The State of Solid Methane as in - ferred from Nuclear Magnetic Resonance

Proton magnetic resonance datal) in solid methane were analyzed by using the one parameter theory2) and the perturbation method. Assuming a single molecule as a unit of reorientation we obtained from the spin-lattice relaxation time the result shown in Fig. 1, where loglo r c is plotted against reciprocal tem perature. r c decreases with increasing temperature and rather sudden alterations of the dominant mechanism for spin-lattice relaxation exist at about 20° K (A. transition), 65° K (anomaly not yet detected by thermal measurements) and 90° K (melting point). The linear character revealed in the. plot suggests that the dominant mechanism above 20° Kis a thermal jumping or tunnelling over some fixed pass, the height of which is estimated