Product operator formalism applied to large spin systems, with INEPT and DEPT examples

Abstract

A modification of the product operator formalism for the description of NMR multipulse experiments is proposed. In the modified formalism the single spin operators I px and I py of particular spins p are replaced by raising and lowering operators I p + and I p − in the product operator base. Use of a such mixed product operator base simplifies the formula for spin system evolution under scalar coupling interaction. Consequently, analysis of experiments on large weakly coupled spin ( I = 1 2 ) systems becomes feasible in the mixed base. The procedure is illustrated by the treatment of INEPT and DEPT experiments performed on spin systems with various hetero- and homonuclear couplings.