QUEST is a new program for the exact simulation of solid-state NMR spectra of quadrupolar nuclei in stationary powdered samples which employs diagonalization of the combined Zeeman-quadrupolar Hamiltonian. The program may be used to simulate NMR spectra over the full regime of Larmor and quadrupolar frequencies, which encompasses scenarios ranging from high-field NMR to nuclear quadrupole resonance (NQR, where the Larmor frequency is zero) and does not make use of approximations when treating the quadrupolar interaction. The program, which uses a graphical user interface, also incorporates chemical shift anisotropy and non-coincident chemical shift and quadrupolar tensor frames. QUEST can be used to simulate static NMR and NQR spectra with any relative size of the Zeeman and quadrupolar interactions and correctly predicts the appearance of “forbidden” or “overtone” NMR as well as NQR transitions. This program is available to download at http://mysite.science.uottawa.ca/dbryce/
QUEST is described in an article which has been accepted for publication in Solid State Nuclear Magnetic Resonance (2012).
F.A. Perras, C.M. Widdifield, and D.L. Bryce, "QUEST – QUadrupolar Exact SofTware: a fast graphical program for the exact simulation of NMR and NQR spectra for quadrupolar nuclei," Solid State Nuclear Magnetic Resonance (2012) accepted. http://dx.doi.org/10.1016/j.ssnmr.2012.05.002
Unequal quadrupolar splitting intensities
Hi everyone
I'm running an experiment looking at a mesoporous organosilica soaked in benzene-d6. The pores are tubular and aligned more or less in the same direction, so the anisotropic environment causes quadrupolar splitting when looking at deuterium. However, the splitting intensities are not equal: the left peak tends to be noticeably larger (~10-20%) than the right. Have tried this with the sample at different orientations in the field. At some angles, such at 180 degrees, the peaks are nearly equal in intensity, but at the rest of them the left is higher.
So my question is: what...
sir_manning
NMR Questions and Answers
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02-06-2012 06:33 PM
High-resolution protein structure determination starting with a global fold calculated from exact solutions to the RDC equations
High-resolution protein structure determination starting with a global fold calculated from exact solutions to the RDC equations
Abstract We present a novel structure determination approach that exploits the global orientational restraints from RDCs to resolve ambiguous NOE assignments. Unlike traditional approaches that bootstrap the initial fold from ambiguous NOE assignments, we start by using RDCs to compute accurate secondary structure element (SSE) backbones at the beginning of structure calculation. Our structure determination package, called rdc-Panda (RDC-based SSE PAcking with...
nmrlearner
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[NMR paper] Low temperature solid-state NMR experiments of half-integer quadrupolar nuclides: cav
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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
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J Magn Reson. 1997 Dec;129(2):111-4
Authors: Aramini JM, Germann MW, Vogel HJ
We have employed soft (Gaussian) pulses to examine 27Al NMR signals arising from Al3+ bound to ovotransferrin. In addition to enhancing the general detectability of 27Al...
nmrlearner
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[U. of Ottawa NMR Facility Blog] Solid State NMR of Half Integer Quadrupolar Nuclei
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Many students who do liquid state NMR or solid state NMR of spin I=1/2 nuclei have very little appreciation for the information content and complexity of the solid state NMR spectra of spin I = n/2 quadrupolar nuclei (n= 3, 5, 7....). In part, I think this may be due to the mathematics involved with explaining the important effects. With this post, I attempt to describe the NMR spectrum of an I = 5/2 nucleus in the soild state without resorting to mathematics. I hope that this post helps to boost the understanding and appreciation for the...
nmrlearner
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NMR Software
NMR SoftwareLinuxNMR
Programs are listed sequentially, according to the normal order of use in a typical NMR structure determination project. Rather than providing detailed tutorials on the use of the various programs, a few comments on the general use of each program are provided, as well as the literature citations and links to the original documentation.
Auto-assignment programs
AutoAssign
AutoAssign is a constraint-based expert system for automating the analysis of backbone resonance assignments using NMR spectra of small proteins. Zimmerman, D.E., Kulikowski, C.A., Huang, Y.,...
QUEST – QUadrupolar Exact SofTware
Linear Mode
