THE USE OF FORWARD FOCUSED PHOTOELECTRONS IN ANALYSIS OF AN ALLOY SURFACE - CUPD[85-15](110)

The thermally induced transition from the (1 x 1) surface, produced after low-temperature sputtering of the CuPd[85:15]{110} surface, to a (2 x 1) ordered phase, has been studied using the variation of the intensity of the Pd 3d5/2 photoelectron line as a function of polar angle in the {112} azimuth. The applicability of the use of the forward scattering of core level photoelectrons to alloy surfaces is discussed. The results indicate that the transition from the high background (1 x 1) LEED pattern to the ordered (2 x 1) is not accompanied by a significant redistribution of Pd in the selvedge save for a removal of Pd from the uppermost layer. Comparisons are made with the behaviour of the analogous Cu3Au{110} surface.