, Kyriakos

    2006-01-01

    We examine environmental effects of surrounding nuclear spins on the electron spin relaxation of the N@C60 molecule (which consists of a nitrogen atom at the centre of a fullerene cage). Using dilute solutions of N@C60 in regular and deuterated toluene, we observe and model the effect of translational diffusion of nuclear spins of the solvent molecules on the N@C60 electron spin relaxation times. We also study spin relaxation in frozen solutions of N@C60 in CS2, to which small quantities of a glassing agent, S2Cl2 are added. At low temperatures, spin relaxation is caused by spectral diffusion of surrounding nuclear (35,37)Cl spins in the S2Cl2, but nevertheless, at 20 K, T2 times as long as 0.23 ms are observed

  18. A Relative Study on Two-photon Absorption Properties of C60 and C70

    Institute of Scientific and Technical Information of China (English)

    ZHOU,Xin(周新); REN,Ai-Min(任爱民); FENG,Ji-Kang(封继康); LIU,Xiao-Juan(刘孝娟)

    2004-01-01

    We have theoretically investigated the one- and two-photon absorption properties of C60 and C70 using the ZINDO method. From the results it is suggested that the one-photon absorption spectra are in agreement with the experimental observations. It is found that the maximum TPA cross section of C70 is more than twice that of C60,which is consistent with the experimental results. A notable point is that the TPA process of C60 is different from that of C70 as well as other ordinary conjugated molecules.

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

    International Nuclear Information System (INIS)

    The ability of scanning tunneling microscopy to manipulate selected C60 molecules within close packed C60 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 C60 molecule (i.e., vacancy formation) and shifting of the C60 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 C60 knockout has been found to be to ensure a proper ‘impact parameter’ (deviation from central impact on the C60 sphere by the tip apex), which should be less than ∼1.5 Å. A certain difference has been detected for the manipulation of C60 in extended molecular arrays and molecular islands of a limited size. While it is possible to manipulate a single C60 molecule in an array, in the case of a C60 island it appears difficult to manipulate a given fullerene without affecting the other ones constituting the island. (paper)

  20. Pentaethylenehexamine-C60 for Temperature Consistent Carbon Capture

    OpenAIRE

    Fabiano, Thales; Soares, Vanessa; Andreoli, Enrico

    2015-01-01

    Fullerene C60 is directly added to and reacted with plain pentaethylenehexamine (PEHA) to give PEHA-functionalized C60 powders. The CO2 capture performance of PEHA-C60 appears to be consistent across a range of temperatures wider than that of polyethyleneimine (PEI)-modified C60, whose high CO2 capture performance drops rapidly with decreasing temperature. At about 30 °C, the CO2 capture capacity of PEHA-C60 is six times higher, 65 mg CO2/g sorbent, than that of PEI-C60, 10 mg/g. In contrast ...

  1. Photon-exposure-dependent photon-stimulated desorption for obtaining photolysis cross section of molecules adsorbed on surface by monochromatic soft x-ray photons

    International Nuclear Information System (INIS)

    Photon-exposure-dependent positive- and negative-ion photon-stimulated desorption (PSD) was proposed to study the photoreactions and obtain the photolysis cross sections of molecules adsorbed on a single-crystal surface by monochromatic soft x-ray photons with energy near the core level of adsorbate. The changes in the F+ and F- PSD ion yields were measured from CF3Cl molecules adsorbed on Si(111)-7x7 at 30 K (CF3Cl dose=0.3x1015 molecules/cm2, ∼0.75 monolayer) during irradiation of monochromatic soft x-ray photons near the F(1s) edge. The PSD ion yield data show the following characteristics: (a) The dissociation of adsorbed CF3Cl molecules is due to a combination of direct photodissociation via excitation of F(1s) core level and substrate-mediated dissociation [dissociative attachment and dipolar dissociation induced by the photoelectrons emitting from the silicon substrate]. (b) the F+ ion desorption is associated with the bond breaking of the surface CF3Cl, CF2Cl, CFCl, and SiF species. (c) the F- yield is mainly due to DA and DD of the adsorbed CF3Cl molecules. (d) The surface SiF is formed by reaction of the surface Si atom with the neutral fluorine atom, F+, or F- ion produced by scission of C-F bond of CF3Cl, CF2Cl, or CFCl species. A kinetic model was proposed for the explanation of the photolysis of this submonolayer CF3Cl-covered surface. Based on this model and the variation rates of the F+/F- signals during fixed-energy monochromatic photon bombardment at 690.2 and 692.6 eV[near the F(1s) edge], the photolysis cross section was deduced as a function of energy.

  2. 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 strain/d

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

    NARCIS (Netherlands)

    Blank, V.D.; Buga, S.G.; Kulbachinskii, V.A.; Kytin, V.G.; Medvedev, V.V.; 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 red

  4. Modification of the electronic properties of Au/molecule/Pd junctions by adsorbed hydrogen: a DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Kucera, Jan; Gross, Axel [Institut fuer Theoretische Chemie, Universitaet Ulm, D-89069 Ulm (Germany)

    2011-07-01

    Metal-molecule-metal contacts assembled from a Pd monolayer deposited on a Au-supported self-assembled monolayer (SAM) of 4-mercaptopyridine or 4-aminothiophenol were recently achieved by means of an electrochemical approach. Subsequent photoelectron spectroscopy showed a strongly reduced Pd density of states (DOS) at the Fermi energy. This phenomenon is still not fully comprehended, however, its understanding is crucial for the use of the sandwich design as a platform for future nanoelectronics. Periodic density functional theory (DFT) calculation revealed that the dehydrogenation of the amino group and the subsequent strong bonding of the remaining nitrogen atom to the Pd layer could explain the observed modification of the DOS. We have now extended this study in order to clarify the role of hydrogen atoms for the electronic properties of the Pd layers. In equilibrium, these layers should always show a considerable hydrogen coverage in an aqueous environment. Our calculations demonstrate that indeed the adsorbed hydrogen atoms significantly modify the electronic structure of the Pd layers.

  5. Aqueous solubilization of C60 fullerene by natural protein surfactants, latherin and ranaspumin-2.

    Science.gov (United States)

    Vance, Steven J; Desai, Vibhuti; Smith, Brian O; Kennedy, Malcolm W; Cooper, Alan

    2016-01-01

    C60 fullerene is not soluble in water and dispersion usually requires organic solvents, sonication or vigorous mechanical mixing. However, we show here that mixing of pristine C60 in water with natural surfactant proteins latherin and ranaspumin-2 (Rsn-2) at low concentrations yields stable aqueous dispersions with spectroscopic properties similar to those previously obtained by more vigorous methods. Particle sizes are significantly smaller than those achieved by mechanical dispersion alone, and concentrations are compatible with clusters approximating 1:1 protein:C60 stoichiometry. These proteins can also be adsorbed onto more intractable carbon nanotubes. This promises to be a convenient way to interface a range of hydrophobic nanoparticles and related materials with biological macromolecules, with potential to exploit the versatility of recombinant protein engineering in the development of nano-bio interface devices. It also has potential consequences for toxicological aspects of these and similar nanoparticles. PMID:27214760

  6. USING OF C60 FULLERENE COMPLEXES WITH ANTITUMOR DRUGS IN CHEMOTHERAPY

    Directory of Open Access Journals (Sweden)

    S. V. Prylutska

    2014-06-01

    Full Text Available The literature data and own research results concerning antitumor effect in vitro and in vivo of C60 fullerene and its derivatives, cytostatics, and conjugated systems on their basis, which enable the practical application of C60 in combined chemotherapy for treatment efficacy improving of malignant tumors are generalized. The mechanism of antitumor action of C60 fullerene in combined treatment with cytostatics is based on antioxidant properties of its molecule, thereby reducing toxic side effects of traditional drugs in a body and ability to their transport purposefully into the target cells. The unique structure of C60 enables to modify its surface with chemotherapeutic drugs. Under combined action of the "fullerene C60-chemotherapy drug" conjugate the anti-tumor effects enhancement is observed both in vitro and in vivo, namely quantity reduction of viable tumor cells, tumor reduction etc. Furthermore, protective effects of fullerene C60 and derivatives relatively toxic effects of chemotherapeutic agents in a body were observed. Conjugate auxesis empowers it to be kept longer in a cell and prolong the duration of drug action. Ability of fullerene C60 to selective accumulation provides its using for target drug delivery.

  7. C60 fragmentation in charge-changing collisions with slow Au+ ions

    International Nuclear Information System (INIS)

    We investigated ionization and fragmentation of C60 in the charge-changing collisions of 2.0 keV/amu Au+ ions with C60 molecules. We performed simultaneous measurements of product ions, the number of secondary electrons, and a charge-selected outgoing Au projectile. The production of C60+ ions was predominant in the single-electron capture (1-capture) process. In contrast, multifragmentation of C60 was predominant in the single-electron loss (1-loss) process. The multifragmentation was enhanced in the 1-loss process compared with the 1-capture process when the same number of electrons was emitted from C60. This enhancement was also observed when a fast Si ion traveled close to a carbon nucleus [T. Majima et al., Phys. Rev. A 74, 033201 (2006)]. The 1-loss process of slow Au+ ions is considered to occur closer to a carbon nucleus than does the 1-capture process. Multifragmentation of C60 is caused by internal electronic excitation although it is probably assisted by nuclear stopping when, at least, the electronic excitation of C60 is small.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-19

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

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

    Science.gov (United States)

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

    2016-05-19

    The efficiency of thin-film organic photovoltaic (OPV) devices relies heavily upon the transport of excitons to type-II heterojunction interfaces, where there is sufficient driving force for exciton dissociation and ultimately the formation of charge carriers. Semiconducting single-walled carbon nanotubes (SWCNTs) are strong near-infrared absorbers that form type-II heterojunctions with fullerenes such as C60. Although the efficiencies of SWCNT-fullerene OPV devices have climbed over the past few years, questions remain regarding the fundamental factors that currently limit their performance. In this study, we determine the exciton diffusion length in the C60 layer of SWCNT-C60 bilayer active layers using femtosecond transient absorption measurements. We demonstrate that hole transfer from photoexcited C60 molecules to SWCNTs can be tracked by the growth of narrow spectroscopic signatures of holes in the SWCNT "reporter layer". In bilayers with thick C60 layers, the SWCNT charge-related signatures display a slow rise over hundreds of picoseconds, reflecting exciton diffusion through the C60 layer to the interface. A model based on exciton diffusion with a Beer-Lambert excitation profile, as well as Monte Carlo simulations, gives the best fit to the data as a function of C60 layer thickness using an exciton diffusion length of approximately 5 nm. PMID:27127916

  10. Electron conductive three-dimensional polymer of cuboidal C60

    OpenAIRE

    Yamanaka, Shoji; Kubo, Akira; Inumaru, Kei; Komaguchi, Kenji; Kini, N. S.; Inoue, Toru; Irifune, Tetsuo

    2006-01-01

    Single crystals of three-dimensional (3D) C60 polymer were prepared by the topotactic conversion of two-dimensional (2D) C60 polymer single crystals at a pressure of 15 GPa at 600°C. The x-ray single crystal study revealed that the 3D C60 polymer crystallized in a body centered orthorhombic space group Immm, and spherical C60 monomer units were substantially deformed to rectangular parallelepiped (cuboidal) shapes, each unit being bonded to eight cuboidal C60 neighbors via [3+3] cycloaddition...

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

    Science.gov (United States)

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

  12. Investigation of tribological properties of composite C60-LB films

    Institute of Scientific and Technical Information of China (English)

    YANG Guanghong; ZHANG Xingtang; XUN Jun; JIANG Xiaohong; ZHANG Pingyu; DU Zuliang

    2006-01-01

    Composite C60-LB films were fabricated by the Langmuir-Blodgett (LB) technique, their micro- structures, micro- and macro-tribological properties were investigated using atomic force microscope/ friction force microscope (AFM/FFM). The results showed that in the confined C60-LB films there were two kinds of structures for the special C60 assembly: grain diameters of one kind were in the range of 150-230 nm; the other was smaller than 20 nm. Mi-cro-tribological studies showed that topographical images of tiny C60 aggregates (<20 nm) were con-sistent with their frictional ones very well, namely, low friction occurred on tiny C60 aggregates compared with fatty chains LB monolayer, and 'Micro-rolling effect' was apparent; but for big large ones frictional forces were relatively high and 'ratchet mechanism' was seen apparently. Macro-tribological data proved large C60 aggregates had wear resistance and load-carrying capacities and anti-wear lives for com- posite C60-LB films were prolonged greatly with dis-persibility of C60 improved and its grain diameter re-duced. Tiny C60 aggregates were mainly the lubricating agents. Friction coefficients of composite C60-LB films gradually reduced with loads increasing having the same friction coefficient-load relations with boundary lubrication films.

  13. Carbon Nanotubes Investigated by N@C60 and N@C70 Spin Probes

    Science.gov (United States)

    Corzilius, B.; Gembus, A.; Dinse, K.-P.; Simon, F.; Kuzmany, H.

    2005-09-01

    Nitrogen atoms encapsulated in C60 can be used to detect small deviations from spherical symmetry via deformation-induced non-vanishing Zero-Field-Splitting (ZFS). In this context, experiments were performed by using these electronic quartet spin probes to investigate single wall carbon nanotubes. Time-fluctuating ZFS interaction would be indicative for rotational and/or translational degrees of freedom. Using pulsed EPR techniques, spin relaxation rates of N@C60 and also of N@C70 molecules with inherent static ZFS were measured. The analysis of their temperature dependence gave information about the dynamics of N@C60 and N@C70 molecules confined to the inside of the tubes.

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

    International Nuclear Information System (INIS)

    Auger and electron energy loss spectra obtained when probing the surface of nanofiber carbon material by an electron beam point out to C60 football-type of covers with the outlet to the surface of nanopipe carbon molecules

  15. Synthesis and separation of fullerenes C60/C70

    International Nuclear Information System (INIS)

    C60/C70 was synthesized by vaporizing graphite rods. It was extracted from soot with benzene or toluene. After slowly evaporating the solution, a brown or black solid material was left. The yield was 9%. Mass spectroscopy shows that it contains mainly C60 and small amount of C70. In transmitted light the crystals appear red-brown in color and have some kinds of crystallitic forms. The mixture of C60/C70 was subjected to column chromatography using neutral alumina or graphite. Column chromatography on neutral alumina with n-hexane as eluant gave satisfactory separation in milligram quantities. Pure factions containing C60 (>99%) were obtained. Column chromatography on graphite with n-hexane-toluene as eluant gave an excellent separation in more than 100 milligram quantities. Pure fractions containing C60 (>99%) were obtained quickly. The result showed that improved column chromatography on graphite is a simple and effective separation method to obtain the pure C60

  16. Continuous-time core-level photon-stimulated desorption spectroscopy for monitoring soft x-ray-induced reactions of molecules adsorbed on a single-crystal surface

    International Nuclear Information System (INIS)

    Continuous-time core-level photon-stimulated desorption (PSD) spectroscopy was proposed for monitoring the soft x-ray-induced reactions of molecules adsorbed on a single-crystal surface. Monochromatic synchrotron radiation was used as a soft x-ray light source in the photon-induced reactions of CF3Cl adsorbed on a Si(111)-7x7 surface at 30 K and also as a probe for studying the produced fluorination states of the bonding surface Si atom in the positive-ion PSD spectroscopy. The F+ PSD spectrum was obtained by monitoring the F+ signal as a function of incident photon energy near the Si(2p) edge (98-110 eV). Sequential F+ PSD spectra were measured as a function of photon exposure at four adsorbate coverages (the first dose=0.3x1015 molecules/cm2, the second dose=0.8x1015 molecules/cm2, the third dose=2.2x1015 molecules/cm2, and the fourth dose=3.2x1015 molecules/cm2). For the first and second CF3Cl-dosed surfaces, the sequential F+ PSD spectra show the variation of their shapes with photon exposure and indicate the formation of surface SiF species. The sequential F+ PSD spectra for the third and fourth CF3Cl-dosed surfaces also show the variation of their shapes with photon exposure and depict the production of surface SiF and SiF3 species

  17. Using water-soluble C60 fullerenes in anticancer therapy

    OpenAIRE

    Prylutska, S. V.; Burlaka, A. P.; Klymenko, P. P.; Grynyuk, I. I.; Prylutskyy, Yu I.; Schütze, Ch.; Ritter, U.

    2011-01-01

    Growth experiments of transplanted malignant tumors in the presence of water-soluble C60 fullerenes were performed on groups of mice. It was found that C60 fullerenes efficiently inhibit the growth of transplanted malignant tumors. This behavior can be explained through their high antioxidant activity and the blocking of the specific cell receptors (for example, endothelial growth factor). The findings demonstrate the possibility of using C60 fullerenes in anticancer therapy.

  18. Low energy Fe+ beam irradiation to C60 thin film

    International Nuclear Information System (INIS)

    We have developed an electron cyclotron resonance ion source apparatus, which is designed for the production of endohedral fullerene. In this study, we irradiated the Fe+ beam to the C60 thin film. We changed the experimental condition of the dose and the ion energy. We could observe the Fe + C60 peak by analysis of the time-of-flight mass spectrometry. The highest intensity of the Fe + C60 peak was observed at the ion energy of 200 eV. The Fe + C60 peak intensity tended to become high in the case of long irradiation time and large dose.

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

    International Nuclear Information System (INIS)

    The impact of alkali-metal (Li/Na/Cs) adsorption on work function of fullerenes C60 and C70 was investigated by first-principles calculations. After adsorption, the work functions of fullerenes C60 and C70 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 C60 and C70. 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 C60 and C70.

  20. C60 chain phases on ZnPc/Ag(111) surfaces: Supramolecular organization driven by competing interactions.

    Science.gov (United States)

    Jin, W; Liu, Q; Dougherty, D B; Cullen, W G; Reutt-Robey, J E; Weeks, J; Robey, S W

    2015-03-14

    Serpentine chain C60 phases were observed in scanning tunneling microscopy (STM) images of C60 layers on zinc phthalocyanine (ZnPc) or pentacene covered Ag(111) and Au(111) surfaces. This low-density, quasi-one-dimensional organization contrasts starkly with the close-packed hexagonal phases observed for C60 layers on bare metal substrates. STM was employed to perform a detailed investigation of these chain structures for C60/ZnPc/Ag(111) heterolayers. Motivated by the similarity of these chain phases, and the chain and stripe organization occurring in dipole-fluid systems, we investigated a model based on competing van der Waals attractions and electrostatic repulsions between C60 molecules as an explanation for the driving force behind these monolayer phases. Density functional theory (DFT) calculations revealed significant charge transfer to C60 from the Ag(111) substrate, through the intervening ZnPc layer, inducing electrostatic interactions between C60 molecules. Molecular dynamics simulations performed with attractive van der Waals interactions plus repulsive dipole-dipole interactions reproduced the C60 chain phases with dipole magnitudes consistent with DFT calculations. PMID:25770499

  1. Resonant electron heating and molecular phonon cooling in single C$_{60}$ junctions

    OpenAIRE

    SCHULZE, G.; Franke, K. J.; Gagliardi, A.; ROMANO, G; Lin, C S; Da Rosa, A.; Niehaus, T. A.; Frauenheim, Th.; A. Di Carlo; Pecchia, A; Pascual, J. I.

    2008-01-01

    We study heating and heat dissipation of a single \\c60 molecule in the junction of a scanning tunneling microscope (STM) by measuring the electron current required to thermally decompose the fullerene cage. The power for decomposition varies with electron energy and reflects the molecular resonance structure. When the STM tip contacts the fullerene the molecule can sustain much larger currents. Transport simulations explain these effects by molecular heating due to resonant electron-phonon co...

  2. Electron spin resonance study of Rb xC 60 and K xC 60 powders

    Science.gov (United States)

    Feng, S. Q.; Jia, Y. Q.; Zhu, S. L.; Fu, J. S.; Wu, E.; Mao, J. C.; Han, R. S.; Gu, Z. N.; Zhou, X. H.; Jin, Z. X.

    1993-11-01

    Rb and K doped C 60 compounds are prepared by the vapor-solid reaction method. Superconductive shielding fraction is determined as 35-75% for Rb xC 60 and 10% for K xC 60. Electron spin resonance (ESR) measurements in absorption mode are performed in the temperature range of 5-300 K. A strong ESR signal at g=2.002 for Rb xC 60 and g=2.003 for K xC 60 has been observed. The g-value is nearly independent upon temperature for both Rb xC 60 and K xC 60 while the linewidth behaves differently, increasing from 2.0 G at 5 K to 6.0 G at 250 K in Rb xC 60 and remaining constant of 2.3 G in K xC 60. No drastic change of the ESR spectra is observed with the onset of superconductivity, leading to a conclusion that the observed dominant ESR signal originates from a non-superconducting phase.

  3. C60 molecular dynamics studied by muon spin relaxation

    International Nuclear Information System (INIS)

    In muonium-substituted organic radicals, the muon spin can serve as a probe of molecular dynamics. The motional perturbation induces transitions between the coupled spin states of muon and unpaired electron. Studies of the resultant muon spin relaxation in C60Mu, the species formed by muon implantation in solid C60, yield the correlation time characteristic of the reorientational motion

  4. Electronic Structure of Superconducting Ba6c60

    OpenAIRE

    Erwin, Steven C.; Pederson, Mark R

    1993-01-01

    We report the results of first-principles electronic-structure calculations for superconducting Ba6C60. Unlike the A3C60 superconductors, this new compound shows strong Ba-C hybridization in the valence and conduction regions, mixed covalent/ionic bonding character, partial charge transfer, and insulating zero-gap band structure.

  5. Synthesis of novel organo-phosphorus C60 dimers

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Carbon bridged organophosphorus C60 dimers were obtained by the reaction of aminome- thylenebisphosphonate anion with C60 and fully characterized by 1HNMR, 31PNMR, 13CNMR, FT- MALDI-MS, FT-IR, UV-Vis, DEPT and HMBC, and the dimeric compounds undergo hydrolysis by using TMSI.

  6. Measuring phase transition temperature of fragmented C60

    International Nuclear Information System (INIS)

    A molecular thermometer based on the momentum distributions of the ionic fragments has been founded. The excitation temperature of fragmented C60 was determined using the novel thermometer. The results provide a clear evidence that a first-order phase transition in the hot C60 is occurring at the temperature around 6050K ± 250K.

  7. Sputtering of thin benzene and polystyrene overlayers by keV Ga and C60 bombardment

    International Nuclear Information System (INIS)

    The mechanisms of ion-stimulated desorption of thin organic overlayers deposited on metal substrates by mono- and polyatomic projectiles are examined using molecular dynamics (MD) computer simulations. A monolayer of polystyrene tetramers (PS4) physisorbed on Ag{1 1 1} is irradiated by 15 keV Ga and C60 projectiles at normal incidence. The results are compared with the data obtained for a benzene overlayer to investigate the differences in sputtering mechanisms of weakly and strongly bound organic molecules. The results indicate that the sputtering yield decreases with the increase of the binding energy and the average kinetic energy of parent molecules is shifted toward higher kinetic energy. Although the total sputtering yield of organic material is larger for 15 keV C60, the impact of this projectile leads to a significant fragmentation of ejected species. As a result, the yield of the intact molecules is comparable for C60 and Ga projectiles. Our data indicate that chemical analysis of the very thin organic films performed by detection of sputtered neutrals will not benefit from the use of C60 projectiles

  8. Fullerene C60 as a multifunctional system for drug and gene delivery

    Science.gov (United States)

    Montellano, Alejandro; da Ros, Tatiana; Bianco, Alberto; Prato, Maurizio

    2011-10-01

    The fullerene family, and especially C60, has delighted the scientific community during the last 25 years with perspective applications in a wide variety of fields, including the biological and the biomedical domains. Several biomedical uses have been explored using water-soluble C60-derivatives. However, the employment of fullerenes for drug delivery is still at an early stage of development. The design and synthesis of multifunctionalized and multimodal C60 systems able to cross the cell membranes and efficiently deliver active molecules is an attracting challenge that involves multidisciplinary strategies. Promising results have emerged in the last years, bringing fullerenes again to the front of interest. Herein, the state of the art of this emerging field is presented and illustrated with some of the most representative examples.

  9. Axis-dependent magnetic behavior of C60 and C60(10+). consequences of spherical aromatic character.

    Science.gov (United States)

    Muñoz-Castro, A

    2015-06-28

    The magnetic response of C60 has been studied and compared to its spherical aromatic counterpart C60(10+), focusing on the overall and local shielding tensors. A high axis dependence behavior at the outside region of the structure is characterized, unravelling a characteristic pattern of the local chemical shift anisotropy as a consequence of the spherical aromatic behavior. PMID:26022142

  10. Relative Photoionization Cross Sections of Super-Atom Molecular Orbitals (SAMOs) in C60.

    Science.gov (United States)

    Bohl, Elvira; Sokół, Katarzyna P; Mignolet, Benoit; Thompson, James O F; Johansson, J Olof; Remacle, Francoise; Campbell, Eleanor E B

    2015-11-25

    The electronic structure and photoinduced dynamics of fullerenes, especially C60, is of great interest because these molecules are model systems for more complex molecules and nanomaterials. In this work we have used Rydberg Fingerprint Spectroscopy to determine the relative ionization intensities from excited SAMO (Rydberg-like) states in C60 as a function of laser wavelength. The relative ionization intensities are then compared to the ratio of the photoionization widths of the Rydberg-like states, computed in time-dependent density functional theory (TD-DFT). The agreement is remarkably good when the same photon order is required to energetically access the excited states. This illustrates the predictive potential of quantum chemistry for studying photoionization of large, complex molecules as well as confirming the assumption that is often made concerning the multiphoton excitation and rapid energy redistribution in the fullerenes. PMID:26551039

  11. Synthesis and properties of polydiphenylsilane/fullerene C60 nanocomposites

    International Nuclear Information System (INIS)

    The efficiency of bulk heterojunction solar cells based on polysilane/C60 nanocomposites could be improved by delaying the radiative recombination of the charge carriers using aromatic side groups as mediators. This paper presents a study of such nanocomposites prepared with a soluble polydiphenylsilane, a polymer that contains a high number of phenyl groups attached to the main chain. Synthesis of this polysilane is challenging and was done by microwave-assisted Wurtz coupling of diphenyldichlorosilanes in the presence of low amounts of methyldichlorosilane. The nanocomposites were obtained in solution by mixing the polymer with C60 of various concentrations. The UV–vis profile shows formation of the intermolecular charge transfer complex between polysilane and C60 which acts as a dopant. Photoluminescence experiments at different concentrations of C60 revealed details concerning the emission from charge transfer states at the interface. Thin films of polysilane/C60 nanocomposites were casted from solutions and studied by AFM and TEM to evidence the main aspects of their microstructure. The obtained results confirmed the high potential of these materials for electro-optical devices. - Highlights: • Fullerene interaction with phenyl saturated polysilanes. • Microwave-assisted heterogeneous Wurtz-type polymerization. • UV–VIS and fluorescence spectroscopy of polydiphenylsilane/C60 nanocomposites. • Phenyls' mechanism to increase efficiency of polysilane/C60 based solar cells

  12. Observation and analysis of Fano-like lineshapes in the Raman spectra of molecules adsorbed at metal interfaces

    Science.gov (United States)

    Dey, S.; Banik, M.; Hulkko, E.; Rodriguez, K.; Apkarian, V. A.; Galperin, M.; Nitzan, A.

    2016-01-01

    Surface-enhanced Raman scattering (SERS) from bipyridyl ethylene adsorbed on gold dumbbells shows Fano-like spectra at high incident light intensity. This is accompanied by an increased electronic temperature, while no vibrational anti-Stokes scattering is observed. Theory indicates that interference between vibrational and electronic Raman scattering can yield such asymmetric scattering lineshapes. The best fit to observations is however obtained by disregarding this coupling and accounting for the detailed lineshape of the continuous electronic component of the SERS.

  13. C60 bonding to graphite and boron nitride surfaces

    Science.gov (United States)

    Reinke, P.; Feldermann, H.; Oelhafen, P.

    2003-12-01

    The present study focuses on the interaction of C60 with the surfaces of highly oriented pyrolitic graphite (HOPG) and sp2-bonded boron nitride (BN). The nanocrystalline BN film was deposited by mass selected ion beams and features an sp2-bonded surface layer, which covers a cubic phase BN film. The first part of the experiment is the sequential deposition of C60, which is monitored by photoelectron spectroscopy in the x-ray (XPS) and ultraviolet (UPS) regime. The growth of the C60 layer on HOPG is close to a layer-by-layer growth mode, but on the BN surface island growth is favored. No charge transfer or chemical reaction (e.g., carbide formation) between the fullerene layer, and the underlying substrate is observed in either case. In the second part of the experiment the samples are heated at a rate of 10 K/min while simultaneously recording the UPS VB spectra. The complete desorption of C60 from the HOPG surface occurs in a small temperature interval between 510-530 K. For the sp2 BN surface the majority of C60 desorbs around 493 K, about half a monolayer (ML) remains, and the C60 concentration decreases gradually with increasing temperature; less than a tenth of a ML can be detected even at 1000 K. The first desorption event at 493 K is attributable to the multilayer desorption from islands. The remaining C60 directly in contact with the BN surface is then removed in a large temperature interval between 500 and 1000 K which indicates the presence of a multitude of adsorption sites. The presence of C60 on the BN film surface also induces a band bending and related B 1s and N 1s core level shifts. An upward band bending is present in the C60 overlayer, which indicates that defects are responsible for the pinning of the Fermi level at the interface.

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

    International Nuclear Information System (INIS)

    Well-uniformed C60 nanotubes were grown at -20 deg. 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 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 C60 nanotubes was examined to investigate an effect of crystallinity on the polymerization kinetics.

