Surface Dynamics



This ultra-high vacuum chamber was designed for studying surface photochemistry, non-linear optical processes, and two-photon photoemission. The resistively heated Pt(111) single crystal is held on a (x, y, z, f) manipulator with an open loop liquid helium cooled cryostat. In addition to photochemical work the chamber is equipped for x-ray photoelectron spectroscopy, Auger electron spectroscopy, and thermal programmed desorption spectroscopy.
Planned experiments include measuring ultrafast wavelength dependent photochemical cross sections of small molecules such as N2, CO2 and CH4, probing ultrafast surface dynamics, and examining unique photochemical reactions driven by short-pulse light. Two-photon photoemission will be used to probe the affinity bands of small molecules adsorbed on the Pt(111) surface as a function of Cs or K promoter coverage. Sum frequency generation studies are also planned, in order to optimize the technique with a minimal number of experimental variables.

Surface characterization techniques include angle-resolved X-ray photoelectron spectroscopy, Auger spectroscopy, and thermal programmed desorption spectroscopy. A flowing liquid helium cryostat built into the sample manipulator can cool samples to 20 K. Resistive heating provides the means to raise a sample's temperature to as high as 1500 K. Current work examines the ultrafast dynamics of adsorbates and electrons on Pt(111) surfaces in studies of catalysis and fs-MALDI.