1H-1H double-quantum CRAMPS NMR at very-fast MAS (νR = 35 kHz): A resolution enhancement method to probe 1H-1H proximities in solids

A High-resolution two-dimensional (2D) 1H double-quantum (DQ) homonuclear recoupling experiments, combined with smooth amplitude-modulation (SAM) homonuclear decoupling is presented. The experiment affords highly resolved and clean 1H DQ-SQ 2D spectra at very-fast MAS rates (νR = 35 kHz). The method is well suited to probe 1H-1H distances in powdered solids and demonstrations are applied on a NaH2PO4 powdered sample, an inorganic compound having hydrogen bonding networks.