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Abstract

The spin-lattice relaxation time T₁ has been measured for the proton and the deuteron resonances in methane -and its deuterated modifications as a function of density ƿ , at low densities where T₁ is proportional to ƿ ; and temperature T, between 110°K and 300°K. For the proton relaxation, plots of log T₁/ƿ versus log T for each of the gases CH₄₌ո Dո, n=0, 1, 2, 3 gave the temperature dependence of T₁/ƿ as T₁/ƿ∝T⁻³ʹ² . The value of T₁/ƿ at constant temperature changed very little with n. This implied that the main interaction contributing to proton spin relaxation was the spin-rotational interaction. For the deuteron results it was found that T₁/ƿ was nearly independent of temperature but differed by a factor of approximately four over the range of isotopic compositions n = 1, 2, 3,4. CD₄ gave the shortest value of T₁ while CHD₃ gave the longest. This was attributed to the dominance of the quadrupolar interaction of the deuteron over the dipolar and spin-rotational interactions.