Polarized Absorption Spectra of Single Crystals of Tetrathiafulvalenium Salts

Abstract

The polarized absorption spectra over the range, 5000–37000 cm−1, were observed on the single crystals of the highly-conductive, mixed-valence tetrathiafulvalenium salts, (TTF)Br0.71, (TTF)I0.71, and (TTF)(SCN)0.57, by using a microspectrophotometer. The spectra of these crystals were very similar to each other. The observed spectra were successfully interpreted in terms of the localized model, considering the charge transfer transitions between TTF species and the local excitations associated with the intramolecular transitions of the molecule and ion of TTF. The spectrum of the (TTF) (ClO4) crystal were also studied to aid the interpretations of the spectra of the mixed-valence TTF salts.