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  • 51. Persson, P-A
    et al.
    Andersson, O.
    Edlund, U.
    Johnels, D.
    Jacobsson, P.
    Soldatov, Alexander
    Sundqvist, B.
    High pressure polymerized C601996Inngår i: Carbon 96, Proceedings of the European Carbon Conference, 1996, s. 746-747Konferansepaper (Fagfellevurdert)
  • 52. Persson, P-A
    et al.
    Andersson, O.
    Jacobsson, P.
    Soldatov, Alexander
    Sundqvist, B.
    Wågberg, T.
    The physical properties of high-pressure polymerized C601997Inngår i: Journal of Physics and Chemistry of Solids, ISSN 0022-3697, E-ISSN 1879-2553, Vol. 58, nr 11, s. 1881-1885Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have studied the structural, thermophysical, and spectroscopic properties of polymeric C60 obtained by high pressure treatment at pressures and temperatures near 1 GPa and 600 K. We present here a brief overview of our results for the structural and thermophysical properties and a more detailed report on recent results obtained by Raman spectroscopy on both thin films, polycrystalline, and single crystal material. The results presented include a comparison between Raman results for photopolymerized and pressure polymerized thin films and a preliminary estimate of the binding energy of polymeric C60.

  • 53. Persson, P-A
    et al.
    Edlund, U.
    Fransson, Å.
    Inaba, A.
    Jacobsson, P.
    Johnels, D.
    Meingast, C.
    Soldatov, Alexander
    Sundqvist, B.
    Physical properties of pressure polymerized C601995Inngår i: High Pressure Science and Technology: Proceedings, XV AIRAPT and XXXIII EHPRG International Conference on High Pressure / [ed] Witold A. Trzeciakowski, Singapore: World Scientific and Engineering Academy and Society, 1995, s. 716-718Konferansepaper (Fagfellevurdert)
  • 54. Persson, P-A
    et al.
    Edlund, U.
    Jacobsson, P.
    Johnels, D.
    Soldatov, Alexander
    Sundqvist, Bertil
    NMR and Raman characterization of pressure polymerized C601996Inngår i: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 258, nr 5-6, s. 540-546Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bulk C60 has been treated at 1.1 GPa and 550-585 K, producing a dense insoluble material which on heating to above 600 K reverts to normal C60. Raman and IR studies on modified material show a large number of new lines, and the Raman pentagon pinch mode shifts from 1469 to 1458 cm-1 as on photopolymerization. MAS NMR shows one broadened line at the original C60 shift 144 ppm and a small peak at about 77 ppm due to the bridging carbons. None of the new resonances observed for C60 polymerized by other methods were observed. The results verify previously suggested polymeric structures where the fullerence cages are connected by four-membered rings.

  • 55.
    Prikhna,, T.
    et al.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Gawalek, W.
    Institut für Photonische Technologien, Jena.
    Savchuk, Y.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Sokolovsky, V.
    Ben-Gurion University of Negev.
    Eisterer,, M.
    Atominstitut, Vienna University of Technology.
    Weber, H.W.
    Atominstitut, Vienna University of Technology.
    Noudem, J,.
    CNRS UMR 6508, CNRS/CRISMAT, 6, Bd du Maréchal Juin, Caen.
    Serga, M.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Turkevich, V.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Tompsic, M.
    Hyper Tech Research, Inc., 1275 Kinnear Road, Columbus.
    Tkach, V.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Danilenko, N
    Institute for Problems in Material Science of the National Academy of Sciences of Ukraine.
    Goldacker, W.
    Institut für Technische Physik, 3640, Forschungszentrum Karlsruhe.
    Karau,, F.
    H.C. Starck GmbH, Goslar.
    Fesenko, I.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Rindfleisch, M.
    Institute for Problems in Material Science of the National Academy of Sciences of Ukraine.
    Dellith, J.
    Institut für Photonische Technologien, Jena.
    Wendt, M.
    Institut für Photonische Technologien, Jena.
    You, Shujie
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Meerovich,, V.
    Ben-Gurion University of Negev.
    Dub, S.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Moshchil, V.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Sergienko, N.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Kozyrev, A.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Sverdun, V.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Effects of high pressure on the physical properties of MgB22011Inngår i: Journal of Superconductivity and Novel Magnetism, ISSN 1557-1939, E-ISSN 1557-1947, Vol. 24, nr 5, s. 137-150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The synthesis of MgB2-based materials under high pressure gave the possibility to suppress the evaporation of magnesium and to obtain near theoretically dense nanograined structures with high superconducting, thermal conducting, and mechanical characteristics: critical current densities of 1.8-1.0×106 A/cm2 in the self-field and 103 A/cm2 in a magnetic field of 8 T at 20 K, 5-3×105 A/cm2 in self-field at 30 K, the corresponding critical fields being Hc2=15 T at 22 K and irreversible fields Hirr=13 T at 20 K, and Hirr=3.5 T at 30 K, thermal conduction of 53±2 W/(m{dot operator}K), the Vickers hardness HV=10.12±0.2 GPa under a load of 148.8 N and the fracture toughness K1 C=7.6±2.0 MPa{dot operator}m0.5 under the same load, the Young modulus E=213 GPa. Estimation of quenching current and AC losses allowed the conclusion that high-pressure-prepared materials are promising for application in transformer-type fault current limiters working at 20-30 K.

