Abstract
The monolayer of adsorbed xenon on the ({A figure is presented}1) surface of silver was studied using low- energy electron diffraction. The structure is an hexagonal lattice aligned with but out of registry with the substrate. The Xe-Xe spacing at 25 K is 4.44 ± 0.01 Å in the full monolayer and 4.47 ± at less than full coverage. The Xe-Ag spacing is 3.5 ± 0.1 Å. Here 〈u⊥〉2 T, the meansquare vibrational amplitude normal to the surface divided by the temperature is (1.83 ± 0.4 × 10-4 A2/K. The heat of adsorption is 0.28 ± 0.03 eV/atom.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 429-456 |
| Number of pages | 28 |
| Journal | Surface Science |
| Volume | 58 |
| Issue number | 2 |
| DOIs | |
| State | Published - 1976 |
Bibliographical note
Funding Information:The physisorption of noble gases t)n m,_tal surfaces has been the subject of continued interest \[1-3\]. The interactions involved include London dispersion forces. tile exchange repulsion between the adalom and substra~,' R.,,1'aation t)l a ch:trge-transfer-no-bond complex, partial polarizal'on of tile adalcm in the sulfate field ~,1 the metal, and dipole--dipole and triple dipole lateral inte~acti ms. No co:npletely satisfactory tlaeoretical treatment including at! tl:cse interacti~,ns is yet available. A major difficulty in sorting out these interactions is that the co~ responding energies are very rapid functions of the structure and spacings of the atisorb(d layer, about wttich little quantitative information is avaiia~ ." :. For example, the adlayer-substrate distance determines :he adsorption energy but as yet there has been nt experimental determination of this spacing. In calculations it is usually assumed tha~ tile sl.,,tcttlg is the sum of bulk radii, although recently Kleiman and Land'nan \[4\] llave suggesled that at least for He adsorption on jellium th;, is not correcl. The m.aior g¢~al ol lhesc experiments is t~., obtain more informatio, aoout the :~tructure ol noi~le gas wetai systems. The ~latural technique to use is l...,.v-energy electron diffractien. Electron diffraction studies of noble gas--metal systems have bccu mt~dc I,)t .X(c * This work supported by the National Science Foundation under gr'mt I).M.R. 74-119/ .,nd by the GraduJtc School Research ('ommittec with fund~ from WARF. ** Present address: Center for Materials Research, Llniversity of ~,|.llylatld, ('o!lc,_'c I',rk, Mary land 20742. USA.