Modern Polymer Spect..

I
5.4 Polypeptides 261
)I
.- +
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0
1 1 1
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Figure 5-4. Infrared spectra of /l-poly(Lalanine).
Upper two panels: mid-IR
region. (-) Electric vector perpendicular
to the stretching direction. (- - -)
Electric vector parallel to the Stretching
direction. (From [SS]) Lower panel:
far-IR region. (From [86])
Frequency (ern-')
2
0) 1
Figure 5-5. Ranian spectrum of /l-poly(L
alanine). (From [SS])
900 800 700 600 500 400 300 200 100
FREQUENCY (cm-'
ma1 mode analysis [22] are given in Table 5-6 (the NH s modes, which are influenced
significantly by Fernii resonances 1901, and the CH s modes are discussed in
an earlier paper [SO]).
There are some general points to note about this normal mode analysis. First, the