  • 56.
    Prikhna, Tatiana
    et al.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Noudem, Jacques
    CNRS/CRISMAT.
    Gawalek, Wolfgang
    Institut für Photonische Technologien, Jena.
    Mamalis, Athanasios G.
    National Technical University of Athens.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Savchuk, Yaroslav
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Moshchil, Viktor
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Eisterer, Michael
    Atomic Institute of Austrian Universities.
    Weber, Harald W
    Atomic Institute of Austrian Universities.
    Dub, Sergey
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Habisreuther, Tobias
    Institut für Photonische Technologien, Jena.
    Dellith, Jan
    Institut für Photonische Technologien, Jena.
    You, Shujie
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Schmidt, Christa
    Institut für Photonische Technologien, Jena.
    Karau, Friedrich
    H.C. Starck GmbH, Goslar.
    Dittrich, Ulrich
    H.C. Starck GmbH, Goslar.
    Vajda, Istvan
    Budapest University of Technology and Economics.
    Sergienko, Nina
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Sokolovsky, Vladimir
    Ben-Gurion University of Negev.
    Litzkendorf, Doris
    Institut für Photonische Technologien, Jena.
    Chaud, Xavier
    CNRS/CRETA, 25, Avenue des Martyrs.
    Sverdun, Vladimir
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Kuznietsov, Roman
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Spark plasma synthesis and sintering of superconducting MgB 2-based materials2012Inngår i: Applied Electromagnetic Engineering for Magnetic, Superconducting and Nano Materials: Selected Peer Reviewed Papers from the Selected Peer-reviewed Papers from the Seventh Japanese-mediterranean and Central European Workshop / [ed] A.G. Mamalis; A. Kaladas; M. Enokizono, Trans Tech Publications Inc., 2012, s. 42437-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Superconducting (SC) and mechanical properties of spark plasma (or SPS) produced MgB 2 -based materials allow their efficient applications in fault current limiters, superconducting electromotors, pumps, generators, magnetic bearings, etc. The synthesized from Mg and B at 50 MPa, 1050 °C for 30 min material has a density of 2.52 g/cm 3, critical current density, j c = 7.1·10 5 A/cm 2 at 10 K , 5.4·10 5 A/cm 2 at 20 K, and 9·10 4 A/cm 2 at 35 K in zero magnetic field; at 20 K its field of irreversibility B irr(20)=7 T and upper critical field B c2(20)=11 T; microhardness H V=10.5 GPa and fracture toughness K 1C =1.7 MPa·m 1/2 at 4.9 N-load. SPS-manufactured in- situ MgB 2- based materials usually have somewhat higher j c than sintered ex-situ. The pressure variations from 16 to 96 MPa during the SPS-process did not affect material SC characteristics significantly; the j c at 10-20 K was slightly higher and the material density was higher by 11%, when pressures of 50-96 MPa were used. The structure of SPS-produced MgB 2 material contains Mg-B-O inclusions and inclusions of higher borides (of compositions near MgB 4, MgB 7, MgB 12, MgB 17, MgB 20), which can be pinning centers. The presence of higher borides in the MgB 2 structure can be revealed by the SEM and Raman spectroscopy.

  • 57.
    Prikhna, Tatjana A.
    et al.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Gawalek, Wolfgang
    Institut für Photonische Technologien, Jena.
    Goldacker, Wilfried
    Karlsruhe Institute of Technology.
    Savchuk, Yaroslav M.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Noudem, Jacques
    CNRS/CRISMAT/ISMRA.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Eisterer, Mikhael
    TU Wien-Atominstitut, Vienna University of Technology Institute of Atomic and Subatomic Physics.
    Weber, Hárakd W.
    TU Wien-Atominstitut, Vienna University of Technology Institute of Atomic and Subatomic Physics.
    Sokolovsky, Vladimir
    Ben-Gurion University of Negev.
    Serga, Maxim
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Dub, Sergey N.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Wendt, Michael
    Institut für Photonische Technologien, Jena.
    You, Shujie
    Sergienko, Nina V.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Moshchil, Viktor E.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Tkash, Vasiliy N.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Dellith, Jan
    Institut für Photonische Technologien, Jena.
    Karau, Friedrich
    H.C. Starck GmbH, Goslar.
    Tomsic, Mikhael
    Hyper Tech Research, Inc., 1275 Kinnear Road, Columbus.
    Shmidt, Shrista
    Institut für Photonische Technologien, Jena.
    Fresenko, Igor P.
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    Habisreuther, Tobias
    Institut für Photonische Technologien, Jena.
    Litzkendorf, Doris
    Institut für Photonische Technologien, Jena.
    Meerovich, Viktor
    Ben-Gurion University of Negev.
    Sverdun, Vladimir
    Institute for Superhard Materials, National Academy of Sciences of Ukraine.
    High-pressure synthesized nanostructural MgB2 materials with high performance of superconductivity, suitable for fault current limitation and other applications2011Inngår i: IEEE transactions on applied superconductivity (Print), ISSN 1051-8223, E-ISSN 1558-2515, Vol. 21, nr 3, s. 2694-2697Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A variety of samples made via different routes were investigated. Samples are nanostructured (average grain sizes are about 20 nm). The advantage of high-pressure (HP)-manufactured (2 GPa, 800-1050 degrees C, 1 h) MgB2 bulk is the possibility to get almost theoretically dense (1-2% porosity) material with very high critical current densities reaching at 20 K, in 0-1 T j(c) = 1.2 - 1.0 . 10(6) A/cm(2) (with 10% SiC doping) and j(c) = 9.2 - 7.3 10(5) A/cm(2) (without doping). Mechanical properties are also very high: fracture toughness up to 4.4 +/- 0.04 MPa . m(0.5) and 7.6 +/- 2.0 MPa . m(0.5) at 148.8 N load for MgB2 undoped and doped with 10% Ta, respectively. The HP-synthesized material at moderate temperature (2 GPa, 600 degrees C, 1 h) from B with high amount of impurity C (3.15%) and H (0.87%) has j(c) = 10(3) A/cm(2) in 8 T field at 20 K, highest irreversibility fields (at 18.4 K H-irr = 15 T) and upper critical fields (at 22 K H-C2 = 15 T) but 17% porosity. HP materials with stoichiometry near MgB12 can have T-c = 37 K and j(c) = 6 . 10(4) A/cm(2) at 0 T and H-irr = 5 T at 20 K. The spark plasma synthesized (SPS) material (50 MPa, 600-1050 degrees C 1.3 h, without additions), demonstrated at 20 K, in 0-1 T j(c) = 4.5 - 4 10(5) A/cm(2). Dispersed inclusions of higher magnesium borides, which are usually present in MgB2 structure and obviously create new pinning centers can be revealed by Raman spectroscopy (for the first time a spectrum of MgB7 was obtained). Tests of quench behavior, losses on MgB2 rings and material thermal conductivity show promising properties for fault current limiters. Due to high critical fields, the material can be used for magnets

