Nitrogen, solid molecular motions

Pure quadrupole resonance has been observed in solid molecular nitrogen, in its low-temperature phase at atmospheric pressure 28) between 1.5 and 35 °K (the transition occurs at 35.5 °K) the frequency is 3.487 MHz at 4.2 °K. In the high-temperature phase, the N.M.R. of nitrogen reveals a low coupling (about 3 kHz at 62° K) which is attributed to a small anisotropy of the reorientational motions in the hexagonal crystal. 

Thus linewidths for the different kinds of nitrogen in the N2O molecule are found to be in the ratio of the respective x values. NQCCs are obtained from microwave spectroscopy of gases and NQR spectroscopy of solids, also by NMR methods on solids and liquid crystals. Values in the liquid phase are usually close to those in the solid, and 10%-15% less than in the gas phase. Determining the NQCC from estimates of t, requires knowledge of the molecular motions. Anisotropic or additional internal motions may be monitored by relaxation measurements on two or more nuclei in the molecule, as of N, 0, and in dimethyl formamide. " ... 

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