Photoelectron imaging, ion spectroscopy, reactive intermediates. Research in our group is focused on gas-phase ion spectroscopy, with a particular emphasis on problems related to reactive intermediates and cluster ions. Our experiments require careful ion synthesis, followed by mass selection in a mass spectrometer. We learn about the ion properties by 1) using infrared or UV lasers to detach electrons in photoelectron imaging or 2) electronic or vibrational spectroscopy by photodissociation.