In:
Canadian Journal of Physics, Canadian Science Publishing, Vol. 50, No. 3 ( 1972-02-01), p. 251-258
Abstract:
The spin–lattice relaxation time T 1 was measured in gaseous CH 4 as a function of density at room temperature between 0.006 and 7.0 amagats. T 1 was found to pass through a minimum near 0.04 amagats in agreement with previous, less precise measurements. The spin–rotation interaction is the dominant relaxation mechanism in gaseous CH 4 . Since the spin–rotation constants are accurately known for CH 4 , the relaxation experiments provide a check on the theory of spin–lattice relaxation for spherical top molecules. In the conventional theory, it is assumed that the correlation function of the spin–rotation interaction is a simple exponential function of time. These experiments show that this assumption is not true for CH 4 gas. The observed fine structure in the plot of relaxation rate versus density is attributed to the influence of centrifugal distortion of the CH 4 molecule, which removes the degeneracy of rotational states having the same value of the quantum number J by an amount somewhat greater than the nuclear Larmor frequency of 30 MHz.
Type of Medium:
Online Resource
ISSN:
0008-4204
,
1208-6045
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
1972
detail.hit.zdb_id:
2021497-2
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