ИСТИНА

Being typically excited at room temperature, low-frequency (LF) intermolecular vibrational modes in crystalline organic semiconductors are known to have a considerable impact on the charge carrier mobility in such materials, representing a kind of dynamic disorder. Although the issue has been addressed within a number of frameworks, LF intermolecular vibrations are typically considered classically within them. To shed light onto the effect of phonon correlations in the LF regime, we make an LF expansion in a Holstein–Peierls model describing a vibrating 1D chain of molecular sites in a fully quantum way. It turns out that in the LF regime, a macroscopically large number of modes can be effectively described by 1–2 auxiliary phonon modes and the quantum dynamics of the chain reduces to a set of two-site Holstein models, which can be easily solved numerically. We thus evaluate the mobility of a number of model crystals and discuss its drivers.