Total spin coherence transfer echo spectroscopy

Abstract

The sensitivity of multiple quantum NMR transitions to magnetic field inhomogeneity and the relative phases and amplitudes of multiple quantum lines are discussed. The technique of total spin coherence transfer echo spectroscopy (TSCTES) is described and experimentally demonstrated. The TSCTES method allows multiple quantum spectra to be obtained which are free of inhomogeneous magnet broadening, yet remain sensitive to spin–spin couplings and chemical shift differences. The method takes advantage of the properties of the total spin coherence, the unique transition between the extreme eigenstates of a coupled spin system. Experimental results are reported for partially oriented acetaldehyde and are analyzed in terms of irreducible tensor operators. Limitations on the method and extensions to heteronuclear spin systems are also discussed.