A way of visualizing NMR experiments on quadrupolar nuclei

Abstract

A graphical representation of the spin states of quadrupolar nuclei in NMR experiments is described. The spherical harmonics represent the irreducible spherical tensor operator basis set, and therefore any density matrix can be illustrated with computer graphics by converting it to a sum of spherical harmonics. Using a multiple quantum-filtered experiment as an example, we demonstrate how the phase and flip angle of RF pulses can be used to create multiple quantum coherences, to suppress the creation of particular coherences, and to select coherences by exploiting their symmetry. This visual approach complements the algebraic description of pulse sequences, providing an intuitive way of designing and analyzing pulse sequences. © 2005 Wiley Periodicals, Inc. Concepts Magn Reson Part A 25A: 40–52, 2005.