Action absorption spectra of protonated (a) pentacene, (b) pentacenequinone, (c) pentacenetetrone, (d) anthraquinone, and (e) phenanthrenequinone. The errorbars are calculated by propagation of error and are due to counting statistics and laser energy variation. The black lines are smoothing lines to guide the eye. The red bars indicate calculated excited state transitions (S₀ → S_n) computed at the CAM-B3LYP/def2TZVP level of theory. The height of the bars corresponds to the oscillator strength. The calculated excitation energies for protonated (b) pentacenequinone and (e) phenanthrenequinone are redshifted to fit the experimental data by 0.5 and 1.5 eV, respectively.