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Papers by Karl-Friedrich Thier
AIP Conference Proceedings, 1998
We investigate the spin arrangement in the magnetically ordered orthorhombic phase of CsC60 by a ... more We investigate the spin arrangement in the magnetically ordered orthorhombic phase of CsC60 by a comparison of 133Cs NMR data and simulations of a 3D ordered anisotropic antiferromagnet. Consistent results are obtained for two different magnetic ordering vectors. The agreement between simulation and experiment can be further improved by including a substantial amount of magnetic disorder. In addition, the metastable
Physical Review B, 1996
87Rb NMR was used to investigate the appearance and disappearance of the T&#3... more 87Rb NMR was used to investigate the appearance and disappearance of the T' line in Rb3C60. One-dimensional and two-dimensional experiments together with T-12 relaxation data reveal an exchange process only between T and T' lines with an activation energy of 580 meV. Different models are discussed in order to explain the data by orientational disorder, vacancy diffusion, and the off-center
Physical review. B, Condensed matter, Jan 15, 1994
13C NMR measurements on single crystals of (fluoranthenyl)2PF6 at variable temperatures and for d... more 13C NMR measurements on single crystals of (fluoranthenyl)2PF6 at variable temperatures and for different orientations of the crystals with respect to the external field reveal strongly temperature-dependent Knight-shift anisotropies. Hyperfine-interaction tensors for the different carbon sites of the fluoranthene molecule were determined and are compared with molecular-orbital-type calculations. The temperature dependence of the paramagnetic spin susceptibility was determined through the
Physical Review B, 1995
... The magic angle spinning (MAS) probe was also home-built and incorporated commercial MAS equi... more ... The magic angle spinning (MAS) probe was also home-built and incorporated commercial MAS equipment (Doty Scientific, South Carolina). Two-dimensional hy-percomplex data sets were acquired and processed as in Ref. ... 9J. Grobelny, J. Obrzut, and FE Karasz, Synth. Met. ...
Physical Review B, 1996
We present 13C high-resolution NMR data on the low-temperature (polymeric) phase of RbC60. From t... more We present 13C high-resolution NMR data on the low-temperature (polymeric) phase of RbC60. From the temperature-dependent line shift we have extracted information about the hyperfine couplings and electron density distribution on the C60 molecules. The data also support the existence of an sp3-like bonding type between the molecules.
Physical Review B, 1999
Electronic properties and molecular dynamics of mixed alkali-alkaline earth fullerides ABa2C60 (A... more Electronic properties and molecular dynamics of mixed alkali-alkaline earth fullerides ABa2C60 (A=K,Rb,Cs) are investigated by NMR and compared to the isostructural alkali fullerides A3C60. Consistent with previous Raman investigations, our results indicate a fivefold charge transfer to the C60, a charge state that is not found in pure alkali fullerides. 13C NMR experiments reveal a metallic ground state for all
Physical Review B, 1997
High resolution 13C NMR experiments prove the existence of sp3 carbon atoms which are assigned to... more High resolution 13C NMR experiments prove the existence of sp3 carbon atoms which are assigned to the dimer bonds in the quenched phase of RbC60. The relative intensities of the sp3 lines support a model where the C60 monomers are connected via a single bond. Spin-lattice relaxation measurements and 13C spectral changes reveal the transition to the polymer phase above
Carbon, 2000
We present evidence for localized and delocalized electrons in the different phases of A C from C... more We present evidence for localized and delocalized electrons in the different phases of A C from C NMR. The phases 1 60 13 discussed are the: polymeric phase, dimer phase and simple cubic phase. The analysis of the C NMR spectra provides a 3 map of the wavefunction of the conduction electrons, identification of sp carbons in the bonding regions and details of anisotropic molecular reorientation.
Applied Physics A: Materials Science & Processing, 1997
ABSTRACT
Applied Magnetic Resonance, 1996
NMR results concerning the electronic and the molecular dynamic properties of alkali fullerides a... more NMR results concerning the electronic and the molecular dynamic properties of alkali fullerides are presented and discussed. The dynamics as observed in line width and spin-spin relaxation is similar for A.C 6o and A 3Cw Spin-lattice relaxation and line shift depend strongly on the electronic properties and differ considerably for the various alkali concentrations.
Applied Magnetic Resonance, 1996
NMR results concerning the electronic and the molecular dynamic properties of alkali fullerides a... more NMR results concerning the electronic and the molecular dynamic properties of alkali fullerides are presented and discussed. The dynamics as observed in line width and spin-spin relaxation is similar for A.C 6o and A 3Cw Spin-lattice relaxation and line shift depend strongly on the electronic properties and differ considerably for the various alkali concentrations.
