Charge-transfer complexes with various organic acceptors

The absorption IR spectra of the organic conductors, of both ion-radical salts and charge-transfer (CT) complexes, created by a given electron acceptor with various donors, share plenty of characteristic features. In addition to rather narrow and weak bands characteristic of the donor D and acceptor A molecules, a few novel absorption bands appear. They are polarized in the plane perpendicular to that of D and A molecules, broad and very intensive. The presence of such unusually polarized bands can be accounted for by the activation of totally symmetric donor or acceptor vibrations resulting from e-mv coupling. Typical polarized reflection spectra of the triethylammonium (TEA) (TCNQ)2 salt for three light polarizations [18] are shown in Fig. 1. It is fascinating that the reflectivity for... 

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