Influence of solid-state effects on the Kβ-to-Kα x-ray intensity ratios of Ni and Cu in various silicide compounds

KP-to-Ka x-ray intensity ratios of Ni and Cu in various silicide compounds Ni2Si, NiSi, Ni2Si3, NiSi2, Cu2Si, CuSi, and CuSi2 have been measured following excitation by 59.54 keV gamma rays from a 200 mCi Am-241 point source. Comparison of the intensity ratios for Ni with the multiconfiguration Dirac-Fock calculations indicates decreasing 3d electron population with the increase of silicon concentration, a trend similar to the one predicted by the previous theoretical calculations [O. Bisi and C. Calandra, J. Phys. C 14, 5479 (1982)]. However, quantitatively our results for the Ni 3d electron population are different from the results reported there. The intensity ratios for Ni and Cu in disilicide compounds indicate enhancement of the K beta-to-K alpha ratio over the pure metal values, but for the other silicide compounds the Ni intensity ratios show opposite behavior than Cu, suggesting a difference in the nature of electron delocalization. [S0163-1829(98)04737-7].