The bonding geometry, fundamental H vibrational frequencies, and dynamic dipole moments for the saturated H coverage phase on W(001) are calculated with the ab initio linear augmented plane wave method. All three mode frequencies agree well with experiment and support earlier electron-energy-loss spectroscopic mode assignments. The present results indicate that nearest-neighbor central-force-constant models at surfaces are inadequate for quantitative analysis of adsorbate vibrations.

• Received 23 January 1986

DOI:https://doi.org/10.1103/PhysRevLett.56.2291