Pressure-induced neutral-ionic transition of (TTF)2(iodanil) and nonsymmetrical charge distribution in the trimer unit

Neutral-ionic transition under pressure in a 2:1 charge transfer crystal of tetrathiafulvalene (TTF) and iodanil (IA) is disscussed using a model of mixed-valence trimer with explicit consideration of electron-intermolecular vibration coupling. Ground state charge distribution in the TTF-IA-TTF trimer is analysed as a function of small polaron binding energies and transfer integral.