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Simulation of radio‐frequency field inhomogeneity effects: application to pulse trains aimed at the determination of CSA–dipolar interference terms
Author(s) -
Leclerc Sébastien,
BouguetBonnet Sabine,
Mutzenhardt Pierre,
Brondeau Jean,
Canet Daniel
Publication year - 2003
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1259
Subject(s) - interference (communication) , relaxation (psychology) , dipole , chemistry , radio frequency , pulse (music) , field (mathematics) , computational physics , nuclear magnetic resonance , statistical physics , physics , telecommunications , computer science , quantum mechanics , voltage , psychology , social psychology , channel (broadcasting) , mathematics , organic chemistry , pure mathematics
Abstract The cross‐correlation relaxation rate constant between dipolar interaction and chemical shift anisotropy (interference term) is of considerable interest for structural and dynamical determinations. The present study focuses on methods related to its impact on longitudinal nuclear relaxation, and especially to a procedure based on the applications of a train of π pulses applied to both nuclei involved in such a process (Levitt MH, Di Bari L. Bull. Magn. Reson. 1994; 16 : 94–114). The resulting steady state leads, in principle, to a straightforward determination of the relevant interference term. Simulations taking into account inhomogeneity of the radio‐frequency (RF) field show that artifacts are responsible for instabilities which in practice preclude such a determination. An alternative method making use of a very limited number of RF pulses, combined with an appropriate filter, proves to be rather robust in view of achieving a proper measurement of the required interference term. Copyright © 2003 John Wiley & Sons, Ltd.