Anomalous KC1(001) Surface Corrugation from Fast He Diffraction at Very Grazing Incidence

摘要

We present theoretical and experimental evidence of an anomalous surface corrugation behavior in He-KCl(001) for incidence along 110 . When the He normal energy decreases below 100 meV, i.e., He-surface distances Z 2 angstrom, the corrugation unexpectedly increases up to an impressive greater than or similar to 85%. This is not due to van der Waals interactions but to the combination of soft potential effects and the evolution of He-cation and He-anion interactions with Z. This feature, not previously analyzed on alkali-halide surfaces, may favor the alignment properties of weakly interacting overlayers.