  15. Cosmic-ray-driven electron-induced reactions of halogenated molecules adsorbed on ice surfaces: Implications for atmospheric ozone depletion and global climate change

    International Nuclear Information System (INIS)

    The cosmic-ray-driven electron-induced reaction of halogenated molecules adsorbed on ice surfaces has been proposed as a new mechanism for the formation of the polar ozone hole. Here, experimental findings of dissociative electron transfer reactions of halogenated molecules on ice surfaces in electron stimulated desorption, electron trapping and femtosecond time-resolved laser spectroscopic measurements are reviewed. This is followed by a review of the evidence from recent satellite observations of this new mechanism for the Antarctic ozone hole, and all other possible physical mechanisms are discussed. Moreover, new observations of the 11-year cyclic variations of both polar ozone loss and stratospheric cooling and the seasonal variations of CFCs and CH4 in the polar stratosphere are presented, and quantitative predictions of the Antarctic ozone hole in the future are given. Finally, a new observation of the effects of CFCs and cosmic-ray-driven ozone depletion on global climate change is also presented and discussed.

  16. On a Possible Melting Curve of C60 Fullerite

    OpenAIRE

    Zubov, V. I.; Rodrigues, C G; Zubov, I. V.

    2004-01-01

    We study thermodynamic properties of the high-temperature modification of fullerites on the basis of the Girifalco intermolecular potential. In the present work, using the Lindemann's melting criterion we estimate a possible melting curve Tm(P) of C60 fullerite. To take into account the lattice anharmonicity that has strong effect at T >700 K, we use the correlative method of unsymmetrized self-consistent field. The melting curve for C60 fullerite has been calculated from the melting point at...

  17. Tailorable acceptor C(60-n)B(n) and donor C(60-m)N(m) pairs for molecular electronics.

    Science.gov (United States)

    Xie, Rui-Hua; Bryant, Garnett W; Zhao, Jijun; Smith, Vedene H; Di Carlo, Aldo; Pecchia, Alessandro

    2003-05-23

    Our first-principles calculations demonstrate that C(60-n)B(n) and C(60-m)N(m) can be engineered as the acceptors and donors, respectively, needed for molecular electronics by properly controlling the dopant number n and m in C60. We show that acceptor C48B12 and donor C48N12 are promising components for molecular rectifiers, carbon nanotube-based n-p-n (p-n-p) transistors, and p-n junctions. PMID:12785911

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

    Science.gov (United States)

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

    2016-04-01

    Recent studies indicate that while unfunctionalized carbon nanomaterials (CNMs) exhibit very low decomposition rates in soils, even minor surface functionalization (e.g., as a result of photochemical weathering) may accelerate microbial decay. We present results from a C60 fullerene-soil incubation study designed to investigate the potential links between photochemical and microbial degradation of photo-irradiated C60. Irradiating aqueous (13)C-labeled C60 with solar-wavelength light resulted in a complex mixture of intermediate products with decreased aromaticity. Although addition of irradiated C60 to soil microcosms had little effect on net soil respiration, excess (13)C in the respired CO2 demonstrates that photo-irradiating C60 enhanced its degradation in soil, with ∼ 0.78% of 60 day photo-irradiated C60 mineralized. Community analysis by DGGE found that soil microbial community structure was altered and depended on the photo-treatment duration. These findings demonstrate how abiotic and biotic transformation processes can couple to influence degradation of CNMs in the natural environment. PMID:26774781

  19. Charge transfer and surface scattering at Cu-C60 planar interfaces

    Science.gov (United States)

    Hebard, A. F.; Ruel, R. R.; Eom, C. B.

    1996-11-01

    Thin-film planar structures of Cu and C60 have been sequentially deposited onto sapphire substrates in high vacuum and studied using in situ resistivity measurements during deposition together with ex situ atomic force microscopy characterization of surface topography. Two different regimes of behavior are identified. In the first of these, the thin-film limit in which the Cu is thin enough to be in the coalescence regime with an islanded morphology, the presence of an adjacent C60 monolayer, doped by charge transfer from the metal, creates a shunting path and a corresponding pronounced decrease in resistance. The sheet resistance of overlying doped monolayers is found to be ~8000 Ω, with a corresponding room-temperature resistivity that is a factor of 2 less than that of the three-dimensional alkali-metal-doped compounds A3C60 (A=K, Rb). The enhanced conductivity of an underlying monolayer of C60 is sufficient to reduce the critical thickness at which an overlying Cu film becomes conducting by almost a factor of 2 even though the roughness of such films is enhanced over that of Cu films deposited directly on the substrate. In the second regime of behavior, the continuous film limit in which the Cu is thick enough to have a size-effect resistivity proportional to the reciprocal of the film thickness, the presence of an adjacent C60 monolayer gives rise to an increase in resistance. Measurements on a number of samples with different thicknesses reveal that this resistance increase is best described by diffuse surface scattering. A scattering cross section of 5 AṦ resulting from a fit to this model represents the contact area under each C60 molecule.

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

    Directory of Open Access Journals (Sweden)

    Manuel R. Gonçalves

    2012-01-01

    Full Text Available 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.

  1. 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.

  2. Spatially resolved electron tunneling spectroscopy on single crystalline Rb3C60

    International Nuclear Information System (INIS)

    A Rb3C60 single crystal (Tc=30.5 K) is investigated in the superconducting state at 2.8 K by scanning tunneling microscopy and scanning tunneling spectroscopy (STS). STS data reveals a spatial variation of the superconducting energy gap Δ on a scale of 50 nm (Δ=2.6 endash 5.2 meV; 2Δ/kBTc=2.0 endash 4.0). This behavior is attributed to varying stoichiometry on the sample surface. An investigation of a Rb3C60 facet shows that I(V) characteristics even vary on molecular scale. I(V) curves acquired between fullerene molecules exhibit a nonvanishing slope at zero bias whereas I(V) characteristics measured above molecules exhibit vanishing slope at zero bias. copyright 1996 American Vacuum Society

  3. Alkylation of C60. Reaction between C60 anions and tert-butyl chloride and mass spectrometry analysis

    Science.gov (United States)

    Bourcier, S.; Chaurand, P.; Ciot, C.; Della-Negra, S.; Fabre, C.; Greugny, V.; Marx, L.; Rassat, A.; Rousseau, A.

    1996-11-01

    Alkylation of C60 in tetrahydrofuran with tert-butyl chloride and lithium gives a variety of products. Adducts of general formula C60Hn(t-Bu)qOx(thf)y (where t-Bu is the tert-butyl group and thf the tetrahydrofuryl group (C4H7O)) have been detected by mass spectrometry, with n <= 8, q + y <= 18 and x = 0, 1, 2 depending on experimental conditions. IR and NMR spectra of products confirm these assignments.

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

    International Nuclear Information System (INIS)

    The influence of fullerene C60 and C60-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

  5. The geometry of C_60: a rigorous approach via Molecular Mechanics

    OpenAIRE

    Friedrich, Manuel; Piovano, Paolo; Stefanelli, Ulisse

    2016-01-01

    Molecular Mechanics describes molecules as particle configurations interacting via classical potentials. These {\\it configurational energies} usually consist of the sum of different phenomenological terms which are tailored to the description of specific bonding geometries. This approach is followed here to model the fullerene $C_{60}$, an allotrope of carbon corresponding to a specific hollow spherical structure of sixty atoms. We rigorously address different modeling options and advance a s...

  6. Investigation of coupling geometry and dimerization effects on thermoelectric properties of a C60 molecular transistor

    OpenAIRE

    Tagani, M. Bagheri; Golsanamlou, Z.; Izadi, S; Soleimani, H. Rahimpour

    2013-01-01

    Thermoelectric properties of a C60 molecular transistor are studied using Green function formalism in linear response regime. A tight-binding model is used to investigate the effect of the dimerization and coupling geometry on the electrical conductance, thermopower, and figure of merit. Increase of the connection points between the molecule and electrodes results in decrease of the number of the peaks of the electrical conductance owing to the interference effects. In addition, oscillation o...

  7. Simulation of structure and electron configuration of polydeck sandwich macromolecules with η5-π- bonds based on bis-cyclopentadiene derivatives C60H10 of C60 fullerene

    International Nuclear Information System (INIS)

    Simulation of structure and electron configuration of the (CpFe)2C60H10 complex of the D5d symmetry where Cp is the C5H5 cyclopentadienyl-radical is carried out through the Hartree-Fock-Rutan method in the 3-21G basis. The hydrogen atoms in this complex are attached to the C60 fullerene carbon atoms located in the α-positions relative to two opposite five-member cycles. Each FeCp semisandwich fragment interacts by the η5-type with the atoms of those five-member cycles. It is established that the energy of the Fe-C60H10 η5-π- bonds in the (CpFe)2C60H10 complex is comparable with the energy of the Fe-Cpη5-π- bond in the Fe-Cp2 ferrocene molecule. The determined optimal geometry of the (CpFe)2C60H10 complex is used for simulating the structure of the [-FeC60H10-]n quasilinear molecule n >> 1. Calculation of the zonal structure of this macromolecule spectrum is accomplished by the crystalline orbital method. The width of the forbidden zone in its spectrum is equal to ∼ 2.27 eV

  8. Detection of the buckminsterfullerene cation (C60+) in space

    CERN Document Server

    Berné, Olivier; Joblin, Christine

    2013-01-01

    In the early 90s, C60+ was proposed as the carrier of two diffuse interstellar bands (DIBs) at 957.7 and 963.2 nm, but a firm identification still awaits gas-phase spectroscopic data. Neutral C60, on the other hand, was recently detected through its infrared emission bands in the interstellar medium and evolved stars. In this contribution, we present the detection of C60+ through its infrared vibrational bands in the NGC 7023 nebula, based on spectroscopic observations with the Spitzer space telescope, quantum chemistry calculation, and laboratory data from the literature. This detection supports the idea that C60+ could be a DIB carrier, and provides robust evidence that fullerenes exist in the gas-phase in the interstellar medium. Modeling efforts to design specific observations, combined with new gas-phase data, will be essential to confirm this proposal. A definitive attribution of the 957.7 and 963.2 nm DIBs to C60+ would represent a significant step forward in the field.

  9. Structures and energetics of carbon bridged C60 clusters

    International Nuclear Information System (INIS)

    The structures and energetics of carbon bridged C60 clusters (C 60)nCm have been studied by simulated annealing technique within the tight-binding molecular-dynamics. The ''sp2 addition'' ball-and-chain dimers exhibit odd-even alternations over the number of chain atoms, with the dimers containing even chain atoms more stable against dissociation than their immediate neighbors containing odd chain atoms. In addition to the usual ''sp2 addition'' dimers, a pentagon-linked C121 isomer and a hexagon-linked C122 isomer are also found to be stable. Based on our tight-binding calculations, trimers and larger clusters can be simply regarded as being made up of independent or weakly interacting dimers, if the C-C60 joints on a single cage are not too close to each other. Large C60 clusters connected by chains each containing only one or two carbon atoms have similar stability to that of constituent dimers, indicating the possibility to form stable C60-carbon polymers. (orig.)

  10. The Nature of the Noncovalent Interactions between Benzene and C60 Fullerene.

    Science.gov (United States)

    Li, Ming-Ming; Wang, Yi-Bo; Zhang, Yu; Wang, Weizhou

    2016-07-21

    Noncovalent interactions between aromatic compounds and fullerenes have received considerable attention in various fields of science and technology. Employing benzene (C6H6) and C60 fullerene as model molecules, we theoretically explored in the present study the nature of this kind of noncovalent interaction. Our results clearly show that the π···π stacking configurations of the complex C6H6···C60 are more strongly bound than in the C-H···π analogues, and the C-H···π interactions in the C-H···π configurations of C6H6···C60 are not of the hydrogen bonds. According to symmetry adapted perturbation theory analyses, all of the configurations of C6H6···C60 are dominated by dispersion forces. The percentage of the dispersion components in the overall attractive interactions for the π···π stacking configurations is smaller than the percentage of the dispersion components in the overall attractive interactions for the C-H···π configurations, whereas the percentage of the electrostatic terms in the overall attractive interactions for the π···π stacking configurations is larger than the percentage of the electrostatic terms in the overall attractive interactions for the C-H···π configurations. This is distinctly different from the case of the benzene dimer. PMID:27366821

  11. Density functional calculation of superatomic molecular orbitals in C60: First truly converged results on a real grid mesh

    Science.gov (United States)

    Drake, Kyle; Bonacum, Jason; Zhang, Guo-Ping

    2014-03-01

    The molecular structure of Buckminster fullerene (C60) allows for electron delocalization in all of the pi-bonding electrons of the molecule. This coupled with the symmetry of the molecule allows for the formation of super-atomic molecular orbitals (SAMOs) similar to those observed in aluminum clusters. The SAMOs behave as if the molecule that they belong to is a single atom. We compute the eigenstates of C60 compulationally using density functional theory (DFT) and a grid mesh. Using larger radii also allows us to accurately describe SAMOs and test the convergence of our data. The results are interesting because for the first time, we can show the true converged super atomic orbitals in C60. Indiana State University SURE Program, Department of Energy, Indiana State University Department of Physics, and Indiana State University Center for Student Creativity and Research.

  12. 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. PMID:23755985

  13. Electronic transport properties of photo-irradiated C60

    International Nuclear Information System (INIS)

    We have investigated field-effect transistor (FET) application on the photo-irradiated C60 thin film. Carrier mobility can be estimated to be 3.5 X 10-4 cm2/Vs after photo-irradiation and it shows a lower mobility than that before irradiation. Probably, it would be due to introduction of many cracks in the C60 thin film induced by polymerization due to ultraviolet light irradiation. However, considering the decrease in the threshold voltage from 12 to 2 V in the ISD-VG characteristics, carrier injection barrier clearly decreases by photo-irradiated polymerization. Furthermore, the photo-irradiated C60 FET works even in atmosphere.

  14. Charging C60 islands with the AFM tip.

    Science.gov (United States)

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

    2016-01-01

    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. PMID:26617348

  15. Binding fullerenol C60(OH24 to dsDNA

    Directory of Open Access Journals (Sweden)

    Mariana Pinteala

    2009-09-01

    Full Text Available Mariana Pinteala, Andrei Dascalu, Cezar UngurenasuPetru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica, Iasi, RomaniaAbstract: The first C60(OH24-DNA complex and its fluorescence enhancement is reported. The enhanced fluorescence intensity of fullerenol C60(OH24 is in proportion to the concentration of DNA in the range of 1 × 10-9 to 8 × 10-5 molL-1 and the detection limit was 1.3 ng mL-1. Fullerenol C60(OH24 binds significantly to the phosphate backbone of native dsDNA and to base-pairs within the major groove of sodium salt of dsDNA.Keywords: nanomedicine, fullerenol, DNA complexation, fluorescent probe

  16. Model for C60 solid doped with metallic ions

    International Nuclear Information System (INIS)

    Full text: Fullerene solids have been extensively studied by doping them with various alkali metal ions. This has been done by varying the dopant as well as the amount of doping. The results of such experimentation have been found to be very interesting, as on doping the C60 solid AxC60 becomes superconducting as long as x ≤3 with its Tc going up to about 30 K depending upon the kind and amount of doping. The doping is found to increase the lattice parameter. Further, the increased lattice parameter is correlated with increase in Tc. We had accounted for several bulk, dynamical and thermodynamical properties of pure C60 solids using a simple 6-exponential potential between C atoms of two bucky balls. We had also accounted for the rise in Tc of doped C60 by equating doping to application of a negative hydrostatic pressure on pure C60, without actually using the interactions of the metallic ions with the bucky balls. In the present paper, we suggest a model to include the metallic ion interactions along with the Van der Waals interactions between the two bucky balls. The interactions considered are the repulsive metal-metal Coulomb interactions screened due to the electron gas, metal-ion -bucky-ball Van der Waals conduction electron-ion and electron-electron interactions are treated within the electron gas jellium model. The net effect of the additional interactions is dominated by repulsive metal-metal interactions, which tend to enhance the lattice parameter as obtained in the undoped C60 solid. This result is in agreement with our earlier conclusion and enables us to correlate doping with negative pressure

  17. Reaction Probability and Infrared Detection of the Primary Ozonide in Collisions of O3 with Surface-Bound C60.

    Science.gov (United States)

    Davis, Erin Durke; Wagner, Alec; McEntee, Monica; Kaur, Manpreet; Troya, Diego; Morris, John R

    2012-11-01

    The kinetics and mechanism of reactions between gas-phase ozone and surface-bound C60 have been investigated by monitoring changes to reflection-absorption infrared spectra within a well-characterized film of C60 during exposure to a controlled flux of pure ozone. These ultrahigh vacuum studies provide direct infrared spectroscopic evidence for the formation and decomposition of a primary ozonide of C60. The spectral assignments of this highly unstable intermediate have been verified using electronic structure calculations. Theory and experiment revealed that C60 oxidized nearly exclusively via addition of ozone across the double bond that links two six-carbon-containing rings of the molecule. Following spectral characterization, the initial probability for ozone to react with the surface was found to be 5.8 ± 0.2 × 10(-4). Once formed, the ozonide quickly thermally decomposed to a variety of carbonyl-containing products. PMID:26296028

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

    International Nuclear Information System (INIS)

    Rational organization of porphyrin and C60 on the electrode surface in photovoltaic structures is essential to yield high quantum efficiency. In the present work, individual TiO2 nanoparticles were modified by introducing C60 and porphyrin units on the surface, and then electrophoretically deposited on an ITO/SnO2 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 C60 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 C60 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.

  19. Photopolymerization of C60 crystal synthesized from organic solution

    International Nuclear Information System (INIS)

    We have been developing a novel process to synthesize C60 polymers as superior functional materials. Polymerization reactions of C60 precipitated from organic solution were investigated under Free Electron Laser (FEL) irradiation. The two processes: a liquid-liquid interfacial precipitation (LLIP) method and an evaporation technique from supersaturated solution, were studied with a respect of crystal structure and/or Raman spectrum for the precipitates before and after FEL irradiation. It was found that the photopolymerization reaction took place effectively in the LLIP precipitate because of its highly packed molecular crystal structure.

  20. 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

    state, that the presence of molecular chiral domains induces asymmetry in the interaction with the substrate and locally transfers the chiral character to the underlying metal atoms participating in the adsorption process; combined information related to the asymmetry of the initial electronic state......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......, which is expected to be chiral, and the final electronic state, which locally probes the asymmetry of the potential, has been obtained. Identification of chirality in the adsorption footprint sheds new light on the transfer of chirality from a chiral modifier to a symmetric metal surface and represents...

  1. Metal-free phthalocyanine (H2Pc molecule adsorbed on the Au(111 surface: formation of a wide domain along a single lattice direction

    Directory of Open Access Journals (Sweden)

    Tadahiro Komeda, Hironari Isshiki and Jie Liu

    2010-01-01

    Full Text Available Using low-temperature scanning tunneling microscopy (STM, we observed the bonding configuration of the metal-free phthalocyanine (H2Pc molecule adsorbed on the Au(111 surface. A local lattice formation started from a quasi-square lattice aligned to the close-packed directions of the Au(111 surface. Although we expected the lattice alignment to be equally distributed along the three crystallographically equivalent directions, the domain aligned normal to the ridge of the herringbone structure was missing in the STM images. We attribute this effect to the uniaxial contraction of the reconstructed Au(111 surface that can account for the formation of a large lattice domain along a single crystallographical direction.

  2. Resonant electron heating and molecular phonon cooling in single C60 junctions.

    Science.gov (United States)

    Schulze, G; Franke, K J; Gagliardi, A; Romano, G; Lin, C S; Rosa, A L; Niehaus, T A; Frauenheim, Th; Di Carlo, A; Pecchia, A; Pascual, J I

    2008-04-01

    We study heating and heat dissipation of a single C(60) molecule in the junction of a scanning tunneling microscope by measuring the electron current required to thermally decompose the fullerene cage. The power for decomposition varies with electron energy and reflects the molecular resonance structure. When the scanning tunneling microscope tip contacts the fullerene the molecule can sustain much larger currents. Transport simulations explain these effects by molecular heating due to resonant electron-phonon coupling and molecular cooling by vibrational decay into the tip upon contact formation. PMID:18517981

  3. On the widths of Stokes lines in Raman scattering from molecules adsorbed at metal surfaces and in molecular conduction junctions

    Science.gov (United States)

    Gao, Yi; Galperin, Michael; Nitzan, Abraham

    2016-06-01

    Within a generic model we analyze the Stokes linewidth in surface enhanced Raman scattering (SERS) from molecules embedded as bridges in molecular junctions. We identify four main contributions to the off-resonant Stokes signal and show that under zero voltage bias (a situation pertaining also to standard SERS experiments) and at low bias junctions only one of these contributions is pronounced. The linewidth of this component is determined by the molecular vibrational relaxation rate, which is dominated by interactions with the essentially bosonic thermal environment when the relevant molecular electronic energy is far from the metal(s) Fermi energy(ies). It increases when the molecular electronic level is close to the metal Fermi level so that an additional vibrational relaxation channel due to electron-hole (eh) exciton in the molecule opens. Other contributions to the Raman signal, of considerably broader linewidths, can become important at larger junction bias.

  4. Free-energy coarse-grained potential for C60

    International Nuclear Information System (INIS)

    We propose a new deformable free energy method for generating a free-energy coarse-graining potential for C60. Potentials generated from this approach exhibit a strong temperature dependence and produce excellent agreement with benchmark fully atomistic molecular dynamics simulations. Parameter sets for analytical fits to this potential are provided at four different temperatures

  5. Electronic and mechanical properties of C60-doped nanotubes

    International Nuclear Information System (INIS)

    Using a generalized tight-binding model, we study the changes induced in the electronic and mechanical properties of carbon nanotubes with encapsulated C60s. Provided enough overlap exists between the electronic states of the nanotube and those of the C60s, a tiny gap (∼0.01-0.02 eV) opens in the band structure of a metallic tube. The gap is seen to be wider for smaller separations between the C60s. For semiconductor tubes, on the other hand, the encapsulated C60s produce donor levels in the gap causing it to narrow. As regards mechanical properties, doped tubes are observed to be slightly 'softer' than undoped ones. This is indicated by reductions of the Young modulus and torsional rigidity of the doped tubes by 0.4-1.8% and 0.6-1.2%, respectively, as compared to those of the pure tubes. Moreover, the Poisson ratio of the doped tubes is seen to be lower by ∼5%. These novel features of the fullerene-doped nanotubes should be of interest in future applications. (author)

  6. ECSTM study of adsorption of C60,C70,C86 and Y@C82 on Au(111)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The adsorption of a variety of fullerenes (C60,C70,C86,Y@C82) on Au(111) electrode surfaces was comprehensively investigated in 0.1 M HClO4 by electrochemical scanning tunneling microscopy (ECSTM).In the ordered C60’s adlayer,C60 molecules formed either (2(1/3) × 2 3~(1/3))or "in-phase" structure.The high resolution STM image shows that the C60 cage is not simply round but shows a bifurcated feature.The adsorption orientation of C60 on Au(111) is tentatively suggested.In the ordered C70’s adlayer,the perpendicular fullerene molecules are the main adsorption mode and form (2 3~(1/3) × 2 3~(1/3)) structure.However,for C86 and Y@C82,the ordered adlayer could not be obtained on Au(111) under the present condition.These differences may be due to the different molecular shapes and sizes,and the encapsulated metal atom which affects the lattice matches with the substrate.The adsorption of fullerene molecules on Au(111) from disorder to order could be tuned simply by steering the dimensional sizes or shapes of the fullerenes used.

  7. Sputtering of amorphous ice induced by C60 and Au3 clusters

    International Nuclear Information System (INIS)

    Molecular dynamics simulations were performed to study the behavior of cluster SIMS. Two predominant cluster ion beam sources, C60 and Au3, were chosen for comparison. An amorphous water ice substrate was bombarded with incident energy of 5 keV. The C60 cluster was observed to shatter upon impact creating a crater of damage approximately 8 nm deep. Although Au3 was also found to both break apart and form a damage crater, it continued along its initial trajectory causing damage roughly 10 nm deep into the sample and becoming completely imbedded. It is suggested that this difference in behavior is due to the large mass of Au relative to the substrate water molecule

  8. Optical and electronic properties of SO2 molecule adsorbed on Si-doped (8, 0) boron nitride nanotube

    Science.gov (United States)

    Guo, Shuang-Shuang; Wei, Xiu-Mei; Zhang, Jian-Min; Zhu, Gang-Qiang; Guo, Wan-Jin

    2016-09-01

    The study of the optical properties of pristine BNNT, Si-doped BNNTs and SO2 molecule adsorption on Si-doped BNNTs is that, to our knowledge, few relevant research have ever been found. In this paper, the adsorption behaviors of Sulfur dioxide (SO2) molecule on Si-doped Boron nitride nanotubes (BNNTs) are investigated applying the first-principles calculations. The main contribution of this paper is that the foremost investigation for the optical properties of the pristine BNNT, Si-doped BNNTs and SO2 adsorption on Si-doped BNNTs. Additionally, the electronic properties and the structural properties are also presented. In our calculations of optical properties, the dielectric constant, the refractive index and the absorption coefficient are obtained. Comparing the pristine BNNT, our results indicate that, the blue-shifts (in the main peaks of the dielectric constant of SiB -BNNT and SO2-SiB -BNNT), and the red-shifts (in the main peaks of the refractive index of SiN -BNNT and SO2-SiN -BNNT) are appeared. Under these conditions, Si-doped BNNT and Si-doped BNNT with SO2 adsorption, the gaps are reduced both for the speculated optical band gaps and the electronic structure band gaps.

  9. 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.

  10. A detailed Auger electron spectroscopy study of the first stages of the growth of C60 thin films

    Science.gov (United States)

    Vidal, R. A.; Ferrón, J.

    2015-11-01

    In this work we take advantage of the large sensitivity and in-depth resolution of Auger electron spectroscopy (AES) to study in a detailed way the growth of C60 over different substrates, namely Cu(1 1 1), Si(1 0 0) and graphene. The ability of AES, as compared to more local probes like STM or AFM, to follow the process in a dynamic way, allows us to study the growth of C60 below and over one ML, including the change of C60 over either Si or Cu to the growth of C60 over a C60 film. We found that the growth always proceeds layer by layer. This result shows that differences in diffusion barriers are not as important as one may think following the idea of diffusion by a jumping mechanism. We propose that the sticking coefficient, governed by the adsorption energy, is responsible for the differences observed between Cu and Si. Our results also point to a different charge transfer among fullerene molecules and these surfaces. The same result is suggested in the case of C60 over graphene, but in this case our conclusion comes from the variable temperature experiments.

  11. 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.

  12. New Ruthenium Complexes of Fullerene C60&C70

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The new complexes [Ru(NO)(PPh3)]2(η2-Cm)(m=60 1 or 70 2) have been prepared by heating a solution of C60(or C70) with [Ru(NO)2(PPh3)2] in toluene. They have been characterized by elemental analysis, IR, UV/VIS, XPS, 13C and 31P NMR spectroscopy. The photovaltaic effect for the new compounds has been studied.

  13. Blocking the Passage:C-60 Geometrically Clogs K+ Channels

    OpenAIRE

    Calvaresi, Matteo; Furini, Simone; Domene, Carmen; Bottoni, Andrea; Zerbetto, Francesco

    2015-01-01

    Classical molecular dynamics (MD) simulations combined with docking calculations, potential of mean force estimates with the umbrella sampling method, and molecular mechanic/Poisson-Boltzmann surface area (MM-PBSA) energy calculations reveal that C-60 may block K+ channels with two mechanisms: a low affinity blockage from the extracellular side, and an open-channel block from the intracellular side. The presence of a low affinity binding-site at the extracellular entrance of the channel is in...

  14. Blocking the passage: C60 geometrically clogs K(+) channels.

    Science.gov (United States)

    Calvaresi, Matteo; Furini, Simone; Domene, Carmen; Bottoni, Andrea; Zerbetto, Francesco

    2015-05-26

    Classical molecular dynamics (MD) simulations combined with docking calculations, potential of mean force estimates with the umbrella sampling method, and molecular mechanic/Poisson-Boltzmann surface area (MM-PBSA) energy calculations reveal that C60 may block K(+) channels with two mechanisms: a low affinity blockage from the extracellular side, and an open-channel block from the intracellular side. The presence of a low affinity binding-site at the extracellular entrance of the channel is in agreement with the experimental results showing a fast and reversible block without use-dependence, from the extracellular compartment. Our simulation protocol suggests the existence of another binding site for C60 located in the channel cavity at the intracellular entrance of the selectivity filter. The escape barrier from this binding site is ∼21 kcal/mol making the corresponding kinetic rate of the order of minutes. The analysis of the change in solvent accessible surface area upon C60 binding shows that binding at this site is governed purely by shape complementarity, and that the molecular determinants of binding are conserved in the entire family of K(+) channels. The presence of this high-affinity binding site conserved among different K(+) channels may have serious implications for the toxicity of carbon nanomaterials. PMID:25873341

  15. Nanobionics of Pharmacologically Active Derivatives of Fullerene C60

    International Nuclear Information System (INIS)

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

  16. Photoionization of bonding and antibonding-type atom-fullerene hybrid states in Cd@C$_{60}$ vs Zn@C$_{60}$60

    CERN Document Server

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

    2014-01-01

    Powerful hybridization of the Cd 4$d$ state with the $d$-angular momentum state of C$_{60}$ $\\pi$ 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$_{60}$.

