  The use of genetic algorithms for the optimisation of magic angle spinning
NMR pulse sequences is discussed. The discussion uses as an example the
optimisation of the C7 dipolar recoupling pulse sequence, aiming to achieve
improved efficiency for spin systems characterised by large chemical shielding
anisotropies and/or small dipolar coupling interactions. The optimised pulse
sequence is found to be robust over a wide range of parameters, requires only
minimal a priori knowledge of the spin system for experimental implementations
with buildup rates being solely determined by the magnitude of the dipolar
coupling interaction, but is found to be less broadbanded than the original C7
pulse sequence. The optimised pulse sequence breaks the synchronicity between
r.f. pulses and sample spinning.
