Cross Polarization and Cross Relaxation from Laser-Polarized Xenon to Surface Species

The high polarization of optically pumped 129Xe was transferred to surface carbon and silicon species under magic angle spinning (MAS) conditions to afford enhanced solid-state NMR of surfaces. High-resolution 29Si MAS spectra of fumed silica and 13C spectra of chemisorbed methanol on silica were obtained using a steady flow of hyperpolarized xenon adsorbed onto the surface at 135 K. Cross polarization to 29Si from SPINOE enhanced hydroxyl protons and to 13C from enhanced methyl protons is observed with good efficiency. A direct SPINOE transfer from 129Xe to 13C without cross polarization is observed to give the highest enhancement under these conditions.