The properties of multiply charged anions are dominated by intramolecular Coulomb repulsion (ICR). Using photoelectron imaging, we show the effect of ICR on photoelectron angular distributions for a series of dianions, ${}^{-}\mathrm{O}_2\mathrm{C}({\mathrm{CH}}_2{)}_n\mathrm{CO}_2{}^{-}$ ($\mathrm{D}_n{}^{2-}$). The observed photoemission band of $\mathrm{D}_n{}^{2-}$ was due to a perpendicular transition from the charged end group. However, photoemission intensities were observed to peak along the laser polarization for smaller $n$ due to the strong ICR that forces electrons to be emitted along the molecular axis. This emission pattern weakens with increasing $n$ and at $\mathrm{D}_{11}{}^{2-}$ the angular distribution reverses back to peak at the perpendicular direction due to the reduced ICR.

• Received 7 June 2008

DOI:https://doi.org/10.1103/PhysRevLett.101.083003