title: Nonlocal electron-phonon coupling in organic semiconductor crystals: the role of acoustic lattice vibrations.
abstract: We discuss, in the context of a tight-binding description, how the electronic and charge-transport properties in single crystals of molecular organic semiconductors are affected by the nonlocal electron-phonon coupling to both acoustic and optical lattice vibrations. While the nonlocal electron-phonon interactions can in general be divided into contributions from symmetric modes and antisymmetric modes, we show that only the antisymmetric coupling mechanism is operational in the case of acoustic vibrations. Interestingly, when the quantum nature of the phonons can be neglected, the effect of electron-phonon interactions with acoustic phonons is found to be equivalent to that of the electron-phonon interactions with optical phonons, in the case where contributions from symmetric and antisymmetric modes are equal.
authors.affiliation: School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, 901 Atlantic Drive NW, Atlanta, Georgia 30332-0400, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Veaceslav
authors.initials: V
authors.lastname: Coropceanu
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Brédas