The Na
+ and K
+ cations have similar electronegativity (0.93 and 0.82, respectively,
on the Pauling scale); however, they differ in terms of ionic radius and atomic mass
and the observed differences in spectra can be associated with the mentioned
parameters. Similar observations were made by analyzing the D6R [36], 4–4=1
[48], and 5–1 (Fig. 10.8) [58] units.
Fig. 10.7 IR spectra calculated for D4R model units terminated by Na
+ and K
+ cations [36]
Fig. 10.8 IR spectra calculated for 5–1 model units terminated by Na
+ and K
+ cations [58]
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