Noise excitation of half-integer quadrupolar spins at high field

Quadrupolar parameters for half-integer nuclear spins are often derived by an analysis of the second-order broadening superposed on the central transition spectrum. Under typical conditions, where the exciting radiofrequency fields are weaker than first-order quadrupolar splittings, distortions in lineshape and intensity are difficult to avoid. We apply stochastic excitation to these systems and demonstrate that undistorted lineshapes can be observed independent of the magnitude of the quadrupolar interaction. This should provide a significant improvement in quantitative measures of nuclear spin densities.