A correlation between NMR peak intensities and a fictitious spin 1/2 presentation of the z‐component of nuclear spins I > 1/2

Abstract

In a recent publication, it was suggested that for I > 1/2 the peaks intensities can be interpreted to be the result of spin dynamics along the z axis. The intensity ratios were found to be independent of the magnetic field, suggesting that the important factor determining the peak intensities is the operator Iz, and its interaction with the radio frequency magnetic field. In the current comment, we suggest that a presentation of this operator as a superposition of fictitious spins 1/2 provides an alternative explanation for the correlation between the Iz operator and the peak intensities. It is further shown that the correlation between the Iz operator and the NMR peak intensities is valid only for nonselective excitation or under conditions where Fermi's golden rule applies. The relevance of the spin‐lock experiment for such a correlation is discussed. © 2014 Wiley Periodicals, Inc. Concepts Magn Reson Part A 42A: 182–186, 2013.