Low frequency Raman studies of β-type BEDT-TTF trihalides

Abstract The investigations of the low frequency Raman spectra for a series of isostructural β-type single crystals of bis(ethylenedithiolo)tetrathiafulvalene (BEDT-TTF) trihalide salts were performed in order to analyze the crystal lattice modes and the trihalide anions Raman active modes. Identification of the low frequency modes, verified by experiments performed for different orientations of single crystals in relation to the incident laser light polarization plane, has allowed to determine the composition of the trihalide anion mixtures in the (BEDT-TTF)2BrxIyCl3−x−y salts and to compare the lattice modes for the isostructural single crystals.