Properties of multiply charged anions are dominated by the intramolecular Coulomb repulsion (ICR). Using photoelectron imaging, we show the effect of ICR on photoelectron angular distributions for a series of dianions, -O2C(CH2)nCO2 -(Dn2-). The observed photoemission band of Dn2- 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 D112- the angular distribution reverses back to peak at the perpendicular direction due to the reduced ICR.
Revised: October 10, 2008 |
Published: August 22, 2008