Optical nuclear polarization for sensitivity enhancement of H-2 NMR single-crystal studies

A gain in detection sensitivity of more than three orders of magnitude is a chieved in high-resolution solid-stare H-2 nuclear magnetic resonance of mo nocrystalline fluorene-d(10) by applying optical nuclear polarization via e xcited tripler states of acridine-h, guest molecules. The sensitivity gain is utilized to measure the angular dependence (rotation pattern) of the H-2 nuclear magnetic resonance lines. In this way the principal values and ori entations of all H-2 quadrupolar tensors are determined. Except for the met hylene deuterons. all tensors belonging to the same molecule have one princ ipal axis in common, namely the axis perpendicular to the molecular plane, showing that in the crystal lattice the fluorene molecule is in a planar co nfiguration.