Colin Harthcock - Orientation--Free and Differentially Pumped Addition of a Low-Flux Reactive Gas Beam to a Surface Analysis System

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      Publication Details (including relevant citation   information):

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      Abstract:

      We describe an example of a piecewise gas chamber that can be   customized to

      incorporate a low 

      ux of reactive gas-phase radicals with an existing surface   analysis

      chamber for in-situ and stepwise gas-surface interaction   experiments without any

      constraint in orientation. This open design provides complete   angular freedom and

      easy alignment in assembling this gas chamber using a   commercially available gas

      source. In addition, the entire gas-surface system is readily   dierentially pumped

      with the surface chamber kept under ultra-high-vacuum during the   gas-surface

      measurements. The piecewise nature of this gas chamber should   allow not only

      straightforward reconstruction to accommodate to the orientation   of dierent surface

      chambers, but for the addition of other desired features, such as   additional pumping,

      to the current conguration. Stepwise interaction between atomic   oxygen and a highly

      ordered pyrolytic graphite surface was chosen to test the   eectiveness of this design,

      and the site-dependent O-atom chemisorption and clustering on the   graphite surface

      was resolved by a scanning tunneling microscope in the nm scale.   X-ray photoelectron

      spectroscopy was used to further conrm the chemisorption of   oxygen atoms on the

      graphite surface.

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