Comment on "Effect of the structural anisotropy and lateral strain on the surface phonons of monolayer xenon on Cu(110)" - art. no. 037401

In a previous paper by Zeppenfeld et al. [Phys. Rev. B 50, 14 667 (1994)] t he dynamics of a Xe monolayer on Cu(110) was determined using inelastic He- atom scattering. Energy losses:at around 3.7 meV were assigned to a longitu dinally polarized phonon localized in the Xe adlayer. The value of 3.7 meV was found to be in good agreement with the predictions derived using the co rresponding Xe-Xe gas-phase potential. Since recently for Xe adsorbed on th e two other low-index Cu single-crystal surfaces, Cu(100) and Cu(111), rath er different results were obtained revealing a pronounced anomaly in the in teraction between adsorbed Xe atoms, we have reinvestigated the Xe/Cu(110) system. Our new data demonstrates that the mode at 3.7 meV is not an inhere nt feature of the Xe adlayer and is most likely related to the presence of contaminations. Ail together the new data indicates that the anomaly in the interaction between the adsorbed Xe atoms is present for Xe adlayers on al l Cu surfaces with low Miller indices, Cu(111), Cu(100), and Cu(110).