Molecular Excitons and Plasmons in Acenes and Their Radical Cations

For existing and potential applications of acenes and acene derivatives, properties of their excited states play a central role. In describing these, the molecular orbital picture can reach its limits, and consideration within the quasi‐particle picture can enable further insight. In this work, exciton size (), hole and electron size ( and ) and correlation coefficient () of excited states of acenes and acene cations are investigated using TD‐DFT at the TDA/CAM‐B3LYP/6‐311G* level, with a focus on their development with increasing acene length. Furthermore, employing a previously established approach, it is shown that the electronic structure of the 1 B b and 2 B b states of neutral and cationic anthracene can be understood as molecular plasmons.