Gas phase and bulk ultraviolet photoemission spectroscopy of 3,4,9,10-perylene-tetracarboxylic dianhydride, 1,4,5,8-naphthalene-tetracarboxylic dianhydride, and 1,8-naphthalene-dicarboxylic anhydride.

The pi-conjugated organic molecules 3,4,9,10-perylene-tetracarboxylic dianhydride, 1,4,5,8-naphthalene-tetracarboxylic dianhydride, and 1,8-naphthalene-dicarboxylic anhydride were investigated via gas phase and bulk ultraviolet photoemission spectroscopy and compared to density functional theory calculations. Values for final state effects such as intermolecular polarization were determined and the differing features in the spectra interpreted as a consequence of interactions in the thin films. Additionally, the highest occupied molecular orbitals of the molecules clearly show distinctive peaks originating from vibrational excitations, leading to results for Franck-Condon factors.