
259Coupled Oscillations and Normal Coordinates
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Equation 8.34 is generally called the normalization condition. The orthogonality condition 8.31
and normalization condition 8.34 are often combined into one statement by the use of the Kronecker
delta symbol δ
ij
:
ACC
jk jr ks
jk
,
=δ . (8.35)
The vector
C
r
dened in this way constitutes an orthonormal set: the set is orthogonal accord-
ing to Equation 8.31 and has been normalized according to Equation 8.34. The orthogonality and
normalization conditions of Equation 8.35 are of more than academic interest; as we shall see, they
prove useful in establishing the consta ...