Abstract
The scattering of 4He atomic beams from several alkali halide crystal surfaces has been studied. The surfaces are prepared by cleavage in situ at pressures usually in the low 10-10 Torr range and are held at room temperature throughout. The atomic beam is highly monochromatic and has a relatively long wavelength (1.04 A). LiF has previously been found to give a relatively simple pattern of principal selective adsorption transitions with a superimposed "fine structure." NaF is more complex; more transitions occur and only a tentative indexing can be given. NaCl is still more complex and no indexing can be given as yet.