The intermolecular contribution to the spin-lattice relaxation
time, T1 inter' can be obtained by subtraction, using the equation
1 1 1
=I-- 1- 1 (16)
1 inter 1 1 intra
The log of T1 inter as a function of 1/T is plotted in
Figures 4, 5, and 6 for o-, m-, and p-chlorofluorobenzene, respectively.
The values are tabulated in Tables 4, 5, and 6 at ten-degree intervals.
The intramolecular dipolar contribution to the relaxation time,
T1 intra d is obtained from the equation
1 intra d1
1 1 1
--- (17)
T T T
1 intra d 1 intra 1 sr
The log of T1 intra d is plotted as a function of 1/T in
Figures 4, 5, and 6 for o-, m-, and p-chlorofluorobenzene, respectively.
The values are tabulated in Tables 4, 5, and 6.
In each case, plots of the log of T1 and T1 in as
a function of 1/T are linear over a wide temperature range.
This linearity indicates a single relaxation process which is
exponentially dependent on temperature. If this assumption is valid,
the energy of activation for the process can be calculated. The spin-
rotation contribution is almost linear in each case,although theory
does not necessarily predict this. As the temperature is increased,
T inter and T intra d become larger in magnitude and become less
1 inter 1 intra d
effective as relaxation processes. This type of temperature depend-
ence is exactly that predicted for dipolar interactions by Bloembergen,