Accession Number:

ADA058623

Title:

Order-Disorder Transformations in Chemisorbed Layers: Oxygen on W(110).

Descriptive Note:

Technical rept.,

Corporate Author:

WISCONSIN UNIV-MADISON

Report Date:

1978-06-13

Pagination or Media Count:

23.0

Abstract:

Order-disorder transformation in oxygen adsorbed on W110 was investigated. An analysis of the ordering at T0 using the lattice gas formalism shows that there must be significant three-particle interactions to break the particle-hole symmetry. This is necessary since there is a p2x2 phase at three-quarter coverage which is not present at one-quarter coverage. Monte Carlo techniques are used to obtain estimates of the strength of the two and three-particle interactions by matching calculated and measured LEED intensity curves. The qualitative characteristics of the phase diagram are discussed with emphasis on the multicritical points which must be present if the transition at half coverage is second order. Evidence in support of a second order transition is reviewed. Author

Subject Categories:

  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE