Accurate prediction of the energy levels (i.e. ionization potential and electronic affinity) of organic semiconductors is essential for understanding related mechanisms and for designing novel organic semiconductor materials. From a theoretical point of view, a major challenge arises from the lack of a reliable method that can provide not only qualitative but also quantitative predictions at an acceptable computational cost. In this study, we demonstrate an approach, combining the polarizable continuum model (PCM) and the optimally tuned range-separated (RS) functional method, which provides the ionization potentials (IPs), electron affinities (EAs), and polarization energies of a series of molecular semiconductors in good agreement with available experimental values. Importantly, this tuning method can enforce the negative frontier molecular orbital energies (−εHOMO, −εLUMO) that are very close to the corresponding IPs and EAs. The success of this tuning method can be further attributed to the fact that the tuned RS functional can provide a good balance for the description of electronic localization and delocalization effects according to various molecular systems or the same molecule in different phases (i.e. gas and solid). In comparison, other conventional functionals cannot give reliable predictions

The equilibrium structure of cyclohexane dication C6H122+ and singly charged ions C2H4+ and C4H8+ suggests that hydrogen migration can proceed in dissociation process of C6H122+ to C2H4+ and C4H8+. Using dc‐slice imaging technique, the fragmentation pathway C6H122+ → C2H4++C4H8+ is detected under an intense femtosecond laser field. Two‐body Coulomb explosion (CE) of C6H122+ to C2H4+ and C4H8+ is securely identified. The quasi‐isotropic distributions of ions indicate the precursor have a relatively long dissociation time. Then, B3LYP density functional theory calculations are performed on this dissociation process, the results show the precursor C6H122+ undergoes molecular rearrangement and 1, 2‐ and 6, 5‐ hydrogen migrations during the dissociation process. These molecular rearrangement and hydrogen migration processes can reduce the anisotropy distribution of fragment ions C2H4+ and C4H8+, which is consistent with the experimental results. The present work will be useful to understand hydrogen migration processes within the hydrocarbon molecules.