  • 58. Prikhna, Tetiana
    et al.
    Gawalek, Wolfgang
    Savchuk, Yaroslav
    Serga, Maxim
    Habisreuther, Tobias
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    You, Shu Jie
    Eisterer, Michael
    Weber, Harald W.
    Noudem, Jacques
    Sokolovsky, Vladimir
    Karau, Friedrich
    Dellith, Jan
    Wendt, Michael
    Tompsic, Mikhael
    Tkach, Vasiliy
    Danilenko, Nikolay
    Fesenko, Igor
    Dub, Sergey N.
    Moshchil, Vladimir
    Sergienko, Nina
    Schmidt, Christa
    Litzkendorf, Doris
    Nagorny, Peter
    Sverdun, Vladimir
    Kósa, Janos
    The effect of oxygen distribution inhomogeneity and presence of higher borides on the critical current density improvement of nanostructural MgB22010Inngår i: Advances in Science and Technology, ISSN 1662-0356, Vol. 75, s. 161-166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    MgB2-based nanostructural materials with rather high oxygen concentration (5-14 wt.%) and dispersed grains of higher borides (MgB12, MgB7) high-pressure (2 GPa or 30 MPa) synthesized (in-situ) or sintered (ex-situ) demonstrated high superconducting characteristics (critical current density, jc, up to 1.8-1.0106 A/cm2 in the self magnetic field and 103 in 8 T field at 20 K, 3-1.5105 A/cm2 in the self field at 35 K, upper critical field up to HC2 = 15 T at 22 K, field of irreversibility Hirr =13 T at 20 K). The additives (Ti, SiC) and synthesis or sintering temperature can affect the segregation of oxygen and formation of oxygen-enriched Mg-B-O inclusions in the material structure, thus reducing the amount of oxygen in the material matrix as well as the formation of higher borides grains, which affects an increase of the critical current density. The record high HC2 and Hirr have been registered for the material high-pressure (2 GPa) synthesized from Mg and B at 600 oC having 17% porosity and more than 7 wt.% of oxygen. The attained values of the critical current, AC losses and thermal conductivity make the materials promising for application for fault current limiters and electromotors. The structural and superconducting (SC) characteristics of the material with matrix close to MgB12 in stoichiometry has been studied and the SC transition Tc=37 K as well as jc= 5×104 A/cm2 at 20 K in the self field were registered, its Raman spectrum demonstrated metal-like behavior.

  • 59.
    Silvera, Isaac F.
    et al.
    Harvard University.
    Chijioke, Akobuije D.
    Harvard University.
    Nellis, W.J.
    Harvard University.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Tempere, J.
    Universiteit Antwerpen.
    Calibration of the ruby pressure scale to 150 GPa2007Inngår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 244, nr 1, s. 460-467Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For many years the ruby pressure standard has been the so-called quasi-hydrostatic scale of Mao, Xu, and Bell published in 1986. The calibration was determined by X-ray diffraction of metal markers in an argon pressurization medium to 80 GPa, along with simultaneous measurement of the shift of the ruby R lines. We have used data in the literature, as well as our own, mostly for ruby in quasi-hydrostatic helium, to produce a new ruby scale with calibration data that extends to 150 GPa. The new scale shows that at the highest shifts of the ruby R lines the pressures are substantially higher than on the old scale. To understand small systematic shifts of the pressures as determined from the X-ray diffraction of metal "markers" used in the calibration, a finite element analysis of quasi-hydrostatic conditions in a diamond anvil cell has been carried out.

  • 60. Sing, M.
    et al.
    Soldatov, Alexander
    Pichler, T.
    Knupfer, M.
    Golden, M.S.
    Fink, J.
    Sundqvist, B.
    Electronic structure studies of pressure-polymerized C601999Inngår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 103, nr 1-3, s. 2454-2455Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have investigated the electronic structure of one and two-dimensional C60 polymers with regard to both their low-lying excitations and C 1s excitation spectra by means of electron energy-loss spectroscopy in transmission. We compare the results with those for pristine C60. In general, the spectra for the polymers resemble those for pristine C60 but show a broadening due to both the lowering of the symmetry and the increased intermolecular overlap. This is also reflected by a reduction of the optical gap in comparison with pristine C60.

