A two-axis goniometer for sensitivity enhancement in single-crystal nuclear magnetic resonance spectroscopy

The construction of a single-crystal nuclear magnetic resonance (NMR) probe with a new two-axis geometry for the goniometer has improved the sensitivi ty of the NMR response from small crystals. This allows studies of the smal lest crystals used so far in single-crystal NMR. The goniometer of the prob e uses only two different mountings of the crystal, and the rotation axis o f the goniometer is tilted 45 degrees with respect to the direction of the magnetic field. By moving the goniometer outside the radio frequency coil, the filling factor and the probe sensitivity increase. The improved sensiti vity for the probe is illustrated by the P-31-{H-1} cross-polarization spec trum of a 0.088 mm(3) crystal of (NH4)(2) HPO4 and a Rb-87 single-pulse spe ctrum of a 0.048 mm(3) crystal of RbZn2(HPO4)PO4. Moreover, the capability to determine precise parameters for the solid-state NMR interactions using the new probe is demonstrated by Na-23 and Rb-87 single-crystal studies of NaNO3 and RbClO4. (C) 1999 American Institute of Physics. [S0034-6748(99)00 703-0].