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

    International Nuclear Information System (INIS)

    Powerful hybridization of the Cd 4d state with the d-angular momentum state of C60 π symmetry is found in the local density approximation (LDA) structure of Cd@C60 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 C60 plasmonic motion coherently coupled to the diffraction-type cavity oscillations induced by local emissions from C60. The Cd@C60 results exhibit a substantial difference from our previous results for Zn@C60. (paper)

  18. Morphology Change of C60 Islands on Organic Crystals Observed by Atomic Force Microscopy.

    Science.gov (United States)

    Freund, Sara; Hinaut, Antoine; Pawlak, Rémy; Liu, Shi-Xia; Decurtins, Silvio; Meyer, Ernst; Glatzel, Thilo

    2016-06-28

    Organic-organic heterojunctions are nowadays highly regarded materials for light-emitting diodes, field-effect transistors, and photovoltaic cells with the prospect of designing low-cost, flexible, and efficient electronic devices.1-3 However, the key parameter of optimized heterojunctions relies on the choice of the molecular compounds as well as on the morphology of the organic-organic interface,4 which thus requires fundamental studies. In this work, we investigated the deposition of C60 molecules at room temperature on an organic layer compound, the salt bis(benzylammonium)bis(oxalato)cupurate(II), by means of noncontact atomic force microscopy. Three-dimensional molecular islands of C60 having either triangular or hexagonal shapes are formed on the substrate following a "Volmer-Weber" type of growth. We demonstrate the dynamical reshaping of those C60 nanostructures under the local action of the AFM tip at room temperature. The dissipated energy is about 75 meV and can be interpreted as the activation energy required for this migration process. PMID:27219352

  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...... structures at temperatures around 390K. X-ray diffractrometry reveals (100) crystalline orientation in the films grown at higher surface temperatures, which corresponds to upright oriented molecules. Rocking curves reveal the lowest mosaicity for samples grown at the highest substrate temperatures. From...

  20. Localization of substrate-induced modification in the electronic structure of C-60 at fullerene-metal interfaces

    OpenAIRE

    Hunt, Michael R. C.; Rudolf, Petra; Modesti, Silvio

    1997-01-01

    Photoemission and electron-energy-loss-spectroscopy studies of C60 films deposited on Au(110) demonstrate that only the first layer of molecules, directly in contact with the metal substrate, display significant changes in electronic structure. If the Au(110) surface is precovered with Cs it is found that, at 298 K, the Cs can diffuse readily into a C60 thin film, preventing the formation of a localized interface. However, if a Cs precovered Au(110) sample is held at 98 K, subsequent depositi...

  1. 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.

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

    International Nuclear Information System (INIS)

    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

  3. Mesoscale aggregation properties of C60 in toluene and chlorobenzene.

    Science.gov (United States)

    Guo, Rong-Hao; Hua, Chi-Chung; Lin, Po-Chang; Wang, Ting-Yu; Chen, Show-An

    2016-07-20

    The mesoscale aggregation properties of C60 in two distinct aromatic solvents (toluene and chlorobenzene) and a practical range of concentrations (c = 1-2 and c = 1-5 mg mL(-1), respectively) were systematically explored by static/dynamic light scattering (SLS/DLS), small angle X-ray scattering (SAXS), depolarized dynamic light scattering (DDLS), and cryogenic transmission electron microscopy (cryo-TEM) analyses. The central observations were as follows: (1) aggregate species of sizes in the range of several hundred nanometers have been independently revealed by SLS, DLS, and DDLS analyses for both solvent systems. (2) DDLS and cryo-TEM measurements further revealed that while C60 clusters are notably anisotropic (rod-like) in chlorobenzene, they are basically isotropic (spherical) in toluene. (3) Detailed analyses of combined SLS and SAXS profiles suggested that varied, yet self-similar, solvent-induced aggregate units were responsible for the distinct (mesoscale) aggregation features noted above. (4) From a dynamic perspective, specially commissioned DLS measurements ubiquitously displayed two relaxation modes (fast and slow mode), with the second (slow) mode being q (wave vector) independent. While the fast mode in both solvent systems was basically diffusive by nature and leads to geometrical features in good agreement with the above static analyses, the slow mode was analyzed and tentatively suggested to reflect the effect of mutual confinement. (5) Micron-scale aggregate morphology of drop-cast thin films displays similar contrasting features for the two solvent media used. Overall, this study suggests that solvent-induced, nanoscale, aggregate units may be a promising factor to control a hierarchy of microscopic aggregation properties of C60 solutions and thin films. PMID:27376417

  4. Correlation effects and electronic structure of Gd-C60

    International Nuclear Information System (INIS)

    We have investigated the electronic structure of Gd-C60 using ab initio calculations, photoemission and resonant photoemission (constant initial state spectroscopy). In comparing our calculations based on the local spin density approximation and the Hubbard model description with the observed photoemission spectra, we conclude that Gd 4f states exhibit enhanced correlation energies. These correlation energies have values larger than those normally observed in metallic gadolinium and gadolinium compounds. We attributed the enhanced correlation to the diminished screening of the encapsulated Gd. Both calculation and experiment confirm a strong hybridization between the valence states of Gd and the C 2p states of the fullerene cage. (fast track communication)

  5. Electron transport and phonon coupling in K3C60

    International Nuclear Information System (INIS)

    The temperature dependence of the resistivity of single-crystal K3C60 below 260 K of Crespi et al. is analyzed utilizing the results of Raman scattering. It is found that coupling to the two lowest intramolecular Hg modes gives an excellent fit to the temperature variation of the resistivity with the inclusion of weak lower frequency acoustic or librational scattering. The relative coupling strength of Hg(1) to Hg(2) is found to be similar to that estimated from Raman studies of thin films. The weaker low-frequency contribution is found to have a value consistent with neutron-scattering studies

  6. 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.

  7. 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

    International Nuclear Information System (INIS)

    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−1 for catechol and 736.8 μmol g−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

  8. Ionization and fragmentation of C60 by highly charged, high-energy xenon ions

    International Nuclear Information System (INIS)

    C60 vapor was bombarded by 136Xe35+ and 136Xe18+ ions in the energy range 420 endash 625 MeV to study the various ionization and fragmentation processes that occur. Since the center-of-mass energies used in this work exceeded those of previous studies by several orders of magnitude, new excitation and dissociation modes were expected and indeed found. Positive ions were extracted from the interaction region and their times of flight were measured both singly and in coincidence with other ionic fragments. A wide range of stable charge states and cluster sizes from monatomic carbon up to C60 was observed. Even-numbered carbon fragments dominated the heavier mass range but both even and odd carbon numbers occurred at lower masses. Evidence was found for three qualitatively different ionization and fragmentation channels suggesting different ranges of collision impact parameters: ionization of the parent C60 molecule, loss of even numbers of carbon atoms, and open-quote open-quote multifragmentation close-quote close-quote into many small fragments. This latter mode included the production of singly charged Cn+ fragments with all values of n being observed from n=1 up to at least n=19. We interpret our results in terms of a theoretical model that indicates that the total interaction cross section contains comparable contributions from (a) excitation of the giant dipole plasmon resonance, and (b) large-energy-transfer processes that lead to multiple fragmentation of the molecule. The distribution of fragment cluster masses for n approx-lt 20 is reproduced by a open-quote open-quote percolation theory close-quote close-quote description analogous to that used to describe multifragmentation of nuclei by high-energy protons. copyright 1996 The American Physical Society

  9. 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.

  10. Optically enhanced charge transfer between C60 and single-wall carbon nanotubes in hybrid electronic devices

    Science.gov (United States)

    Allen, Christopher S.; Liu, Guoquan; Chen, Yabin; Robertson, Alex W.; He, Kuang; Porfyrakis, Kyriakos; Zhang, Jin; Briggs, G. Andrew D.; Warner, Jamie H.

    2013-12-01

    In this article we probe the nature of electronic interactions between the components of hybrid C60-carbon nanotube structures. Utilizing an aromatic mediator we selectively attach C60 molecules to carbon nanotube field-effect transistor devices. Structural characterization via atomic force and transmission electron microscopy confirm the selectivity of this attachment. Charge transfer from the carbon nanotube to the C60 molecules is evidenced by a blue shift of the Raman G+ peak position and increased threshold voltage of the transistor transfer characteristics. We estimate this charge transfer to increase the device density of holes per unit length by up to 0.85 nm-1 and demonstrate further optically enhanced charge transfer which increases the hole density by an additional 0.16 nm-1.In this article we probe the nature of electronic interactions between the components of hybrid C60-carbon nanotube structures. Utilizing an aromatic mediator we selectively attach C60 molecules to carbon nanotube field-effect transistor devices. Structural characterization via atomic force and transmission electron microscopy confirm the selectivity of this attachment. Charge transfer from the carbon nanotube to the C60 molecules is evidenced by a blue shift of the Raman G+ peak position and increased threshold voltage of the transistor transfer characteristics. We estimate this charge transfer to increase the device density of holes per unit length by up to 0.85 nm-1 and demonstrate further optically enhanced charge transfer which increases the hole density by an additional 0.16 nm-1. Electronic supplementary information (ESI) available: AFM line scans of the substrate before and after functionalization; scheme for measuring amorphous carbon coverage from TEM images; diameter comparisons of ac-TEM image and simulation of C60 molecule; Raman spectra D peak comparison; optical response of transfer properties of pristine devices; comparison between swept and pulsed Vg measurements

  11. Collision of low energy Na+ ion with C60

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The collision-induced reaction of Na+ ion with neutral C6o vapour was investigated at the energy range of 10 to 150 eV. The deposited films were studied via laser desorption time-of-flight mass spectroscopy (TOFMS). The fragment products of C60 with even number of carbon atoms, such as Cn+ (n=58, 56, 54), and adduct products, such as Cn+ (n=62, 64, 66, 68) were obser.vcd in the positively charged TOF mass spectra. The endohedral fullerene ion of Na@C60+ was detected when collision energies are above 20 eV. Besides, no negative endohedral fullerene was detected, the products appearing in positively charged mass spectra were also observed in the negatively charged mass spectra. In addition, a series of products with odd number of carbon atoms, such as Cn- (n=53, 55, 57, 59, 61, 63, 65, 67), also appeared, but the intensities of their signals were not as high as that of even numbered. Finally, it is interesting to find that the deposited films are insoluable in toluene, benzene or water. Their Fourier transform infrared (FTIR) spectra seem like those photopolymerized ones. Some of the reaction schemes are proposed to explain the experimental results.

  12. Adsorption and trace detection of pharmacologically significant 5-methylthio-1, 3, 4-thiadiazole-2-thiol molecule adsorbed on silver nanocolloids and understanding the role of Albrecht's “A” and Herzberg-Teller contributions in the SERS spectra

    Science.gov (United States)

    Chowdhury, Joydeep; Chandra, Subhendu; Ghosh, Manash

    2015-01-01

    The surface enhanced Raman scattering (SERS) spectra of biologically and industrially significant 5-methylthio-1, 3, 4-thiadiazole 2-thiol molecule have been investigated. The SERS spectra at various concentrations of the adsorbate are compared with the Fourier transform Infrared (FTIR) and normal Raman spectra (NRS) of the probe molecule recorded in different environmental conditions. The optimized molecular structures of the most probable thione and the thiol forms of the molecule have been estimated from the density functional theory (DFT) calculations. The vibrational signatures of the molecule have been assigned from the potential energy distributions (PEDs). The detail vibrational analyses reveal that ∼54% of the thione form of the molecule is prevalent in the solid state and its population increases to ∼65% in ACN solvent medium. Concentration dependent SERS, together with the 2-dimensional correlation spectra (2D-COS), corroborate the presence of both the thione and the thiol forms of the molecule even in the surface adsorbed state. The orientations of the thione and the thiol forms of the molecule on the nanocolloidal silver surface have been predicted from the surface selection rule. The selective enhancement of Raman bands in the SERS spectra have been explored from the view of the Albrecht's "A" and Herzberg-Teller (HT) charge transfer (CT) contribution.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    Organic molecular beam grown α-sexithiophene (α-6T) forms nanostructured thin films on buckminsterfullerene (C60) thin film layers. At substrate temperatures of 300 K during growth a rough continuous film is observed, which develops to larger elongated islands and dendritic- as well as needle-like structures at temperatures around 390 K. X-ray diffractrometry reveals (100) crystalline orientation in the films grown at higher surface temperatures, which corresponds to upright oriented molecules. Rocking curves reveal the lowest mosaicity for samples grown at the highest substrate temperatures. From fluorescence polarimetry measurements the in-plane orientation within the needle like structures is determined. The polarimetry investigations together with the intensity of the fluorescence strongly indicate that the needle like structures consist of lying molecules. - Highlights: • Growth of α-sexithiophene nanostructures on buckminsterfullerene • X-ray spectrometry analysis of fabricated structures • Fluorescence polarimetry analysis of α-sexithiophene needle like structures

  15. An ab-initio density functional theory investigation of fullerene/Zn-phthalocyanine (C60/ZnPc) interface with face-on orientation

    Energy Technology Data Exchange (ETDEWEB)

    Javaid, Saqib [EMMG, Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); National Centre of Physics, Islamabad (Pakistan); Javed Akhtar, M., E-mail: javedakhtar6@gmail.com [EMMG, Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

    2015-07-28

    We have employed density functional theory to study the C60/ZnPc interface with face-on orientation, which has recently been tailored experimentally. For this purpose, adsorption of ZnPc on C60 has been studied, while taking into account different orientations of C60. Out of various adsorption sites investigated, 6:6 C-C bridge position in apex configuration of C60 has been found energetically the most favourable one with C60-ZnPc adsorption distance of ∼2.77 Å. The adsorption of ZnPc on C60 ensues both charge re-organization and charge transfer at the interface, resulting in the formation of interface dipole. Moreover, by comparing results with that of C60/CuPc interface, we show that the direction of interface dipole can be tuned by the change of the central atom of the phthalocyanine molecule. These results highlight the complexity of electronic interactions present at the C60/Phthalocyanine interface.

  16. An ab-initio density functional theory investigation of fullerene/Zn-phthalocyanine (C60/ZnPc) interface with face-on orientation

    International Nuclear Information System (INIS)

    We have employed density functional theory to study the C60/ZnPc interface with face-on orientation, which has recently been tailored experimentally. For this purpose, adsorption of ZnPc on C60 has been studied, while taking into account different orientations of C60. Out of various adsorption sites investigated, 6:6 C-C bridge position in apex configuration of C60 has been found energetically the most favourable one with C60-ZnPc adsorption distance of ∼2.77 Å. The adsorption of ZnPc on C60 ensues both charge re-organization and charge transfer at the interface, resulting in the formation of interface dipole. Moreover, by comparing results with that of C60/CuPc interface, we show that the direction of interface dipole can be tuned by the change of the central atom of the phthalocyanine molecule. These results highlight the complexity of electronic interactions present at the C60/Phthalocyanine interface

  17. Structure and optical properties of C60 thin films

    International Nuclear Information System (INIS)

    By varying the deposition conditions of C60 thin films and using X-ray diffraction techniques to study the results, we obtain a continuum of structure types ranging from crystalline to amorphous. By measuring the absorption spectra of these films we find that as the film crystallinity increases the fundamental absorption edge and nearby spectral features shift progressively to longer wavelengths. Using a Tauc-type approximation, we find that the optical bandgap Eg=1.3-1.6 eV for crystalline films and Eg=2.4-2.6 eV for amorphous films. Intermediate values of Eg are obtained depending upon the degree of crystallinity of the film. (orig.)

  18. Preparation and characterisation of the C 60 charge transfer complex C 60-.[1,1',3,3'-tetramethyl-Δ 2,2'-bi(imidazolidine)] +.

    Science.gov (United States)

    Schilder, A.; Gotschy, B.; Seidl, A.; Gompper, R.

    1995-04-01

    Ferromagnetism in the C 60 charge transfer salt C 60-.[1,1',3,3'-tetramethyl-Δ 2,2'-bi(imidazolidine)] +. (C 60[TMBI]) with Curie temperatures Tc above 140 K and coercive forces Hc of about 1000 Oe were reported by Wang and Zhu (J. Phys. Chem. Solids 55 (1994) 437). This dramatic increase of Tc and Hc by a small variation of the counterion compared to the first C 60 ferromagnet C 60-.[tetrakis(dimethylamino)ethylene] +. (Allemand et al., Science 253 (1991) 301) triggered us to elucidate the charge transfer from TMBI to C 60 by absorption measurements in the VIS/NIR. We found that the reaction kinetics is much more complex than in C 60[TDAE]. Solid state investigations of C 60[TMBI] with EPR and microwave conductivity are in clear disagreement with the results published by Wang and Zhu. We found instead strong evidence that C 60[TMBI] is rather a diamagnetic C 60 CT complex with a lot of structural defects than a high temperature molecular ferromagnet.

  19. Theoretical modelling of Jahn-Teller distorted C60 anions on a surface

    International Nuclear Information System (INIS)

    Through the use of scanning tunnelling microscopy (STM), it is possible to directly observe the molecular orbitals associated with a particular molecule. For the charged ions of the C60 fullerene, the interpretation of these experimental images has an additional complication due to the inherent presence of the Jahn-Teller (JT) effect. In this work, the influence of the JT effect on STM images is examined. We also include interactions between the molecule and both the surface substrate on which it rests, and, when present within a monolayer, the nearest neighbours. Simple symmetry arguments are used to explain the effects of these external interactions on the energy of the different JT wells relating to molecular distortions of D3d, D5d, and D2h symmetry. We first investigate the C−60 monoanion, and then, through the construction of multi-electron states, move on to consider anions with higher charges. It is found that for high symmetry orientations of the molecule on the surface, the wells that are degenerate in the absence of external interactions split into equal energy subgroups, with the grouping dependent on the orientation of the molecule. Hückel molecular orbital theory is then used to investigate the effect this has on STM images. We show that when dynamic JT effects are considered, the images are always formed from some linear combination of the squares of the individual single electron molecular orbitals that make up the lowest unoccupied molecular orbital of the neutral molecule.

  20. C60 sputtering of organics: A study using TOF-SIMS, XPS and nanoindentation

    International Nuclear Information System (INIS)

    Sputtering of organic materials using a C60 primary ion beam has been demonstrated to produce significantly less accumulated damage compared to sputtering with monatomic and atomic-cluster ion beams. However, much about the dynamics of C60 sputtering remains to be understood. We introduce data regarding the dynamics of C60 sputtering by evaluating TOF-SIMS depth profiles of bulk poly(methyl methacrylate) (PMMA). Bulk PMMA provides an ideal test matrix with which to probe C60 sputter dynamics because there is a region of steady-state secondary ion yield followed by irreversible signal degradation. C60 sputtering of PMMA is evaluated as a function of incident ion kinetic energy using 10 keV C60+, 20 keV C60+ and 40 keV C60++ primary ions. Changes in PMMA chemistry, carbon accumulation and graphitization, and topography as a function of total C60 ion dose at each accelerating potential is addressed.

  1. Variation of Excited-State Dynamics in Trifluoromethyl Functionalized C60 Fullerenes

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-07

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

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

    Science.gov (United States)

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

    2016-08-17

    We report on electronically excited-state dynamics of three different trifluoromethyl C60 fullerenes (TMFs, C60(CF3)n: C60/4-1, C60/6-2, and C60/10-1, featuring four, six, and ten trifluoromethyl groups, respectively) using steady-state and time-resolved optical spectroscopy as well as ultrafast pump/probe transient absorption spectroscopy. C60/4-1 and C60/6-2 dissolved in toluene solvent show near-unity S1 → T1 intersystem crossing quantum yield (ΦISC), ca. 1 ns S1-state lifetimes, and microsecond-timescale T1-state lifetimes, which are typical of the fullerene class. On the other hand, C60/10-1 exhibits a dominant sub-nanosecond nonradiative S1 → S0 relaxation mechanism and negligible ΦISC, therefore decreasing the average excited-state lifetime (τavg) by about 5 orders of magnitude compared to that of C60/4-1 and C60/6-2 (τavg ≈ 17 μs and 54 μs for C60/4-1 and C60/6-2, respectively, whereas τavg ≈ 100 ps for C60/10-1). These excited-state characteristics of C60/4-1 and C60/6-2 are preserved in polymer matrix, suggesting that fullerene/polymer interactions do not modulate intrinsic photophysics of trifluoromethyl-substituted fullerenes. The contrasting excited-state study results of C60/4-1 and C60/6-2 to that of C60/10-1 infer that intrinsic optical properties and excited-state dynamics can be affected by the substitution on the fullerene. PMID:27485768

  3. Theoretical Study for Structures and Spectroscopic Properties of C60(CH2)nOH (n=0∼2) and C60(OH)2

    International Nuclear Information System (INIS)

    The possible minimum structures of C60(CH2)nOH (n=0∼2) and C60(OH)2 have been optimized using density functional theory (DFT) with the 6-311G (d,f) basis set. The harmonic vibrational frequencies and IR intensities are also determined to confirm that all the optimized geometries are true minima. Also zero-point vibrational energies (ZPVE) have been considered to predict the binding energies. The predicted binding energy of C60CH2OH is about 10 kcal/mol more stable than the binding energy of C60OH

  4. Interpretation of anomalous normal state optical conductivity of K3C60 fullerides

    Indian Academy of Sciences (India)

    K K Choudhary

    2013-02-01

    The observed frequency dependent optical response of alkali–metal-doped fulleride superconductors (c ≈ 19 K) has been theoretically analysed. The calculations of the optical conductivity, (), have been made within the two-component schemes: one is the coherent Drude carriers (electrons) responsible for superconductivity and the other is incoherent motion of carriers from one atom to other atom of C60 molecule to a pairing between Drude carriers. The approach accounts for the anomalies reported (frequency dependence of optical conductivity) in the optical measurements for the normal state. The model has only one free parameter, the relaxation rate. The frequency dependent relaxation rates are expressed in terms of memory functions. The coherent Drude carriers form a sharp peak at zero frequency and a long tail at higher frequencies, i.e. in the infrared region. However, the hopping of carriers from one atom to the other (incoherent motion of doped electrons) yields a peak value in the optical conductivity centred at mid-infrared region. It is found that both the Drude and hopping carriers will contribute to the optical process of conduction in the K3C60 and shows similar results on optical conductivity in the mid-infrared as well as infrared frequency regions as those revealed from experiments.

  5. Topological edge properties of C60+12n fullerenes

    Directory of Open Access Journals (Sweden)

    A. Mottaghi

    2013-06-01

    Full Text Available A molecular graph M is a simple graph in which atoms and chemical bonds are the vertices and edges of M, respectively. The molecular graph M is called a fullerene graph, if M is the molecular graph of a fullerene molecule. It is well-known that such molecules exist for even integers n ≥ 24 or n = 20. The aim of this paper is to investigate the topological properties of a class of fullerene molecules containing 60 + 12n carbon atoms.

  6. C60 ion sputtering of layered organic materials

    International Nuclear Information System (INIS)

    Two different organic materials, Irganox1010 and Irganox3114, were vacuum deposited as alternating layers. The layers of Irganox3114 were thin (∼2.5 nm) in comparison to the Irganox1010 (∼55 or ∼90 nm); we call these 'organic delta layers'. Both materials are shown to have identical sputtering yields and the alternating layers may be used to determine some of the important metrological parameters for cluster ion beam depth profiling of organic materials. The sputtering yield for C60 ions is shown to diminish with ion dose. Comparison with atomic force microscopy data from films of pure Irganox1010, demonstrates that the depth resolution is limited by the development of topography. Secondary ion intensities are a well-behaved function of sputtering yield and may be employed to obtain useful analytical information. Organic delta layers are shown to be valuable reference materials for comparing the capabilities of different cluster ion sources and experimental arrangements for the depth profiling of organic materials.

  7. 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

    International Nuclear Information System (INIS)

    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√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 (√3 x √3) reconstruction on the (111) face of the α-CuAl alloy has been determined

  8. 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.

  9. Uptake and Sequestration of Naphthalene and 1,2-Dichlorobenzene by C60

    International Nuclear Information System (INIS)

    The interactions of common environmental contaminants with C60 have been studied to evaluate the environmental impact of carbon nanomaterials. The adsorption and desorption interaction of the hydrophobic contaminants naphthalene and 1,2-dichlorobenzene with C60 was characterized. Processes that cause the wetting and disaggregating of C60 particles also affect the extent of organic contaminant sorption to C60 aggregates by orders of magnitude. C60 dissolved in organic solvents such as toluene can form stable nanoscale aggregates upon vigorous mixing in water. These nanoscale C60 particles form stable suspensions in water and are referred to as 'nano-C60'. Desorption of contaminants from stable suspensions of nano-C60 exhibits hysteresis. The experimentally observed adsorption/desorption hysteresis is described by a two-compartment desorption model: first, adsorption to the external surfaces that are in contact with water, and second, adsorption to the internal surfaces within the aggregates

  10. FABRICATION OF SELF-ASSEMBLY DNA-C60 MULTI LAYER FILMS

    Institute of Scientific and Technical Information of China (English)

    Shu-guang Yang; Yong-jun Zhang; Xin-hu Daia; Wen-hong Tang; Chun-yan Liu; Wei-xiao Cao; Yu-liang Li; Jian Xu

    2002-01-01

    Electrostatic layer-by-layer self-assembly multilayer films were successfully fabricated from C60-ethylenediamineadduct (C60-EDA) and DNA. Under visible light irradiation, DNA is ready to be cleaved and the films are destroyed.

  11. Local structure and chemical reaction of C60 films on Si(111)7 x 7 studied by HREELS-STM

    International Nuclear Information System (INIS)

    We have investigated the thermal stability and the chemical reactions of C60 thin films on Si(111)7 x 7 surfaces by the combined measurements of the high-resolution electron-energy-loss spectroscopy (HREELS) and the scanning tunneling microscopy (STM), HREELS-STM. After heating the Si up to 400 C, the molecules did not align perfectly but made local arrangements. The energy shifts of the inelastic electrons indicate that the electrons in the Si dangling bond transfer to the C60 molecules. The value of the charge transfer is estimated to be 1+1 electron(s). After heating the Si up to 800 C, the smooth C60 monolayer film aggregates and forms islands. The nearest neighbouring distance between the C60 molecules is shortened from 10 A to 9.3 A. The intensity of the 92 and 101 meV peaks drastically increase. These results indicate the formation of a covalent bond between the C60 molecules. After heating the Si up to 1100 C, an SiC film grows. (orig.)

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2015-07-01

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

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

    Science.gov (United States)

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

    2010-04-28

    The parameters of fullerene C(60) dissolved in carbon disulfide CS(2) are analyzed by small-angle neutron scattering (SANS) in a wide interval of momentum transfer. To exclude the influence of nonequilibrium conditions, the solutions are prepared without applying shaking, stirring or ultrasound. No indication of the equilibrium cluster state of C(60) (with the cluster size below 60 nm) in the final solutions is revealed. Molecular dynamic simulations are complementary used to find out the partial volume of C(60) in CS(2) and the scattering contribution of the solvent organization at the interface with the fullerene molecule, which is shown to be small. Among several approaches for describing SANS data the preference is given to the model, which takes into account the presence of stable C(60) dimers (comprising 10% of the total particle number density) in the solution. PMID:20441296

  15. Interfacial molecular recognition of adenine, adenosine and ATP by a C60-uracil adduct via complementary base pairing

    Science.gov (United States)

    Marczak, Renata; Hoang, Vu T.; Noworyta, Krzysztof; Zandler, Melvin E.; Kutner, Wlodzimierz; D'Souza, Francis

    2002-10-01

    A new C60-uracil adduct was demonstrated to recognize adenine, adenosine, or adenosine 5'-triphosphate (ATP) via complementary base pairing which led to complex formation. The base-pairing mechanism was modeled by ab initio B3LYP/3-21G(*) calculations which revealed the Watson-Crick (A-T) interactions. Stable "expanded liquid" Langmuir films of the complexes were prepared with the limiting area per molecule increasing for different subphase composition in the order: water < adenine < adenosine < ATP solution. Comparison of experimental and calculated areas per molecule and dipole moments suggest both prevailing horizontal orientation of the complexes in films.

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

    Directory of Open Access Journals (Sweden)

    Carroll David L

    2006-12-01

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

  17. Structural and magnetic properties of Co films on highly textured and randomly oriented C60 layers

    Science.gov (United States)

    Kim, Dong-Ok; Choi, Jun Woo; Lee, Dong Ryeol

    2016-03-01

    The structural and magnetic properties of Co/C60/pentacene and Co/C60 thin film structures were investigated. Atomic force microscopy and x-ray reflectivity analysis show that the presence or absence of a pentacene buffer layer leads to a highly textured or randomly oriented C60 layer, respectively. A Co film deposited on a randomly oriented C60 layer penetrates into the C60 layer when it is deposited at a slow deposition rate. The Co penetration can be minimized, regardless of the Co deposition rate, by growth on a highly textured and nanostructured C60/pentacene layer. Vibrating sample magnetometry measurements show that the saturation magnetization of Co/C60/pentacene is significantly reduced compared to that of Co/C60. On the other hand, the Co penetration does not seem to have an effect on the magnetic properties, suggesting that the structural properties of the Co and C60 layer, rather than the Co penetration into the organic C60 layer, are critical to the magnetic properties of the Co/C60.

  18. Electron elastic scattering off endohedral fullerenes A@C60: The initial insight

    CERN Document Server

    Dolmatov, V K; Hunter, H E

    2014-01-01

    The initial insight into electron elastic scattering off endohedral fullerenes A@C60 is gained in the framework of a theoretical approach where the C60 cage is modelled by a rectangular (in the radial coordinate) potential well, as in many other A@C60 studies. The effect of a noticeably weaker electron elastic scattering off A@C60 compared to that off empty C60 or even the isolated atom A itself, as well as a strong sensitivity of e + A@C60 scattering to the spin of the captured atom A are unraveled, for certain kinds of atoms. Obtained results lay out the initial qualitative basis for identifying interesting measurements and/or more rigorous calculations of e + A@C60 elastic scattering to perform.

