Broadband homonuclear cross polarization in 2D N.M.R. using DIPSI-2

Abstract

We discuss broadband homonuclear cross polarization of J-coupled spin systems in liquids, and compare a new windowless sequence, called DIPSI-2, to the broadband spin decoupling sequences MLEV-16 and WALTZ-16. We find that DISPI-2 leads to more rapid and complete cross polarization for a given expenditure of radiofrequency power. Either longitudinal or transverse magnetization components can be exchanged by DIPSI-2. Using DIPSI-2 as a mixing sequence to induce longitudinal magnetization transfer can give absorption-mode 2D correlation spectra with a minimum of phase cycling steps.