NMR spectra in the semimedium-coupling range

General formulas are derived for the semimedium - couplingrange, accurate to the third approximation of perturbation theory for the frequencies and the second approximation for the intensities. A general formula is derived for the fourth-approximation frequencies in the case in which this approximation makes the main contribution to the splitting. It is shown that the spectra of systems of non-equivalent nuclei preserves in the third approximation the structure characteristic for the first - order spectra. General relations are obtained for determination of the sequence of the lines formed as a result of lifting of degeneracy.