Photoionization of buckybowls: Sumanene and derivatives

•Electronic structures of sumanene and its derivatives.•Simulated UV photoelectron spectra of sumanene and derivatives in the gas phase.•Relationship between the electronic structures and geometry. The electronic structures of sumanene and several heterasumanenes have been calculated using high-level ab initio method: Green’s function method (OVGF). The vertical, valence ionization energies were calculated and gas phase photoelectron spectra simulated on the basis of those ionization energies. The Franck-Condon analysis of vibronic effects has also been performed and changes between molecular geometries in neutral and ionic state have been discussed Standard formation enthalpies for some sumanenes were calculated using isodesmic reaction scheme. The results help in the understanding of how is the electronic structure affected when molecule deviates from planar geometry and what is the influence of substituents in benzylic positions. We have demonstrated that the substituent effects affect not only geometry, but also the electronic structure (reflected in ionization energies). This can be used in preparing new functional materials for various applications.