PdAg(1 0 0) ordered surface alloys have been prepared by e-beam evaporation technique in situ in UHV and were investigated using high energy photoemission and normal incidence X-ray standing wave (NIXSW) techniques with wiggler radiation. The line shapes of 3d core levels of Ag and Pd exhibited interesting changes with the increase of Pd concentration in the alloys. The Ag 3d core level exhibited a disorder induced broadening that gradually increased with Pd concentration. On the other hand Pd 3d core level exhibited an asymmetry on the high binding energy side of the peak which gradually increased with Pd concentration. Interestingly, Pd core level did not exhibit a broadening with increase of Pd content in the alloy. (C) 2009 Elsevier B. V. All rights reserved.