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Your search keyword '"Mehring M"' showing total 8 results
Start Over Author "Mehring M" Topic fullerenes
8 results on '"Mehring M"'

1. Photo-induced electron-transfer processes in (anthracene-) quinquethiophene-fullerene diads and...

Author

Knorr, S., Grupp, A., Mehring, M., Grube, G., and Effenberger, F.

Subjects
CHARGE exchange, FULLERENES
Abstract

Investigates novel model systems for photo-induced intramolecular electron-transfer processes in anthracene- or quinquethiophene-fullerene diads and triads. Occurrence of charge transfer after excitation; Detection of a free induction decay and a broad spin-echo spectrum in both diad and triads at low temperatures.

Published
1999
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2. Superconductivity in K3C60 and Rb3C60 surfaces

Author

Tjeng, LH, Hesper, R, Heeres, A, Sawatzky, GA, Kuzmany, H, Fink, J, Mehring, M, and Roth, S

Subjects
FULLERENES, Condensed Matter::Superconductivity, SINGLE-CRYSTALLINE RB3C60, PHONON, ELECTRON-TUNNELING SPECTROSCOPY, DOPED C-60, NUCLEAR-MAGNETIC-RESONANCE, ENERGY-GAP, FULLERIDES
Abstract

We present a detailed investigation of the surface electronic structure of solid K;CM, and Rb3C60 in connection with their electronic transport properties. The best conducting samples with the highest superconducting transition temperature T, have the highest density of states at the Fermi level as measured by photoemission, but the valence of the CM ions at the surface deviates appreciable from the 3- bulk value, namely 2.5- or even 1.5- depending on the preparation procedure. Despite the large discrepancy in the electronic structure, we find, using ultra-high resolution photoemission, that these surfaces have a BCS-like superconducting gap A which is not reduced from the bulk value, i.e. close to the weak coupling 2Delta/k(B)T(i) = 3.53 value.

Published
2001

3. Entanglement of Spin States in 15N@C60.

Author

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

Subjects
FULLERENES, ELECTRON spin echoes, QUANTUM theory, PHYSICS, QUANTUM computers
Abstract

The endohedral fullerene 15N@C60 comprises an electron spin S = 3/2 coupled to a nuclear spin I = 1/2 and is therefore ideally suited for experimental testing of basic properties of quantum mechanics. We will show that the 15N@C60 molecule represents a multi qubit system where different kinds of entangled states can be generated. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2004
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4. ESR Investigations on 13C enriched Sc3@C82.

Author

Rahmer, J., Mehring, M., and Dorn, H. C.

Subjects
*FULLERENES, *ELECTRON paramagnetic resonance
Abstract

[SUP13]C enrichment of Sc[SUB3]@C[SUB82] for the first time allows the resolution of [SUP13]C hyperfine satellite lines in the electron spin resonance (ESR) spectra of this material. A simple model is proposed to simulate the spectra. The ESR data is well reproduced under the assumption that two or three carbon atoms have a significantly stronger hyperfine coupling than all other atoms. Relating this result to the geometry of the C[SUB3v] cage leads to the conclusion that the electron density is concentrated on the upper hemisphere of the C[SUB82] cage. [ABSTRACT FROM AUTHOR]

Published
2002

5. Synthesis, Isolation and Characterisation of New Alkaline Earth Endohedral Fullerenes M@Cn (M = Ca, Sr; n = 74, 76).

Author

Grupp, A., Haufe, O., Jansen, M., Mehring, M., Panthöfer, M., Rahmer, J., Reich, A., Rieger, M., and Wei, X.-W.

Subjects
FULLERENES, HIGH performance liquid chromatography, ELECTRON paramagnetic resonance spectroscopy
Abstract

New alkaline earth endohedral Fullerenes M@C[SUBn] (M = Ca, Sr; n = 74, 76), prepared by means of the RF-method, have been isolated by HPLC and characterised by means of mass, Raman, VIS-NIR and photo-excited triplet-state ESR spectroscopy. The experimental findings are compared with the results of quantum-chemical investigations. [ABSTRACT FROM AUTHOR]

Published
2002

6. Dimer formation in bis(toluene) chromium fulleride.

Author

Rahmer, J., Mehring, M., Ho¨nnerscheid, A., van Wu¨llen, L., and Jansen, M.

Subjects
*DIMERS, *FULLERENES, *TRANSITION metals, *CHARGE transfer, *NUCLEAR magnetic resonance
Abstract

Bis (toluene) chromium fulleride is a member of a new group of fullerides which in contrast to the well-known alkali fullerides incorporate transition metals. Upon formation, a charge-transfer between the reactants Cr(C[sub7]H[sub8])[sub2] and C[sub60] occurs, yielding a cubic CsCl-type room-temperature phase in which each component carries charge and spin. Cooling the fulleride below 250 K leads to a phase transition into a stable (C[sub60])[sup2−][sub2] dimer phase. This scenario is validated by X-ray diffraction, SQUID measurements, ESR at standard and high fields, and [sup13]C NMR results. [ABSTRACT FROM AUTHOR]

Published
2001

7. Electrically detected magnetic resonance in photoexcited fullerenes.

Author

Eickelkamp, T., Roth, S., and Mehring, M.

Subjects
FULLERENES, SPIN excitations, EXCHANGE reactions, THIN films, SPECTRUM analysis
Abstract

Electrically detected electron spin resonance spectra are reported of fullerene C60 and C70 thin films after photoexcitation. The spin-dependent recombination of positive and negative charge carriers (polarons) leads to a decrease in the conductivity under resonance conditions. The spectra recorded are simulated within a radical pair model including different g factors and g anisotropy of the polarons and exchange ( J ) and dipolar ( D ) coupling. [ABSTRACT FROM AUTHOR]

Published
1998
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8. Pulsed ESR investigations of anisotropic interactions in M@C[sub 82] (M=Sc,Y,La).

Author

Knorr, S., Grupp, A., Mehring, M., Kirbach, U., Bartl, A., and Dunsch, L.

Subjects
FULLERENES, MAGNETIC fields, HYPERFINE interactions, ELECTRONS
Abstract

Abstract. We report on pulsed ESR investigations of the endohedral fullerenes Sc@C[sub 82], Y@C[sub 82], and La@C[sub 82] in frozen solutions. We were able to determine the g tensors of these molecules by analysing magnetic field spectra at X-band (9.5 GHz) and W-band (94 GHz) frequencies. Moreover, in Y@C[sub 82] we have investigated the hyperfine interaction of the [sup 89]Y nuclear spin (I = 1/2) with the electron spin on the C[sub 82] cage. The principal values of the hyperfine tensor A and the relative orientation of g and A tensors were determined by applying three- and four-pulse electron spin echo envelope modulation techniques (ESEEM). [ABSTRACT FROM AUTHOR]

Published
1998
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