Influence of Structural Dynamics on Polarization Energies in Anthracene Single Crystals

Normal mode sampling and molecular dynamics simulations are coupled to a valence-bond/Hartree-Fock approach to evaluate the impact of the lattice and molecular vibrations on site energies in anthracene single crystals. The calculations are conducted in the temperature range 0-400 K and show substantial contributions from high-frequency modes, which calls for a quantum-mechanical model even at room temperature. External reorganization energies are also obtained from these modeling studies and found to be much smaller than their internal counterparts. Implications for charge transport in organic single crystals are discussed.