Nuclear Transfer Effects in Nuclear Magnetic Resonance Pulse Experiments

The Bloch equations for the nuclear magnetic resonance of a single nuclear species which is transferred between state environments having different relaxation times (T1 or T2) and different resonance frequencies have been solved for rf pulse experiments. Expressions have been obtained for the free precession signals in two‐pulse experiments. A theoretical study of the signal envelopes has been made for several specific instances. In particular, the effect of the frequency difference between the two states on transverse (T2) relaxation has been investigated; the predicted effect is large in some cases. The longitudinal (T1) relaxation is independent of the frequency separation. A reduction of phase dispersion by the second pulse which is similar to that in molecular diffusion is also predicted.