Unoccupied Electronic Structure of Metal Surfaces

Investigated with the Inverse Photoemission Technique

The technique of Inverse Photoemission Spectroscopy (IPES) is a relatively new technique for investigating the unoccupied electronic structure of surfaces and adsorbates on surfaces. Using a low energy electron gun with a Geiger-Muller type detector operating at ~9.5 eV photon energy, we can examine the low energy unoccupied valence states of metals and other surfaces and map out the two-dimensional band structure of surface and adsorbate states. Over the past few years, we have used IPES to investigate the systems of Na/Cu(111), Na/Cu(110), and ion bombardment of Cu(110).

Current Interests:

• Unoccupied Electronic Structure of Imperfect Surfaces (steps and defect sites)
• Unoccuoied Electronic Structure of Adsorbates on Imperfect Surfaces

Research Team:

• David Heskett (URI)
• Michael Tammaro (URI-theorist)
• James Warner (URI-graduate student)
• Uriah Petit (URI-undergraduate student)
• Debra DePietro (URI-undergraduate student)

Funding:

• Petroleum Research Fund

The IPES technique is introduced with the following presentation featuring examples from previous investigations of Na/Cu(110) (ref: Surf. Sci. 295, 427 (1993) and Surf. Sci. 310, 45 (1994)) and sputtered Cu(110) (submitted).