Kaminker, I., et al., Population transfer for signal enhancement in pulsed EPR experiments on half integer high spin systems. Phys Chem Chem Phys, 2009. 11(31): p. 6799-806.
High resolution pulse EPR techniques applied to half integer high spin systems, such as Mn(2+) (S = 5/2), usually focus only on the central |-1/2--> |1/2 transition. The reason is that at high fields, where the zero field splitting is considerably smaller than the Zeeman interaction, the spectrum of this transition is intense and narrow. However, because the experiments are carried out at low temperatures, the low lying levels are heavily populated and the signal of the central transition is nevertheless diminished. This, in turn affects the sensitivity of the pulse EPR technique applied. A transfer of populations from the lower lying levels, which for Mn(2+) are the |-3/2 and |-5/2 levels, to the |-1/2 level will therefore increase the sensitivity. Here we describe such an experiment, where a rapid magnetic field sweep over the |-3/2--> |-1/2 sub-spectrum is carried out, concomitantly with a low power microwave (mw) irradiation, which results in population inversion. After this sweep any pulsed EPR sequence can be applied to the central transition that now has a population difference that deviates from the equilibrium value. The feasibility of the experiment is demonstrated at W-band (95 GHz) on Mn(2+) doped in MgO for echo-detected EPR measurements and the dependence of the signal enhancement on the rate and range of the magnetic field sweep and on the mw power is described. The results are then accounted for theoretically by considering a simple fictitious spin 1/2 system. In addition, preliminary enhanced (55)Mn pulse ENDOR electron nuclear double resonance (ENDOR) spectra are presented.
Covariance spectroscopy with a non-uniform and consecutive acquisition scheme for signal enhancement of the NMR experiments
Covariance spectroscopy with a non-uniform and consecutive acquisition scheme for signal enhancement of the NMR experiments
Publication year: 2012
Source:Journal of Magnetic Resonance</br>
Yixuan Li, Qiang Wang, Zhengfeng Zhang, Jun Yang, Bingwen Hu, Qun Chen, Isao Noda, Feng Deng</br>
Two-dimensional covariance (COV2D) spectroscopy with non-uniform and consecutive acquisition (NUCA) scheme is introduced. This NUCA-COV2D method allows the number of t1 points to be reduced by a factor of 1.5~3 without any broadening of the linewidth. Furthermore, the...
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Covariance spectroscopy with a non-uniform and consecutive acquisition scheme for signal enhancement of the NMR experiments
Covariance spectroscopy with a non-uniform and consecutive acquisition scheme for signal enhancement of the NMR experiments
Publication year: 2012
Source: Journal of Magnetic Resonance, Available online 6 March 2012</br>
Yixuan*Li, Qiang*Wang, Zhengfeng*Zhang, Jun*Yang, Bingwen*Hu, ...</br>
Two-dimensional covariance (COV2D) spectroscopy with non-uniform and consecutive acquisition (NUCA) scheme is introduced. This NUCA-COV2D method allows the number of t1points to be reduced by a factor of 1.5~3 without any broadening of the linewidth. Furthermore, the signal-to-noise ratio (S/N) can...
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03-08-2012 08:46 AM
[NMR paper] Low temperature solid-state NMR experiments of half-integer quadrupolar nuclides: cav
Low temperature solid-state NMR experiments of half-integer quadrupolar nuclides: caveats and data analysis.
Related Articles Low temperature solid-state NMR experiments of half-integer quadrupolar nuclides: caveats and data analysis.
J Magn Reson. 2004 May;168(1):66-74
Authors: Lipton AS, Heck RW, Sears JA, Ellis PD
Solid-state NMR spectroscopy of half-integer quadrupolar nuclides has received a lot of interest recently with the advent of new methodologies and higher magnetic fields. We present here the extension of our previous low...
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[Stan NMR blog] Half-integer nuclei?
Half-integer nuclei?
A query about the use/abuse of the term "high half-integer spin" in NMR
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11-23-2010 07:10 AM
Signal enhancement in protein NMR using the spin-noise tuning optimum
Signal enhancement in protein NMR using the spin-noise tuning optimum
Abstract We have assessed the potential of an alternative probe tuning strategy based on the spin-noise response for application in common high-resolution multi-dimensional biomolecular NMR experiments with water signal suppression on aqueous and salty samples. The method requires the adjustment of the optimal tuning condition, which may be offset by several 100 kHz from the conventional tuning settings using the noise response of the water protons as an indicator. Although the radio frequency-pulse durations are...
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Signal enhancement in protein NMR using the spin-noise tuning optimum.
Signal enhancement in protein NMR using the spin-noise tuning optimum.
Signal enhancement in protein NMR using the spin-noise tuning optimum.
J Biomol NMR. 2010 Oct 6;
Authors: Nausner M, Goger M, Bendet-Taicher E, Schlagnitweit J, Jerschow A, Müller N
We have assessed the potential of an alternative probe tuning strategy based on the spin-noise response for application in common high-resolution multi-dimensional biomolecular NMR experiments with water signal suppression on aqueous and salty samples. The method requires the adjustment of the...
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10-07-2010 10:33 AM
[Stan NMR blog] Half-integer nuclei?
Half-integer nuclei?
A query about the use/abuse of the term "high half-integer spin" in NMR
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Population transfer for signal enhancement in pulsed EPR experiments on half integer high spin systems
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