Cation vibrational energy levels of 1,3-benzodioxole obtained via zero kinetic energy photoelectron spectroscopy

We report vibrational analysis of the cation of 1,3-benzodioxole using two-color zero kinetic energy photoelectron spectroscopy. With the aid of density functional calculations, vibrational modes of the cation have been assigned, and the adiabatic ionization potential has been determined to be 64 341 ± 5 cm−1 (7.9772 ± 0.0006 eV). Unlike the ground state and the first electronically excited state of the neutral molecule, the ground state of the cation is proven to be planar. This revelation will help with the vibrational analysis of the excited electronic state.