  19. Measurement of Small Molecular Dopant F4TCNQ and C60F36 Diffusion in Organic Bilayer Architectures.

    Science.gov (United States)

    Li, Jun; Rochester, Chris W; Jacobs, Ian E; Friedrich, Stephan; Stroeve, Pieter; Riede, Moritz; Moulé, Adam J

    2015-12-30

    The diffusion of molecules through and between organic layers is a serious stability concern in organic electronic devices. In this work, the temperature-dependent diffusion of molecular dopants through small molecule hole transport layers is observed. Specifically we investigate bilayer stacks of small molecules used for hole transport (MeO-TPD) and p-type dopants (F4TCNQ and C60F36) used in hole injection layers for organic light emitting diodes and hole collection electrodes for organic photovoltaics. With the use of absorbance spectroscopy, photoluminescence spectroscopy, neutron reflectometry, and near-edge X-ray absorption fine structure spectroscopy, we are able to obtain a comprehensive picture of the diffusion of fluorinated small molecules through MeO-TPD layers. F4TCNQ spontaneously diffuses into the MeO-TPD material even at room temperature, while C60F36, a much bulkier molecule, is shown to have a substantially higher morphological stability. This study highlights that the differences in size/geometry and thermal properties of small molecular dopants can have a significant impact on their diffusion in organic device architectures. PMID:26673846

  20. Photoelectron spectroscopy investigation of the C60/calcium interface

    Energy Technology Data Exchange (ETDEWEB)

    Wetzstein, Holger; Schoell, Achim; Reinert, Friedrich [Experimental Physics VII, Julius-Maximilians-University of Wuerzburg, D-97074 Wuerzburg (Germany); Bunandar, Darius [Department of Physics, University of Texas at Austin, Austin, TX 78712-0264 (United States); Schafferhans, Julia; Deibel, Carsten [Experimental Physics VI, Julius-Maximilians-University of Wuerzburg, D-97074 Wuerzburg (Germany)

    2011-07-01

    Device lifetime is a crucial point for organic solar cells. Therefore it is important to understand the degradation mechanisms as well as their consequence on the performance of these photovoltaic devices. We observed a characteristic S-shape in the I/V-curves of P3HT/PCBM-bulk heterojunction cells with calcium contacts. A tentative origin of this behavior is a reaction of the calcium with oxygen, which leads to alterations in the regime of the anode interface. To shed more light on this issue we investigated the electronic structure of the Ca/C{sub 60} interface, which serves as a model for the PCBM/Ca contact. X-ray (XPS) and ultra-violet photoelectron spectroscopy (UPS) measurements were performed on C{sub 60} layers adsorbed on epitaxially grown Calcium as well as on Ca deposited on C{sub 60}. In both cases, the data clearly show the formation of an interface state due to the charge transfer from the Ca into the C{sub 60}, which is an indication for a chemical reaction. Moreover, we studied the effect of oxygen exposure on the interfacial chemical and electronic structure under conditions comparable to the conditions during device operation.

  1. Exohedral M–C60 and M2–C60 (M = Pt, Pd) systems as tunable-gap building blocks for nanoarchitecture and nanocatalysis

    International Nuclear Information System (INIS)

    Transition metal–fullerenes complexes with metal atoms bound on the external surface of C60 are promising building blocks for next-generation fuel cells and catalysts. Yet, at variance with endohedral M@C60, they have received a limited attention. By resorting to first principles simulations, we elucidate structural and electronic properties for the Pd–C60, Pt–C60, PtPd–C60, Pd2–C60, and Pt2–C60 complexes. The most stable structures feature the metal atom located above a high electron density site, namely, the π bond between two adjacent hexagons (π-66 bond). When two metal atoms are added, the most stable configuration is those in which metal atoms still stand on π-66 bonds but tends to clusterize. The electronic structure, rationalized in terms of localized Wannier functions, provides a clear picture of the underlying interactions responsible for the stability or instability of the complexes, showing a strict relationship between structure and electronic gap

  2. 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

  3. A comparative electrochemical study of electrosorbed 2- and 4-mercaptopyridines and their application as corrosion inhibitors at C60 steel

    Indian Academy of Sciences (India)

    Nazly Hassan; Rudolf Holze

    2009-09-01

    The electrochemistry of self-assembled monolayers (SAMs) prepared from 2-mercaptopyridine (2 Mpy) and 4-mercaptopyridine (4 Mpy) dissolved in either water or an aqueous solution of 0.1 M H2SO4 on a polycrystalline gold electrode has been investigated in an aqueous electrolyte solution (0.5 M H2SO4) using cyclic voltammetry. Results suggest that 2 Mpy is adsorbed more strongly than 4 Mpy due to the formation of a S-Au-N chelate. The under- and over-potential deposition of copper from an aqueous solution of 0.1 M sulphuric acid is inhibited in the presence of these SAMs suggesting strong interactions between these adsorbates and the gold surface. A copper adlayer was partially displaced by adsorbing 2 Mpy and 4 Mpy. The inhibition effect of these SAMs on the corrosion of C60 steel has been investigated using electrochemical impedance measurements (EIM) in an aqueous 3.5 wt% NaCl solution. The polarization resistance and the inhibition efficiency were calculated. 2 Mpy has higher inhibition efficiency than 4 Mpy.

  4. A theoretical study of adsorbate-adsorbate interactions on Ru(0001)

    DEFF Research Database (Denmark)

    Mortensen, Jens Jørgen; Hammer, Bjørk; Nørskov, Jens Kehlet

    1998-01-01

    Using density functional theory we study the effect of pre-adsorbed atoms on the dissociation of N(2) and the adsorption of N, N(2), and CO on Ru(0001). We have done calculations for pre-adsorbed Na, Cs, and S, and find that alkali atoms adsorbed close to a dissociating N(2) molecule will lower t...

  5. Frictional and atomic-scale study of C60 thin films by scanning force microscopy

    International Nuclear Information System (INIS)

    Scanning force microscopy (SFM) was employed to characterize C60 island films in an ultra-high vacuum (UHV). The initial growth stage of C60 on NaCl cleavage faces and nanotribological properties of this solid lubricant are investigated. In comparison to the NaCl(001) face, higher friction is measured on the C60 islands, resulting in a ratio of friction of 1:3 for NaCl:C60. The friction coefficient of the (111) oriented C60 island is determined to be 0.15±0.05. High-resolution SFM images reveal the hexagonal lattice of the unreconstructed (111) top surfaces and the overgrowth relationships of the C60 islands. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-25

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

  7. X-Ray Photoelectron Spectrum Analysis of Yb3C60 Compound

    Institute of Scientific and Technical Information of China (English)

    CAO Xue-Wei; SHAO Yue; WANG Yu-Fang; LAN Guo-Xiang

    2001-01-01

    The nominal composition of the Yb3 C60 compound is characterized by means of x-ray photoelectron spectroscopy.Evidence of the divalent state for the Yb cation in the as-grown crystalline Yb3C60 is obtained. After exposure to air, the Yb3C60 compound transforms to an amorphous phase and Yb2O3 compound, while the valence state of the Yb cations changes from divalent to trivalent.

  8. 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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2010-12-01

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

  11. Solvent-free functionalization of fullerene C60 and pristine multi-walled carbon nanotubes with aromatic amines

    Science.gov (United States)

    Ramírez-Calera, Itzel J.; Meza-Laguna, Victor; Gromovoy, Taras Yu.; Chávez-Uribe, Ma. Isabel; Basiuk, Vladimir A.; Basiuk, Elena V.

    2015-02-01

    We employed a direct one-step solvent-free covalent functionalization of solid fullerene C60 and pristine multi-walled carbon nanotubes (MWCNTs) with aromatic amines 1-aminopyrene (AP), 2-aminofluorene (AF) and 1,5-diaminonaphthalene (DAN). The reactions were carried out under moderate vacuum, in a wide temperature range of 180-250 °C, during relatively short time of about 2 h. To confirm successful amine attachment, a large number of analytical techniques were used (depending on the nanomaterial functionalized) such as Fourier transform infrared, Raman, X-ray photoelectron, 13C cross-polarization magic angle spinning NMR spectroscopy, thermogravimetric analysis, laser-desorption ionization time-of-flight mass spectrometry, temperature-programmed desorption with mass spectrometric detection, as well as scanning and transmission electron microscopy. The nucleophilic addition of the aromatic amines to C60 molecule was studied theoretically by using density functional theory (PBE GGA functional with Grimme dispersion correction in conjunction with the DNP basis set). In the case of crystalline C60, the solvent-free technique has a limited applicability due to poor diffusion of vaporous aromatic amines into the bulk. Nevertheless, the approach proposed allows for a facile preparation of aromatic amine-functionalized pristine MWCNTs without contamination with other chemical reagents, detergents and solvents, which is especially important for a vast variety of nanotube applications spanning from nanoelectronics to nanomedicine.

  12. Scanning tunneling microscopy theory for an adsorbate: Application to adenine adsorbed on a graphite surface

    OpenAIRE

    Ou-Yang, Hui; Marcus, R. A.; Källebring, Bruno

    1994-01-01

    An expression is obtained for the current in scanning tunneling microscopy (STM) for a single adsorbate molecule. For this purpose the ``Newns–Anderson'' treatment (a ``discrete state in a continuum'' treatment) is used to obtain wave functions and other properties of the adsorbate/substrate system. The current is expressed in terms of the adsorbate–tip matrix elements, and an effective local density of states of the adsorbate/substrate system, at the adsorbate. As an example, the treatment i...

  13. Phase transitions and photoinduced transformations at high pressure in the molecular donor-acceptor fullerene complex {Cd(dedtc)2}2 · C60

    Science.gov (United States)

    Meletov, K. P.; Konarev, D. V.; Tolstikova, A. O.

    2015-06-01

    The Raman spectra of crystals of C60 fullerene-cadmium diethyldithiocarbamate molecular donor-acceptor complexes {Cd(dedtc)2}2 · C60 were measured at pressures of up to 17 GPa, and the crystal lattice parameters of these complexes were determined at pressures of up to 6 GPa. An increase in pressure up to ˜2 GPa leads to changes in the Raman spectra, which are manifested by splitting of the intramolecular H g (1)- H g (8) phonon modes and by softening of the A g (2) mode of the C60 molecule. A further increase in pressure up to 17 GPa does not induce significant new changes to the Raman spectra, while a decrease is accompanied by the reverse transformation at a pressure of about 2 GPa. The pressure dependence of the lattice parameters also exhibits a reversible feature at 2 GPa related to a jumplike decrease in compressibility. All these data are indicative of a phase transition in the vicinity of 2 GPa related to the formation of covalent bonds between C60 molecules and, probably, the appearance of C120 dimers in fullerene layers. It was also found that, in the pressure interval from 2 to 6.3 GPa, the Raman spectra of complexes exhibit photoinduced transformations under prolonged exposure to laser radiation with a wavelength of λ = 532 nm and power density up to 5000 W/cm2. These changes are manifested by splitting and softening of the A g (2) mode and resemble analogous changes accompanying the photopolymerization of C60 fullerene. The intensity of new bands exhibits exponential growth with increasing exposure time. The photopolymer yield depends on both the laser radiation power and external pressure. The A g (2) mode splitting under irradiation can be related to the formation of photo-oligomers with various numbers of intermolecular covalent bonds per C60 molecule.

  14. Phase transitions and photoinduced transformations at high pressure in the molecular donor-acceptor fullerene complex (Cd(dedtc)2)2 · C60

    International Nuclear Information System (INIS)

    The Raman spectra of crystals of C60 fullerene-cadmium diethyldithiocarbamate molecular donor-acceptor complexes (Cd(dedtc)2)2 · C60 were measured at pressures of up to 17 GPa, and the crystal lattice parameters of these complexes were determined at pressures of up to 6 GPa. An increase in pressure up to ∼2 GPa leads to changes in the Raman spectra, which are manifested by splitting of the intramolecular Hg(1)-Hg(8) phonon modes and by softening of the Ag(2) mode of the C60 molecule. A further increase in pressure up to 17 GPa does not induce significant new changes to the Raman spectra, while a decrease is accompanied by the reverse transformation at a pressure of about 2 GPa. The pressure dependence of the lattice parameters also exhibits a reversible feature at 2 GPa related to a jumplike decrease in compressibility. All these data are indicative of a phase transition in the vicinity of 2 GPa related to the formation of covalent bonds between C60 molecules and, probably, the appearance of C120 dimers in fullerene layers. It was also found that, in the pressure interval from 2 to 6.3 GPa, the Raman spectra of complexes exhibit photoinduced transformations under prolonged exposure to laser radiation with a wavelength of λ = 532 nm and power density up to 5000 W/cm2. These changes are manifested by splitting and softening of the Ag(2) mode and resemble analogous changes accompanying the photopolymerization of C60 fullerene. The intensity of new bands exhibits exponential growth with increasing exposure time. The photopolymer yield depends on both the laser radiation power and external pressure. The Ag(2) mode splitting under irradiation can be related to the formation of photo-oligomers with various numbers of intermolecular covalent bonds per C60 molecule

  15. Sputtering of Langmuir-Blodgett multilayers by keV C60 projectiles as seen by computer simulations

    International Nuclear Information System (INIS)

    Fundamental processes induced in a thick organic system composed of long, well-organized linear molecules by an impact of 5-20 keV C60 are investigated. The organic system is represented by Langmuir-Blodgett multilayers formed from bariated molecules of arachidic acid. The thickness of the system varies between 2 and 16 nm. Coarse-grained molecular dynamics computer simulations are applied to investigate the energy transfer pathways and sputtering yields as a function of the kinetic energy of the projectile and the thickness of the organic overlayer. The results indicate that an impact of keV C60 projectiles leads to significant ejection of organic material. The efficiency of desorption increases with the kinetic energy of the projectile for a given layer thickness. For a constant primary kinetic energy, the sputtering yield goes through a maximum and finally saturates as the LB layer becomes thicker. Such behaviour is caused by a competition between signal enhancement due to increasing number of organic molecules and signal decrease due to lowering of the amount of the primary energy being backreflected into the organic overlayer by the receding organic/metal interface as the layer is getting thicker. When the sample thickness becomes much larger than the penetration depth of the projectile, the sputtering yield is independent of thickness. The deposited energy is channelled by an open and ordered molecular structure, which leads to abnormally long projectile penetration and ion-induced damage.

  16. Solvent-free functionalization of fullerene C60 and pristine multi-walled carbon nanotubes with aromatic amines

    International Nuclear Information System (INIS)

    Highlights: • Pristine multi-walled carbon nanotubes were functionalized with aromatic amines. • The amines add onto nanotube defects, likewise they add onto fullerene C60. • The addition takes place at elevated temperature and without organic solvents. • Functionalized nanotubes were characterized by a number of instrumental techniques. - Abstract: We employed a direct one-step solvent-free covalent functionalization of solid fullerene C60 and pristine multi-walled carbon nanotubes (MWCNTs) with aromatic amines 1-aminopyrene (AP), 2-aminofluorene (AF) and 1,5-diaminonaphthalene (DAN). The reactions were carried out under moderate vacuum, in a wide temperature range of 180–250 °C, during relatively short time of about 2 h. To confirm successful amine attachment, a large number of analytical techniques were used (depending on the nanomaterial functionalized) such as Fourier transform infrared, Raman, X-ray photoelectron, 13C cross-polarization magic angle spinning NMR spectroscopy, thermogravimetric analysis, laser-desorption ionization time-of-flight mass spectrometry, temperature-programmed desorption with mass spectrometric detection, as well as scanning and transmission electron microscopy. The nucleophilic addition of the aromatic amines to C60 molecule was studied theoretically by using density functional theory (PBE GGA functional with Grimme dispersion correction in conjunction with the DNP basis set). In the case of crystalline C60, the solvent-free technique has a limited applicability due to poor diffusion of vaporous aromatic amines into the bulk. Nevertheless, the approach proposed allows for a facile preparation of aromatic amine-functionalized pristine MWCNTs without contamination with other chemical reagents, detergents and solvents, which is especially important for a vast variety of nanotube applications spanning from nanoelectronics to nanomedicine

  17. Synthesis, Structure, and Properties of the Fullerene C60 Salt of Crystal Violet, (CV(+) )(C60 (.-) )⋅0.5 C6 H4 Cl2 , which Contained Closely Packed Zigzagged C60 (.-) Chains.

    Science.gov (United States)

    Konarev, Dmitri V; Kuzmin, Alexey V; Khasanov, Salavat S; Ishikawa, Manabu; Otsuka, Akihiro; Yamochi, Hideki; Saito, Gunzi; Lyubovskaya, Rimma N

    2016-06-01

    The reduction of fullerene C60 by zinc dust in the presence of crystal violet cations (CV(+) ) yielded a deep-blue solution, from which crystals of (CV(+) )(C60 (.-) )⋅0.5 C6 H4 Cl2 (1) were obtained by slow mixing with n-hexane. The salt contained isolated, closely packed zigzagged chains that were composed of C60 (.-) radical anions with a uniform interfullerene center-to-center distance of 9.98 Å. In spite of the close proximity of the fullerenes, they did not dimerize, owing to spatial separation by the phenyl substituents of CV(+) . The room-temperature conductivity of compound 1 was 3×10(-2)  S cm(-1) along the fullerene chains. The salt exhibited semiconducting behavior, with an activation energy of Ea =167 meV. Spins localized on C60 (.-) were antiferromagnetically coupled within the fullerene chains, with a Weiss temperature of -19 K without long-range magnetic ordering down to 1.9 K. PMID:27062654

  18. Spin–orbit coupling effect on Au–C60 interaction: A density functional theory study

    International Nuclear Information System (INIS)

    Graphical abstract: Inclusion of spin–orbital effect in density functional theory calculations predicts enhanced Au–C60 interaction, but does not alter the relative stability of Au–C60 isomers. Highlights: ► DFT study with spin–orbit coupling effect on Au–C60 complexes. ► Optimal interaction pattern of Au–C60 isomers identified. ► Spin–orbit coupling enhances Au–C interaction. ► Stabilization energy depends on Au cluster size, Au–C distance and Au–C bonding. - Abstract: Density functional theory (DFT) calculations with relativistic spin–orbit (SO) effect are performed to exohedral Au–C60 and Au2–C60–Au2 complexes. The optimal interaction patterns are identified. SO effect tends to enhance the Au–C60 interaction and depends on both Au–C distance and Au–C bonding. However, inclusion of SO effect has only limited impact on the relative stability of Au–C60 isomers that is predicted by scalar relativistic DFT calculations because the SO enhancement has roughly the same order with the Au–C interacting strength. In addition, the stabilization energy contributed from SO effect tends to increase with Au cluster size.

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

    Science.gov (United States)

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

    1991-01-01

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

  20. Optical and photoelectrical studies of gold nanoparticle-decorated C60 films

    International Nuclear Information System (INIS)

    Optical and photoelectrical studies were performed on octane-1,8-dithiol cross-linked fullerene films, with supported gold nanoparticles (C60-DT-Au). According to high-resolution transmission electron microscopy observations, the average size of obtained gold nanoparticles was about 5 nm, and the shape was spherical. The comparative investigation of optical properties of pristine and cross-linked with octane-1,8-dithiol C60 films, decorated with gold nanoparticles, found the difference in the extinction coefficient spectra, which was observed also in the photocurrent spectra of barrier heterostructure Au/C60/Si. The analysis of dark current-voltage characteristics for Au/C60/Si heterostructures showed that the model for them includes the barrier at the C60/Si interface and internal barriers in the C60 layer, caused by the trapping centers. The hopping mechanism of the current transport in the C60 layer was supplemented with the Poole-Frenkel emission process on these centers, with the barrier height greater for the fullerene C60 film cross-linked with octane-1,8-dithiol.

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

    Science.gov (United States)

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

    2015-05-01

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

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

    Science.gov (United States)

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

  3. 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.

  4. 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

    Thin films of fullerenes (C60) were deposited onto silicon using matrix-assisted pulsed laser evaporation (MAPLE). The deposition was carried out from a frozen homogeneous dilute solution of C60 in anisole (0.67 wt%), and over a broad range of laser fluences, from 0.15 J/cm2 up to 3.9 J/cm2. MAPL...

  5. Theory of sum-frequency generation spectroscopy of adsorbed molecules using the density matrix method-broadband vibrational sum-frequency generation and applications

    International Nuclear Information System (INIS)

    A generalized theory of frequency- and time-resolved vibrational sum-frequency generation (SFG) spectroscopy of adsorbates at surfaces is presented using the density matrix formalism. Our theoretical treatment is specifically aimed at addressing issues that accompany the relatively novel SFG approach using broadband infrared pulses. The ultrashort duration of these pulses makes them ideally suited for time-resolved investigations, for which we present a complete theoretical treatment. A second key characteristic of these pulses is their large bandwidth and high intensity, which allow for highly non-linear effects, including vibrational ladder climbing of surface vibrations. We derive general expressions relating the density matrix to SFG spectra, and apply these expressions to specific experimental results by solving the coupled optical Bloch equations of the density matrix elements. Thus, we can theoretically reproduce recent experimentally demonstrated hot band SFG spectra using femtosecond broadband infrared excitation of carbon monoxide (CO) on a Ru(001) surface

  6. 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.

  7. Interaction of Human Serum Album and C60 Aggregates in Solution

    Directory of Open Access Journals (Sweden)

    Hailin Wang

    2011-08-01

    Full Text Available An important property of C60 in aquatic ecotoxicology is that it can form stable aggregates with nanoscale dimensions, namely nC60. Aggregation allows fullerenes to remain suspended for a long time, and the reactivity of individual C60 is substantially altered in this aggregate form. Herein, we investigated the interaction of nC60 and human serum album (HSA using the methods of fluorescence, fluorescence dynamics, circular dichroism (CD, and site marker competitive experiments. We proposed a binding model consistent with the available experimental results for the interactions of nC60 with HSA. During the interaction process, the structure and conformation of HSA were affected, leading to functional changes of drug binding sites of HSA.

  8. Lix@C60: Calculations of the Encapsulation Energetics and Thermodynamics

    Directory of Open Access Journals (Sweden)

    Shigeru Nagase

    2008-09-01

    Full Text Available Li@C60 and Li@C70 can be prepared and thus, their calculations at higher levels of theory are also of interest. In the report, the computations are carried out on Li@C60, Li2@C60 and Li3@C60 with the B3LYP density-functional theory treatment in the standard 3-21G and 6-31G* basis sets. The computed energetics suggests that Lix@C60 species may be produced for a few small x values if the Li pressure is enhanced sufficiently. In order to check the suggestion, a deeper computational evaluation of the encapsulation thermodynamics is carried out.

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

    International Nuclear Information System (INIS)

    A C60-based ebselen derivative 4 was synthesized through the cycloaddition of C60 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 C60). Its structure was characterized by 1H NMR, 13C NMR, IR, UV, and FAB-MS. To verify that the C60-based ebselen derivative 4 had enhanced antioxidative and neuroprotective activity, the C60 derivative 5 and the ebselen derivative 6 were selected to treat cortical neuronal cells using the same procedures as with the C60-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 C60-based ebselen derivative 4 (MTT (OD) 0.340 ± 0.035, LDH release (UL-1) 4.80 ± 0.16) against H2O2-mediated neuronal injury have an advantage over those of C60 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 (C60 component and ebselen component) may be a desirable way of obtaining a new and more biologically effective C60-based compound. (author)

  10. Electrical transport properties of a CNT/C60/CNT hybrid junction with closed end CNT leads using Green's function method

    Science.gov (United States)

    Shokri, Aliasghar; Nikzad, Shaghayegh

    2013-01-01

    We investigate transport properties of an all-carbon molecular device consisting of a CNT/C60/CNT hybrid system with closed end (5,5) CNT leads. Two different ways of coupling are considered for C60 molecule through one and five atoms to the cap-edges of CNTs. Our calculations are based on the Green's function method in the nearest neighbor tight-binding approximation in the coherent regime. In this paper, the sensitivity of electron transport on the geometry of the CNT electrodes-C60 interface is shown. Within the framework of the Landauer-Buttiker formalism, the electrical transmission and current-voltage characteristic are calculated at room temperature. We have investigated the effect of a gate voltage on the current in the considered geometry. In the considered structure, the appearance of the conductance resonances is a manifestation of resonant states of CNT caps, which lie within the HOMO-LUMO gap.

  11. Coherence of Auger and inter-Coulombic decay processes in the photoionization of Ar@C60 versus Kr@C60

    CERN Document Server

    Magrakvelidze, Maia; Javani, Mohammad H; Madjet, Mohamed E; Manson, Steven T; Chakraborty, Himadri S

    2015-01-01

    For the asymmetric spherical dimer of an endohedrally confined atom and a host fullerene, an innershell vacancy of either system can decay through the continuum of an outer electron hybridized between the systems. Such decays, viewed as coherent superpositions of the single-center Auger and two-center inter-Coulombic (ICD) amplitudes, are found to govern leading decay mechanisms in noble-gas endofullerenes, and are likely omnipresent in this class of nanomolecules. A comparison between resulting autoionizing resonances calculated in the photoionization of Ar@C60 and Kr@C60 exhibits details of the underlying processes.

  12. Physicochemical insights in supramolecular interaction of fullerenes C60 and C70 with a monoporphyrin in presence of silver nanoparticles

    Science.gov (United States)

    Mitra, Ratul; Chattopadhyay, Subrata; Bhattacharya, Sumanta

    2012-04-01

    The present article reports for the first time on supramolecular interaction between fullerenes (C60 and C70) and a designed monoporphyrin in solution, e.g., 5,10,15,20-tetrakis(4-methoxyphenyl)-21H,23H-porphine (1), in absence and presence of silver nanoparticles (AgNp) having varying diameter of range between 3 and 7 nm. Ground state electronic interaction between fullerenes and 1 has been evidenced from the observation of decrease in the intensity of the Soret absorption band of 1 after complexation with C60 and C70 in toluene. However, in presence of AgNp, extent of decrease in the intensity of Soret absorption band of 1 has been reduced following its complexation with fullerenes. Steady state fluorescence measurements establish quenching of fluorescence of 1 by fullerenes and the most interesting aspect of the present work is that quenching efficiencies of C60 and C70 are found to be less in presence of AgNp. Steady state fluorescence measurement reveals reduction in the binding constant (K) value for both C60-1 (K-1=2355 dm mol) and C70-1 complex (K-1=11,980 dm mol) in presence of AgNp (K-1=340   and   K-1=7380 dm mol). The new physical insight of the present studies is that 1 acts as excellent discriminator molecule for C70 in presence of AgNp as selectivity in binding is estimated to be ˜21.7 in presence of AgNp compared to the situation when fullerene-1 mixture does not contain any AgNp (i.e., selectivity in binding = ˜5.0) in solution. Time-resolved fluorescence studies establish the role of static quenching mechanism behind fluorescence decay of 1 by fullerenes in absence and presence of AgNp. Magnitude of rate constant for charge separation and quantum yield of charge separation indicates that C70-1 complex exhibits highest value of such parameters in absence of AgNp compared to the situation when AgNp particles are present in the composite mixture of C70 and 1. Dynamic light scattering (DLS) measurement reveals while particle size of AgNp is

  13. Heterogeneous catalytic processes on cobalt, molybdenum and cobalt-molybdenum catalysts studied by temperature-programmed desorption and temperature-programmed reaction. 27 H-D exchange between adsorbed hydrogen and various coadsorbed molecules on the surface of Co-Mo catalysts

    International Nuclear Information System (INIS)

    The H-D-exchange between hydrogen adsorbed on the surface of reduced catalyst Co-Mo/Al2O3 and molecules of coadsorbates: D2O, benzene C6D6, cyclohexane C6D12 and propanethiol C3H7SH, has been studied under conditions of temperature-programmed reaction. It has been discovered that al the forms of hydrogen adsorbed on the catalyst take part in H-D-exchange. Spillover hydrogen adsorbed on a substrate features a high degree of Y-D-exchange with the coadsorbates mentioned. 2 refs., 6 figs

  14. NEXAF/XPS study of organic molecules adsorbed on rutile TiO2(110) and Al2O3/ Ni3Al(111) substrates

    OpenAIRE

    Naboka, Michael

    2014-01-01

    The spectroscopic studies of metal oxide surface interaction with different organic molecules have been performed for the needs of organic electronics, heterogeneous catalysis and surface chemistry. Three different systems: terephthalic acid (TPA) on rutile TiO2(110), azobenzene on rutile-TiO2(110), and tetracene on Al2O3/Ni3Al (111) were investigated.

  15. 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

  16. 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.

  17. Toxic effect of C60 fullerene-doxorubicin complex towards tumor and normal cells in vitro

    Directory of Open Access Journals (Sweden)

    Prylutska S. V.

    2014-09-01

    Full Text Available Creation of new nanostructures possessing high antitumor activity is an important problem of modern biotechnology. Aim. To evaluate cytotoxicity of created complex of pristine C60 fullerene with the anthracycline antibiotic doxorubicin (Dox, as well as of free C60 fullerene and Dox, towards different cell types – tumor, normal immunocompetent and hepatocytes. Methods. Measurement of size distribution for particles in C60 + Dox mixture was performed by a dynamic light scattering (DLS technique. Toxic effect of C60 + Dox complex in vitro towards tumor and normal cells was studied using the MTT assay. Results. DLS experiment demonstrated that the main fraction of the particles in C60 + Dox mixture had a diameter in the range of about 132 nm. The toxic effect of C60 + Dox complex towards normal (lymphocytes, macrophages, hepatocytes and tumor (Ehrlich ascites carcinoma, leukemia L1210, Lewis lung carcinoma cells was decreased by ~10–16 % and ~7–9 %, accordingly, compared with the same effect of free Dox. Conclusions. The created C60 + Dox composite may be considered as a new pharmacological agent that kills effectively tumor cells in vitro and simultaneously prevents a toxic effect of the free form of Dox on normal cells.

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

    Science.gov (United States)

    Zuev, Vjacheslav V.

    2014-05-01

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

  19. Role of intermolecular interactions on the electronic and geometric structure of a large Pi-conjugated molecule adsorbed on a metal surface

    OpenAIRE

    Kilian, L.; Hauschild, A.; Temirov, R.; Soubatch, S.; Schoell, A.; Bendounan, A.; Reinert, F.; Lee, T. L.; Tautz, F. S.; Sokolowski, M.; Umbach, E

    2008-01-01

    The organic semiconductor molecule 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) exhibits two adsorption states on the Ag(111) surface: one in a metastable disordered phase, prepared at low temperatures, the other in the long-range ordered monolayer phase obtained at room temperature. Notably, the two states differ substantial in their vertical bonding distances, intramolecular distortions, and electronic structures. The difference is explained by intermolecular interactions, which ar...

