Radical addition to ruthenocene at low temperatures: characterization of ruthenocenyl radicals by μSR spectroscopy

2018 ◽  
Vol 96 (3) ◽  
pp. 358-362 ◽  
Author(s):  
Iain McKenzie
Keyword(s):  
Dft Calculations ◽  
Spin Relaxation ◽  
Muon Spin ◽  
Transverse Field ◽  
Relaxation Mechanism ◽  
Coupling Constants ◽  
Muon Spin Rotation ◽  
Electron Spin Relaxation ◽  
Spin Resonance ◽  
Experimental Values

The radicals formed by muonium (Mu) addition to ruthenocene at low temperature (4–200 K) have been characterized by transverse field muon spin rotation (TF-μSR) and avoided level crossing muon spin resonance (ALC-μSR) spectroscopy. The structures of the muoniated radicals have been identified by comparing the experimentally measured muon hyperfine coupling constants with values obtained from DFT calculations (UB3LYP/DGDZVP). Mu addition was observed at the ruthenium and at the cyclopentadiene (Cp) rings, both from the exterior and interior directions. Closer agreement between the DFT calculations and the experimental values are obtained if it is assumed the structures of the Mu adducts of the Cp rings are distorted due to interactions with neighbouring molecules. Changes in the ALC-μSR spectra with temperature indicated that the electron spin relaxation rate of the Cp adducts increases with temperature; however, the specific spin relaxation mechanism is unknown.

Germanium-centered free radicals studied by muon spin spectroscopy

2014 ◽  
Vol 92 (6) ◽  
pp. 508-513 ◽  
Author(s):  
Robert West ◽  
Kerim Samedov ◽  
Amitabha Mitra ◽  
Paul W. Percival ◽  
Jean-Claude Brodovitch ◽  
...  
Keyword(s):  
Free Radicals ◽  
Density Functional ◽  
Muon Spin ◽  
Coupling Reaction ◽  
Transverse Field ◽  
Coupling Constants ◽  
Muon Spin Rotation ◽  
Functional Theory ◽  
Hyperfine Constant ◽  
Germanium Compounds

Transverse-field muon spin rotation (TF-μSR) spectra have been recorded for free radicals formed by positive muon irradiation of nine different divalent germanium compounds. Muon-electron hyperfine coupling constants (Aμ) were determined from the spectra and compared with values predicted from density functional theory molecular orbital (DFT-MO) calculations on the muoniated radicals formed by muonium addition to the germanium atom. The muon hyperfine constants for germylenes containing N–Ge bonds are generally quite large, from 593 to 942 MHz, indicating strong interaction between the muon and the unpaired electron in these radicals. The radical derived from one of the germylenes exhibited a significantly lower muon hyperfine constant, suggesting that in this case the muoniated germyl radical undergoes a coupling reaction to form a digermanyl radical, which is what is detected by μSR.

scholarly journals Examples of the Application of Muon Spin Relaxation to Studies of Magnetism in Cuprates

1998 ◽  
Vol 51 (2) ◽  
pp. 385 ◽  
Author(s):  
F. J. Litterst ◽  
M. Birke ◽  
B. Büchner ◽  
M. Hillberg ◽  
H.-H. Klauβ ◽  
...  
Keyword(s):  
Spin Relaxation ◽  
Muon Spin ◽  
Magnetic Moments ◽  
High Sensitivity ◽  
Muon Spin Relaxation ◽  
Spin Rotation ◽  
Muon Spin Rotation ◽  
Slow Dynamic ◽  
Magnetic Correlations ◽  
Superconducting Phases

After a brief introduction to muon spin rotation and relaxation (µSR) some recently achieved results on La2-x-yNdxSryCuO4, La2-x-yEuxSryCuO4 and Nd2-xCexCuO4 are presented demonstrating the high sensitivity of the method for the dynamics and ordering of small magnetic moments close to the superconducting phases. The µSR experiments give evidence for static and relatively slow dynamic magnetic correlations in these cuprates.

Theory of Nuclear Quadrupole Interactions of 14N, 17O, and 35Cl Nuclei in p-Cl-Ph-CH-N=TEMPO

2002 ◽  
Vol 57 (6-7) ◽  
pp. 527-531
Author(s):  
Junho Jeong ◽  
Tina M. Briere ◽  
N. Sahoo ◽  
T. P. Das ◽  
S. Ohira ◽  
...  
Keyword(s):  
Muon Spin ◽  
Hyperfine Interactions ◽  
Rotation Frequency ◽  
Coupling Constants ◽  
Muon Spin Rotation ◽  
Hartree Fock ◽  
Nuclear Quadrupole Interactions ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Asymmetry Parameters

The nuclear quadrupole coupling constants and asymmetry parameters have been studied for the 35Cl, 17O, and 14N nuclei in the molecular ferromagnet 4-(p-chlorobenzylideneamino)-TEMPO (2,2,6,6-tetramethyl- piperidin-1-yloxyl) using elctronic stuctures obtained by the Hartree-Fock procedure for the bare system and systems with trapped muon and muonium. Trends in the sizes of the coupling constants and asymmetry parameters for the various nuclei have been studied, and possible physical explanations have been proposed. For the systems with trapped muon or muonium, very substantial influences of the muon and muonium on the coupling constants and asymmetry parameters for the nuclei close to the trapping sites have been observed. The coupling constants and asymmetry parameters are found to be very different for the various nuclei, for the two cases where muon is trapped near chlorine and muonium near oxygen, indicating that, if experimental data were available to compare with theory, one could make conclusions about which of these two centers is responsible for the observed muon spin rotation frequency associated with the muon magnetic hyperfine interactions in these two trapped systems

