for the dipolar part of T1 as modified by Solomon [14], Kubo and
Tomita [15], and Powles and Neale [16] may be written
1 2 d f(Tda) + N oa- (r) (1)
T d g i>j5 2
where
f(T) = ] (2)
1 + W2 T 1 + 4m2 2
r r
y = magnetogyric ratio,
i = Planck's constant,
ng = number of nuclei in a group in a molecule interacting
with one another,
d.. = distance between i and t nucleus,
13
n = number of resonant nuclei in a molecule,
m
N = number of molecules per cubic centimeter,
o
a = effective radius of the molecule,
T = angular position correlation time involving functions
da as (3 cos2 9 1),
Td = complex position correlation time involving functions
as r-3(3 cos 9 1) involving nuclei in different molecules,
r) = resonant angular frequency, and
T = correlation time of the interaction.
In the extreme narrowing situation where ur d << 1, the case
in most liquids, the intramolecular and intermolecular dipole contribu-
tions may be calculated as