Theoretical study on the vibrational structures in the conductance spectra of a weakly coupled polycyclic aromatic hydrocarbon molecule

Abstract

The conductance spectra of a 5,10,15,20-tetraphenylbisbenz[5,6]indeno[1,2,3-cd: 1′,2′,3′-lm]perylene molecule that was experimentally studied recently were simulated based on density functional theory and Franck-Condon simulations. The vibrational structures in available experimental conductance spectra associated with different frontier orbitals of the molecule were nicely reproduced. The good agreement between simulated and experimental results enables the unambiguous identification of the vibrational modes involved in the charge transport processes. Differences to the vibrational progressions in the conductance spectra associated with the frontier orbitals were found to be caused by changes of the electron-vibration coupling properties of the corresponding electronic transitions.