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We have developed several techniques to study the atomic level structure
of surfaces in equilibrium with gases at pressures that are relevant of
chemical, environmental and catalytic processes, i.e. near one
atmosphere. This is very important as under these conditions the
surface is covered by a dense layer of adsorbates that compete for sites
and impede free diffusion and reaction. I will discuss recent results
obtained using High Pressure Scanning Tunneling Microscopy to discover
novel structures that have not previously been observed using surface
science techniques that operate under high vacuum conditions. I will
also show results using a Photoelectron Spectrometer that operates in a
gas atmosphere of a few torr and allows us to obtain electronic
structure information of surfaces in the presence of gases. The
combination of these two techniques is a very powerful tool for
fundamental studies of surface structure in equilbrium with gases and
vapors at near atmospheric pressures as I will illustrate with several
examples. |