The Geometry of Adsorbates on Metal Surfaces

Using the X-ray Standing Wave Technique

X-ray Standing Waves (XSW) is a relatively new technique for studying the structure of surfaces, and in particular the geometry of adsorbates on metal surfaces, which is the main focus of these investigations. The XSW technique has the advantages of a high degree of positional accuracy, elemental specificity, and relatively simple data analysis. Over the past few years, we have used X-ray Standing Waves at the National Synchrotron Light Source (NSLS) in the back-reflection geometry (BRXSW) to investigate the structure and geometry of Rb/Cu(111), Rb/Cu(110), CO/Ni(111), S/Ni(100), Hg/Ni(100), and CO/Ni(117).

Current Interests:

• Geometry of Adsorbates on Imperfect Surfaces (at steps and defect sites)
• Site-specific valence electronic structure

Research Team:

• David Heskett (URI)
• James Warner (URI-graduate student)
• Uriah Petit (URI-undergraduate student)
• Joe Woick (NIST)
• Erik Nelson (NIST-postdoc)
• Lonny Berman (NSLS)

Funding:

• Petroleum Research Fund
• DOE Facilities Initiative Grant

The XSW technique is introduced with the following presentation featuring examples from previous investigations of Rb/Cu(111) (ref: Surf. Sci. 344, 267 (1995)) and CO/Ni(111) (unpublished).