H 1 to H2 uniform cross-polarization nuclear magnetic resonance using H2 Lee–Goldburg irradiation in static powders

Abstract

Application of conventional cross polarization (CP) to (2)H results in only a narrowband enhancement of the powder line shape due to the quadrupole interaction. We propose a CP scheme to uniformly enhance (2)H spectra in static powders. In this method, a Hartmann-Hahn matched (2)H rf field is applied on the Lee-Goldburg (LG) condition to remove the zeroth-order quadrupole interaction. In order to achieve a uniformly enhanced (2)H powder line shape with a limited (2)H rf intensity, the (1)H rf amplitude in CP is stepwise altered during the contact time. We develop a spin-thermodynamic theory to describe polarization transfer due to CP with LG irradiation (LG-CP) under the influence of the quadrupole interaction, which can successfully reproduce the LG-CP line shapes observed under various experimental conditions. Experimental and simulated (2)H powder spectra are reported for some compounds.