Spectroscopic studies of the radical cation salt (BEDT-TTF)(2)Pt(NO2)(4)

We report on spectroscopic studies of the charge transfer salt formed by th e organic donor bis(ethelenedithio)tetrathiafulvalene (BEDT-TTF) and [Pt(NO 2)(4)](2-) anions. In this salt BEDT-TTF molecules are arranged in well-iso lated (BEDT-TTF+)(2) dimers. Polarized reflectance spectra of single crysta ls were measured in the IR region (650-6500 cm(-1)). Moreover, absorption s pectra (400-15,000 cm(-1)) and Fr-NIR Raman spectra of powdered crystals di spersed in KBr pellets were recorded. Vibrational and electronic features a re discussed. We suggest that the frequency of the C=C stretching nu (3)(a( g)) mode depends non-linearly on the degree of ionization of BEDT-TTF. (C) 2001 Elsevier Science B.V. All rights reserved.