COMPLETE SOLUTION FOR 2 COUPLED SPIN-1/2 NUCLEI EVOLVING UNDER CHEMICAL-SHIFT AND DIPOLAR INTERACTION

The spin dynamics for two coupled spin-1/2 nuclei evolving under isotropic chemical shifts and a dipole-dipole interaction, in the high-field limit, is presented using Fano's unit spherical tensors (U) over cap((K)(Q)(I-i,I-j) as a basis set. For simplicity, relaxation effects are ignored. The results are used to discuss the frequently used dipole-dipole approximations for both homonuclear and heteronuclear spin systems. In particular, it is shown that it is possible to analyse NMR spectra of two spin-1/2 systems where the chemical shift differences and the dipolar interactions are of similar magnitude.