Abstract
The time-differential perturbed angular distribution (DPAC) technique may be employed to study the nuclear quadrupole interaction in solids, including many systems not measurable by other methods. A "state of the art" report on recent experiments is given. The difficulties and limitations of this method are due to the timing conditions, the target lattices available, and, foremost, the radiation damage created by the recoil nucleus. Possibilities to overcome these problems and some extensions of the technique are discussed. A large amount of data already now exists, particularly for the s-p metals. At several instances, however, "key" experiments by other HFI techniques would be needed to accurately determine the nuclear quadrupole moments and electric field gradients involved.