AG L-EDGE X-RAY-ABSORPTION NEAR-EDGE-STRUCTURE STUDY OF CHARGE REDISTRIBUTION AT THE AG SITE IN AU-AG ALLOYS

Ag L-edge x-ray-absorption near-edge-structure spectra have been obtai ned for a series of Au-Ag alloys: Au0.75Ag0.25, Au0.67Ag0.33, Au0.5Ag0 .5, and Au0.25Ag0.75. The results show a significant decrease in the A g L2,3-edge white-line area relative to pure Ag upon dilution of Ag in Au, indicating an increase in d charge at the Ag site. The value of t he transition matrix element R(d)2P = 1.2(1) X 10(-10) cm for Ag has b een derived based on the experimental results. A semiquantitative anal ysis of the results shows that the number of unoccupied d states (4d h ole counts) at the Ag site in the alloys decreases by as much as 0.130 in Au0.75Ag0.25. The relevance of this finding to Friedel charge scre ening and Au-Ag d-d interaction is discussed.