The linear portions of Figures 1, 2, and 3 were extrapolated
to higher temperatures to obtain the dipolar contributions. The
extrapolated plots are designated by the symbol T1 d on Figures 1, 2,
and 3.
Since the various relaxation processes are additive in
contributing to the total spin-lattice relaxation process, and since
the reciprocals of the various relaxation times are effectively
transition probabilities, the spin-rotational contribution can be
obtained by subtraction. The spin-rotational contribution is indicated
in Figures 1, 2, and 3 by TI sr and calculated from the equation
1 1 1
T I I- (15)
1 sr 1 1 d
Calculated values of T1 sr at ten-degree intervals are listed in
Tables 4, 5, and 6 for o-, m-, and p-chlorofluorobenzene.
The intramolecular contribution to T1 is obtained by the method
of extrapolation to infinite dilution, which has been discussed pre-
viously. Carbon tetrachloride was the solvent. The quadrupolar moment
of the chlorine nucleus may be neglected. The intramolecular contri-
bution, T intra is plotted as a function of 1/T for o-, -, and
1 intra'
p-chlorofluorobenzene, respectively, in Figures 4, 5, and 6. The
values are tabulated in Tables 7, 8, and 9. Values at ten-degree
intervals, taken from the plots of T intra in Figures 4, 5, and 6, are
1 intra
listed in Tables 4, 5, and 6 for the purpose of calculating subsequent
quantities.