This program displays the net magnetization vector in the rotating frame, an energy level diagram, and a density matrix. The program can model one spin, AX homonuclear or AX heteronuclear spin systems. The user sets the observed frequency for each nuclei, the T1 and T2* relaxation rates, and the coupling constants. Then apply different pulse sequences and observe the evolution of the spin system with the rotating vectors after the pulse. Note: this program uses the left hand rule.