LOW-ENERGY ELECTRON SCATTERING FROM CLEAN AND HYDROGEN-COVERED NB (110) SURFACES

Low-energy electron diffraction (LEED) and inelastic electron scattering (IES) measurements are used to characterize the chemisorption of hydrogen onto the Nb (110) surface. It is found that hydrogen chemisorbs readily at room temperature, causing no rearrangement or faceting of the surface, and with only small changes in the work function. Distinctive changes in the intensity curves indicate that the hydrogen is chemisorbed in a crystalline layer with the same lattice structure as the Nb (110). Removal of the hydrogen is easily accomplished by heating to 400°C, and residual gas measurements show a higher mass 1 peak than usual, indicating that the hydrogen is adsorbed as atoms. Changes in both the LEED intensity curves and in the IES measurements both suggest that the beam penetrates more deeply into the crystal when hydrogen is chemisorbed than for the clean surface. © 1969 The American Institute of Physics.