Optical constants of iron and nickel metal and an assessment of their relative influences on silicate mixture spectra from the FUV to the NIR

We report new measurements of the optical constants of iron and nickel metal in the ultraviolet, visible, and near-infrared portions of the electromagnetic spectrum (∼0.16-3.59 µm), building upon the measurements of Cahill et al. (2012). These values were determined from metal films vapor-deposited onto fused-silica prisms. Our measurement of optical constants employed ellipsometry performed within the prism, sensing the side of the metal film unexposed to the ambient atmosphere. The data we report have important implications for modeling planetary reflectance and emittance spectra, especially in relation to space-weathering effects observed in remotely sensed data for the surfaces of the Moon, Mercury, and asteroids.