  • 61. Soldatov, Alexander
    et al.
    Aleksandrovski, A. N.
    Manzheli, V. G.
    Ralei, V.V.
    Strzhemechny, M. A.
    Thermal expansion of solid hydrogens1992Inngår i: Soviet Journal of Low Temperature Physics, ISSN 0360-0335, Vol. 18, nr 2, s. 116-122Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The linear thermal expansion coefficient α of solid deuterium with paramodification content of 2.25% was determined in the temperature interval 1.5-5.6 K. The contributions of the translational vibrations of the lattice αlat and the rotational motion of the molecules αrot to α are separated. The temperature dependence of αlat was determined by the expression αlat =1.475 · 10 - 7 T3+(4.5-7) · 10 - 10 T5. The possibilities of a universal description of the thermal expansion of cryocrystals with a central interaction, including quantum crystals of hydrogen isotopes, are discussed. A theoretical description is proposed and the temperature dependence of αrot is analyzed.

  • 62. Soldatov, Alexander
    et al.
    Alexandrovskii, A.N.
    Manzhelii, V.G.
    Strzhemechny, M.A.
    Thermal expansion of solid D2 at helium temperatures1993Inngår i: Proceedings: International Conference Physics in Ukraine Low Temperature Physics, 1993, s. 228-Konferansepaper (Fagfellevurdert)
  • 63. Soldatov, Alexander
    et al.
    Alexandrovskii, A.N.
    Manzhelii, V.G.
    Strzhemechny, M.A.
    Thermal expansion of solid H2 , HD, D2 at helium temperatures1993Inngår i: Proceedings of the 13th General Conference of the Condensed Matter Division of the European Physical Society: in conjunction with Arbeitskreis Festkörperphysik, Deutsche physikalische Gesellschaft / [ed] H. Hoffmann; R. Klein; M. Schwoerer, Physica scripta , 1993, s. 1053-Konferansepaper (Fagfellevurdert)
  • 64. Soldatov, Alexander
    et al.
    Andersson, O.
    Thermal conductivity of pressure polymerized C601997Inngår i: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 64, nr 3, s. 227-229Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have studied the kinetics of C60 polymerization in the temperature interval \rangeunit{450}{500}{K} at pressures below \valunit{1}{GPa} by measurements of the time dependence of the thermal conductivity. It has been found at \valunit{450}{K} that the polymerization process at \valunit{0.8}{GPa} is slower than the reverse transformation from "polymeric" to "monomeric" phase at \valunit{0.08}{GPa}. The thermal conductivity \lambda of polymerized C60 was measured in the temperature range \rangeunit{100}{430}{K} and found to increase with increasing temperature, which reflects strong phonon scattering. Both the presence of non-bonded C60 molecules and a high degree of structural disorder in the crystalline lattice of the polymeric phase might be responsible for the behaviour of \lambda(T). The results for \lambda(T) are qualitatively similar to those reported previously for C60 polymerized at higher p, T but an order of magnitude smaller.

  • 65. Soldatov, Alexander
    et al.
    Andersson, O.
    Sundqvist, B.
    Prassides, K.
    Transport and vibrational properties of pressure polymerised C601998Inngår i: Molecular crystals and liquid crystals science and technology, ISSN 1058-7276, E-ISSN 1563-5295, Vol. 11, nr 1-2, s. 1-6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The vibrational spectrum of polycrystalline C-60 polymerized at 1.1 GPa and 585 K was studied by inelastic neutron scattering. We find drastic changes in the spectrum compared with the vibrational spectrum of pristine C-60: the appearance of a new, bread vibrational band at low energies, and splining and significant changes in the peak positions of various modes. The thermal conductivity lambda of polymerized C-60 was measured in the temperature range 150-320 K and was found to increase with a rise temperature, which reflects strong phonon scattering. A high degree of structural disorder in the crystalline lattice of the polymeric phase is most probably responsible for the glass-like behaviour of lambda(T).

  • 66. Soldatov, Alexander
    et al.
    Jacobsson, P.
    Persson, P-A
    Sundqvist, B.
    Edlund, U.
    Johnels, D.
    Fullerenes and fullerene nanostructures1996Inngår i: Fullerenes and fullerene nanostructures: proceedings of the International Winterschool on Electronic Properties of Novel Materials, Kirchberg, Tyrol, Austria, 2 - 9 March 1996 / [ed] Hans Kuzmany; M. Mehring; S. Roth, Singapore: World Scientific and Engineering Academy and Society, 1996, s. 344-348Konferansepaper (Fagfellevurdert)
  • 67. Soldatov, Alexander
    et al.
    Johnels, D.
    13C solid state NMR of polymerised C702000Inngår i: NMR Newsletters, nr 497Artikkel i tidsskrift (Annet vitenskapelig)
  • 68. Soldatov, Alexander
    et al.
    Kuchnev, V.I.
    Tolkachev, A.M.
    Alexandrovskii, A.N.
    Ivanov, A. Yu.
    Minchina, I.Ya.
    Capacitive dilatometer for measurements in the temperature range of 0.8-20 K1991Inngår i: Instruments and experimental techniques (New York), ISSN 0020-4412, E-ISSN 1608-3180, Vol. 2, s. 984-987Artikkel i tidsskrift (Fagfellevurdert)
  • 69. Soldatov, Alexander
    et al.
    Nagel, P.
    Pasler, V.
    Meingast, C.
    Roth, G.
    Sundqvist, B.
    Polymeric fullerenes: from C60 to C701999Inngår i: Electronic properties of novel materials - science and technology of molecular nanostructures: XIII international winterschool, Kirchberg, Tirol, Austria, February - March 1999 / [ed] Hans Kuzmany, Woodbury, NY: American Institute of Physics (AIP), 1999, s. 12-15Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For the first time polymerization of both powder and single crystals of C70 fullerene was established after their subjection to high pressure (1.1-2.0 GPa) at elevated temperature (500-580 K). High-resolution capacitance dilatometry, FTIR/Raman spectroscopy and thermal conductivity were employed to characterize the polymeric phase of C70. The results demonstrate drastic changes in the physical properties of C70 on polymerization. We report on a reverse transformation to the monomeric state on heating the polymer to 500 K at ambient pressure. The activation energy of depolymerization was determined to be 1.8(1) eV. We discuss our results in terms of existing structural models for polymerization of C70 and compare the physical properties of C70 and C60 polymers.

