Difference between the local density of unoccupied states in Ag-Pd and Cu-Ni alloys

X-ray L absorption edges have been measured for the palladium atoms in a series of Ag-Pd solid solutions. The local density of unfilled $4d$ states per palladium atom declines upon alloying with silver, whereas previous measurements have shown that the local density of unfilled $3d$ states per nickel atom does not diminish with the addition of copper.