On the structure of CO adlayers on Cu(100) and Cu(111)

Alternative models for the high coverage compressed overlayers of CO on copper (100) and (111) are proposed in which the LEED patterns previously attributed to out-of-registry, uniformly compressed structures are re-interpreted in terms of adsorption on linear and bridged sites. The models provide a simpler explanation for the small influence of compression on the frequency of the infrared adsorption bond near 2000 cm^?1 compared with the large change of surface potential.