Knowledge Bank

Photoelectron imaging can reveal a wealth of information on the structural and dynamical properties of small molecules and their $ionsa$. Using nanosecond lasers we distinguish direct and autoionization pathways in transient and reactive atoms and molecular radicals such as Fe from a discharge source or S atoms from OCS photodissociation. With picosecond lasers the rapid change in molecular geometry as methyl iodide dissociates is revealed in the photoelectron image as rich vibrational structure of excited $CH3I+$. Trends from these simple systems are used to help interpret the complex time-dependent photoelectron images measured in femtosecond pump-probe studies of the molecule tetrakis, an amino-substituted ethylene. This overview describes work done in Nijmegen, at the FORTH facility in Crete with T. Kitsopoulos, and at the SLIC facility in Saclay with B. Soep and coworkers.