Figure 2.

The simulated NMR spectrum of a two-spin system, with ν_α = 100 Hz, ν_β = 400 Hz, and J_αβ = 40 Hz. From left to right, the four peaks in this spectrum correspond to the transitions 0 ↔ 1, 2 ↔ 3, 0 ↔ 2, and 1 ↔ 3 indicated in Fig. 1 (be forewarned, however, that NMR spectroscopists traditionally plot their spectra with frequency increasing from right to left). In practice, this spectrum would be obtained by applying a nonselective π/2 pulse to the equilibrium state and Fourier transforming the resulting signal.