Theory of 14N and 17O Nuclear Quadrupole Interactions in the Single Amino Acids Occurring in the Protein Chain of Cytochrome c

2002 ◽  
Vol 57 (6-7) ◽  
pp. 532-536 ◽  
Author(s):  
R. H. Scheicher ◽  
D. Cammarere ◽  
N. Sahoo ◽  
K. Nagamine ◽  
T. P. Das
Keyword(s):  
Experimental Data ◽  
Amino Acids ◽  
Cytochrome C ◽  
Muon Spin ◽  
Coupling Constants ◽  
Muon Spin Rotation ◽  
Protein Chain ◽  
Cyt C ◽  
Nuclear Quadrupole

The understanding of electron transport in proteins based on a novel technique involving muon spin rotation (μSR)measurements is a topic of great current interest. The technique, which involves study of spin relaxation of a positive muon (μ+) trapped in amino acids in protein chains due to the fluctuating magnetic field that the moving electron produces, is based on the premise that the electron is generated by ionization of a muonium (Mu) which was trapped at the same site as the μ+ left behind. In attempting to test this premise from first-principles for the Cytochrome c (Cyt c) system in which recent μSR measurements have been made, we have carried out Hartree- Fock investigations of the electronic structures of the bare amino acids and amino acids with + and Mu trapped at the oxygen of the C=O group common to all amino acids. With the aim that the comparison of theoretically predicted experimental nuclear quadrupole interaction (NQI) parameters will provide a useful test of the electron distribution in the amino acids of Cyt c, we present results for the nuclear quadrupole coupling constants (e2qQ) and asymmetry parameters (η) for the bare amino acids and the amino acids with trapped μ+ and Mu. The trends in 2 and for 14N and 17O between the various amino acids, as well as the changes in these parameters in the presence of μ+ and Mu are being analyzed. It would be helpful to have experimental data for e2qQ and to η compare with our predictions for the amino acids as they occur in vitro in polycrystalline Cyt c in which the SR measurements have been carried out. It is also hoped that the μSR technique will be able to provide experimental data on e2qQ and for the 14N and 17O nuclei to compare with our predictions

The Impurity Spin-Dependent Scattering Effects in the Transport and Spin Resonance of Conduction Electrons in Bismuth Doped Silicon

2015 ◽  
Vol 242 ◽  
pp. 327-331 ◽  
Author(s):  
Andrey V. Soukhorukov ◽  
Davud V. Guseinov ◽  
Alexei V. Kudrin ◽  
Sergey A. Popkov ◽  
Alexandra P. Detochenko ◽  
...  
Keyword(s):  
Hall Effect ◽  
Spin Relaxation ◽  
Electron Spin ◽  
Anomalous Hall Effect ◽  
Hall Resistance ◽  
Resonance Spectroscopy ◽  
Electron Spin Relaxation ◽  
Conduction Electrons ◽  
Spin Resonance ◽  
Hall Effect Measurements

Transport and spin relaxation characteristics of the conduction electrons in silicon samples doped with bismuth in the 1.1·1013- 7.7·1015cm-3concentration range were studied by the Hall and electron spin resonance spectroscopy. Hall effect measurements in the temperature range 10-80 K showed a deviation from the linear dependence of the Hall resistance in the magnetic field, which is a manifestation of the anomalous Hall effect. The magnetoresistance investigation shows that with current increasing magnetoresistance may change its sign from positive to negative, which is most clearly seen when the bismuth concentration goes up to 7.7·1015cm-3. The conduction electron spin relaxation rate dramatically increases in silicon samples with sufficiently low concentration of bismuth ~ 2·1014cm-3. All these results can be explained in terms of the concept of spin-dependent and spin flip scattering induced by heavy bismuth impurity centers.

scholarly journals Two-gap superconductivity in Lu2Fe3Si5: A transverse-field muon spin rotation study

2011 ◽  
Vol 83 (5) ◽  
Author(s):  
P. K. Biswas ◽  
G. Balakrishnan ◽  
D. McK. Paul ◽  
M. R. Lees ◽  
A. D. Hillier
Keyword(s):  
Muon Spin ◽  
Transverse Field ◽  
Spin Rotation ◽  
Muon Spin Rotation ◽  
Rotation Study

scholarly journals Transverse field muon-spin rotation signature of the skyrmion-lattice phase inCu2OSeO3

2015 ◽  
Vol 91 (22) ◽  
Author(s):  
T. Lancaster ◽  
R. C. Williams ◽  
I. O. Thomas ◽  
F. Xiao ◽  
F. L. Pratt ◽  
...  
Keyword(s):  
Muon Spin ◽  
Transverse Field ◽  
Spin Rotation ◽  
Muon Spin Rotation

Studies on Electron Spin Relaxation in AlGaAs/GaAs Multi Quantum Wells

2011 ◽  
Vol 143-144 ◽  
pp. 216-219
Author(s):  
Yu Wu
Keyword(s):  
Quantum Wells ◽  
Spin Relaxation ◽  
Electron Spin ◽  
Carrier Density ◽  
Relaxation Mechanism ◽  
Electron Spin Polarization ◽  
Time Resolved ◽  
Pump Probe ◽  
Electron Spin Relaxation ◽  
Probe Spectroscopy

Time-resolved circularly polarized pump-probe spectroscopy is used to study the carrier density dependence of the electron spin polarization dynamics in AlGaAs/GaAs multi quantum wells at room temperature. Experimental results show that the spin relaxation time increases with the carrier density, which is in conformity with D'yakonov-Perel relaxation mechanism.

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