NNR IN RAPIDLY ROTATED METALS By - Nottingham eTheses ...

Aý T. B a A"T"B
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It is a general property that T can be divided into a symmetric
tensor T* and an antisymmetric tensor T. If Tpp are the principal
values of the tensor T* and apt are the direction cosines of the
principal axes (p = 1,2,3) with respect to the laboratory reference
frame (2., m, n) then
where subscript
TRm Lx
p=1,2,3
PýX PM PP
Em is used to imply summation over all axes, 9, m
and n. Under the condition of rapid isotropic reorientation the
time dependence of 1 only arises out of the motion of the principal
axes, the principal values remaining constant. The isotropic
average of Tjm is given by
Hence
Tim cLPP
P
P
T*a3TrT*
TPP
3a km TPP
The antisymmetric component Tt is given by
tach
TIm
(,
a, b
.
fi
7ý
at bm Tab
where a, b refers to any pair of axes of a convenient co-ordinate
system in the molecule. This expression can be rewritten as
(3.1)
(3.2)
(3.3)