Electron molecular vibration coupling in vibrational spectra of BEDT-TTF based radical cation salts

Abstract

The i.r. and Raman spectra of monovalent bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) based charge transfer salts were investigated. The assignment of the fundamental vibrations of the BEDT-TTF radical cation, the identification of the frequency shifts following the ionization of the molecule, and an interpretation of the vibronic bands revealed in the i.r. spectra of these compounds are reported. A normal coordinate analysis together with a semiempirical MNDO calculation of the radical cation electronic structure were used to obtain the electron-molecular vibration coupling constants. The calculated values are in good agreement with the experimental data.