Product-operator formalism in I≥1/2 and S≥3/2 J-coupled nuclear spins:: Application to J assessment via SEDOR experiment

Product-operator formalism has been extended to weakly coupled I greater than or equal to 1/2 and S greater than or equal to 3/2 nuclear spills to describe the result of nuclear SEDOR (spin echo double resonance) experiments for such spin numbers. By SEDOR modulation, the indirect nuclear spin-spin coupling constant J(IS) can be measured also when the quadrupolar broadening hides the high resolution evaluation of J(IS) and the method based on scalar relaxation of the second kind cannot be utilized because of the low quadrupolar relaxation efficiency. Furthermore, the nuclear SEDOR modulation can be performed in low intensity and homogeneity magnetic field. The theory has been applied to estimate J(IS) of the coupled nuclear spins I = 1/2 (F-19) and S = 9/2 (Nb-93) in NbF6- (octahedral symmetry) and of I = 1/2 (H-1) and S = 3/2 (B-11) in (Na2B12H11SH)-H-11 (icosahedral symmetry). (C) 1998 American Institute of Physics. [S0021-9606(98)01238-0].