STRUCTURE OF THE BE(11(2)OVER-BAR-0) SURFACE

The equilibrium structure of the <Be(11(2)over bar 0)> surface has bee n determined using LEED I-V analysis. This surface exhibits a stable ( 1 x 3) reconstruction over the range of temperatures investigated (100 -720 K) where the surface starts to disorder. The equilibrium structur e consists of a missing-row reconstruction in which every third surfac e chain of the bulk-terminated structure is absent. The experimentally determined structure is at odds with first-principles calculations, w hich favor a relaxed but unreconstructed bulk termination.