Category Archives: Spin Noise

Spin Noise Detection of Nuclear Hyperpolarization at 1.2 K

Poschko, M.T., et al., Spin Noise Detection of Nuclear Hyperpolarization at 1.2 K. ChemPhysChem, 2015: p. n/a-n/a.

http://www.ncbi.nlm.nih.gov/pubmed/26477605

We report proton spin noise spectra of a hyperpolarized solid sample of commonly used “DNP juice” containing TEMPOL and irradiated by a microwave field at a temperature of 1.2 K in a magnetic field of 6.7 T. The line shapes of the spin noise power spectra are sensitive to the variation of the microwave irradiation frequency and change from dip to bump, when the electron Larmor frequency is crossed, which is shown to be in good accordance with theory by simulations. Small but significant deviations from these predictions are observed, which can be related to spin noise and radiation damping phenomena that have been reported in thermally polarized systems. The non-linear dependence of the spin noise integral on nuclear polarization provides a means to monitor hyperpolarization semi-quantitatively without any perturbation of the spin system by radio frequency irradiation.

The Observation and Dynamics of 1H NMR Spin Noise in Methanol

Jurkiewicz, A., The Observation and Dynamics of 1H NMR Spin Noise in Methanol. Appl. Magn. Reson., 2013: p. 1-18.

http://dx.doi.org/10.1007/s00723-013-0473-7

The observation of 1H spin noise in relation to prior established mag- netization and radiation damping has revealed a correlated dynamics. The spin noise of methyl satellites in 13C-enriched methanol was observed in the presence of an antiphase magnetization, created by the combination of 1H–13C J coupling evolution and radiofrequency (RF) ulses. A gradient pulse was applied to remove residue spin coherence coming from the RF pulses, and as a result spin noise phenomena were uncovered. While magnetization was in an inverted metastable state, the spin– spin relaxation time was shortened to prevent a super radiation burst. The relation between magnetization, radiation amping, and absorption or emission of the spin noise of methyl satellites has been studied. In relation to agnetization and radiation damping, spin noise bump and dip have been observed simultaneously in the same molecule. Both can be created through a proper inversion of magnetization. The revealed spin noise dynamics of spin system coupling to the probe circuit via radiation damping allows performance of a transformation from dip into bump by proper application of pulses combined with 1H–13C J coupling evolution.

The Observation and Dynamics of 1H NMR Spin Noise in Methanol

Jurkiewicz, A., The Observation and Dynamics of 1H NMR Spin Noise in Methanol. Appl. Magn. Reson., 2013: p. 1-18.

http://dx.doi.org/10.1007/s00723-013-0473-7

The observation of 1H spin noise in relation to prior established mag- netization and radiation damping has revealed a correlated dynamics. The spin noise of methyl satellites in 13C-enriched methanol was observed in the presence of an antiphase magnetization, created by the combination of 1H–13C J coupling evolution and radiofrequency (RF) ulses. A gradient pulse was applied to remove residue spin coherence coming from the RF pulses, and as a result spin noise phenomena were uncovered. While magnetization was in an inverted metastable state, the spin– spin relaxation time was shortened to prevent a super radiation burst. The relation between magnetization, radiation amping, and absorption or emission of the spin noise of methyl satellites has been studied. In relation to agnetization and radiation damping, spin noise bump and dip have been observed simultaneously in the same molecule. Both can be created through a proper inversion of magnetization. The revealed spin noise dynamics of spin system coupling to the probe circuit via radiation damping allows performance of a transformation from dip into bump by proper application of pulses combined with 1H–13C J coupling evolution.

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