Nonideal rotations in nuclear magnetic resonance: Estimation of coherence transfer leakage

When spherical tensors are rotated by certain angles, coherence transfer se lection rules may apply. For example, a pi rotation cleanly inverts the coh erence order. A pi/2 rotation of a T-0(1) tensor creates only T-+/- 1(1) te nsors. In this work estimations are given for the coherence transfer leakag e under the action of rotations with small errors in the rotation angle or axis. Although the theory is stated with particular applications to NMR (nu clear magnetic resonance) in mind it is equally applicable wherever nonidea l rotations of spherical tensors are considered (e.g., quantum computing an d relaxation theory). In NMR it is useful for the estimation of coherence t ransfer leakage, especially in pulse sequences with many n pi pulses. The r esults are also applicable to spinors and half-integer representations of t he rotation group. (C) 2000 American Institute of Physics. [S0021-9606(00)0 0227-0].