Optical Constants of Silver-Gold Alloys

Optical constants of silver-gold alloys of several compositions were determined by reflection measurements in spectral region 2eV∼20eV to investigate the shift of the structures in ε 2 spectra with increase of composition of gold. In the lower energy region 2eV∼10eV, six characteristic structures were found and they shifted smoothly with composition, converging to the structures of pure gold at 2.0, 3.5, 4.1, 5.0, 6.0, 6.5eV respectively. They were assigned as the interband transitions corresponding to L 3 - L 2 ', X 5 - X 4 ', L 2 '- L 1 , X 1 - X 4 ', W 1 '- W 3 , W 1 '- W 2 ' in Segall's energy diagram.