SURFACE REFLECTANCE SPECTROSCOPY OF HYDROGEN CHEMISORBED ON W(100), W(110) AND W(111)

Hydrogen chemisorbed on tungsten is studied by Surface Reflectance Sprectroscopy (SRS) at room temperature in the energy range from 0.6 to 6 eV. The (100), (110) and (111) faces were studied with s polarized light and in addition the (100) face was studied with p polarized light. The s polarized spectra are analyzed for the surface optical conductance using an inversion technique developed by Prange and the present authors. The technique is based on the Kramers-Kronig dispersion relations and preserves the fine structure in the spectra. The resulting surface conductance for the W(100) face is found to correlate well with the surface band structure calculation of Smith and Mattheiss. Evidence for intrinsic surface states are found for all three symmetry faces. The p polarization data were compared with the s polarization data using the McIntyre-Aspnes theory. The results indicate that the McIntyre-Aspnes theory is not well obeyed by the p polarization data and therefore the effects of anisotropy and/or nonlocal effects may be important. © 1979.