Publication year: 2011 Source: Journal of Magnetic Resonance, Available online 17 September 2011
Yuki*Asada, Risa*Mutoh, Masahiro*Ishiura, Hiroyuki*Mino
The use of a polychromatic microwave pulse to expand the pumping bandwidth in pulsed electron-electron double resonance (PELDOR) was investigated. The pumping pulse was applied in resonance with the broad (~100 mT) electron paramagnetic resonance (EPR) signal of the manganese cluster of photosystem II in the S2state. The observation pulses were in resonance with the narrow EPR signal of the tyrosine radical, YD. It was found that in the case of the polychromatic pumping pulse containing five harmonics with the microwave frequencies between 8.5 and 10.5 GHz the PELDOR effect corresponding to the dipole interaction between the Mn cluster and YDwas about 2.9 times larger than that achieved with a monochromatic pulse. In addition to the dipolar modulation, the nuclear modulation effects were observed. The effects could be suppressed by averaging the PELDOR trace over the time interval between the observation microwave pulses. The polychromatic excitation technique described will be useful for improving the PELDOR sensitivity in the measurements of long distances in biological samples, where the pair consists of a radical with a narrow EPR spectrum and slow phase relaxation, and a metal center that has a broad EPR spectrum and a short phase relaxation time. Graphical abstract
Highlights
? Application of multiple microwave frequencies for pulsed EPR. ? Efficiency of the spin excitation was evaluated by PELDOR. ? Improvement of signal-to-noise ratio of the PELDOR in photosystem II. ? Examination of the PELDOR in site-directed spin-labeled protein.
NMR Excitation, Dephasing and Spin Echoes
NMR Excitation, Dephasing and Spin Echoes
http://i.ytimg.com/vi/KtWnmFg-u5g/default.jpg
NMR Excitation, Dephasing and Spin Echoes
This short animation shows the process of NMR excitation in the laboratory and the rotating frame, as well as the dephasing that occurs from field inhomogeneity and the formation of the Hahn spin echo. Please credit (c)2010 Mark Cohen (mscohen@ucla.edu) during re-use.
From:markcat3t
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http://gdata.youtube.com/static/images/icn_star_full_11x11.gif http://gdata.youtube.com/static/images/icn_star_full_11x11.gif...
nmrlearner
NMR educational videos
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01-29-2012 07:45 PM
Two-photon excitation in nuclear magnetic and quadrupole resonance
Two-photon excitation in nuclear magnetic and quadrupole resonance
Publication year: 2010
Source: Progress in Nuclear Magnetic Resonance Spectroscopy, Volume 56, Issue 3, April 2010, Pages 232-246</br>
P.T.*Eles, C.A.*Michal</br>
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Journal club
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09-13-2011 09:15 PM
[U. of Ottawa NMR Facility Blog] Excitation Profiles for Shaped Pulses
Excitation Profiles for Shaped Pulses
Shaped pulses are very commonly used for selective excitation and nonselective inversion in a large number of NMR pulse sequences. The frequency domain excitation profile of a radio frequency pulse is the Fourier transform of the time dependent pulse shape and determines the width, uniformity and phase of the frequency spectrum excited. Since time and frequency are reciprocals of one another, short rf pulses have very wide excitation profiles and long rf pulses have very narrow selective excitation profiles. In a previous BLOG post the excitation...
nmrlearner
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01-21-2011 03:31 AM
[NMR paper] Highly selective excitation in biomolecular NMR by frequency-switched single-transiti
Highly selective excitation in biomolecular NMR by frequency-switched single-transition cross-polarization.
Related Articles Highly selective excitation in biomolecular NMR by frequency-switched single-transition cross-polarization.
J Am Chem Soc. 2002 Mar 13;124(10):2076-7
Authors: Ferrage F, Eykyn TR, Bodenhausen G
A new method for selective excitation in biomolecular NMR uses two-fold single-transition cross-polarization between protons and nitrogen-15 or carbon-13 nuclei. Switching the frequencies between the forward and backward transfer...
nmrlearner
Journal club
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11-24-2010 08:49 PM
[NMR paper] Development of NMR instrumentation to achieve excitation of large bandwidths in high-
Development of NMR instrumentation to achieve excitation of large bandwidths in high-resolution spectra at high field.
Related Articles Development of NMR instrumentation to achieve excitation of large bandwidths in high-resolution spectra at high field.
J Magn Reson. 2001 Jun;150(2):161-6
Authors: Luchinat C, Piccioli M, Pierattelli R, Engelke F, Marquardsen T, Ruin R
A prototype 2.5-mm (1)H high-resolution probe for an 18.8-T (800 MHz) nuclear magnetic resonance spectrometer has been designed, together with a dedicated amplifier capable of...
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11-19-2010 08:32 PM
[NMR paper] Improved excitation pulse bandwidths using shaped pulses, with application to heteron
Improved excitation pulse bandwidths using shaped pulses, with application to heteronuclear half filters in macromolecular NMR.
Related Articles Improved excitation pulse bandwidths using shaped pulses, with application to heteronuclear half filters in macromolecular NMR.
J Magn Reson B. 1995 Jul;108(1):12-21
Authors: Hyre DE, Spicer LD
The advantageous use of sinc-shaped pulses in heteronuclear half filters is explored for studying biological macromolecules. The typical square, or hard, pulse used in half-filter pulse sequences for...
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08-22-2010 03:41 AM
[U. of Ottawa NMR Facility Blog] Gradient Spin Echoes for Selective Excitation
Gradient Spin Echoes for Selective Excitation
Shaped excitation pulses can replace the non-selective hard pulses typically used in a one-pulse measurement to achieve selective excitation. Another method of achieving selective excitation is the gradient spin echo using a selective 180° pulse. This technique is demonstrated in the figure below. http://4.bp.blogspot.com/_5wBTR2kKTqA/S_UxeG5oXdI/AAAAAAAAAzc/BHWef-Tse7s/s400/grad_spin_echo.jpgA non-selective hard 90°x pulse is first given followed by a pair of identical pulsed field gradients sandwiching a soft selective 180° pulse about the y...
nmrlearner
News from NMR blogs
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08-21-2010 08:15 PM
why radio frequency
Dear sir,
Why we are using radio frequency excluding other electro magnetic radiation.
thankx
Nonselective excitation of pulsed ELDOR using multi-frequency microwaves
Linear Mode
