Computer Simulations of Multiple-Quantum NMR Experiments. I. Nonselective Excitation

The multiplequantum (MQ) evolution of anisotropic spin systems with four to eight coupled protons is analyzed using a computer for the basic three-pulse sequence. MQ intensities are first investigated as a function of preparation time. The concept of timeindependent intensities is then introduced, and an algorithm for efficient computation of these quantities is described. A correlation between the distribution of dipolar coupling values and the intensity of highquantum lines is discussed; in many cases, these intensities are predicted to be considerably larger than a simple statistical argument would suggest. The effect of varying the preparation and detection times independently is analyzed as a random walk problem. o 1984 Academic mess, hc.