  • 70. Soldatov, Alexander
    et al.
    Prassides, K.
    Andersson, O.
    Sundqvist, Bertil
    Vibrational and thermal properties of pressure polymerized C601998Inngår i: Proceedings of the Symposium on Recent Advances in the Chemistry and Physics of Fullerenes and Related Materials: [based on papers presented at the sixth symposium of the Fullerenes Group of the Electrochemical Society, held at the 193rd Meeting of the Electrochemical Society in San Diego, California, May 3 - 8, 1998. This symposium, entitled Fullerenes: Chemistry, Physics and New Directions XI ...] / [ed] Karl M. Kadish, Pennington, NJ: Electrochemical Society, Incorporated , 1998, s. 769-778Konferansepaper (Fagfellevurdert)
  • 71. Soldatov, Alexander
    et al.
    Roth, Georg
    Institut fur Kristallographie der Rheinisch-Westfahlische Technische Hochschule Aachen.
    Dzyabchenko, Alexander
    Karpov Institute of Physical Chemistry, Moscow.
    Johnels, Dan
    Umeå university.
    Lebedkin, Sergei
    Forschungszentrum Karlsruhe Technik und Umwelt.
    Meingast, Christoph
    Forschungszentrum Karlsruhe Technik und Umwelt.
    Sundqvist, Bertil
    Umeå university.
    Haluska, Miro
    Institut fur Materialphysik, Universität Wien.
    Kuzmany, Hans
    Institut fur Materialphysik, Universität Wien.
    Topochemical polymerization of C70 controlled by monomer crystal packing2001Inngår i: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 293, s. 680-683Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polymeric forms of C60 are now well known, but numerous attempts to obtain C70 in a polymeric state have yielded only dimers. Polymeric C70 has now been synthesized by treatment of hexagonally packed C70 single crystals under moderate hydrostatic pressure (2 gigapascals) at elevated temperature (300¡C), which conÞrms predictions from our modeling of polymeric structures of C70. Single-crystal x-ray diffraction shows that the molecules are bridged into polymeric zigzag chains that extend along the c axis of the parent structure. Solid-state nuclear magnetic resonance and Raman data provide evidence for covalent chemical bonding between the C70 cages.

  • 72. Soldatov, Alexander
    et al.
    Sundqvist, B.
    Phase transitions in C70 at high pressure: a thermal conductivity study1995Inngår i: Proceedings of the Symposium on Recent Advances in the Chemistry and Physics of Fullerenes and Related Materials: : [papers presented at the second symposium held at the 187th Meeting of the Electrochemical Society in Reno, Nevada, May 16-21, 1995] / [ed] Rodney S. Ruoff; K.M. Kadish, Pennington, NJ: Electrochemical Society, Incorporated , 1995, s. 881-890Konferansepaper (Fagfellevurdert)
  • 73. Soldatov, Alexander
    et al.
    Sundqvist, Bertil
    Molecular rotation in C70 at high pressures: a thermal conductivity study1996Inngår i: Journal of Physics and Chemistry of Solids, ISSN 0022-3697, E-ISSN 1879-2553, Vol. 57, nr 9, s. 1371-1375Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have measured the thermal conductivity ε and the heat capacity per unit volume ρcp of highly pure C70 in the temperature interval 100-450 K under pressures up to 1 GPa. Anomalies indicating freezing of uniaxial molecular rotation were observed in λ and ρcp upon both cooling and increasing pressure. The phase boundary for this transition has an approximate slope dT/dp = 70 K Gpa-1. The temperature and pressure dependence of λ indicate a substantial amount of structural defects in the sample and strong metastability effects.

  • 74. Sundqvist, B.
    et al.
    Andersson, O.
    Lundin, A.
    Persson, P-A
    Soldatov, Alexander
    Fullerenes under pressure: structure, order, and disorder1995Inngår i: High Pressure Science and Technology: proceedings of the joint XV AIRAPT & XXXIII EHPRG international conference, Warsaw, Poland, September 11 - 15, 1995 / organized by High Pressure Research Center (UNIPRESS), Polish Academy of Sciences and Institute of Experimental Physics, Warsaw University / [ed] Witold A. Trzeciakowski, Singapore: World Scientific and Engineering Academy and Society, 1995, s. 697-701Konferansepaper (Fagfellevurdert)
  • 75. Sundqvist, B.
    et al.
    Andersson, O.
    Lundin, A.
    Soldatov, Alexander
    Phase diagram, structure, and disorder in C60 below 300 K and 1 GPa1995Inngår i: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 93, nr 2, s. 109-112Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Earlier structural studies have shown that the pentagon-to-hexagon orientation ratio in the orientationally ordered simple cubic phase of C60 decreases under pressure. From anomalies observed in the compressibility and thermal conductivity of C60 under pressure we have deduced a pressure-temperature phase diagram for this substance in the range below 300 K and 1 GPa (10 kbar). We conclude that C60 forms a new, completely "hexagon" ordered structural phase above about 0.6 GPa at 150 K (1.2 GPa at 300 K), and that the glass transition shifts upwards in T under pressure by 54 K GPa-1. However, above 0.1 GPa, pentagon-to-hexagon orientation relaxation seems to occur on heating at an almost pressure independent temperature near 100 K.

