W. Carl Lineberger

PES stands for photoelectron spectroscopy, which in the case of our lab is performed on negative ions. Here's how negative ion photoelectron spectroscopy works: a laser is used to detach the extra electron from a mass-selected beam of negative ions, and the kinetic energies of the electrons are measured in a hemispherical energy analyzer.

The cluster labs include two separate ion beam machines that share a nanosecond pulse dye laser with OPO and a  femtosecond Ti:Sapphire laser with a TOPAS OPA used for time-resolved dynamics.

This form of ultrafast laser spectroscopy involves pump-probe photoelectron detachment, changing the charge state of an anion from Negative to Neutral to Positive, and therefore has been referred to as NeNeuPo or Charge Reversal Spectroscopy, in addition to PDPI spectroscopy. The purpose of PhotoDetachment PhotoIonization (NeNePO) spectroscopy is to explore the ultrafast dynamics of neutral species through electron photodetachment from precursor anions.