  20. Time-resolved observation of laser-excited C60 decay

    International Nuclear Information System (INIS)

    A technique for measuring the time-resolved delayed electrons and C+n ions from C60 excited by nanosecond or picosecond laser irradiation is presented. Ions produced well after the laser pulse (delayed ionization) are mainly C+60 with weak signals from large fragments such as C+58, C+56, C+50, and no low-mass ions are observed. A dominant slow electron (thermal with kT∼0.3 eV) distribution was observed for the excitation of C60 for wavelengths longer than ∼210 nm. These results are discussed in relation to a ''thermionic'' emission model

  1. Relationship between indium tin oxide surface treatment and hole injection in C60 modified devices

    Science.gov (United States)

    Kim, Sung Hyun; Jang, Jyongsik; Lee, Jun Yeob

    2006-12-01

    The effect of indium tin oxide (ITO) surface treatment on hole injection in organic light-emitting diode with C60 as a buffer layer on ITO was studied. Double surface dipole layer was induced on oxygen plasma treated ITO surface, while no dipole formation was observed on ITO without surface treatment. Interfacial energy barrier between ITO and hole transport layer was reduced by 0.4eV by C60 modification on oxygen plasma treated ITO surface, while there was no change of interfacial energy barrier by C60 on ITO without surface treatment.

  2. Si(111)-7×7表面上C60多层膜的生长及其纳米摩擦学性质%Growth and Nanotribological Properties of C60 Multilayer Films on Si(111 )-7×7 Surface

    Institute of Scientific and Technical Information of China (English)

    杜晓清; 李慧琴; 朱齐荣; 邹志强; 梁齐

    2011-01-01

    在超高真空(UHV)条件下,用分子束外延(MBE)方法,通过对生长过程中蒸发速率和衬底温度等参数的控制,可以避免C60分子在Si(111)-7×7重构表面多层生长时团聚岛的形成,得到了逐层生长的C60多层膜.同时利用超高真空扫描隧道显微镜(UHV-STM)对这种多层膜结构进行了观察并对这种现象产生的机理做了分析,测定了不同层数C60薄膜的黏附力和摩擦力曲线,发现分子层数对薄膜的摩擦性质有显著影响,随着沉积层数的增加,样品的摩擦力明显降低,摩擦系数也有降低的趋势.由于分子层数的增加导致C60分子转动程度增强,本文得出结论,摩擦力的降低是由C60分子的转动引起的,C60分子在这里充当了“纳米滚动轴承”,即C60分子的转动为微观结构提供了能量耗散通道.%C60 layer by layer films without clusters were obtained on Si(111)-7X7 reconstructed surface by controlling parameters such as the evaporation speed and the temperature of substrate during the growth process. The experiments were carried out under ultra-high vacuum (UHV) using molecular beam epitaxy (MBE). These films were observed by ultra-high vacuum scanning tunneling microscopy (UHV-STM) and the mechanism of this phenomenon was analyzed. The adhesion and frictional force curves of these C60 films with different layers were measured. Their frictional properties were found to be affected by the number of layers. The frictional force decreased obviously with the increase in layers and the frictional coefficient also showed a downward tendency. Our simulation showed that adhesion was not the main effect that led to a decrease in the frictional force. Since the increase of layers leads to a higher level of rotation for C60 molecules, we conclude that the decrease in the frictional force is caused by the rotation of the Ceo molecules. C60 molecule acts as "nano rolling bearing" here. That is, the rotation of the C60 molecules provides

  3. Influence of CO molecular impurity on the structural and thermodynamic properties of fullerite C60, in a broad range of sorption temperatures

    Science.gov (United States)

    Meleshko, V. V.; Legchenkova, I. V.; Stetsenko, Y. E.; Prokhvatilov, A. I.

    2016-02-01

    An x-ray diffraction study of how sorption of CO gas at a pressure of 30 atm in the temperature range of 150-600 °C influences the structural characteristics of polycrystalline and single crystal fullerite C60. The sorption kinetics are studied by constructing a dependence of the lattice parameter on the time it takes for fullerite to be saturated by CO molecules. At temperatures Tsorb > 300 °C there is an observed dissociation of carbon monoxide, accompanied by the precipitation of carbon powder and the chemical interaction of atomic oxygen with C60 and CO molecules, and possibly with the carbon condensate. These processes have a strong influence on the structural characteristics of fullerite, thus creating, in part, a nonmonotonic dependence of the parameter and lattice matrix volume on the impurity saturation temperature. The concentrations of solid solutions C60(CO)x poly- and single crystal samples are determined in the physisorption range for two modes (150 and 250 °C). It is found that the CO impurity has a linear effect on the lattice parameter and the temperature of the orientational transition of fullerite C60.

  4. Detailed low-energy electron diffraction analysis of the (4×4) surface structure of C60 on Cu(111): Seven-atom-vacancy reconstruction

    Science.gov (United States)

    Xu, Geng; Shi, Xing-Qiang; Zhang, R. Q.; Pai, Woei Wu; Jeng, H. T.; Van Hove, M. A.

    2012-08-01

    A detailed and exhaustive structural analysis by low-energy electron diffraction (LEED) is reported for the C60-induced reconstruction of Cu(111), in the system Cu(111) + (4 × 4)-C60. A wide LEED energy range allows enhanced sensitivity to the crucial C60-metal interface that is buried below the 7-Å-thick molecular layer. The analysis clearly favors a seven-Cu-atom vacancy model (with Pendry R-factor Rp = 0.376) over a one-Cu-atom vacancy model (Rp = 0.608) and over nonreconstructed models (Rp = 0.671 for atop site and Rp = 0.536 for hcp site). The seven-Cu-atom vacancy forms a (4 × 4) lattice of bowl-like holes. In each hole, a C60 molecule can nestle by forming strong bonds (shorter than 2.30 Å) between 15 C atoms of the molecule and 12 Cu atoms of the outermost and second Cu layers.

  5. Decoration of C60 nanorods with nickel and their magnetic properties

    Institute of Scientific and Technical Information of China (English)

    CHEN Ao; LIU BingBing; HOU YuanYuan; WEN GeHui; LIU DeDi; LU ShuangChen; LI ZePeng; LI XiangLin; ZOU YongGang; ZOU Bo; LI DongMei; CUI Tian; ZOU GuangTian

    2009-01-01

    We studied the coating of C60 nanorods with nickel by electroless plating method and investigated their magnetic properties. The morphology and structure of the nickel layer coated on C60 nanorods were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Raman spectroscopy. The coated nickel is in the form of nano-sized crystals and becomes a continuous layer as reaction time increases. The hysteresis loop shows a super paramagnetic characteristic similar to that of nanometer-sized nickel particle. These results suggest that the average size of nickel particles on C60 rods is below 10 nm. Our study has shown that electroless plating is an efficient and simple method for coating C60 nanorods with nickel.

  6. Optimization of the Thermoelectric Figure of Merit in Crystalline C60 with Intercalation Chemistry.

    Science.gov (United States)

    Kim, Jeong Yun; Grossman, Jeffrey C

    2016-07-13

    Crystalline C60 is an appealing candidate material for thermoelectric (TE) applications due to its extremely low thermal conductivity and potentially high electrical conductivity with metal atom intercalation. We investigate the TE properties of crystalline C60 intercalated with alkali and alkaline earth metals using both classical and quantum mechanical calculations. For the electronic structure, our results show that variation of intercalated metal atoms has a large impact on energy dispersions, which leads to broad tunability of the power factor. For the thermal transport, we show that dopants introduce strong phonon scattering into crystalline C60, leading to considerably lower thermal conductivity. Taking both into account, our calculations suggest that appropriate choice of metal atom intercalation in crystalline C60 could yield figures of merit near 1 at room temperature. PMID:27322341

  7. FABRICATION AND AFM/FFM STUDIES OF C60-CONTAINING POLYELECTROLYTE SELF-ASSEMBLED FILMS

    Institute of Scientific and Technical Information of China (English)

    Lan Huang; Xiao-rong Hou; Yuan-kang He; Xiao-liang Zheng; Fang Wei; Xin-sheng Zhao; Wei-xiao Cao

    2002-01-01

    An initial investigation on the roughness and frictional properties of the self-assembled thin films from polyelectrolytes is presented. Star-shaped C60-poly(styrene-maleic anhydride) was successful prepared. The multilayer thin films have been fabricated on mica with diazoresin as the cationic polyelectrolyte and hydrolyzed star-shaped C60-poly(styrene-maleic anhydride) as the anionic polyelectrolyte via self-assembly technique. The crosslinking structure of the films is formed from the conversion of ionic bond to covalent bond after UV irradiation. AFM/FFM investigations provide insights into the roughness and frictional properties on a microscale. The roughness depends strongly on the number of film layers in the case of C60-containing films. The frictional forces of the films exhibited a well behaved non-linear relationship in response to the change of applied load. It supports the prediction of enhanced load-bearing property of C60-containing thin films.

  8. Electron propagator calculations on the ground and excited states of C60(-).

    Science.gov (United States)

    Zakrzewski, V G; Dolgounitcheva, O; Ortiz, J V

    2014-09-01

    Electron propagator calculations in two approximations—the third-order algebraic, diagrammatic construction and the outer valence Green’s function (OVGF)—have been performed on the vertical electron affinities of C60 and the vertical electron detachment energies of several states of C60(–) with a variety of basis sets. These calculations predict bound (2)T1u and (2)T1g anions, but fail to produce (2)T2u or (2)Hg anionic states that are more stable than ground-state C60. The electron affinity for the (2)Ag state is close to zero, but no definitive result on its sign has been obtained. This state may be a resonance or marginally bound anion. The OVGF prediction for the vertical electron detachment energy of (2)T1u C60(–), 2.63 eV, is in excellent agreement with recent anion photoelectron spectra. PMID:24813804

  9. A 2:1 receptor/C60 complex as a nanosized universal joint.

    Science.gov (United States)

    Yanney, Michael; Fronczek, Frank R; Sygula, Andrzej

    2015-09-14

    Buckycatcher II, a C51 H24 hydrocarbon with two corannulene pincers on a dibenzonorbornadiene tether, exhibits an affinity toward C60 in organic solvents that is dramatically higher than the original buckycatcher C60 H28 and other corannulene-based molecular receptors for fullerenes. In addition to the formation of an usual 1:1 C60 @catcher inclusion complex, a trimeric C60 @(catcher)2 assembly is detected in solutions and in the solid state. X-ray structure determination reveals a remarkable "universal joint" solvent-free crystal arrangement of the trimer, with a single fullerene cage wrapped by four corannulene subunits of two cooperating catcher receptors. PMID:26352025

  10. Electrochemical and photoelectronic studies on C60-pyrrolidine-functionalised poly(terthiophene)

    International Nuclear Information System (INIS)

    Graphical abstract: - Abstract: A novel donor-acceptor poly(terthiophene) derivative bearing a C60 pendant was electropolymerizated from N-methyl-2-(2-[4,4′’-didecyloxy-2,2′;5′,2′’]terthiophen-3′-yl-ethenyl) fullero[3,4]pyrrolidine (TTh–C60) solution. The electroreduction of TTh-C60 and poly(TTh-C60) showed the presence of complex peaks related to fulleropyrrolidine reduction. The dual nature of these redox couples may be related to increasing Coulombic repulsion or coupling between C60 substituents. Electrochemical, X-Ray photoelectron spectroscopy (XPS), Ultra-Violet photoelectron (UPS) and UV-Vis spectroscopy also confirm the nature of poly(TTh-C60). Electrochemical band gap of poly(TTh-C60) is 0.63 ± 0.20 eV in TBAP electrolyte and propylene carbonate (PC) solution. Furthermore, we obtained the value of optical energy band gap (Eopt = 0.59 ± 0.03 eV), the transport energy band gap (Egtrans = 1.17 ± 0.20 eV) and the exciton binding energy (Eb = 0.58 ± 0.20 eV) for poly(TTh-C60). The ionization energy values (IE) were determined using UPS spectroscopy (IE = 4.92 ± 0.10 eV) and electrochemical investigations of the poly(TTh-C60) polarized in TBAP/DCM (IE = 5.01 ± 0.10 eV) and TBAP/PC solution (IE = 4.95 ± 0.10 eV) demonstrating good coincidence of the value. The electrochemical method revealed, that the location of the Fermi level relative to the valence and conduction bands indicates p-type character of semiconducting poly(TTh-C60). On the other hand photoemission spectroscopy manifests n-type behavior of examined sample. In turn, the UV-Vis result showed that the charge transfer (CT) between poly(TTh) and C60 unit can suggest, that these chromophores are not entirely independent

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

    OpenAIRE

    Jeffrey G. Lundin; Spencer L. Giles; Robert F. Cozzens; James H. Wynne

    2014-01-01

    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,...

  12. 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.

  13. Aqueous solubilization of C60 fullerene by natural protein surfactants, latherin and ranaspumin-2

    OpenAIRE

    Vance, Steven J.; Desai, Vibhuti; Smith, Brian O.; Kennedy, Malcolm W.; Cooper, Alan

    2016-01-01

    C60 fullerene is not soluble in water and dispersion usually requires organic solvents, sonication or vigorous mechanical mixing. However, we show here that mixing of pristine C60 in water with natural surfactant proteins latherin and ranaspumin-2 (Rsn-2) at low concentrations yields stable aqueous dispersions with spectroscopic properties similar to those previously obtained by more vigorous methods. Particle sizes are significantly smaller than those achieved by mechanical dispersion alone,...

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

    Science.gov (United States)

    Mukherjee, B.; Weaver, J. W.

    2009-12-01

    The fate and transport of colloidal fullerenes (n-C60) in the environment are likely to be guided by their electrokinetic and aggregation behavior. In natural water bodies inorganic ions exert significant effects in determining the size and charge of dispersed n-C60. Although the effects of cations on the behavior of n-C60 have been studied extensively; studies on the effect of anions are relatively few and thus were the focus of our investigation. The effects of anions (e.g., Cl- , SO42-) on average aggregate size (DH) and zeta potential (ZP) of n-C60 were found to be absent in presence of monovalent cations (e.g., Na+) over the tested range of pH (3-to-12) and ionic strength (0-to-20 mM). Similar observations were noted in the presence of multivalent cations (e.g., Mg2+) near acidic and neutral pH conditions. However, under alkaline conditions (pH~10) a strong anion-dependent reversal of surface charge was noted. The ZP of n-C60 changed from -65 mV, when dispersed in DI water, to +4 mV and +40 mV in the presence of SO42- and Cl-, respectively in a 10mM salt concentration (i.e., MgCl2 and MgSO4). The corresponding DH of the dispersed n-C60 changed simultaneously from 115 nm, in DI water, to 1450 nm and 225 nm for the MgSO4 and MgCl2 electrolytes. These findings provide a better understanding of interfacial interaction characteristics of n-C60 NPs, and may lead to remediation strategies for n-C60 NPs in the environment.

  15. Ionization and fragmentation of C-60 via multiphoton-multiplasmon excitation

    OpenAIRE

    Hunsche, S; Starczewski, Tomas; L'Huillier, Anne; Persson, Anders; Wahlström, Claes-Göran; vandenHeuvell, B. V. L; Svanberg, Sune

    1996-01-01

    We study the intensity dependence of ionization and fragmentation of buckminsterfullerene (C-60) in strong laser fields. Our data provide strong evidence that at intensities less than or similar to 10(14) W/cm(2) these processes occur predominantly via multiphoton excitation of the 20 eV plasmon resonance of C-60 At least two plasmons have to be created to initiate fragmentation or multiple ionization.

  16. Coulomb interaction effects on nonlinear optical response in C60, C70, and higher fullerenes

    OpenAIRE

    Harigaya, Kikuo

    1998-01-01

    Nonlinear optical properties in the fullerene C$_{60}$ and the extracted higher fullerenes -- C$_{70}$, C$_{76}$, C$_{78}$, and C$_{84}$ -- are theoretically investigated by using the exciton formalism and the sum-over-states method. We find that off-resonant third order susceptibilities of higher fullerenes are a few times larger than those of C$_{60}$. The magnitude of nonlinearity increases as the optical gap decreases in higher fullerenes. The nonlinearity is nearly proportional to the fo...

  17. Experimental evidence of a dynamic Jahn-Teller effect in C-60(+)

    Energy Technology Data Exchange (ETDEWEB)

    Canton, S.E.; Yencha, A.J.; Kukk, E.; Bozek, J.D.; Lopes, M.C.A.; Snell, G.; Berrah, N.

    2002-05-20

    Detailed analysis of the HOMO bandshape in the photoelectron spectrum of gaseous C60 reveals a dynamic Jahn-Teller effect in the ground state of C60+. The direct observation of three tunneling states asserts a D3d geometry for the isolated cation, originating from a strong vibronic coupling. These results show that the ionic motion of the ions plays an important role in the electron-phonon interaction.

  18. Preparation of C60 Nanowhiskers-SnO2 Nanocomposites and Photocatalytic Degradation of Organic Dyes.

    Science.gov (United States)

    Park, Hae Soo; Ko, Weon Bae

    2015-10-01

    C60 nanowhiskers were prepared using a liquid-liquid interfacial precipitation (LLIP) method. Tin oxide (SnO2) nanoparticles were synthesized by a reaction of tin (IV) chloride pentahydrate with ammonium nitrate in an electric furnace. The C60 nanowhiskers-SnO2 nanocomposites were calcined in an electric furnace at 700 °C under an inert argon gas atmosphere for 2 h. The crystallinity, morphology and optical properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and UV-vis spectrophotometry. The photocatalytic activity of the C60 nanowhiskers-SnO2 nanocomposites in the degradation of the organic dyes, such as methylene blue, methyl orange, rhodamine B, and brilliant green, under ultraviolet light at 254 nm by UV-vis spectrophotometry was evaluated and compared with that of C60 nanowhiskers and SnO2 nanoparticles. The experimental results showed that C60 nanowhiskers-SnO2 nanocomposites exhibited remarkably higher photocatalytic degradation of organic dyes compared to C60 nanowhiskers and SnO2 nanoparticles. PMID:26726474

  19. 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.

  20. 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.

  1. Non-detection of C60 fullerene at two mass extinction horizons

    Science.gov (United States)

    Carrasquillo, Anthony J.; Cao, Changqun; Erwin, Douglas H.; Summons, Roger E.

    2016-03-01

    Fullerene (C60) have been reported in a number of geologic samples and, in some cases, attributed to carbonaceous materials delivered during bolide impact events. The extraction and detection of C60 poses significant analytical challenges, and some studies have been called into question due to the possibility of C60 forming in situ. Here, we extracted samples taken from the Permian-Triassic boundary section in Meishan, South China and the Cretaceous-Paleogene boundary exposed at Stevns Klint, Denmark, and analyzed the residues using a fast and reliable method for quantifying C60. Extraction of both whole rock and completely demineralized samples were completed under conditions that previously yielded C60 as well as using an optimized approach based on recent literature reports. These extracts were analyzed using mass spectrometry with the soft-ionization techniques, atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI), which have not been shown to form fullerenes in-situ. In no case were we able to detect C60, nor could we corroborate previous reports of its occurrence in these sediments, thereby challenging the utility of fullerene as a proxy for bolide impacts or mass extinction events.

  2. Synthesis and ESR Spectrum Study of C60-Polystyrene by Direct Reaction of Polystyrene and C60 under UV Photoinitiator%紫外光照下C60与聚苯乙烯直接反应合成C60-聚苯乙烯衍生物及电子自旋共振(ESR)研究

    Institute of Scientific and Technical Information of China (English)

    沈建中; 陈士明; 郭崇东; 蔡瑞芳

    2003-01-01

    在室温,紫外光照下溶液相中C60与聚苯乙烯的直接反应合成得聚苯乙烯的C60加合物.衍生物中C60的含量可由C60的投料比来控制.得到的产物经UV-Vis,FTIR,GPC,TGA及DSC等波谱表征,测得产物的分子量比母体聚苯乙烯的分子量稍高.对溶液相的反应进行了现场的ESR研究,得到强的PSC-@60的自由基信号,g值为2.0024.同时对C60和聚苯乙烯混合物固相体系的光照反应进行了ESR测试.结果表明在反应过程中及最终产物中均存在稳定的C60-高分子链烃基自由基阴离子RC-@60表明了反应的自由基机理.

  3. Fluorescence dynamics of microsphere-adsorbed sunscreens

    Science.gov (United States)

    Krishnan, R.

    2005-03-01

    Sunscreens are generally oily substances which are prepared in organic solvents, emulsions or dispersions with micro- or nanoparticles. These molecules adsorb to and integrate into skin cells. In order to understand the photophysical properties of the sunscreen, we compare steady-state and time-resolved fluorescence in organic solvent of varying dielectric constant ɛ and adsorbed to polystyrene microspheres and dispersed in water. Steady-state fluorescence is highest and average fluorescence lifetime longest in toluene, the solvent of lowest ɛ. However, there is no uniform dependence on ɛ. Sunscreens PABA and padimate-O show complex emission spectra. Microsphere-adsorbed sunscreens exhibit highly non-exponential decay, illustrative of multiple environments of the adsorbed molecule. The heterogeneous fluorescence dynamics likely characterizes sunscreen adsorbed to cells.

  4. C60高性能混凝土配合比设计与应用%Design and Application of C60 High Performance Concrete Proportion

    Institute of Scientific and Technical Information of China (English)

    郝峰

    2014-01-01

    Based on engineering practice, this paper discusses the selection method of concrete material in beam span structure construction, points out the related problems in the design of C60 high performance concrete mix proportion in engineering practice and puts forward the correct mix proportion and parameters design requirements.%本文结合工程实践,探讨梁跨结构施工中混凝土用原材料的选择方法,指出工程实践中C60高性能混凝土配合比设计的相关问题,提出正确的配合比及参数设计要求。

  5. Biomimetic hydroxyapatite nanocrystals in composites with C60 and Au-DNA nanoparticles: IR-spectral study

    International Nuclear Information System (INIS)

    Due to growing interest towards development so-called 'smart biomaterials'-mainly composites with targeted biological action consisting of inorganic nanoparticles and organic compounds-the primary tasks in this field include synthesis of proper nanoparticles and studying chemical interaction between them and organic constituents. Exactly such kind of research is the object of this study - synthesis of composites in the system HAP:DNA:Au:C60:H2O including components of this system-composites HAP:DNA:Au:H2O, DNA:Au:H2O, HAP:C60:H2O, HAP:BSF, C60:H2O and studying chemical interaction in this system by comparison of IR spectra. All materials in this system are typical ingredients of smart biomaterials. The HAP nanocrystals were synthesized by chemical synthesis in a biomimetic route, all other materials were acquired on the market. We chose the simplest method of the composite synthesis-by mixing at room temperature. Comparative study of IR spectra of these composites revealed the considerable distortion, shifting or full disappearance of some absorption bands of the components of the composites. The largest alterations were found in the range of deformation vibrations and they are different for different modes of vibrations. In the range of valence vibrations the components' absorption bands are mostly preserved. These features are the ample evidence of chemical interaction between these components. Identification of the absorption bands that were changed most of all indicates the chemical bonds which directly participate in the chemical interaction. For example loss of the DNA absorption band at wave number 1704 cm-1 can serve as indication of new chemical bond with this part of the DNA molecule, namely C=O bond in thymine. The spectra alteration and their dependence vs. components concentration in the system HAP-DNA reveal that the HAP nanoparticles supposably are localized due to interaction with DNA molecules and that results in significant alteration of the

  6. Ab-inito calculation of energy level alignment and vacuum level shift at CuPc/C60 interfaces

    Science.gov (United States)

    Sai, Na; Zhu, Xiaoyang; Chelikowsky, James; Leung, Kevin

    2012-02-01

    The alignment of the donor and acceptor enegy levels is of crucial importance for organic photovotaic performance. We investigate the interfaical electronic structure and energy level alignment of copper phthalocyanine (CuPc)/fullerene (C60) using ab-inito density functional theory calculations including van der Waals interactions and hybrid density functionals. We show that energy level alignment critically depends on the standing-up and lying-down orientation of the CuPc molecules relative to C60 at the interface. We calculate the magnitude of the interface dipole at different molecular orientations and compare them to the vacuum level shift observed in photoemission spectroscopy. The validity of existing theoretical models which invoke charge transfer on this organic interface will be discussed in light of our predictions. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Deparment of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  7. 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.

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

    International Nuclear Information System (INIS)

    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. - Highlights: → Fullerenes were detected in cosmetics up to 1.1 μg/g. → Liquid-liquid extraction efficiently recovers fullerenes in cosmetic matrices. → Solid-phase extraction reduces LC-MS detection interferences for C60. → Cosmetics can increase human and environmental fullerene exposures. - Fullerenes were detected in cosmetics with liquid chromatography-mass spectrometry up to 1.1 μg/g, demonstrating a source for human/environmental exposure.

  9. 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).

  10. nC60 deposition kinetics: the complex contribution of humic acid, ion concentration, and valence.

    Science.gov (United States)

    McNew, Coy P; LeBoeuf, Eugene J

    2016-07-01

    The demonstrated toxicity coupled with inevitable environmental release of nC60 raise serious concerns about its environmental fate and transport, therefore it is crucial to understand how nC60 will interact with subsurface materials including attached phase soil and sediment organic matter (AP-SOM). This study investigated the attachment of nC60 onto a Harpeth humic acid (HHA) coated silica surface under various solution conditions using a quartz crystal microbalance with dissipation monitoring. The HHA coating greatly enhanced nC60 attachment at low ion concentrations while hindering attachment at high ion concentrations in the presence of both mono and divalent cations. At low ion concentrations, the HHA greatly reduced the surface potential of the silica, enhancing nC60 deposition through reduction in the electrostatic repulsion. At high ion concentrations however, the reduced surface potential became less important due to the near zero energy barrier to deposition and therefore non-DLVO forces dominated, induced by compaction of the HHA layer, and leading to hindered attachment. In this manner, observed contributions from the HHA layer were more complex than previously reported and by monitoring surface charge and calculated DLVO interaction energy alongside attachment experiments, this study advances the mechanistic understanding of the variable attachment contributions from the humic acid layer. PMID:27061365

  11. Charge Transfer and Surface Scattering at Cu/C_60 Planar Interfaces

    Science.gov (United States)

    Hebard, A. F.; Ruel, R. R.; Eom, C. B.

    1996-03-01

    Thin films of Cu and C_60 have been sequentially deposited onto insulating substrates in high vacuum and studied using in situ resistivity measurements during deposition. Different regimes of behavior, which manifest the transfer of electrons from the Cu metal across the planar interface to the C_60, are identified. For example, in the continuous film limit, in which the Cu is thick enough to have a size-effect resistivity proportional to the reciprocal of the film thickness, the presence of an adjacent C_60 monolayer gives rise to an increase in resistance. This resistance increase is quantitatively described by a scattering model in which the interfacial diffuse scattering cross section is found to be 5Åthe approximate area of a face of the molecular cage. In a second regime of behavior, in which the ultra-thin Cu films have a morphology of coalescing islands, the presence of an adjacent C_60 monolayer, doped by charge transfer from the metal, creates a shunting path with sheet resistance ~8000Ω/Box accompanied by a pronounced decrease in resistance. The inferred room-temperature resistivity is more than a factor of two less than that of the 3-dimensional alkali-metal-doped compounds, A_3C_60 (A=K,Rb).

  12. Electron elastic scattering off $A$@C$_{60}$: The role of atomic polarization under confinement

    CERN Document Server

    Dolmatov, V K; Chernysheva, L V

    2015-01-01

    The present paper explores possible features of electron elastic scattering off endohedral fullerenes $A$@C$_{60}$. It focuses on how dynamical polarization of the encapsulated atom $A$ by an incident electron might alter scattering off $A$@C$_{60}$ compared to the static-atom-$A$ case, as well as how the C$_{60}$ confinement modifies the impact of atomic polarization on electron scattering compared to the free-atom case. The aim is to provide researchers with a "relative frame of reference" for understanding which part of the scattering processes could be due to electron scattering off the encapsulated atom and which due to scattering off the C$_{60}$ cage. To meet the goal, the C$_{60}$ cage is modeled by an attractive spherical potential of a certain inner radius, thickness, and depth which is a model used frequently in a great variety of fullerene studies to date. Then, the Dyson equation for the self-energy part of the Green's function of an incident electron moving in the combined field of an encapsulat...

  13. 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.

  14. Theoretical Studies on Electronic States of Rh-C60. Possibility of a Room-temperature Organic Ferromagnet

    Directory of Open Access Journals (Sweden)

    K. Yamaguchi

    2004-08-01

    Full Text Available A possible mechanism for a ferromagnetic interaction in the rhombic (Rh formof C60 (Rh-C60 is suggested on the basis of theoretical studies in relation to cage distortionof the C60 unit in the polymerized 2D-plane. Band structure calculations on Rh-C60 showthat cage distortion leads to competition between diamagnetic and ferromagnetic states,which give rise to the possibility of thermally populating the ferromagnetic state.

  15. 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.