  • 76. Sundqvist, B.
    et al.
    Andersson, O.
    Lundin, A.
    Soldatov, Alexander
    Structure, disorder, and phase diagram of C60 up to 1 GPa and below 300 K1994Inngår i: High Pressure in Material Science and Geoscience: Proceedings of the XXXII Annual Meeting of the European High Pressure Research Group / [ed] L.J. Kamarad; Z. Arnold; A. Kapicka, Prometeus , 1994, s. 109-112Konferansepaper (Fagfellevurdert)
  • 77. Sundqvist, B.
    et al.
    Andersson, O.
    Soldatov, Alexander
    Comment on "Pressure-Induced Structural Metastability in Crystalline C60"1995Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 75, nr 15, s. 2906-2906Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    A Comment of the Letter by J. A. Wolk, P. J. Horoyski, and M. L. W. Thewalt Phys. Rev. Lett. 74, 3483 (1995). The authors of the Letter offer a Reply

  • 78. Sundqvist, B.
    et al.
    Edlund, U.
    Jacobsson, P.
    Johnels, D.
    Jun, J.
    Launois, P.
    Moret, R.
    Persson, P-A
    Soldatov, Alexander
    Wågberg, T.
    Structural and physical properties of pressure polymerized C601998Inngår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 36, nr 5-6, s. 657-660Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We discuss the structural and dynamic properties of C60 polymerized under low-P, low-T conditions, and suggest that the disordered mixed orthorhombic-tetragonal-rhombohedral phases produced under these conditions arise from nucleation of molecular chains in random directions because of the quasi-free molecular rotation under standard reaction conditions in the fcc phase of C60. Polymerization in He gives results qualitatively different from those obtained in other media.

  • 79. Sundqvist, B.
    et al.
    Soldatov, Alexander
    Andersson, O.
    Lundin, A.
    Persson, P-A
    Orientational disorder and the p-T phase diagrams of fullerenes1995Inngår i: Proceedings of the Symposium on Recent Advances in the Chemistry and Physics of Fullerenes and Related Materials: [papers presented at the second symposium held at the 187th Meeting of the Electrochemical Society in Reno, Nevada, May 16-21, 1995] / [ed] Rodney S. Ruoff; K.M. Kadish, Pennington, NJ: Electrochemical Society, Incorporated , 1995, s. 891-905Konferansepaper (Fagfellevurdert)
  • 80. Sundqvist, B.
    et al.
    Soldatov, Alexander
    Lundin, A.
    Andersson, O.
    Measurements of thermophysical properties as tools to study the phase diagrams of fullerenes under pressure1997Inngår i: High Temperatures-High Pressures, ISSN 0018-1544, E-ISSN 1472-3441, Vol. 29, nr 1, s. 119-124Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The 14th ECTP is part of a conference series initiated in 1968 in Baden-Baden, Germany, as a European effort to collect expertise and to present the latest research in the area of measurement and theoretical predictions of thermophysical properties of materials -solids and fluids- which are of technical and industrial interest

  • 81. Sundqvist, Bertil
    et al.
    Andersson, O.
    Edlund, U.
    Fransson, Å.
    Inaba, A.
    Jacobsson, P.
    Johnels, D.
    Launois, P.
    Meingast, C.
    Moret, R.
    Moritz, T.
    Persson, P-A
    Soldatov, Alexander
    Wågberg, T.
    Physical properties of pressure polymerized C601996Inngår i: Proceedings of the Symposium on Recent Advances in the Chemistry and Physics of Fullerenes and Related Materials: Based on papers presented at the third symposium of the Fullerenes Group of the Electrochemical Society, held at the 189th Meeting of the Electrochemical Society in Los Angeles, California, May 5-10, 1996. This symposium, entitled Fullerenes: Chemistry, Physics and New Directions VIII ...] / [ed] Karl M. Kadish; Rodney S. Ruoff, Pennington, NJ: Electrochemical Society, Incorporated , 1996, s. 1014-1028Konferansepaper (Fagfellevurdert)
  • 82. Sundqvist, Bertil
    et al.
    Jacobsson, P.
    Jun, J.
    Launois, P.
    Moret, R.
    Soldatov, Alexander
    Wågberg, T.
    Polymerization of C60 under hydrostatic and non-hydrostatic pressure conditions1997Inngår i: Proceedings of the Symposium on Recent Advances in the Chemistry and Physics of Fullerenes and Related Materials: [based on papers presented at the fourth symposium of the Fullerenes Group of the Electrochemical Society, held at the 192nd Meeting of the Electrochemical Society in Paris, France, from August 31 to September 5, 1997. This symposium, entitled Fullerenes: Chemistry, Physics and New Directions X ...] / [ed] Karl M. Kadish, Pennington, NJ: Electrochemical Society, Incorporated , 1997Konferansepaper (Fagfellevurdert)
  • 83.
    Vigolo, Birgitte
    et al.
    Nancy Université.
    Vincent, Brice
    Nancy Université.
    Eschbach, Julien
    Nancy Université.
    Bourson, Patrice
    University of Metz & Supelec.
    Mareche, Jean-Francois
    Nancy Université.
    McRae, Edward
    Nancy Université.
    Müller, Andreas
    Luleå tekniska universitet.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hiver, Jean-Marie
    Nancy Université.
    Dahoun, Abdesselam
    Nancy Université.
    Rouxel, Didier
    Nancy Université.
    Multiscale characterization of single-walled carbon nanotube/polymer composites by coupling Raman and Brillouin spectroscopy2009Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, nr 41, s. 17648-17654Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present paper reports on an original experimental approach to the characterization of SWNT/polymer composites. This work deals with the multiscale characterization of nanocomposites. Covalently functionalized SWNTs were incorporated in a PMMA matrix using an in situ polymerization procedure. We show that their presence does not affect the radical polymerization process. Combining Brillouin and Raman spectroscopy, we were able to associate the obtained mechanical properties of the material at the macroscopic scale to the state of functionalization of the SWNTs within the polymer matrix.

