1. Electron Transfer in cluster Anions:
Dissociative Attachment Processes in Real Time
Richard Mabbs, Chemistry Department, Washington University in St. Louis
Photoelectron imaging is a powerful extension of photoelectron spectroscopy. Brighter areas in an image represent a greater density of electrons. The distance from the center is related to the kinetic energy (eKE) while the angular distribution sensitively probes the electronic structure.
The first year of the project has concentrated on the production and characterization of cluster anions such as the series of superoxide, water clusters shown. These serve as calibration systems and yield interesting results in their own right.
O2-(H2O)n
400 nm
O2- + n(H2O) + e-
Photoelectron
Images
Spectra
eKE / eV
0.0
1.0
2.0
3.0
In subsequent work photoexcitation with an ultrafast laser pulse will effect an electron transfer within a cluster anion to initiate a chemical reaction. The photoelectron imaging technique will be used to interrogate the transient anionic species created, following its evolution on the timescale of the atomic motions within the molecules using a second, temporally delay ultrafast photon pulse
X-Y
Excitation
pulse
XY-
Probe
X+Y+ e-
Anions selection by time of flight mass spectrometry