Infra-red absorption and low-energy electron-diffraction measurements of H adsorbed on W(100) showed that distinct wave-numbers characterized the H-substrate stretching modes associated with the long-range structures of the complicated T-θ phase diagram. Hydrogen was bonded at a two-fold bridge site at all temperatures and coverages investigated and the wave-number of the symmetrical stretch mode, v1, was determined by the local geometry, i.e. the substrate dimer length. Analysis of the coverage dependence of the v1 wave-number showed that, at coverages of less than 0.3, the effective H-H interactions led to a uniform H layer on W(100). In general, the phase transitions were continuous on W(100), with regions of intermediate structures.

Hydrogen-Induced Reconstruction on W(100) and Mo(100) by Surface Infrared Spectroscopy. Y.J.Chabal, S.B.Christman, J.J.Arrecis, J.A.Prybyla, P.J.Estrup: Journal of Electron Spectroscopy and Related Phenomena, 1987, 44[1], 17-26