Coupling of Electrons To Low-Frequency Phonons in Cation Radical Salts of TTF Studied by Resonance Raman Scattering

We report results obtained by measuring the low frequency (40-150 cm -1 ) resonance Raman scattering (RRS) spectra and excitation profiles of the cation radical salt (TTF) 2 (W 6 O 19 ) whose structure consists of almost isolated (TTF + ) 2 dimers that are characterized by a CT absorption band at 850 nm. Quantitative analysis of the RRS data has been performed based on a Peierls-Hubbard model for an isolated dimer. The parameters required for the calculation of the RRS data are derived analytically from the microscopic parameters of the Peierls-Hubbard Hamiltonian, which include the intermolecular (EIP) coupling constants. The excitation profiles have been calculated using the time correlator technique and their fitting provides the first experimental estimates of the EIP coupling constants