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Behavior of Two Almost Identical Spins during the CPMG Pulse Sequence
Author(s) -
Tošner Zdeněk,
Škoch Antonín,
Kowalewski Jozef
Publication year - 2010
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200900699
Subject(s) - spins , pulse sequence , relaxation (psychology) , chemistry , dipole , pulse (music) , nuclear magnetic resonance , spin (aerodynamics) , atomic physics , spectroscopy , sequence (biology) , molecular physics , spin echo , condensed matter physics , physics , optics , magnetic resonance imaging , quantum mechanics , medicine , psychology , social psychology , biochemistry , organic chemistry , radiology , detector , thermodynamics
Multiple‐spin‐echo experiments have found wide use in nuclear magnetic resonance spectroscopy. In particular, the Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence is used to determine transverse relaxation times T 2 . Herein it is demonstrated, both theoretically and experimentally, that for a pair of almost identical spins‐1/2 the experimental setup can have a profound effect on the observed spin dynamics. It is shown that, in the case of dipolar relaxation, the measured T 2 values can roughly vary between the limits of identical and unlike spins, just depending on the repetition rate of π pulses with respect to chemical shift separation. Such an effect can, in the extreme narrowing regime, amount to a 50 % difference.