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

    International Nuclear Information System (INIS)

    In both molecular and periodic solid-state systems there is a need for the accurate determination of the ionization potential and the electron affinity for systems ranging from light harvesting polymers and photocatalytic compounds to semiconductors. The development of a Green's function approach based on the coupled cluster (CC) formalism would be a valuable tool for addressing many properties involving many-body interactions along with their associated correlation functions. As a first step in this direction, we have developed an accurate and parallel efficient approach based on the equation of motion-CC technique. To demonstrate the high degree of accuracy and numerical efficiency of our approach we calculate the ionization potential and electron affinity for C60 and C70. Accurate predictions for these molecules are well beyond traditional molecular scale studies. We compare our results with experiments and both quantum Monte Carlo and GW calculations

  17. Self-healing phenomenon and dynamic hardness of C60-based nanocomposite coatings.

    Science.gov (United States)

    Penkov, Oleksiy V; Pukha, Volodymyr E; Devizenko, Alexander Yu; Kim, Hae-Jin; Kim, Dae-Eun

    2014-05-14

    The phenomenon of surface self-healing in C60-based polymer coatings deposited by ion-beam assisted physical vapor deposition was investigated. Nanoindentation of the coatings led to the formation of a protrusion rather than an indent. This protrusion was accompanied by an abnormal shape of the force-distance curve, where the unloading curve lies above the loading curve due to an additional force applied in pulling the indenter out of the media. The coatings exhibited a nanocomposite structure that was strongly affected by the ratio of C60 ion and C60 molecular beam intensities during deposition. The coatings also demonstrated the dynamic hardness effect, where the effective value of the hardness depends significantly on the indentation speed. PMID:24697539

  18. Quantum and classical features of the photoionization spectrum of C$_{60}$

    CERN Document Server

    Verkhovtsev, Alexey V; Solov'yov, Andrey V

    2013-01-01

    Considering the photoionization process of the C$_{60}$ fullerene, we elucidate the contributions of various classical and quantum physics phenomena manifesting themselves in this process. Comparing the results, based on the {\\it ab initio} and model approaches, we map the well-resolved features of the photoionization spectrum to single-particle and collective excitations having the different physical nature. We demonstrate that the peculiarities arising in the photoionization spectrum of C$_{60}$ atop the dominating plasmon excitations have the quantum origin. In particular, we demonstrate that a series of individual peaks can be assigned to the optically allowed discrete transitions, ionization of particular molecular orbitals of the system, or to the single-electron transitions to the continuum. The analysis performed gives a detailed information on the nature of numerous features in the photoionization spectrum of C$_{60}$.

  19. Performance improvement in pentacene organic thin film transistors by inserting a C60 ultrathin layer

    Institute of Scientific and Technical Information of China (English)

    Sun Qin-Jun; Xu Zheng; Zhao Su-Ling; Zhang Fu-Jun; Gao Li-Yan

    2011-01-01

    The contact effect on the performances of organic thin film transistors is studied here. A C60 ultrathin layer is inserted between Al source-drain electrode and pentacene to reduce the contact resistance. By a 3 nm C60 modification,the injection harrier is lowered and the contact resistance is reduced. Thus, the field-effect mobility increases from 0.12to 0.52 cm2/(V.s). It means that inserting a C60 ultra thin layer is a good method to improve the organic thin film transistor (OTFT) performance. The output curve is simulated by using a charge drift model. Considering the contact of OTFTs should be carried out.

  20. A study on electrospray mass spectrometry of fullerenol C60(OH24

    Directory of Open Access Journals (Sweden)

    Mihaela Silion

    2013-07-01

    Full Text Available Full characterization of fullerenol C60(OH24 by HPLC ESI-MS in negative and positive ionization modes was achieved. Fragmentor voltage and capillary voltage were optimized in order to obtain a good signal stability and the best peak intensity distribution for the fullerenol C60(OH24 in both negative and positive modes. While the predominant base peak observed for C60(OH24 in the negative ionization mode was [M − H]− at m/z 1127, those observed in the positive mode were multiply charged [M − H2O + 4H]4+ at m/z 279 and [M − 12H2O + 2NH3 + 6H]6+ at m/z 158.

  1. Mass spectrometric identification of C60 fragmentation regimes under energetic Cs+ bombardment

    CERN Document Server

    Zeeshan, Sumaira; Ahmad, Shoaib

    2016-01-01

    Three C60 fragmentation regimes in fullerite bombarded by Cs+ are identified as a function of its energy. C2 is the major species sputtered at all energies. For E(Cs+) < 1 keV C2 emissions dominate. C2 and C1 have highest intensities between 1 and 3 keV with increasing contributions from C3 and C4. Intensities of all fragments maximize around 2 keV. Above 3 keV, fragments densities stabilize. The roles of and the contributions from direct recoils and collision cascades are determined. Maximum direct recoil energy delivered to the C60 fullerite cage is 210 eV at which only C2 emissions occur is identified and an explanation provided. The three fragmentation regimes under continued Cs+ bombardment eventually lead to complete destruction of the C60 cages transforming fullerite into amorphous carbon

  2. Synthesis of N-acetamide C60 nitride and its performance of optical limiting

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    N-acetamide C60 nitride (N-acetamide-1,2-dihydro-1,2-aza-fullerene[60]) has been synthesized by the reaction of C60 and azidoacetamide and initially characterized. Its mechanism was that the objective product is formed through intermediate triazoline. The computational study shows that N-nitride structure is thermodynamically more stable by using the semi-empirical AM1 SCF-MO method. The properties of optical limiting were tested by using double frequency Nd∶YAG pulse laser system and showed that the optical limiting mechanism is reverse saturation absorption. A wavelength of 532 nm, compared with optical limiting for ns pulse, this new material has good optical limiting character for ps pulse. At wavelength of 707 nm, the capacity of optical limiting of the derivative is prior to C60.

  3. A First Principle Comparative Study on Chemisorption of H2 on C60, C80, and Sc3N@C80 in Gas Phase and Chemisorption of H2 on Solid Phase C60

    OpenAIRE

    Hongtao Wang; Lijuan Chen; Yongkang Lv; Jianwen Liu; Gang Feng

    2014-01-01

    The chemisorptions of H2 on fullerenes C60 and C80, endofullerene Sc3C@C80 and solid C60 were comparatively studied. A chain reaction mechanism for dissociative adsorption of H2 on solid C60 is proposed under high pressure. The breaking of H–H bond is concerted with the formation of two C–H bonds on two adjacent C60 in solid phase. The adsorption process is facilitated by the application of high pressure. The initial H2 adsorption on two adjacent C60 gives a much lower barrier 1.36 eV in comp...

  4. 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...

  5. Skin penetration and kinetics of pristine fullerenes (C60) topically exposed in industrial organic solvents

    International Nuclear Information System (INIS)

    Pristine fullerenes (C60) in different solvents will be used in many industrial and pharmaceutical manufacturing and derivatizing processes. This report explores the impact of solvents on skin penetration of C60 from different types of industrial solvents (toluene, cyclohexane, chloroform and mineral oil). Yorkshire weanling pigs (n = 3) were topically dosed with 500 μL of 200 μg/mL C60 in a given solvent for 24 h and re-dosed daily for 4 days to simulate the worst scenario in occupational exposures. The dose sites were tape-stripped and skin biopsies were taken after 26 tape-strips for quantitative analysis. When dosed in toluene, cyclohexane or chloroform, pristine fullerenes penetrated deeply into the stratum corneum, the primary barrier of skin. More C60 was detected in the stratum corneum when dosed in chloroform compared to toluene or cyclohexane. Fullerenes were not detected in the skin when dosed in mineral oil. This is the first direct evidence of solvent effects on the skin penetration of pristine fullerenes. The penetration of C60 into the stratum corneum was verified using isolated stratum corneum in vitro; the solvent effects on the stratum corneum absorption of C60 were consistent with those observed in vivo. In vitro flow-through diffusion cell experiments were conducted in pig skin and fullerenes were not detected in the receptor solutions by 24 h. The limit of detection was 0.001 μg/mL of fullerenes in 2 mL of the receptor solutions.

  6. The fragment ion distribution of C60 in close collision with fast carbon ions

    International Nuclear Information System (INIS)

    We have measured the mass distribution of fragment ions of C60 produced by collisions with 15.6 MeV carbon ions in different charge states. Close collisions were selectively measured using the coincidence method with the change of the projectile charge state. For the electron capture and loss by C5+.6+ projectile ions, which are the K-electron processes, the multifragmentation was observed evidently. In L-electron loss channels of the C2+ projectile, the peaks of the multiply ionized C60 ions and the multiply ionized fullerene-like fragment ions are more intense or as intense as the small fragment ions. (author)

  7. Pressure dependence of the electronic density of states and Tc in superconducting Rb3C60

    International Nuclear Information System (INIS)

    The functional dependence of the superconducting transition temperature Tc on the electronic density of states N(Ef) was determined for Rb3C60 by measuring the magnetic susceptibility under hydrostatic pressure to ∼ 1 GPa in a commercial SQUID magnetometer. Both Tc and N(Ef) decrease under pressure at the rates -31%/GPa and -14.5%/GPa, respectively, but lie above the corresponding values for K3C60 at the same lattice parameter. The present results are consistent with weak-coupling BCS theory with characteristic energy Echar/kB≅ 320 endash 810 K. copyright 1996 The American Physical Society

  8. Irradiation-induced polymerization and damages of fulleriteC60 under irradiation with Fe ions

    International Nuclear Information System (INIS)

    Results of thin fullerite C60 films irradiation with Fe+ ions, energy of which is E= 140 keV and doses varied from 1.2·1012to 0.66·1014 ions/cm2 are considered. Raman spectroscopy and XRD data show that after irradiation of fullerenes C60 with Fe+ ions dimmers and polymers with orthorhombic and tetragonal structures are formed that is similar to phases formed under high temperatures and pressure. At higher doses polymerized phases disappear because of destruction and formation of amorphous phase

  9. The strength of electron electron correlation in Cs3C60

    OpenAIRE

    Baldassarre, L.; Perucchi, A.; Mitrano, M.; Nicoletti, D.; Marini, C.; Pontiroli, D.; Mazzani, M.; Aramini, M.; Riccó, M.; Giovannetti, G.; M. Capone; Lupi, S.

    2015-01-01

    Cs3C60 is an antiferromagnetic insulator that under pressure (P) becomes metallic and superconducting below T c  = 38 K. The superconducting dome present in the T − P phase diagram close to a magnetic state reminds what found in superconducting cuprates and pnictides, strongly suggesting that superconductivity is not of the conventional Bardeen-Cooper-Schrieffer (BCS) type We investigate the insulator to metal transition induced by pressure in Cs3C60 by means of infrared spectroscopy suppleme...

  10. Electron transfer from end-capped quaterthiophene to photoexcited C60: a pulsed EPR investigation

    International Nuclear Information System (INIS)

    We report on a pulsed EPR investigation of the photoinduced electron transfer from end-capped quaterthiophene to the photoexcited triplet state of C60 in liquid solutions. Fourier transform of the free induction decays results in spectra of the transient triplet state and of the transient C60 monoradical anion. Electron transfer rates were deduced from the observed triplet quenching rates at different temperatures. The results give evidence for the formation of an intermediate donor-acceptor exciplex in the charge transfer mechanism. (orig.)

  11. Analysis of diffuse orientation transition parameters in C60 crystals at 250-260 K

    International Nuclear Information System (INIS)

    The analysis of the orientation-structural transformation parameters in the C60 crystals within the temperature range of 250-260 K is carried out on the basis of the analysis of temperature dependences of thermal capacity and velocity of inelastic (ferroelectric) deformation, observed in the transition area experience. The value of the transformation elementary volume by the C60 (11-83 nm3) correlated molecular motion and the value of spontaneous shear deformation of the lattice 2.4 x 10-2 by its restructuring from a simple cubical one into a face-centered one are determined in the course of the analysis

  12. Evidence for Jahn-Teller coupling and Fano-resonance of lower Hg modes in K3C60 and Rb3C60 films from Raman scattering

    International Nuclear Information System (INIS)

    The Raman scattering study of superconducting thin film of A3C60 (A = K,Rb) carried out upon laser excitations at 1.16 and 2.41 eV have revealed the significant broadening and Fano-lineshapes of several low energy Hg intramolecular modes with relative intensities and widths depending om excitation energies. The most interesting feature of the 1.16 eV excited spectrum is the wide asymmetric band at 400 cm-1 which can be assigned by Fano-shape fitting to enormously broadened Hg(2) mode red shifted compared to its bare frequency of 408 cm-1. The narrowing of all lower Hg modes in insulating A6C60 phase indicates strong electron-phonon coupling of this Jahn-Teller modes in x=3 phase and suggests that this low energy vibrations are contributing to superconducting pairing. However, the possibility to interpret the wide band at 400 cm-1 as the maximum of electronic background can not be ruled out yet and is supported by our preliminary observations of its disappearance at low temperature below Tc. (author). 31 refs, 3 figs

  13. 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)

    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 (C60), which forms colloidal aggregates in water, and its water-soluble derivative fullerol (C60(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 (1O2) quencher; (2) fullerene induced toxicity with or without UV-A incidence, with a significant (p 1O2 generation; and (3) fullerol also decreased GCL activity and GSH formation (p 1O2 formation.

  14. Mechanism for doping induced p type C60 using thermally evaporated molybdenum trioxide (MoO3) as a dopant

    Science.gov (United States)

    Yang, Jin-Peng; Wang, Wen-Qing; Cheng, Li-Wen; Li, Yan-Qing; Tang, Jian-Xin; Kera, Satoshi; Ueno, Nobuo; Zeng, Xiang-hua

    2016-05-01

    Thermally evaporated molybdenum trioxide (MoO3) doped C60 films, which could change n type features of pristine C60 to form a p type mixed C60 layer, are investigated by x-ray and ultraviolet photoelectron spectroscopy. It is found that C60 HOMO progressively shifts closer to the Fermi level after increased MoO3 doping concentration, and final onset of C60 HOMO is pinned at binding energy of 0.20 eV, indicating the formation of p type C60 films. It is proposed that in charge transfer induced p type C60 formation, due to large electron affinity of MoO3 (6.37 eV), electrons from HOMO of C60 could easily transfer to MoO3 to form cations and therefore increase hole concentration, which could gradually push C60 HOMO to the Fermi level and finally form p type C60 films. Moreover, clear different types of C60 species have been confirmed from UPS spectra in highly doped films.

  15. Mechanism for doping induced p type C60 using thermally evaporated molybdenum trioxide (MoO3) as a dopant.

    Science.gov (United States)

    Yang, Jin-Peng; Wang, Wen-Qing; Cheng, Li-Wen; Li, Yan-Qing; Tang, Jian-Xin; Kera, Satoshi; Ueno, Nobuo; Zeng, Xiang-Hua

    2016-05-11

    Thermally evaporated molybdenum trioxide (MoO3) doped C60 films, which could change n type features of pristine C60 to form a p type mixed C60 layer, are investigated by x-ray and ultraviolet photoelectron spectroscopy. It is found that C60 HOMO progressively shifts closer to the Fermi level after increased MoO3 doping concentration, and final onset of C60 HOMO is pinned at binding energy of 0.20 eV, indicating the formation of p type C60 films. It is proposed that in charge transfer induced p type C60 formation, due to large electron affinity of MoO3 (6.37 eV), electrons from HOMO of C60 could easily transfer to MoO3 to form cations and therefore increase hole concentration, which could gradually push C60 HOMO to the Fermi level and finally form p type C60 films. Moreover, clear different types of C60 species have been confirmed from UPS spectra in highly doped films. PMID:27058225

  16. EPR, FTIR, and FAB mass spectrometric investigation of reaction of H atoms with C 60 in a cyclohexane matrix

    Science.gov (United States)

    Howard, J. A.

    1993-03-01

    Hydrogen atoms have been reacted with C 60 in a cyclohexane matrix at 77 K in a rotating cryostat. Species HC 60, H 2 n + 1 C 60, and H 2 nC 60 have been identified by EPR, FTIR and FAB mass spectrometry. HC 60 has the magnetic parameters aH(1) = 92.9 ± 0.5 MHz and g = 2.00218 ± 0.00004. These values are compared to the deuterium and muonium analogs. Reasons for the isotope effect in the hydrogen and muon hyperfine interactions of HC 60 and MuC 60 are discussed. The narrow line widths of the EPR transitions of H 2 n + 1C 60 may be associated with globe-trotting hydrogen atoms. C 60 acts as a H atom sponge at high atom fluxes and H 2 nC 60s with n as large as 17 have been identified.

  17. Photophysical properties in aqueous solutions of C60 embedded in 2:1 γ-cyclodextrin/[60]fullerene inclusion complexes

    Science.gov (United States)

    Quaranta, Annamaria; Qu, Huanhuan; Vencel, Thomas; Zhang, Yongmin; Leibl, Winfried; Leach, Sydney; Bensasson, René V.

    2014-10-01

    To resolve conflicting results in the literature, we determine quantitatively the properties of the lowest triplet excited state of water soluble 2:1 host:guest complexes of C60 embedded in γ-cyclodextrin (γ-CD/C60) using laser flash photolysis. The results show that the triplet excited state characteristics of γ-CD/C60 in aqueous solutions are very similar to those observed for C60 in organic solvents. Moreover oxygen, in contrast with non-gaseous solutes, can reach the proximity of C60 embedded in 2:1 γ-CD inclusion complexes. In addition, photodestruction quantum yields have been determined for C60 in toluene and for C60 in γ-CD inclusion complexes in water.

  18. Analytical study of PPV-oligomer- and C60-based devices for optimising organic solar cells

    NARCIS (Netherlands)

    Geens, Wim; Poortmans, Jef; Jain, Suresh C.; Nijs, Johan; Mertens, Robert; Veenstra, Sjoerd C.; Krasnikov, Viktor V.; Hadziioannou, Georges

    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

  19. Conformational, IR spectroscopic and electronic properties of conium alkaloids and their adducts with C60 fullerene

    Science.gov (United States)

    Zabolotnyi, M. A.; Prylutskyy, Yu I.; Poluyan, N. A.; Evstigneev, M. P.; Dovbeshko, G. I.

    2016-08-01

    Conformational, IR spectroscopic and electronic properties of the components of Conium alkaloids (Conium maculatum) in aqueous environment were determined by model calculations and experiment. With the help of FT-IR spectroscopy the possibility of formation of an adduct between γ-coniceine alkaloid and C60 fullerene was demonstrated, which is important for further application of conium analogues in biomedical purposes.

  20. Ab-initio modeling of an anion $C_{60}^-$ pseudopotential for fullerene-based compounds

    CERN Document Server

    Vrubel, I I; Ivanov, V K

    2015-01-01

    A pseudopotential of $C_{60}^-$ has been constructed from ab-initio quantum-mechanical calculations. Since the obtained pseudopotential can be easily fitted by rather simple analytical approximation it can be effectively used both in classical and quantum molecular dynamics of fullerene-based compounds.

  1. Electron energy loss spectroscopy of free C60 and C70

    International Nuclear Information System (INIS)

    Electron energy loss spectroscopy has been performed with samples of pure C60 and C70 using primary electron energies between 10 and 1100 eV. The experimental data could be explained in terms of optically forbidden and allowed transitions, and by collective excitations (plasmons), which could be distinguished by their dependence on the energy of the primary electron. (orig.)

  2. Orientation effect of coulomb interactions in superconducting phase of Rb3 C60 crystal

    International Nuclear Information System (INIS)

    Calculating the Coulomb interaction energies in superconducting phase of Rb3 C60 we find the essential dependences of the ground state energy on rotational angles of spheroidal anions of C603-. The results obtained assume of frozen rotations of fullerene ions in the crystal due to Coulomb fields. 17 refs., 3 figs

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

    DEFF Research Database (Denmark)

    Sanz, Alejandro; Wong, Him Cheng; Nedoma, Alisyn J.;

    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...

  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

    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 co...

  5. Nonequilibrium electron-vibration coupling and conductance fluctuations in a C-60 junction

    DEFF Research Database (Denmark)

    Ulstrup, Soren; Frederiksen, Thomas; Brandbyge, Mads

    2012-01-01

    We investigate chemical bond formation and conductance in a molecular C-60 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 c...

  6. Simulations of C60 bombardment of Si, SiC, diamond and graphite

    International Nuclear Information System (INIS)

    Molecular dynamics simulations of the 20-keV C60 bombardment at normal incidence of Si, SiC, diamond and graphite targets were performed. The unique feature of these targets is that strong covalent bonds can be formed between carbon atoms from the C60 projectile and atoms in the solid material. The mesoscale energy deposition footprint (MEDF) model is used to gain physical insight into how the sputtering yields depend on the substrate characteristics. A large proportion of the carbon atoms from the C60 projectile are implanted into the lattice structure of the target. The sputtering yield from SiC is ∼twice that from either diamond or Si and this can be explained by both the region of the energized cylindrical tract created by the impact and the number density. On graphite, the yield of sputtered atoms is negligible because the open lattice allows the cluster to deposit its energy deep within the solid. The simulations suggest that build up of carbon with a graphite-like structure would reduce any sputtering from a solid with C60+ bombardment.

  7. Colloidal Behavior of Fullerenes (nC60): Role of Coions

    Science.gov (United States)

    Effects of coions on the average initial aggregate size (DH) and zeta potential (ZP) of nC60 in mono and divalent counterion (10 mM) systems were investigated at pH 3, 5.8, and 10. Differences in the effects of SO42-and Cl- could not be established, in presence of Na+, for all pH...

  8. 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. PMID:22344044

  9. 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.

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

    International Nuclear Information System (INIS)

    Sodium was incorporating at the copper-phthalocyanine (CuPc)/C60 interface in CuPc/C60-based small-molecular solar cells to enhance their power conversion efficiency. C60 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/C60 interface • Annealing importantly improved the cell efficiency of Na-doped devices. • Change in the carrier mobility and concentration was investigated

  11. Mono- and bis(pyrrolo)tetrathiafulvalene derivatives tethered to C60

    DEFF Research Database (Denmark)

    Vico Solano, Marta; Della Pia, Eduardo Antonio; Jevric, Martyn; Schubert, Christina; Wang, Xintai; van der Pol, Cornelia; Kadziola, Anders; Nørgaard, Kasper; Guldi, Dirk M.; Nielsen, Mogens Brøndsted; Jeppesen, Jan Oskar

    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...

  12. Electrochemical Generation of Porphyrin-Porphyrin and Porphyrin-C60 Polymeric Photoactive Organic Heterojunctions

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Photoactive organic-organic interfaces were formed by electrochemical synthesis. • Zn(II), free base porphyrin and C60 films were used to form donor-aceptor bilayers. • Photoinduced electron transfer between the interfaces were analyzed by SPV. • The heterojunctions were able to produce photoinduced charge separated states. - Abstract: Photoactive organic-organic interfaces are formed by electrochemical synthesis. The generation of porphyrin/porphyrin and porphyrin/C60 heterojunctions over indium tin oxide electrodes by successive electropolymerization steps is described. Functionalized C60 buckminsterfullerene holding a carbazol residue and porphyrins containing carbazol and phenylamino moieties are able to form electrodeposited layers by cyclic voltammetry. Photoinduced electron transfer between Zn(II), free base porphyrins and C60 films were analyzed by both, light modulated surface photovoltage spectroscopy and laser induced transient photovoltage. The results showed that the electrochemical generated polymeric heterojunctions are able to produce photoinduced charge separated states, which could present a potential application in the design and construction of organic optoelectronic devices

  13. Nanovalved Adsorbents for CH4 Storage.

    Science.gov (United States)

    Song, Zhuonan; Nambo, Apolo; Tate, Kirby L; Bao, Ainan; Zhu, Minqi; Jasinski, Jacek B; Zhou, Shaojun J; Meyer, Howard S; Carreon, Moises A; Li, Shiguang; Yu, Miao

    2016-05-11

    A novel concept of utilizing nanoporous coatings as effective nanovalves on microporous adsorbents was developed for high capacity natural gas storage at low storage pressure. The work reported here for the first time presents the concept of nanovalved adsorbents capable of sealing high pressure CH4 inside the adsorbents and storing it at low pressure. Traditional natural gas storage tanks are thick and heavy, which makes them expensive to manufacture and highly energy-consuming to carry around. Our design uses unique adsorbent pellets with nanoscale pores surrounded by a coating that functions as a valve to help manage the pressure of the gas and facilitate more efficient storage and transportation. We expect this new concept will result in a lighter, more affordable product with increased storage capacity. The nanovalved adsorbent concept demonstrated here can be potentially extended for the storage of other important gas molecules targeted for diverse relevant functional applications. PMID:27124722

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

    International Nuclear Information System (INIS)

    A comprehensive study of molecular dynamics and structure in new heterogenous nanocomposites based on poly(butylene terephthalate) and nanoparticles C60 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 1H 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.

  15. Ecological applications of the irradiated adsorbents

    International Nuclear Information System (INIS)

    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

  16. Computer simulations of material ejection during C60 and Arm bombardment of octane and β-carotene

    International Nuclear Information System (INIS)

    Molecular dynamics (MD) computer simulations are used to investigate material ejection and fragment formation during keV C60 and Arm (m = 60, 101, 205, 366, 872 and 2953) bombardment of organic solids composed from octane and β-carotene molecules at 0° and 45° impact angle. Both systems are found to sputter efficiently. For the octane system, material removal occurs predominantly by ejection of intact molecules, while fragment emission is a significant ejection channel for β-carotene. A difference in the molecular dimensions is proposed to explain this observation. It has been shown that the dependence of the sputtering yield Y on the primary kinetic energy E and the cluster size n can be expressed in a simplified form if represented in reduced units. A linear and nonlinear dependence of the Y/n on the E/n are identified and the position of the transition point from the linear to nonlinear regions depends on the size of the cluster projectile. The impact angle has a minor influence on the shape of the simplified representation

  17. Epitaxial Growth of an Organic p-n Heterojunction: C60 on Single-Crystal Pentacene.

    Science.gov (United States)

    Nakayama, Yasuo; Mizuno, Yuta; Hosokai, Takuya; Koganezawa, Tomoyuki; Tsuruta, Ryohei; Hinderhofer, Alexander; Gerlach, Alexander; Broch, Katharina; Belova, Valentina; Frank, Heiko; Yamamoto, Masayuki; Niederhausen, Jens; Glowatzki, Hendrik; Rabe, Jürgen P; Koch, Norbert; Ishii, Hisao; Schreiber, Frank; Ueno, Nobuo

    2016-06-01

    Designing molecular p-n heterojunction structures, i.e., electron donor-acceptor contacts, is one of the central challenges for further development of organic electronic devices. In the present study, a well-defined p-n heterojunction of two representative molecular semiconductors, pentacene and C60, formed on the single-crystal surface of pentacene is precisely investigated in terms of its growth behavior and crystallographic structure. C60 assembles into a (111)-oriented face-centered-cubic crystal structure with a specific epitaxial orientation on the (001) surface of the pentacene single crystal. The present experimental findings provide molecular scale insights into the formation mechanisms of the organic p-n heterojunction through an accurate structural analysis of the single-crystalline molecular contact. PMID:27171402

  18. Kelvin probe force microscopy of C60 on metal substrates: towards molecular resolution

    International Nuclear Information System (INIS)

    Surface workfunction changes upon C60 adsorption onto different metal single crystals are investigated by Kelvin probe force microscopy (KPFM). Literature values for similar metal/organic systems, showing a broad variation for both the measured metal workfunction and workfunction change, are compared to the acquired KPFM values. Good agreement is found between nanoscopic KPFM results and macroscopic photoelectron spectroscopy or Kelvin probe literature data. The model of a linear dependence between the metal substrate workfunction and the C60-induced workfunction change is confirmed. Former numerical simulations predicted a lateral quantitative KPFM resolution in the range of 10 nm, in this work results are published that show the achievement of this resolution with Cr coated, sharp tips. Furthermore, numerical simulations are presented that show the possibility of molecular contrast for KPFM

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

    International Nuclear Information System (INIS)

    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 deg. 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

  20. Synthesis of a novel perylene diimide derivative and its charge transfer interaction with C60

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel organic electron acceptor, N,N′-dipyrimidinyl-3,4,9,10-perylene-tetracarboxylic diimide (DMP), was designed and synthesized. The molecular structure was characterized by FTIR spectrum and elemental analysis. By cyclic voltammetry measurements, DMP was found to possess a lower LUMO energy level than N,N′-diphenyl-3,4,9,10-perylene-tetracarboxylic diimide due to the stronger electron-withdrawing pyrimidinyl group than the phenyl group. Fluorescence quenching is observed in a dual-layer film consisting of a DMP layer and a C60 layer and was attributed to the charge transfer at the interface due to the energy level offset between DMP and C60.

  1. C60 spin-charging’ with an eye on a quantum computer

    International Nuclear Information System (INIS)

    A question whether there exists an interaction between the spins of the endohedral atom A@C60 and the properties of the confining shell which might affect the alignment of, or manipulation by, the spins for building a register for a quantum computer is discussed. It is argued that an effect, termed the ‘C60 spin-charging’ effect, can occur in endohedral atoms and would affect the operation of a quantum register. The effect is exemplified by choosing the 3d (Cr and Mn) and 4d (Mo and Tc) transition metal atoms as well as a rare-earth Eu atom as the case study. A class of high-spin atoms which are less suitable for building a quantum register is, thus, identified. (paper)

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

    Science.gov (United States)

    Palade, D. I.; Baran, V.

    2016-09-01

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

  3. Ultrafast dynamics and fragmentation of C60 in intense laser pulses

    CERN Document Server

    Lin, Zheng-Zhe

    2014-01-01

    The radiation-induced fragmentation of the C60 fullerene was investigated by the tight-binding electron-ion dynamics simulations. In intense laser field, the breathing vibrational mode is much more strongly excited than the pentagonal-pinch mode. The fragmentation effect was found more remarkable at long wavelength lambda>800 nm rather than the resonant wavelengths due to the internal laser-induced dipole force, and the production ratio of C and C2 rapidly grows with increasing wavelength. By such fragmentation law, C atoms, C2 dimers or large Cn fragments could be selectively obtained by changing the laser wavelength. And the fragmentation of C60 by two laser pulses like the multi-step atomic photoionization was investigated.

  4. XPS depth profile analysis of ArF immersion resists by using C60 ion beam

    International Nuclear Information System (INIS)

    Argon ion sputtering is one of the most accepted techniques for depth profiling in practical X-ray photoelectron spectroscopy (XPS) analysis, while this technique is known to cause severe degradation especially with organic materials. Sputtering system using buckminsterfullerene (C60) ion beam has recently been introduced to XPS apparatus as a new sputtering tool for depth profiling. It enables the XPS depth analysis of organic materials such as photoresists without chemical damages. In this paper, the XPS analysis using the C60 ion sputtering was applied to examine the depth distributions of a fluoropolymer in ArF immersion resists to clarify the mechanism of the water-repellency change between the co-polymer and blend polymer. In addition, the depth profiling of the resist is compared to those observed with other techniques such as angle resolved XPS analysis and XPS analysis on the gradient shaved surfaces. (author)

  5. Photodegradation of the electronic structure of PCBM and C60 films in air

    Science.gov (United States)

    Anselmo, Ana S.; Dzwilewski, Andrzej; Svensson, Krister; Moons, Ellen

    2016-05-01

    Fullerenes are common electron acceptors in organic solar cells. Here the photostability in air of the electronic structures of spin-coated PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) and evaporated C60 films are studied using ultraviolet photoelectron spectroscopy (UPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. After exposing these materials in air to simulated sunlight, the filled and empty molecular orbitals are strongly altered, indicating that the conjugated π-system of the C60-cage has degraded. Even a few minutes in normal lab light induces changes. These results stress the importance of protecting fullerene-based films from light and air during processing, operation, and storage.

