Analytical Coherence-Transfer Functions for the General AMX Spin System under Isotropic Mixing

Abstract

Analytical coherence- and polarization-transfer functions are presented for spin systems consisting of three spins-$\text{1}\text{2}$ with arbitrary coupling constants under isotropic-mixing conditions. Based on these transfer functions, optimal durations for the mixing-time period can be determined for correlations of interest. The analytical expressions also make it possible to prove that isotropic-mixing polarization-transfer functions cannot become negative for three coupled spins-$\text{1}\text{2}$.