Dimers of the acenes naphthalene, anthracene, tetracene, and pentacene are shown to have a C2 symmetric X-shaped lowest minimum structure, while slipped-stacked and cross-shaped minima have higher energies. This is shown at the B3LYP-D3(BJ)/def2-TZVP level of theory and validated with the PNO-LCCSD(T)-F12 method. A SAPT analysis provides insight into the nature of the interaction. Finally, we performed experimental UV-Vis spectroscopy and fluorescence studies to shed light on assembling in solution. The comparison of computed UV-spectra of different dimers with experimental results helps in understanding the association process.
Matsokin et al. (2026) studied this question.