  6. In situ Raman study of C60 polymerization during isothermal pressurizing at 800 K

    International Nuclear Information System (INIS)

    The first in situ Raman study of C60 isothermal compression at 800 K and up to 32 GPa was performed using rhombohedral and tetragonal phases as starting materials. The rhombohedral phase shows a phase transition to 3D polymer above 10 GPa, similar to that in experiments where isobaric heating was used at pressures of 9-13 GPa. It is shown that the T-P diagram of C60 polymeric phases (temperature increase followed by pressurizing) is significantly different from the known P-T diagram (pressurizing followed by heating). Tetragonal polymer exhibited significantly stronger stability and can be followed at least up to ∼15 GPa. Heating up to 800 K of tetragonal polymer at pressures of 6-8 GPa confirms that, due to geometrical frustrations, the tetragonal phase remains stable even at pressure and temperature conditions at which rhombohedral polymer is usually formed

  7. Antioxidant activity and cytotoxicity of solubilized C60 and its conjugates with butylated hydroxytoluene

    OpenAIRE

    Nunes, A. S.; A Matias; Caetano, Liliana Aranha; Graça, Anabela; Simplício, Ana Luísa

    2011-01-01

    It has been described that fullerenes (C60) present interesting properties with potential application in clinical conditions related to oxidative stress. One of the most prominent features of fullerenes is the ability to quench free radicals. However, because of its poor solubility, this has been studied mostly in organic solutions, while the antioxidant activity and cytotoxicity of fullerenes and their derivates in aqueous medium is not well characterized. The antioxidant capacity of s...

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

    OpenAIRE

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

    2011-01-01

    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 t...

  9. Report on neutron depolarisation measurements of C60 and 57Cr3 steel samples

    International Nuclear Information System (INIS)

    In this report initial measurements of C60 and 57Cr3 steel samples using neutron depolarization are discussed. During the experiments, the austenite to ferrite and perlite transformation was studied. The ferrite fraction formed and the mean ferrite particle radius were determined from the rotation and the shortening of the polarization vector of the neutron beam. Besides an overview of the performed experiments, the theoretical approach which was used to determine the transformation parameters, is described. (orig.)

  10. Pressure-dependent photopolymerization kinetics in C60 crystals: Observation of exponential dependence on intermolecular distance

    International Nuclear Information System (INIS)

    Raman-scattering experiments under hydrostatic pressure have been performed to investigate the pressure dependence of photopolymerization reaction coefficients in C60 crystals. Reaction coefficients of photopolymerization have been obtained from the observed variation of Raman spectra with irradiation time and a rate equation analysis. The dependence on the intermolecular distance clearly shows an exponential-type behavior, which suggests a photoreaction process described by the potential-energy surface with multiple minima

  11. An optically stimulated superconducting-like phase in K3C60 far above equilibrium Tc

    OpenAIRE

    Mitrano, M.; Cantaluppi, A.; Nicoletti, D.; Kaiser, S.; Perucchi, A.; Lupi, S.; Di Pietro, P.; Pontiroli, D.; Riccò, M.; A. Subedi; Clark, S. R.; Jaksch, D.; A. Cavalleri

    2015-01-01

    The control of non-equilibrium phenomena in complex solids is an important research frontier, encompassing new effects like light induced superconductivity. Here, we show that coherent optical excitation of molecular vibrations in the organic conductor K3C60 can induce a non-equilibrium state with the optical properties of a superconductor. A transient gap in the real part of the optical conductivity and a low-frequency divergence of the imaginary part are measured for base temperatures far a...

  12. Possible superstructures of metallic ions in nonstoichiometric fullerites Mx C60

    International Nuclear Information System (INIS)

    The ordered structures of alkali metal M=K,Rb,Cs atoms are considered in the Mx C60 systems for x<6 on the basis of symmetry analysis. Using the static concentration wave approach the x values and the corresponding vectors resulting in periodic structures are determined. The phase diagram that agrees qualitatively with the one observed experimentally is obtained. (author). 17 refs., 10 figs

  13. Observation of photorefractive effects in blue-phase liquid crystal containing fullerene-C60.

    Science.gov (United States)

    Khoo, Iam Choon; Chen, Chun-Wei; Ho, Tsung-Jui

    2016-01-01

    Photorefractive effects manifested in two beam coupling and side diffractions are observed in fullerene-C60 doped blue-phase liquid crystals (BPLC-C60) upon application of a DC bias field. The mechanism at work here is attributed to BPLC lattice distortion by the combined DC (Edc)+ photorefractive space-charge (Ephoto) fields, in addition to the DC + optical field induced effects reported in previous studies of dye-doped system. The first order diffraction efficiency of ∼2×10-3 and beam coupling gain of over 2% are observed in a 55 μm thick sample with input laser beam power of 5 mW at an applied DC voltage of 160 V. The effective nonlinear index coefficient n2 of BPLC-C60 is measured to be on the order of 10-2  cm2/W, which is slightly lower than their NLC counterparts. Owing to the isotropy of BPLC optical properties, these effects can be observed with more relaxed requirements on the laser polarizations, directions of incidence, and sample orientations. PMID:26696174

  14. Molecular triads composed of ferrocene, C60, and nitroaromatic entities: electrochemical, computational, and photochemical investigations.

    Science.gov (United States)

    Zandler, Melvin E; Smith, Phillip M; Fujitsuka, Mamoru; Ito, Osamu; D'Souza, Francis

    2002-12-27

    Synthesis and physicochemical characterization of a series of molecular triads composed of ferrocene, C(60), and nitroaromatic entities are reported. Electrochemical studies revealed multiple redox processes involving all three redox active ferrocene, C(60), and nitrobenzene entities. Up to eight redox couples within the accessible potential window of o-dichlorobenzene containing 0.1 M (TBA)ClO(4) are observed. A comparison between the measured redox potentials with those of the starting compounds revealed absence of any significant electronic interactions between the different redox entities. The geometric and electronic structure of the triads are elucidated by using ab initio B3LYP/3-21G methods. In the energy-optimized structures, as predicted by electrochemical studies, the first HOMO orbitals are found to be located on the ferrocene entity, while the first LUMO orbitals are mainly on the C(60) entity. The coefficients of the subsequent LUMO orbitals track the observed site of electrochemical reductions of the triads. The photochemical events of the triads are probed by both steady-state and time-resolved techniques. The steady-state emission intensities of the triads and the starting dyad, 2-(ferrocenyl)fulleropyrrolidine, are found to be completely quenched compared to fulleropyrrolidine bearing no redox active substituents. The subpicosecond and nanosecond transient absorption spectral studies revealed efficient charge separation (and rapid charge recombination) in the triads, and this has been attributed to the close spacing of the redox entities of the triad to one another. PMID:12492311

  15. A correlation between ionization energies and critical temperatures in superconducting A3C60 fullerides

    International Nuclear Information System (INIS)

    Highlights: • A correlation between the ionization energies and the critical temperatures of A3C60 compounds is presented. • It is also qualitatively related to the known lattice parameter – Tc correlation. • Ionization energies could represent a more proper quantum mechanically scale than ionization radii. • A threshold emerges that corresponds to fullerides which have not been found to be superconductive. - Abstract: Buckminster A3C60 fullerides (A = alkali metal) are usually superconductors with critical temperatures Tc in the range 2.5–40 K. Although they are very similar in size, structure and many other aspects, the effect of the alkali atoms on Tc has generally been understood in terms of the variation of the lattice constant. Here we show that there seems to be a direct correlation between the sum of the ionization energies of the three alkali atoms in the superconducting A3C60 compounds and the corresponding critical temperatures. A linear fit of the correlation implies a certain limit for the sum, below which superconductivity should not occur. Ionization energies have so far not been connected to superconductivity

  16. 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.

  17. Theoretical study of C60 as catalyst for dehydrogenation in LiBH4.

    Science.gov (United States)

    Scheicher, Ralph H; Li, Sa; Araujo, C Moyses; Blomqvist, Andreas; Ahuja, Rajeev; Jena, Puru

    2011-08-19

    Complex light metal hydrides possess many properties which make them attractive as a storage medium for hydrogen, but typically catalysts are required to lower the hydrogen desorption temperature and to facilitate hydrogen uptake in the form of a reversible reaction. The overwhelming focus in the search for catalysing agents has been on compounds containing titanium, but the precise mechanism of their actions remains somewhat obscure. A recent experiment has now shown that fullerenes (C(60)) can also act as catalysts for both hydrogen uptake and release in lithium borohydride (LiBH(4)). In an effort to understand the involved mechanism, we have employed density functional theory to carry out a detailed study of the interaction between this complex metal hydride and the carbon nanomaterial. Considering a stepwise reduction of the hydrogen content in LiBH(4), we find that the presence of C(60) can lead to a substantial reduction of the involved H-removal energies. This effect is explained as a consequence of the interaction between the BH(x)( - ) complex and the C(60) entity. PMID:21788688

  18. Possible light-induced superconductivity in K3C60 at high temperature.

    Science.gov (United States)

    Mitrano, M; Cantaluppi, A; Nicoletti, D; Kaiser, S; Perucchi, A; Lupi, S; Di Pietro, P; Pontiroli, D; Riccò, M; Clark, S R; Jaksch, D; Cavalleri, A

    2016-02-25

    The non-equilibrium control of emergent phenomena in solids is an important research frontier, encompassing effects such as the optical enhancement of superconductivity. Nonlinear excitation of certain phonons in bilayer copper oxides was recently shown to induce superconducting-like optical properties at temperatures far greater than the superconducting transition temperature, Tc (refs 4-6). This effect was accompanied by the disruption of competing charge-density-wave correlations, which explained some but not all of the experimental results. Here we report a similar phenomenon in a very different compound, K3C60. By exciting metallic K3C60 with mid-infrared optical pulses, we induce a large increase in carrier mobility, accompanied by the opening of a gap in the optical conductivity. These same signatures are observed at equilibrium when cooling metallic K3C60 below Tc (20 kelvin). Although optical techniques alone cannot unequivocally identify non-equilibrium high-temperature superconductivity, we propose this as a possible explanation of our results. PMID:26855424

  19. The structural and electronic evolution of Li4C60 through the polymer-monomer transformation

    International Nuclear Information System (INIS)

    In this paper, we combine synchrotron powder x-ray diffraction, 7Li nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) experiments to study the structural evolution of Li4C60 and how its electronic ground state depends on the crystal symmetry. The compound in the two-dimensional polymer phase with mixed interfullerene bonding motifs is a band gap insulator. EPR, however, reveals the presence of intrinsic centers originating from broken C60-C60 bonds and local Li off-stoichiometry that create states in the band gap and account for the complex temperature dependence of the spin susceptibility as well as the residual temperature dependence of the 7Li NMR shift. At low temperatures, the Li+ ions are statically disordered on the 7Li NMR timescale. The observed 7Li NMR line narrowing at T>200 K is ascribed to the Li+ diffusion dynamics and above room temperature the polymer phase is already a good ionic conductor. Heating the sample to temperatures above ∼470 K results in gradual depolymerization to the metallic monomer fcc high temperature structure. The transformation is first order and polymer as well as monomer phases coexist over a broad temperature interval (130 K)

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

    International Nuclear Information System (INIS)

    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 C60/C70 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 C60/C70 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 C60 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)

  1. Infrared spectroscopy of small-molecule endofullerenes

    CERN Document Server

    Rõõm, T; Ge, Min; Hüvonen, D; Nagel, U; Mamone, S; Levitt, M H; Carravetta, M; Chen, J Y -C; Lei, Xuegong; Turro, N J; Murata, Y; Komatsu, K

    2013-01-01

    Hydrogen is one of the few molecules which has been incarcerated in the molecular cage of C$_{60}$ and forms endohedral supramolecular complex H$_2$@C$_{60}$. In this confinement hydrogen acquires new properties. Its translational motion becomes quantized and is correlated with its rotations. We applied infrared spectroscopy to study the dynamics of hydrogen isotopologs H$_2$, D$_2$ and HD incarcerated in C$_{60}$. The translational and rotational modes appear as side bands to the hydrogen vibrational mode in the mid infrared part of the absorption spectrum. Because of the large mass difference of hydrogen and C$_{60}$ and the high symmetry of C$_{60}$ the problem is identical to a problem of a vibrating rotor moving in a three-dimensional spherical potential. The translational motion within the C$_{60}$ cavity breaks the inversion symmetry and induces optical activity of H$_2$. We derive potential, rotational, vibrational and dipole moment parameters from the analysis of the infrared absorption spectra. Our ...

  2. Photoemission and inverse photoemission study of the electronic structure of C60 fullerenes encapsulated in single-walled carbon nanotubes

    OpenAIRE

    Shiozawa, Hidetsugu; Ishii, Hiroyoshi; Kihara, Hideo; Sasaki, Naoya; Nakamura, Satoshi; Yoshida, Tetsuo; Takayama, Yasuhiro; Miyahara, Tsuneaki; Suzuki, Shinzo; Achiba, Yohji; Kodama, Takeshi; Higashiguchi, Mitsuharu; Chi, Xiaoyu; Nakatake, Masashi; Shimada, Kenya

    2006-01-01

    We have measured the valence-band photoemission and inverse photoemission spectra of single-walled carbon nanotubes (SWNTs) with mean radii of 0.7 and 0.64 nm encapsulating C60 fullerenes (peas), so-called "peapods." The photoemission spectrum of the C60 peas in the SWNTs is obtained by subtracting the spectrum of empty SWNTs from the spectrum of the peapod. The structures in the C60 pea spectra correspond well to those in the spectrum of a C60 face-centered-cubic solid. No structure is obser...

  3. 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: 12.113, year: 2014

  4. Multiscale Simulation and Modeling of Multilayer Heteroepitactic Growth of C60 on Pentacene.

    Science.gov (United States)

    Acevedo, Yaset M; Cantrell, Rebecca A; Berard, Philip G; Koch, Donald L; Clancy, Paulette

    2016-03-29

    We apply multiscale methods to describe the strained growth of multiple layers of C60 on a thin film of pentacene. We study this growth in the presence of a monolayer pentacene step to compare our simulations to recent experimental studies by Breuer and Witte of submonolayer growth in the presence of monolayer steps. The molecular-level details of this organic semiconductor interface have ramifications on the macroscale structural and electronic behavior of this system and allow us to describe several unexplained experimental observations for this system. The growth of a C60 thin film on a pentacene surface is complicated by the differing crystal habits of the two component species, leading to heteroepitactical growth. In order to probe this growth, we use three computational methods that offer different approaches to coarse-graining the system and differing degrees of computational efficiency. We present a new, efficient reaction-diffusion continuum model for 2D systems whose results compare well with mesoscale kinetic Monte Carlo (KMC) results for submonolayer growth. KMC extends our ability to simulate multiple layers but requires a library of predefined rates for event transitions. Coarse-grained molecular dynamics (CGMD) circumvents KMC's need for predefined lattices, allowing defects and grain boundaries to provide a more realistic thin film morphology. For multilayer growth, in this particularly suitable candidate for coarse-graining, CGMD is a preferable approach to KMC. Combining the results from these three methods, we show that the lattice strain induced by heteroepitactical growth promotes 3D growth and the creation of defects in the first monolayer. The CGMD results are consistent with experimental results on the same system by Conrad et al. and by Breuer and Witte in which C60 aggregates change from a 2D structure at low temperature to 3D clusters along the pentacene step edges at higher temperatures. PMID:26937559

  5. Crystal structure of the 4 + 2 cycloadduct of photooxidized anthracene and C60 fullerene

    Directory of Open Access Journals (Sweden)

    Gábor Bortel

    2014-11-01

    Full Text Available The structure of the title compound, 5,6-[(1R,10S-2,9-dioxatricyclo[8.6.03,8.011,16]hexadecane-1,10-diyl]-(C60–Ih[5,6]fullerene methanedithione 0.1-solvate, C74H10O2·0.1CS2, has tetragonal (P42/n symmetry at 100 K. It has a unique eight-membered ring, with two incorporated O atoms in place of the original central ring of the anthracene. The distortion of the molecular geometry around the cycloadduct bonds corresponds to that seen in related fullerene derivatives. Close packing of the adduct forms cavities partially filled with disordered carbon disulfide solvent molecule. The 41% occupancy of the cavities yields an overall 1:0.103 adduct–solvent ratio. Reaction steps are described as light-assisted singlet-oxygen generation, peroxide, epoxide and dioxocin derivative formation and the final step of thermally activated cycloaddition.

  6. 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

    2016-05-01

    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. PMID:27059290

  7. Kinetic energy distributions of fragment ions in collisions of energetic heavy ions with C60

    International Nuclear Information System (INIS)

    Mass distributions of fragment ions of C60 produced in collisions with energetic heavy ions have been measured by means of time-of-flight (TOF) method. From the peak profile analysis, initial kinetic energy distributions (KED) of fragment ions were obtained. KED were investigated for three different projectiles. For all fragment ions except for C1+, KED peaked at a few eV kinetic energies. KED of C1+ was found to have a double-peak structure, indicating that the C1+ ions were produced through two different mechanisms. Also, it was found that the mean kinetic energies had strong correlation with electronic stopping cross-section. (author)

  8. Optical response of C60 fullerene from a Time Dependent Thomas Fermi approach

    CERN Document Server

    Palade, D I

    2014-01-01

    We study the collective electron dynamics in C60 clusters within the Time Dependent Thomas Fermi method in the frame of jellium model. The results regarding the optical spectrum are in good agreement with the experimental data, our simulations being able to reproduce both resonances from 20eV and 40eV . We compare also, the results with those from other theoretical approaches and investigate the implications of quantum effects including exchange-correlation corrections, or gradient corrections from a Weizsacker term. The nature of the second resonance is studied using transition densities and phase analysis and interpreted as being a collective surface plasmon

  9. In situ x-ray diffraction studies of three-dimensional C60 polymers

    International Nuclear Information System (INIS)

    In situ investigations into the P/T field of C60 fullerene were performed using energy-dispersive x-ray diffraction techniques. Isobars were obtained at 11 and 9 GPa accompanied by isotherms at 750 and 800 K with pressure reaching 13 GPa. The P/T history and pressure isotropy were investigated with the aim of optimizing conditions for 3D polymer formation. Confirmation of the formation of 3D polymers was performed in situ; however, the reclaimed sample did not exhibit the expected high hardness value, due to depolymerization on pressure release. Isotropy in the pressure field promoted formation and retention of the face-centred-cubic structure

  10. Atomic force microscope studies of fullerene films - Highly stable C60 fcc (311) free surfaces

    Science.gov (United States)

    Snyder, Eric J.; Tong, William M.; Williams, R. S.; Anz, Samir J.; Anderson, Mark S.

    1991-01-01

    Atomic force microscopy and X-ray diffractometry were used to study 1500 A-thick films of pure C60 grown by sublimation in ultrahigh vacuum onto a CaF2 (111) substrte. Topographs of the films did not reveal the expected close-packed structures, but they showed instead large regions that correspond to a face-centered cubic (311) surface and distortions of this surface. The open (311) structure may have a relatively low free energy because the low packing density contributes to a high entropy of the exposed surface.

  11. Formation of fullerene clusters in the system C60/NMP/water by SANS

    International Nuclear Information System (INIS)

    Solutions of fullerenes in nitrogen-containing solvents constitute a specific class characterized by the formation of fullerene clusters. In the given work, we report the effect of cluster rearrangement in the system C60/N-methylpyrrolidone (NMP) after addition of water (miscible with NMP) as observed by small-angle neutron scattering (SANS). The effect has a critical character and takes place if the water relative content is higher than 40%. Despite a small scattering signal, estimates of the mean scattering length density of the clusters by SANS contrast variation can be done

  12. Electronic structure evolution in doping of fullerene (C60) by ultra-thin layer molybdenum trioxide

    International Nuclear Information System (INIS)

    Ultra-thin layer molybdenum oxide doping of fullerene has been investigated using ultraviolet photoemission spectroscopy (UPS) and X-ray photoemission spectroscopy (XPS). The highest occupied molecular orbital (HOMO) can be observed directly with UPS. It is observed that the Fermi level position in fullerene is modified by ultra-thin-layer molybdenum oxide doping, and the HOMO onset is shifted to less than 1.3 eV below the Fermi level. The XPS results indicate that charge transfer was observed from the C60 to MoOx and Mo6+ oxides is the basis as hole dopants

  13. Preparation and Expansion Properties Analysis of C60 Expansive Self-compacting Concrete

    Directory of Open Access Journals (Sweden)

    Jia Li-li

    2016-01-01

    Full Text Available Concrete Design of concrete filled steel tube should not only meet the requirements of self-compacting, but also need suitable expansion properties. On the basis of working performance requirement, study impact of expansive agent on concrete working performance, strength and expansion properties, preparation of C60 concrete filled steel to meet the self-compacting and expansion properties. Expander should not be too much, otherwise working performance and strength will be affected. Meanwhile study the correlation between restrained expansion and free expansion of expansive concrete, and analyze the mechanism of expansive concrete.

  14. Photochemical reduction of water-soluble C60 derivatives (EPR study)

    International Nuclear Information System (INIS)

    The photochemical reduction of three bis-functionalized C60 derivatives resulted in the formation of a single radical product, characterized by relatively narrow EPR line (gM = 2.0007, pp < 0.02 mT). In the irradiated aqueous solutions containing L-ascorbic acid, in the addition to the EPR line related to bis-adduct mono-anion, also 6-line EPR spectrum of ascorbyl radical was observed. Consequently, the photoinduced formation of ascorbyl radical was attributed to the intermolecular quenching of fullerenes excited states. (authors)

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

    International Nuclear Information System (INIS)

    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.

  16. 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. ...

  17. Voltammetric determination of adenosine and guanosine using fullerene-C(60)-modified glassy carbon electrode.

    Science.gov (United States)

    Goyal, Rajendra N; Gupta, Vinod K; Oyama, Munetaka; Bachheti, Neeta

    2007-02-28

    A fullerene-C(60)-modified glassy carbon electrode (GCE) is used for the simultaneous determination of adenosine and guanosine by differential pulse voltammetry. Compared to a bare glassy carbon electrode, the modified electrode exhibits an apparent shift of the oxidation potentials in the cathodic direction and a marked enhancement in the voltammetric peak current response for both the biomolecules. Linear calibration curves are obtained over the concentration range 0.5muM-1.0mM in 0.1M phosphate buffer solution at pH 7.2 with a detection limit of 3.02x10(-7)M and 1.45x10(-7)M for individual determination of adenosine and guanosine, respectively. The interference studies showed that the fullerene-C(60)-modified glassy carbon electrode exhibited excellent selectivity in the presence of hypoxanthine, xanthine, uric acid and ascorbic acid. The proposed procedure was successfully applied to detect adenosine and guanosine in human blood plasma and urine, without any preliminary pre-treatment. PMID:19071420

  18. Modelling of C2 addition route to the formation of C60

    CERN Document Server

    Khan, Sabih D

    2016-01-01

    To understand the phenomenon of fullerene growth during its synthesis, an attempt is made to model a minimum energy growth route using a semi-empirical quantum mechanics code. C2 addition leading to C60 was modelled and three main routes, i.e. cyclic ring growth, pentagon and fullerene road, were studied. The growth starts with linear chains and, at n = 10, ring structures begins to dominate. The rings continue to grow and, at some point n > 30, they transform into close-cage fullerenes and the growth is shown to progress by the fullerene road until C60 is formed. The computer simulations predict a transition from a C38 ring to fullerene. Other growth mechanisms could also occur in the energetic environment commonly encountered in fullerene synthesis, but our purpose was to identify a minimal energy route which is the most probable structure. Our results also indicate that, at n = 20, the corannulene structure is energetically more stable than the corresponding fullerene and graphene sheet, however a ring str...

  19. Strong-field effects in the photo-emission spectrum of the C$_{60}$ fullerene

    CERN Document Server

    Gao, Cong-Zhang; Kluepfel, Peter; Meier, Chris; Reinhard, Paul-Gerhard; Suraud, Eric

    2016-01-01

    Considering C$_{60}$ as a model system for describing field emission from the extremity of a carbon nanotip, we explore electron emission from this fullerene excited by an intense, near-infrared, few-cycle laser pulse ($10^{13}$-$10^{14}~{\\rm W/cm}^2$, 912 nm, 8-cycle). To this end, we use time-dependent density functional theory augmented by a self-interaction correction. The ionic background of C$_{60}$ is described by a soft jellium model. Particular attention is paid to the high energy electrons. Comparing the spectra at different emission angles, we find that, as a major result of this study, the photoelectrons are strongly peaked along the laser polarization axis forming a highly collimated electron beam in the forward direction, especially for the high energy electrons. Moreover, the high-energy plateau cut-off found in the simulations agrees well with estimates from the classical three-step model. We also investigate the build-up of the high-energy part of a photoelectron spectrum by a time-resolved a...

  20. The strength of electron electron correlation in Cs3C60.

    Science.gov (United States)

    Baldassarre, L; Perucchi, A; Mitrano, M; Nicoletti, D; Marini, C; Pontiroli, D; Mazzani, M; Aramini, M; Riccó, M; Giovannetti, G; Capone, M; Lupi, S

    2015-01-01

    Cs3C60 is an antiferromagnetic insulator that under pressure (P) becomes metallic and superconducting below Tc = 38 K. The superconducting dome present in the T - P phase diagram close to a magnetic state reminds what found in superconducting cuprates and pnictides, strongly suggesting that superconductivity is not of the conventional Bardeen-Cooper-Schrieffer (BCS) type We investigate the insulator to metal transition induced by pressure in Cs3C60 by means of infrared spectroscopy supplemented by Dynamical Mean-Field Theory calculations. The insulating compound is driven towards a metallic-like behaviour, while strong correlations survive in the investigated pressure range. The metallization process is accompanied by an enhancement of the Jahn-Teller effect. This shows that electronic correlations are crucial in determining the insulating behaviour at ambient pressure and the bad metallic nature for increasing pressure. On the other hand, the relevance of the Jahn-Teller coupling in the metallic state confirms that phonon coupling survives in the presence of strong correlations. PMID:26468959

  1. Application of the Correlation Method to Vibrational Spectra of C60 and Other Fullerenes: Predicting the Number of IR- and Raman-Active Bands

    Science.gov (United States)

    Nakamoto, Kazuo; McKinney, Michael A.

    2000-06-01

    The C60 molecule (Buckyball/soccer ball) exhibits only 4 IR and 10 Raman bands although it possesses 174 (3 x 60 - 6) normal vibrations. This striking reduction in the number of observed bands is evidently due to the molecule's extremely high symmetry (Ih point group). First, the 120 symmetry elements of its truncated icosahedral structure are identified and the local (site) symmetry of the carbon atoms (Cc) is determined. Use of molecular models greatly facilitates the process in determining the local and molecular symmetries. Then the correlation method is used to derive a table that classifies the 174 normal vibrations into the respective symmetry species of the Ih point group. In this method, symmetry properties of atomic displacements in terms of the local point group (Cc) are correlated with those in terms of the molecular point group (Ih). After the normal vibrations are classified into respective symmetry species, the numbers of IR- and Raman-active vibrations can be determined by the symmetry selection rules for IR and Raman spectra. The vibrational spectra of C60 and C70 (rugby ball) are analyzed by the above procedure, and the results obtained for C28, C32, C50, and dodecahedrane are provided.

  2. Transport of fullerene nanoparticles (nC60) in saturated sand and sandy soil: controlling factors and modeling.

    Science.gov (United States)

    Zhang, Lunliang; Hou, Lei; Wang, Lilin; Kan, Amy T; Chen, Wei; Tomson, Mason B

    2012-07-01

    Understanding subsurface transport of fullerene nanoparticles (nC(60)) is of critical importance for the benign use and risk management of C(60). We examined the effects of several important environmental factors on nC(60) transport in saturated porous media. Decreasing flow velocity from approximately 10 to 1 m/d had little effect on nC(60) transport in Ottawa sand (mainly pure quartz), but significantly inhibited the transport in Lula soil (a sandy, low-organic-matter soil). The difference was attributable to the smaller grain size, more irregular and rougher shape, and greater heterogeneity of Lula soil. Increasing ionic strength and switching background solution from NaCl to CaCl(2) enhanced the deposition of nC(60) in both sand and soil columns, but the effects were more significant for soil. This was likely because the clay minerals (and possibly soil organic matter) in soil responded to changes of ionic strength and species differently than quartz. Anions in the mobile phase had little effect on nC(60) transport, and fulvic acid in the mobile phase (5.0 mg/L) had a small effect in the presence of 0.5 mM Ca(2+). A two-site transport model that takes into account both the blocking-affected attachment process and straining effects can effectively model the breakthrough of nC(60). PMID:22681192

  3. 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.

  4. 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.

