Hydrogen-induced reconstruction of stepped W(001) surfaces studied with LEED and EELS

Low energy electron diffraction patterns show that the W(001) surface reconstructs at room temperature when exposed to hydrogen with a (..sqrt..2x..sqrt..2)R45/sup 0/ structure having a c2mm symmetry. Vibrational EELS data indicate that the tungsten atoms move together to form dimers which must be aligned in directions to satisfy the symmetry requirements. The two possible dimer orientations define two orthogonal, degenerate domains. It has been shown that steps on a surface may limit the growth of the reconstruction domains and may also influence the relative abundance of the domain orientations. We report here an extension of previous work on step effects involving the relationship of step orientation to domain growth and selection. 7 refs., 2 figs.