Chemisorbed hydrogen on a tungsten(100) surface produces major effects in two regions of the adatom density, at ${\rho }_1\simeq 3\times {10}^{14}$ and ${\rho }_2\approx 5\times {10}^{14}$ H atoms/${\mathrm{cm}}^2$. Changes at ${\rho }_2$ are probably caused by conventional adatom-adatom interactions, but the effects at ${\rho }_1$ appear to have a different origin and we propose that hydrogen produces displacement waves in the metal surface which gradually disappear above ${\rho }_1$. This type of adsorbate-induced reconstruction may also have been observed for H on Mo(100) and Cs on W(100).

• Received 27 February 1978

DOI:https://doi.org/10.1103/PhysRevLett.41.1307