  5. Structural organization of C60 fullerene, doxorubicin, and their complex in physiological solution as promising antitumor agents

    International Nuclear Information System (INIS)

    Specific features of structural self-organization of C60 fullerene (1 nm size range), antitumor antibiotic doxorubicin (Dox) and their complex in physiological solution (0.9 % NaCl) have been investigated by means of atomic-force microscopy, dynamic light scattering, and small-angle X-ray scattering. Significant ordering of the mixed system, C60 + Dox, was observed, suggesting the complexation between these drugs, and giving insight into the mechanism of enhancement of Dox antitumor effect on simultaneous administration with C60 fullerene

  6. Discussion on the Design and Application of the Proportion of C60 High Performance Concrete%C60高性能混凝土配合比设计与应用探讨

    Institute of Scientific and Technical Information of China (English)

    孟剑波

    2014-01-01

    C60 high performance concrete is widely used in current engineering construction, for it is concrete of good pe-rformance, which is significant to improve the level of quality engineering. In this paper, combining with practical cases, the author discusses the mix design and application of C60 high performance concrete.%C60高性能混凝土是当前工程建设中应用广泛的混凝土,该种类的混凝土性能优良,对于提升工程的质量水平具有重要意义。本文结合实际案例,探讨了 C60高性能混凝土的配合比设计和应用。

  7. Preparation and EPR characterization of N@C60 and N@C70 based peapods

    Science.gov (United States)

    Corzilius, B.; Gembus, A.; Weiden, N.; Dinse, K.-P.

    2005-09-01

    Using the quartet spin of encased nitrogen atoms as an electron paramagnetic resonance (EPR) probe, it is possible to examine the fullerene/nanotube interactions in a peapod. A purification method is developed which allows low temperature filling of nanotubes with endohedral fullerenes. The paramagnetic impurities of undoped single wall carbon nanotubes (SWNT) are characterized via EPR resulting in a broad superparamagnetic signal of the remaining catalyst particles and a rather narrow signal of carbonaceous material. Comparison of EPR spectra of several nitrogen endohedral doped peapods with their analogues obtained in a solid fullerene matrix shows a significant broadening of N@C60 and N@C70 EPR signals. This broadening is related to a non-vanishing zero-field splitting caused by deformation of the fullerene cage upon encapsulation.

  8. Intensity-dependent equivalent circuit parameters of organic solar cells based on pentacene and C60

    Science.gov (United States)

    Yoo, Seunghyup; Domercq, Benoit; Kippelen, Bernard

    2005-05-01

    We present studies of the current-voltage characteristics of organic solar cells based on heterojunctions of pentacene and C60 as a function of illumination intensity. The photovoltaic response at a given illumination level is parameterized and modeled using the equivalent circuit model developed for inorganic pn-junction solar cells. Reduction in shunt resistance and increase in diode reverse saturation current density are observed upon increase of the light intensity. We demonstrate that this effect can be modeled by a refined equivalent circuit model that contains an additional shunt resistance and an additional diode the properties of which are functions of the light intensity. The effects of these additional components on the overall photovoltaic performance are discussed.

  9. N-Block Separable Random Phase Approximation: Application to metal clusters and C60 fullerene

    CERN Document Server

    Palade, D I

    2015-01-01

    Starting from the Random Phase Approximation (RPA), we generalize the schematic model of separable interaction defning subspaces of ph excitations with different coupling constants between them. This ansatz simplifies the RPA eigenvalue problem to a finite, small dimensional system of equations which reduces the numerical effort. Associated dispersion relation and the normalization condition are derived for the new defined unknowns of the system. In contrast with the standard separable approach, the present formalism is able to describe more than one collective excitation even in the degenerate limit. The theoretical framework is applied to neutral and singly charged spherical sodium clusters and C60 fullerene with results in good agreement with full RPA calculations and experimental data.

  10. 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...... of the threshold for s-wave detachment at 2.664 ± 0.005 eV, slightly lower than a recent value of the electron binding, 2.683 ± 0.008 eV, obtained from the energy spectrum of photo electrons. The detachment yield is observed to increase sharply for photon energies above a threshold at 2.78 eV, maybe caused...

  11. Magnetization under high-pressure in organic ferromagnet α-TDAE-C60

    International Nuclear Information System (INIS)

    The magnetization measurements under pressure were performed on the fullerene-based ferromagnet, α-TDAE-C60. We found that the saturation magnetization below the ferromagnetic ordering temperature Tc is rapidly suppressed with increasing pressure and disappeared above Pc2=0.1-0.2GPa. This pressure is remarkably lower than the critical pressure of polymerization Pc=0.7GPa. On the contrary, Tc is almost pressure independent below Pc2, but, above Pc2, could not be entirely determined because of the strong suppression of the magnetization. In the paramagnetic region, the susceptibility under pressure indicates the total number of spins remains unchanged around Pc2 as well as Pc. We discuss these results compared with the high-pressure ESR

  12. Communication: The H2@C60 inelastic neutron scattering selection rule: Expanded and explained

    Science.gov (United States)

    Poirier, Bill

    2015-09-01

    Recently [M. Xu et al., J. Chem. Phys. 139, 064309 (2013)], an unexpected selection rule was discovered for the title system, contradicting the previously held belief that inelastic neutron scattering (INS) is not subject to any selection rules. Moreover, the newly predicted forbidden transitions, which emerge only in the context of coupled H2 translation-rotation (TR) dynamics, have been confirmed experimentally. However, a simple physical understanding, e.g., based on group theory, has been heretofore lacking. This is provided in the present paper, in which we (1) derive the correct symmetry group for the H2@C60 TR Hamiltonian and eigenstates; (2) complete the INS selection rule, and show that the set of forbidden transitions is actually much larger than previously believed; and (3) evaluate previous theoretical and experimental results, in light of the new findings.

  13. EFFECTS OF C60 FULLERENE — CISPLATIN COMPLEX ON HONEYBEE Apis mellifera L.

    Directory of Open Access Journals (Sweden)

    Kuznietsova H. M.

    2015-08-01

    Full Text Available The toxicity of С60 fullerene, traditional cytostatic cisplatin and С60 fullerene-cisplatin complex on honeybee Apis mellifera L. toxicity estimation test system was assessed. Water-soluble pristine C60 fullerenes were nontoxic for honeybee when consumed with the food in doses equivalent nontoxic and effective ones for mammalian. Cisplatin toxicity for honeybee in the doses exceed the same for mammalian in 2 times was observed as fallows: honeybee 56% death occurred after consumption of 60 mg/kg of bee weight. С60 fullerene-cisplatin complex proved to be more toxic for honeybee in comparison with free cisplatin and caused honeybee 50% lethality after consumption of 40 mg/kg bee weight.

  14. Wave-dispersed third-order nonlinear optical properties of C 60 thin films

    Science.gov (United States)

    Kajzar, F.; Taliani, C.; Danieli, R.; Rossini, S.; Zamboni, R.

    1994-01-01

    Results of wave-dispersed third harmonic generation measurements in sublimed C 60 thin films are reported and discussed within a three-level model. Two strong resonant enhancements in cubic susceptibility χ (3)(-3ω; ω, ω, ω) are observed. The first one, occurring at a fundamental wavelength of 1.3 μm with a χ (3)(-3ω; ω, ω, ω) maximum value of 6.1×10 -11 esu, is interpreted in terms of a two-photon resonance with the one-photon forbidden electronic T 1g level. The second resonance at 1.064 μm, with a maximum value of χ (3)(-3ω; ω, ω, ω)=8.2×10 -11 esu is interpreted as a three-photon resonance with the lowest one-photon allowed T 1u electronic level.

  15. Communication: The H2@C60 inelastic neutron scattering selection rule: Expanded and explained

    International Nuclear Information System (INIS)

    Recently [M. Xu et al., J. Chem. Phys. 139, 064309 (2013)], an unexpected selection rule was discovered for the title system, contradicting the previously held belief that inelastic neutron scattering (INS) is not subject to any selection rules. Moreover, the newly predicted forbidden transitions, which emerge only in the context of coupled H2 translation-rotation (TR) dynamics, have been confirmed experimentally. However, a simple physical understanding, e.g., based on group theory, has been heretofore lacking. This is provided in the present paper, in which we (1) derive the correct symmetry group for the H2@C60 TR Hamiltonian and eigenstates; (2) complete the INS selection rule, and show that the set of forbidden transitions is actually much larger than previously believed; and (3) evaluate previous theoretical and experimental results, in light of the new findings

  16. Superconductivity with intergrowth, modulation and structural transformation in BSCCO, YBCO and MxC60 superconductors

    International Nuclear Information System (INIS)

    The article has described the relationship between superconductivity and microstructure features in BSCCO, YBCO and MxC60 materials. The intergrowth in YBCO materials can introduce effective pinning sites, so the Jc could be enhanced. However, the intergrowth in BSCCO materials can be obstacle for obtaining higher critical current if the intergrowth plane have coherent (100) interfaces. Superconductivity is not directly related to the modulation but related with oxygen contents in the materials. However, the oxygen content in materials could make great influence on superconductivity. The phase transformation (at x value down to 0.4 from 1.0) between the tetragonal (T) and the orthorhombic (O) system in Bi2Sr2Ca1-xYxCu2O8 would be responsible for obtaining of superconductivity of the material. (orig.)

  17. Establishment of structure-conductivity relationship for tris(2,2'-bipyridine) ruthenium ionic C(60) salts.

    Science.gov (United States)

    Hong, Jie; Shores, Matthew P; Elliott, C Michael

    2010-12-20

    Three ionic C(60) salts with [Ru(bpy)(3)](m+) (bpy = 2,2'-bipyridine) as cations were synthesized. The UV-vis-NIR spectra, XPS spectra, and elemental analysis have demonstrated their compositions: [Ru(bpy)(3)](2)(C(60)) (1), [Ru(bpy)(3)](C(60)) (2), and [Ru(bpy)(3)](C(60))(2) (3). Single crystals of polycrystalline compounds 1 and 2 were obtained as solvates. At room temperature, all three salts are semiconducting with the highest four-probe conductivity observed for compound 1 at ∼10 S m(-1). The electronic conduction mechanisms can be described appropriately by an electron hopping model in this immobilized polyvalent redox system. PMID:21070047

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

    International Nuclear Information System (INIS)

    Au n+ and C60+ 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+, Au3+ and C60+ primary ion beams. C60+ 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 C60+ 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

  19. Synthesis of C60(O)3: an open-cage fullerene with a ketolactone moiety on the orifice.

    Science.gov (United States)

    Xin, Nana; Yang, Xiaobing; Zhou, Zishuo; Zhang, Jianxin; Zhang, Showxin; Gan, Liangbing

    2013-02-01

    Four isomers are currently known for the trioxygenated fullerene derivative C(60)(O)(3), three regioisomers with all of the oxygen addends as epoxy groups and the unstable ozonide isomer with a 1,2,3-trioxlane ring. Here we report the synthesis of an open-cage isomer for C(60)(O)(3) with a ketolactone moiety embedded into the fullerene skeleton through a three-step procedure mediated by fullerene peroxide chemistry. Two fullerene skeleton carbon-carbon bonds are cleaved in the process. The open-cage derivative C(60)(O)(3) can be converted back to C(60) through deoxygenation with PPh(3). Single crystal X-ray structure confirmed the open-cage structure. PMID:23311689

  20. Characterization of Plasma Gun with TiH2/C60 Cartridge for Disruption Mitigation in Tokamaks

    Science.gov (United States)

    Bogatu, I. N.; Thompson, J. R.; Galkin, S. A.; Kim, J. S.; HyperV Technologies Corp. Team

    2011-10-01

    Impurity injection for disruption mitigation in tokamaks must be faster than growth time of plasma instabilities, requires sufficient mass to get critical electron density, high penetrability, and large assimilation fraction in the core plasma, with rapid impurity redistribution over the whole plasma. FAR-TECH, Inc. proposed the innovative idea to use hyper-velocity (>30 km/s), high-density (>1023 m-3) C60/C plasma jets with high ram pressure to deliver the impurity mass in plasma accelerator. We report the complete characterization of the TiH2/C60 cartridge with 5 kJ capacitive driver which demonstrated the capability of producing >30 mg of C60 gas in coaxial plasma gun (~35 cm length) prototype with TiH2/C60 cartridge for a small scale, proof-of-principle experiment on a tokamak. Work supported by the US DOE DE-FG02-08ER85196 grant.

  1. Absorption and fluorescence spectra of C60 fullerene concentrated solutions in hexane and polystyrene at 77-300 K

    International Nuclear Information System (INIS)

    The locations of the 000-bands for S1 #60 solutions in hexane. It is shown that the profile of the S1 #00-band in the forbidden 11T1g #1Ag transition is explained by symmetry reduction in the C60+environment system due to the interaction of electrons with local phonons. The temperature coefficients of the red shift for the 256,3- and 328,3-nm bands of allowed 1T1u #1Ag transitions for C60 in hexane are equal to -1.45 and -0.46 cm-1@K-1, respectively. The peak and half-width values of the 337,2-nm band for C60 in polystyrene remain unchanged on cooling to 77 K. Absorption in the 700-800-nm region for concentrated hexane solutions of fullerene at 292 K results from the production of (C60)n-clusters. (authors)

  2. 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

    The potential of C60-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...

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

    International Nuclear Information System (INIS)

    A theoretical study of the subshell photoionization of the Xe atom endohedrally confined in C60 is presented. Powerful hybridization of the Xe 5s state with the bottom edge of C60 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 C60 giant plasmon resonance via the atom-fullerene dynamical interchannel coupling. Beyond the C60 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.

  4. 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.

  5. Fullerene (C60)-based tumor-targeting nanoparticles with "off-on" state for enhanced treatment of cancer.

    Science.gov (United States)

    Shi, Jinjin; Wang, Binghua; Wang, Lei; Lu, Tingting; Fu, Yu; Zhang, Hongling; Zhang, Zhenzhong

    2016-08-10

    The traditional drug delivery systems always suffer from the unexpected drug release during circulation and the sluggish release of drug in target site. To address the problem, an "off-on" type drug delivery system with precise control was developed in this study. Doxorubicin (DOX) was covalently conjugated to fullerene (C60) nanoaggregates via a reactive oxygen species (ROS)-sensitive thioketal linker (C60-DOX NPs), and then the hydrophilic shell (Distearoyl-sn-glycero-3-phosphoethanolamine-PEG-CNGRCK2HK3HK11, DSPE-PEG-NGR) was attached to the outer surface of C60-DOX, giving it (C60-DOX-NGR NP) excellent stability in physiological solutions and active tumor-targeting capacity. C60-DOX-NGR NPs were able to entrap DOX efficiently even at acidic environment (pH5.5) when they were "off" state. In sharp contrast, when the NPs were "on" state, a large number of ROS were generated by C60, leading to the breaking of ROS-sensitive linker, thereby enabling the burst release of DOX. The "off" or "on" state of C60-DOX-NGR NPs could be precisely remote-controlled by a 532nm laser (at a low power density) with a high spatial/temporal resolution. In the in vivo and in vitro studies, the C60-based drug delivery system with "off-on" state exhibited a high antitumor efficacy and a low toxicity to normal tissues due to its tumor-targeting ability, remote-controlled drug release property and combined therapeutic effect (photodynamic therapy combined with chemotherapy). PMID:27276066

  6. フラーレンC60 の骨格合成と変換反応

    OpenAIRE

    蜂谷, 宝人; Hachiya, Houjin; 加部, 義夫; Kabe, Yoshio

    2009-01-01

    Recent attempts at the synthesis of the fullerene C60 framework and its transformation reaction are surveyed. In particular, the framework transformation of fulleroids and bisfulleroids followed by singlet oxygen oxygenation can create openings on the surface of fullerene C60cages resulting in the formation of open-cage fullerenes. Silyl-and germyl-Substituted fullerenes developed by our laboratory provide new synthetic tools for open-cage fullerenes.

  7. 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

  8. Structure and properties of water film adsorbed on mica surfaces

    Science.gov (United States)

    Zhao, Gutian; Tan, Qiyan; Xiang, Li; Cai, Di; Zeng, Hongbo; Yi, Hong; Ni, Zhonghua; Chen, Yunfei

    2015-09-01

    The structure profiles and physical properties of the adsorbed water film on a mica surface under conditions with different degrees of relative humidity are investigated by a surface force apparatus. The first layer of the adsorbed water film shows ice-like properties, including a lattice constant similar with ice crystal, a high bearing capacity that can support normal pressure as high as 4 MPa, a creep behavior under the action of even a small normal load, and a character of hydrogen bond. Adjacent to the first layer of the adsorbed water film, the water molecules in the outer layer are liquid-like that can flow freely under the action of external loads. Experimental results demonstrate that the adsorbed water layer makes the mica surface change from hydrophilic to weak hydrophobic. The weak hydrophobic surface may induce the latter adsorbed water molecules to form water islands on a mica sheet.

  9. Influence of fullerene (C60) on soil bacterial communities: aqueous aggregate size and solvent co-introduction effects

    Science.gov (United States)

    Tong, Zhong-Hua; Bischoff, Marianne; Nies, Loring F.; Carroll, Natalie J.; Applegate, Bruce; Turco, Ronald F.

    2016-01-01

    Fullerene C60 nanoparticles are being used in broad range of applications. It is important to assess their potential impacts in the environment. We evaluated the effects of C60 introduced as aqueous suspensions of nC60 aggregates of different particle size or via organic solvents on soils with different organic matter contents in this study. Impacts of the application were evaluated by measuring total microbial biomass, metabolic activity and bacterial community structure. Results show that nC60 aggregates, introduced as an aqueous suspension, had size-dependent effects on soil bacterial community composition in the low organic matter system, but induced minimal change in the microbial biomass and metabolic activity in soils with both high and low organic matter contents. Fullerene C60, co-introduced via an organic solvent, did not influence the response of soil microbes to the organic solvents. Our results suggest that nC60 aggregates of smaller size may have negative impact on soil biota and soil organic matter may play a key role in modulating the environmental effect of nanomaterials. PMID:27306076

  10. Influence of fullerene (C60) on soil bacterial communities: aqueous aggregate size and solvent co-introduction effects

    Science.gov (United States)

    Tong, Zhong-Hua; Bischoff, Marianne; Nies, Loring F.; Carroll, Natalie J.; Applegate, Bruce; Turco, Ronald F.

    2016-06-01

    Fullerene C60 nanoparticles are being used in broad range of applications. It is important to assess their potential impacts in the environment. We evaluated the effects of C60 introduced as aqueous suspensions of nC60 aggregates of different particle size or via organic solvents on soils with different organic matter contents in this study. Impacts of the application were evaluated by measuring total microbial biomass, metabolic activity and bacterial community structure. Results show that nC60 aggregates, introduced as an aqueous suspension, had size-dependent effects on soil bacterial community composition in the low organic matter system, but induced minimal change in the microbial biomass and metabolic activity in soils with both high and low organic matter contents. Fullerene C60, co-introduced via an organic solvent, did not influence the response of soil microbes to the organic solvents. Our results suggest that nC60 aggregates of smaller size may have negative impact on soil biota and soil organic matter may play a key role in modulating the environmental effect of nanomaterials.

  11. Influence of fullerene (C60) on soil bacterial communities: aqueous aggregate size and solvent co-introduction effects.

    Science.gov (United States)

    Tong, Zhong-Hua; Bischoff, Marianne; Nies, Loring F; Carroll, Natalie J; Applegate, Bruce; Turco, Ronald F

    2016-01-01

    Fullerene C60 nanoparticles are being used in broad range of applications. It is important to assess their potential impacts in the environment. We evaluated the effects of C60 introduced as aqueous suspensions of nC60 aggregates of different particle size or via organic solvents on soils with different organic matter contents in this study. Impacts of the application were evaluated by measuring total microbial biomass, metabolic activity and bacterial community structure. Results show that nC60 aggregates, introduced as an aqueous suspension, had size-dependent effects on soil bacterial community composition in the low organic matter system, but induced minimal change in the microbial biomass and metabolic activity in soils with both high and low organic matter contents. Fullerene C60, co-introduced via an organic solvent, did not influence the response of soil microbes to the organic solvents. Our results suggest that nC60 aggregates of smaller size may have negative impact on soil biota and soil organic matter may play a key role in modulating the environmental effect of nanomaterials. PMID:27306076

  12. β-Cyclodextrin functionalized carbon quantum dots as sensors for determination of water-soluble C60 fullerenes in water.

    Science.gov (United States)

    Cayuela, Angelina; Laura Soriano, M; Valcárcel, Miguel

    2016-04-25

    A selective photoluminescence method based on Carbon Quantum Dots (CQDs) functionalized with carboxymethyl-β-cyclodextrin for the direct determination of water-soluble C60 fullerene has been developed. CQDs were synthesized using a top-down methodology from multiwall carbon nanotubes (MWCNTs) and further functionalized with N-Boc-ethylenediamine to confer monoprotected amine groups onto their surface. Once amine-functionalized CQDs were obtained after deprotection, an amidation reaction with carboxymethyl-β-cyclodextrin cavitands was achieved and the obtained fluorescent β-cyclodextrin functionalized Carbon Quantum Dots (cd-CQDs) were investigated for the inclusion complexation of water-soluble C60. Quenching of their fluorescence was observed owing to the non-covalent self-assembly of cd-CQDs and C60, making possible the quantification of C60. A method to determine water-soluble C60 is then proposed with detection and quantification limits of 0.525 and 1.751 μg mL(-1), respectively. The method was validated by determining soluble C60 fullerene in spiked river water. One added value of the paper is the fact that it can be ascribed to the "Third Way in Analytical Nanoscience and Nanotechnology". PMID:26870854

  13. The adsorption of water isotopomers on carbon adsorbents

    International Nuclear Information System (INIS)

    Adsorption isotherms in the range 50-80 Deg C were measured by gas chromatography, and isosteric adsorption heats of isotopomers of water were calculated in the range of low fillings at two activated carbons (Norit and FAS) with close volume of micropores (0.38 and 0.37 cm3/g), but various surface chemistry (AC Norit with hydrophilic surface and AC FAS with hydrophobic one). Adsorption of H2O and D2O at AC Norit exceeds adsorption at AC FAS at all equilibrium pressures. Adsorption isotherms of H2O and D2O at every adsorbents are close, but some excess of isotherms and adsorption heats of D2O as compared with H2O ones observes. It is connected with the differences in adsorbate-adsorbent and adsorbate-adsorbate interactions as well as with the structure of molecules of adsorbates

  14. Study of preparation and gas separation property of ethyl cellulose/C60 composite membranes%乙基纤维素/C60复合膜制备及气体分离性能研究

    Institute of Scientific and Technical Information of China (English)

    马诚; 孔瑛; 杨金荣

    2012-01-01

    Ethyl cellulose/C60 composite membranes with different C60 content were prepared in this paper. The structure and gas permeation properties of the obtained membranes were investigated by UV-visible specmma,atomic force microscopy, X-ray diffraction and gas permeation tests. The results show that for the ethyl cellulose/Qo composite membranes with the C0content of 1. 6%,the permeation coefficients of CO2,H2 are 61. 29 Barrer and 78. 88 Barrer, respectively; the separation factors of H2/N2,CO2/N2 are 9.979 and 12. 84, respectively. Both gas permeation coefficient and separation factor of the above ethyl cellulose/C60composite membrane are higher than that of ethyl cellulose membrane. The effect of UV irradiation on the structure and gas permeation properties of the ethyl cellulose/C60 composite membranes was also studied. The results showed that the morphology of C60 on the surface of ethyl cellulose/C60 composite membranes changes from a discrete cluster structure to a continuous gentle hill-like structure during UV irradiation process. UV irradiation process has no noticeable effect on the d-spacing of ethyl cellulose molecular chain. The gas permeation properties of ethyl cellulose/C50 composite membranes, however,are significantly influenced by UV irradiation. By UV irradiation for ten minutes,the H2 and CO2 permeation coefficients of the ethyl cellulose/C60 composite membranes with C60 content of 1. 6% nearly reduces by 30%,and the separation factors of H2/N2 and CO2/N2 increase about 2 times.%为制备C60含量不同的乙基纤维素(EC)/C60复合膜,采用UV-可见光谱、AFM和XRD等手段对紫外光辐照前后复合膜结构进行表征,并考察其对气体分离及渗透性能的影响.结果表明,复合膜经紫外光辐照后,C60在膜表面的分布由独立的簇状结构转变为连续平缓的丘陵状结构,膜表面更加致密光滑;复合膜分子链间距未发生明显变化,但对N2、CO2、H2的渗透性能和H2/N2、CO2/N2分离性能产生明显影响.当C

  15. STUDY ON THE MICROTRIBOLOGICAL PROPERTIES OF STAR-SHAPED C60-STYRENE COPOLYMER AND C60-END-CAPPED POLYSTYRENE THIN FILMS%两种不同取代结构C60-苯乙烯共聚物薄膜微摩擦性能的研究

    Institute of Scientific and Technical Information of China (English)

    黄兰; 于颖; 沈显峰; 李俊伟; 史兵

    2001-01-01

    用自由基聚合法合成星状C60-苯乙烯共聚物和用原子转移自由基聚合法(ATRP)合成单取代C60-苯乙烯共聚物,利用LB技术考察了它们的成膜性能并制备了多层薄膜,运用原子力显微镜/摩擦力显微镜(AFM/FFM)初步研究比较这两种不同取代结构C60-苯乙烯共聚物薄膜的表面形貌和在极轻载荷下的微摩擦性能.研究结果显示了星状C60-苯乙烯共聚物相对具有较好的润滑性能.

  16. Electrochemistry of composite films of C 60 and multiwalled carbon nanotubes: A robust conductive matrix for the fine dispersion of fullerenes

    Science.gov (United States)

    Zhang, Hua; Fan, Louzhen; Fang, Yueping; Yang, Shihe

    2005-09-01

    The electrochemical behavior of a C 60/MWCNT (multi-walled carbon nanotube) film cast on GC electrode in acetonitrile solution was investigated. Repeated cyclic voltammetric scans transformed the precursor to a C 60-MWCNT composite film which exhibited reversible electron-transfer reactions and superpose the redox feature of the bare MWCNTs with monotonic charge injection over the whole potential range. This is in contrast to both C 60 film and peapods of C 60 inside carbon nanotubes but resembles the behavior of C 60 dissolved in organic solutions. The formation and structure of the C 60-MWCNT composite films were studied by UV-Vis, FT-IR, and TEM.

  17. Quasi-ordered C60 molecular films grown on the pseudo-ten-fold (1 0 0) surface of the Al13Co4 quasicrystalline approximant.

    Science.gov (United States)

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

    2016-09-01

    The growth of C60 films on the pseudo-ten-fold (1 0 0) surface of the orthorhombic Al13Co4 quasicrystalline approximant was studied experimentally by scanning tunneling microscopy, low-energy electron diffraction and photoemission spectroscopy. The (1 0 0) surface terminates at bulk-planes presenting local atomic configurations with five-fold symmetry-similar to quasicrystalline surfaces. While the films deposited at room temperature were found disordered, high-temperature growth (up to 693 K) led to quasi-ordered molecular films templated on the substrate rectangular unit mesh. The most probable adsorption sites and geometries were investigated by density functional theory (DFT) calculations. A large range of adsorption energies was determined, influenced by both symmetry and size matching at the molecule-substrate interface. The quasi-ordered structure of the film can be explained by C60 adsorption at the strongest adsorption sites which are too far apart compared to the distance minimizing the intermolecular interactions, resulting in some disorder in the film structure at a local scale. Valence band photoemission indicates a broadening of the molecular orbitals resulting from hybridization between the substrate and overlayer electronic states. Dosing the film at temperature above 693 K led to molecular damage and formation of carbide thin films possessing no azimuthal order with respect to the substrate. PMID:27365317

  18. Effect of surfactants on the removal and acute toxicity of aqueous nC60 aggregates in water treatment process.

    Science.gov (United States)

    Ge, Ling; Kirumba, George; Zhang, Bo; Pal, Amrita; He, Yiliang

    2015-07-01

    This work aimed to evaluate the effect of surfactants on the removal of aqueous nC60 aggregates by coagulation-filtration process and assess the acute toxicity of filtrates by Microtox test. Three surfactants including cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and Triton X-100 (TX100) were selected representing cationic, anionic, and nonionic types, respectively. Results showed that the change of physicochemical properties of nC60 associating with different types of surfactants determined nC60's removal efficiency and acute toxicity. CTAB increased the number of large particles. It also changed the zeta potential of nC60 from negative to positive, leading to the low removal rates (17.3-50.2%) when CTAB concentration was designed in the range of 0.03-1 g/L, and the filtrates showed acute toxicity to bioluminescent bacteria (inhibition rate > 80%). On the contrary, TX100 obviously increased the proportion of small particles, and it is noteworthy that even less than 1 mg/L of nC60 (20% of the initial concentration) with TX100 remaining in filtrates could evoke phototoxicity due to reactive oxygen species (ROS) generation under UV irradiation. Compared to CTAB and TX100, SDS exerted an effect on the removal process and toxicity of nC60 only when concentration was beyond the critical micelle concentration (CMC; 2.5 g/L). These findings collectively suggest that characteristics of nC60 are flexible and strongly dependent on surfactant modification, as a result of which these particles could potentially find their way through water treatment route and exert a potential toxicity risk. PMID:25631739

  19. On the polarity of buckminsterfullerene with a water molecule inside

    NARCIS (Netherlands)

    B. Ensing; F. Costanzo; P.L. Silvestrelli

    2012-01-01

    Since the recent achievement of Kurotobi and Murata to capture a water molecule in a C60 fullerene (Science2011, 333, 613), there has been a debate about the properties of this H2O@C60 complex. In particular, the polarity of the complex, which is thought to be underlying the easy separation of H2O@C

  20. Orientational order and disorder in solid C60: theory and diffraction experiments

    International Nuclear Information System (INIS)

    Starting from a microscope model of the intermolecular potential, a unified description is presented of the Bragg scattering law in the orientationally disordered and in the ordered phase of solid C60. The orientational structure factor is expanded in terms of symmetry-adapted surface harmonics. The expansion coefficients are calculated from theory and compared with experiment. Their temperature evolution is studied in the disordered phase at the 260 K transitions and in the ordered phase. In the ordered phase, new results from high-resolution neutron powder diffraction are given. In the disordered phase, space group Fm anti 3m, the reflections have A1g symmetry; in the ordered phase, space group Pa anti 3, reflections of T2g symmetry appear and in addition the A1g reflections are renormalized. The orientational density distribution is calculated. The effective crystal-field potential is constructed, its temperature evolution in the ordered phase is studied and related to the occurrence of an orientational glass. (orig.)