Electronic absorption spectra of neutral pentacene (C22H14) and its positive and negative ions in Ne, Ar, and Kr matrices

The absorption spectra of neutral pentacene (C22H14) and its radical cation (C22H14+) and anion (C22H14-) isolated in solid Ne, Ar, and Kr have been measured from the ultraviolet to the near-infrared. The associated vibronic band systems and their spectroscopic assignments are discussed together with the physical and chemical conditions governing molecular anion production in matrices doped with alkali metal (Na or K). TD-DFT calculations were carried out to assist in the assignments for the measured spectral features of the pentacene ions.