Reflectance spectra and dielectric functions for Ag in the region of interband transitions

New measurements have been made of the reflectances of single crystals of Ag and of Ag films in the (3.5-30)-eV range. The data were analyzed with the Kramers-Kronig method and the resultant dielectric functions were compared with those in the literature and with recent calculations. We find all structures previously seen, and a new weak peak at 11.5 eV. Our magnitudes for ${\epsilon }_2$ are in considerably better agreement with those of the calculated spectra than are those in the literature. Second-derivative spectra of the absorption coefficient have been calculated and compared with previously measured thermotransmission spectra, showing the latter to arise primarily by temperature-dependent broadening.