SPECTROSCOPIC EFFECTS OF NEUTRAL-IONIC TRANSITION IN TTF(2)IA

Pressure-dependent infrared and visible spectra of bis-tetrathiafulval ene-iodanil (TTF(2)IA) are analyzed within the donor-acceptor-donor tr imer model, taking into account electron-molecular vibration coupling. Conditions for transition from quasi-neutral to quasi-ionic states ar e found. Asymmetric charge distribution between donors is shown to be possible for sufficiently large small-polaron binding energy of the do nor molecule. The complex conductivity is calculated and a wagr to ded uce parameters of the model from absorbance data is proposed.