  • 84. Winter, J.
    et al.
    Burger, B.
    Hulman, M.
    Kuzmany, H.
    Soldatov, Alexander
    Experimental access to doped fullerene polymers1997Inngår i: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 64, nr 3, s. 257-262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present Raman measurements performed to study the experimental access to doped fullerene polymers. The polymeric orthorhombic AC60 compound could be obtained by slow cooling the high temperature fcc phase and by quenching with subsequent annealing. The various phases after quenching and during annealing were studied in detail. No evidence for a direct doping of undoped C60 to the polymeric AC60 phase was found. Due to the local character of the doping process the formation of A3C60 clusters is observed. The same results were obtained from doping experiments performed with undoped polymeric structures like phototransformed and pressure polymerized C60.

  • 85.
    Winter, J.
    et al.
    Institut fur Materialphysik, Universität Wien.
    Kuzmany, H.
    Institut fur Materialphysik, Universität Wien.
    Soldatov, Alexander
    Persson, P-A
    Department of Experimental Physics, Umeå University.
    Jacobsson, P.
    Department of Experimental Physics, Umeå University.
    Sundqvist, B.
    Department of Experimental Physics, Umeå University.
    Charge transfer in alkali-metal-doped polymeric fullerenes1996Inngår i: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 54, nr 24, s. 17486-17492Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present room-temperature Raman measurements of pressure-polymerized C60 and compare them with the spectra of RbC60 in the orthorhombic phase. Although both materials were prepared according to two completely different routes the spectra show a surprising similarity with respect to mode positions and line splitting. We concluded from this that both materials, the uncharged pressure-polymerized C60 and the rubidium-doped orthorhombic compound, have the same overall structure and the AC60 compounds can be considered as the doped species of the C60, polymerized using moderate low pressure and high temperatures. From a detailed comparison between both spectra mode shifting and line broadening as a consequence of the charge transfer was determined and electron-phonon coupling constants were estimated for the high-frequency Hg(7) and Hg(8) modes. The low values for the coupling constants compared to the ones in the K3C60 can explain the lack of superconductivity in the AC60 compounds

  • 86. Wågberg, T.
    et al.
    Nyeanchi, E. B.
    Soldatov, Alexander
    Sundqvist, B.
    2D polymerization and doping of fullerenes under pressure2000Inngår i: High Pressure Research, ISSN 0895-7959, E-ISSN 1477-2299, Vol. 18, nr 1-6, s. 139-143Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tetragonal polymeric C60 has been studied by Raman spectroscopy and other methods. Attempts have been made to transform samples from the tetragonal to the orthorhom-bic phase and vice versa. The results suggest that the transformation is direct with no intermediate stage with free molecules. Tetragonal C60 has also been intercalated by potassium metal

  • 87.
    Wågberg, Thomas
    et al.
    Department of Physics, Umeå University.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Sundqvist, Bertil
    Department of Physics, Umeå University.
    Spectroscopic study of phase transformations between orthorhombic and tetragonal C60 polymers2006Inngår i: European Physical Journal B: Condensed Matter Physics, ISSN 1434-6028, E-ISSN 1434-6036, Vol. 49, nr 1, s. 59-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a detailed study of transformations between the orthorhombic and tetragonal polymeric states of C60. The transformations are characterised by Raman spectroscopy and X-ray diffraction. We show that the transformation from the orthorhombic (O) phase to the tetragonal (T) phase is very fast and our results indicate that the transformation goes via an intermediate dimer (D) state in a two-stage process, O → D and D → T the tetragonal to the orthorhombic phase is significantly slower, indicating a high-energy threshold to break the polymer bonds at the temperatures used. The results also support earlier suggestions that the tetragonal phase contains disordered dimers that can be viewed as lattice defects in the formation of higher polymers.

