1D AND 2D MAS NMR-SPECTRA OF A DIPOLAR-COUPLED HOMONUCLEAR SPIN-1 2 PAIR/

An analytical approach based on the average Hamiltonian theory is prop osed for efficient calculation of the MAS NMR spectra of a dipolar-cou pled homonuclear spin-1/2 pair. For this purpose a superoperator forma lism is developed which allows one to describe the spectra over a broa d span of sample spinning rates, including the exact rotational resona nces. This formalism can also be applied to the description of 2D pola rization exchange spectra, which in many cases turns out to be useful for measuring the coupling strength. The experimental MAS NMR and the 2D spectra of doubly C-13-labeled zinc acetate were found to be in goo d agreement with the calculated spectra. (C) 1997 Academic Press.