Branching-ratio photoelectron holography has been employed to study th
e structure of Sb adsorbed on Si(111). The Sb 4d core-level emission w
as measured as a function of emission direction, and the branching rat
io between the two spin-orbit-split components was determined, The dat
a were holographically transformed to yield an image for the atomic di
stributions near the Sb emitter. The results are consistent with a tri
mer model. (C) 1997 Elsevier Science B.V.