  • 88. You, Shujie
    et al.
    Mases, Mattias
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Dobryden, Illia
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Green, Alexander A.
    Department of Materials Science and Engineering, Northwestern University, Evanston, IL.
    Hersam, Mark C.
    Department of Materials Science and Engineering, Northwestern University, Evanston, IL.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Probing structural stability of double-walled carbon nanotubes at high non-hydrostatic pressure by Raman spectroscopy2011Inngår i: High Pressure Research, ISSN 0895-7959, E-ISSN 1477-2299, Vol. 31, nr 1, s. 186-190Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Theoretical calculations predict that the collapse pressure for double-walled carbon nanotubes (DWCNTs) is proportional to 1/R3, where R is the effective or average radius of a DWCNT. In order to address the problem of CNT stability at high pressure and stress, we performed a resonance Raman study of DWCNTs dispersed in sodium cholate using 532 and 633 nm laser excitation. Raman spectra of the recovered samples show minor versus irreversible changes with increasing ID/IG ratio after exposure to high non-hydrostatic pressure of 23 and 35 GPa, respectively. The system exhibits nearly 70% pressure hysteresis in radial breathing vibrational mode signals recovery on pressure release which is twice that predicted by theory.

  • 89.
    Zhu, Chuantao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Materials and Environmental Chemistry, Stockholm University.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mathew, Aji
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Materials and Environmental Chemistry, Stockholm University.
    Advanced microscopy and spectroscopy reveal the adsorption and clustering of Cu(II) onto TEMPO-oxidized cellulose nanofibers2017Inngår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 9, nr 22, s. 7419-7428Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    TEMPO (2,2,6,6-tetramethylpiperidine-1-oxylradical)-mediated oxidation nanofibers (TOCNF), as a biocompatible and bioactive material, have opened up a new application of nanocellulose for the removal of water contaminants. This development demands extremely sensitive and accurate methods to understand the surface interactions between water pollutants and TOCNF. In this report, we investigated the adsorption of metal ions on TOCNF surfaces using experimental techniques atthe nano and molecular scales with Cu(II) as the target pollutant in both aqueous and dry forms. Imaging with in situ atomic force microscopy (AFM), together with a study of the physiochemical properties of TOCNF caused by adsorption with Cu(II) in liquid, were conducted using the PeakForce Quantitative NanoMechanics (PF-QNM) mode at the nano scale. The average adhesion force between the tip and the target single TOCNF almost tripled after adsorption with Cu(II) from 50 pN to 140 pN. The stiffness of the TOCNF was also enhanced because the Cu(II) bound to the carboxylate groups and hardened the fiber. AFM topography, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) mapping and X-ray photoelectron spectroscopy (XPS) indicated that the TOCNF were covered by copper nanolayers and/or nanoparticles after adsorption. The changes in the molecular structure caused by the adsorption were demonstrated by Raman and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). This methodology will be of great assistance to gain qualitative and quantitative information on the adsorption process and interaction between charged entities in aqueous medium.

  • 90.
    Öberg, Sven
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Adjizian, Jean-Joseph
    Department of Chemistry, University of Sussex, Falmer, Brighton , Nanoscopic Physics (NAPS), Université catholique de Louvain.
    Erbahar, D.
    Institut des Mat´eriaux Jean Rouxel (IMN), Universit´e de Nantes, Centre national de la recherche scientifique (CNRS).
    Rio, J.
    Institut des Mat´eriaux Jean Rouxel (IMN), Universit´e de Nantes, Centre national de la recherche scientifique (CNRS).
    Humbert, Bernard
    Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Nancy Université, Institut des Mat´eriaux Jean Rouxel (IMN), Universit´e de Nantes, Centre national de la recherche scientifique (CNRS).
    Dossot, Manuel
    Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Nancy Université, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, UMR 7564, CNRS–University of Lorraine.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Lefrant, S.
    Institut des Mat´eriaux Jean Rouxel (IMN), Universit´e de Nantes, Centre national de la recherche scientifique (CNRS).
    Mevellec, J-Y
    Institut des Mat´eriaux Jean Rouxel (IMN), Universit´e de Nantes, Centre national de la recherche scientifique (CNRS).
    Briddon, Patrick R.
    Department of Physics, University of Newcastle, School of Electrical, Electronic and Computer Engineering, University of Newcastle upon Tyne, School of Natural Science, University of Newcastle upon Tyne, Institut des Mat´eriaux Jean Rouxel (IMN), Universit´e de Nantes, Centre national de la recherche scientifique (CNRS).
    Rayson, Mark
    Department of Chemistry, The University of Surrey, Guildford, School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne.
    Ewels, Christopher P.
    Department of Physics, University of Exeter, CPES, University of Sussex, Falmer, Brighton, Université de Nantes, Institut des Mat´eriaux Jean Rouxel (IMN), Universit´e de Nantes, Centre national de la recherche scientifique (CNRS).
    Effect of functionalization and charging on resonance energy and radial breathing modes of metallic carbon nanotubes2016Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 93, nr 4, artikkel-id 45408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    While changes in resonant Raman scattering measurements are commonly used to measure the effect of chemical functionalization on single-walled carbon nanotubes, the precise effects of functionalization on these spectra have yet to be clearly identified. In this density functional theory study, we explore the effects of functionalization on both the nanotube resonance energy and frequency shifts in radial breathing mode. Charge transfer effects cause a shift in the first Van Hove singularity spacings, and hence resonance excitation energy, and lead to a decrease in the radial breathing mode frequency, notably when the Fermi level decreases. By varying stochastically the effective mass of carbon atoms in the tube, we simulate the mass effect of functionalization on breathing mode frequency. Finally, full density functional calculations are performed for different nanotubes with varying functional group distribution and concentration using fluorination and hydrogenation, allowing us to determine overall effect on radial breathing mode and charge transfer. The results concur well with experiment, and we discuss the importance when using Raman spectroscopy to interpret experimental functionalization treatments

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