Scattering of He atoms from crystal surfaces: A tentative analysis on the surface crystallography of LiF(001)
This Letter describes a theoretical treatment of the excellent experimental results of Boato, Cantini, and Mattera for the He-LiF(001) system, in terms of a hard corrugated model for the surface. From the agreement achieved between theory and experiments, I conclude that one can represent the corrugated surface by z/sub 1/(x,y) =1/2xi/sub 1/ (cos(2..pi..x/a)+cos(2..pi..y/a))+1/2xi/sub 2/ )cos(2..pi.. (x+y)/a)+cos(2..pi.. (x-y)/a)), with xi/sub 1/=0.307 +- 0.003 A and xi/sub 2/=0.017 +- 0.003 A. This implies that the Li/sup +/ appear to be displaced upwards from the crystal surface by 0.036 +- 0.006 A. (AIP)