Oligoacenes such as naphthalene, anthracene, tetracene, and pentacene are among the best hole-transport organic semiconductors. An important parameter in the determination of the hole mobility is the coupling between the charge carrier and the vibrational modes. Here, we have evaluated the hole-vibration coupling constants in the radical-cation ground state of these molecules by means of the range-separated LC-ωPBE and ωB97 density functionals, with non-empirical optimization of the range-separation parameter ω. Our results indicate that both ω-tuned functionals yield similar relaxation energies and coupling constants. A comparison of the simulated vibrational structures of the first ionization band to the gas-phase ultraviolet photoelectron spectroscopy data underlines that the hole-vibration coupling constants derived by means of the non-empirically tuned LC-ωPBE and ωB97 functionals are in excellent agreement with experiment and superior to those derived from B3LYP calculations.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films