AIP Conference Proceedings, 1998
We investigate the spin arrangement in the magnetically ordered orthorhombic phase of CsC60 by a ... more We investigate the spin arrangement in the magnetically ordered orthorhombic phase of CsC60 by a comparison of 133Cs NMR data and simulations of a 3D ordered anisotropic antiferromagnet. Consistent results are obtained for two different magnetic ordering vectors. The agreement between simulation and experiment can be further improved by including a substantial amount of magnetic disorder. In addition, the metastable
Physical Review B, 1996
87Rb NMR was used to investigate the appearance and disappearance of the T&#3... more 87Rb NMR was used to investigate the appearance and disappearance of the T' line in Rb3C60. One-dimensional and two-dimensional experiments together with T-12 relaxation data reveal an exchange process only between T and T' lines with an activation energy of 580 meV. Different models are discussed in order to explain the data by orientational disorder, vacancy diffusion, and the off-center
Physical review. B, Condensed matter, Jan 15, 1994
13C NMR measurements on single crystals of (fluoranthenyl)2PF6 at variable temperatures and for d... more 13C NMR measurements on single crystals of (fluoranthenyl)2PF6 at variable temperatures and for different orientations of the crystals with respect to the external field reveal strongly temperature-dependent Knight-shift anisotropies. Hyperfine-interaction tensors for the different carbon sites of the fluoranthene molecule were determined and are compared with molecular-orbital-type calculations. The temperature dependence of the paramagnetic spin susceptibility was determined through the
Physical Review B, 1995
... The magic angle spinning (MAS) probe was also home-built and incorporated commercial MAS equi... more ... The magic angle spinning (MAS) probe was also home-built and incorporated commercial MAS equipment (Doty Scientific, South Carolina). Two-dimensional hy-percomplex data sets were acquired and processed as in Ref. ... 9J. Grobelny, J. Obrzut, and FE Karasz, Synth. Met. ...
Physical Review B, 1996
We present 13C high-resolution NMR data on the low-temperature (polymeric) phase of RbC60. From t... more We present 13C high-resolution NMR data on the low-temperature (polymeric) phase of RbC60. From the temperature-dependent line shift we have extracted information about the hyperfine couplings and electron density distribution on the C60 molecules. The data also support the existence of an sp3-like bonding type between the molecules.
Physical Review B, 1999
Electronic properties and molecular dynamics of mixed alkali-alkaline earth fullerides ABa2C60 (A... more Electronic properties and molecular dynamics of mixed alkali-alkaline earth fullerides ABa2C60 (A=K,Rb,Cs) are investigated by NMR and compared to the isostructural alkali fullerides A3C60. Consistent with previous Raman investigations, our results indicate a fivefold charge transfer to the C60, a charge state that is not found in pure alkali fullerides. 13C NMR experiments reveal a metallic ground state for all
Physical Review B, 1997
High resolution 13C NMR experiments prove the existence of sp3 carbon atoms which are assigned to... more High resolution 13C NMR experiments prove the existence of sp3 carbon atoms which are assigned to the dimer bonds in the quenched phase of RbC60. The relative intensities of the sp3 lines support a model where the C60 monomers are connected via a single bond. Spin-lattice relaxation measurements and 13C spectral changes reveal the transition to the polymer phase above
Carbon, 2000
We present evidence for localized and delocalized electrons in the different phases of A C from C... more We present evidence for localized and delocalized electrons in the different phases of A C from C NMR. The phases 1 60 13 discussed are the: polymeric phase, dimer phase and simple cubic phase. The analysis of the C NMR spectra provides a 3 map of the wavefunction of the conduction electrons, identification of sp carbons in the bonding regions and details of anisotropic molecular reorientation.
Applied Physics A: Materials Science & Processing, 1997
ABSTRACT
Applied Magnetic Resonance, 1996
NMR results concerning the electronic and the molecular dynamic properties of alkali fullerides a... more NMR results concerning the electronic and the molecular dynamic properties of alkali fullerides are presented and discussed. The dynamics as observed in line width and spin-spin relaxation is similar for A.C 6o and A 3Cw Spin-lattice relaxation and line shift depend strongly on the electronic properties and differ considerably for the various alkali concentrations.
Applied Magnetic Resonance, 1996
NMR results concerning the electronic and the molecular dynamic properties of alkali fullerides a... more NMR results concerning the electronic and the molecular dynamic properties of alkali fullerides are presented and discussed. The dynamics as observed in line width and spin-spin relaxation is similar for A.C 6o and A 3Cw Spin-lattice relaxation and line shift depend strongly on the electronic properties and differ considerably for the various alkali concentrations.