Anomalous NMR Line Shapes in Solid Ordered Ortho-Hydrogen and Para-Deuterium

Some highly anomalous features have been observed in the low-temperature NMR spectrum of high-purity (> 99% J=1), solid para-deuterium. The intensity of the low-frequency side of the Pake doublet is enhanced and that of the high-frequency side reduced, sometimes becoming negative, corresponding to an emission of power. The anomaly is particularly pronounced and of the opposite sign for the I=2 resonance of the J=0 impurity molecules which …