The electron-phonon coupling strength in TTF-TCNQ

An ab-initio calculation of the electron relaxation rates in TTF-TCNQ for one phonon and two-phonon processes, resulting from the linear and quadratic electron-phonon coupling is performed. This calculation is based on the detailed molecular structure. It is shown that the relaxation rates due to quadratic coupling processes are at least of the same order of magnitude as the relaxation rate for one-phonon processes. The quadratic coupling processes are dominated by molecular librations, while the linear coupling processes are dominated by translations.