Abstract: A New density operator formalism for describing high-spin nuclei systems-angular momentum product operator and Z operator was proposed. The product operator and {Z} operator evolution formulae were derived under the effect of spin-spin couplings and radio frequency pulses. The theory dercription can be used to analyse NMR multi-pulse experiments for high-spin nuclei systems. Re-focused INEPT, DEPT and Homonuclear Cosy for high-spin nuclei systems were calculated by using the new density operator. The Caculation method is discussed.

Key words: Product operator, {Z}operator, Extended product operator, Highspin system