Temperature-dependent infrared optical and radiative properties of platinum

We propose a spectral thermophysical model for the infrared optical and radiative properties of metals. The model is suitable for metals possessing nontrivial valency and interband dynamics activated at infrared wavelengths, and consists of an anomalous intraband component and a Gaussian-Lorentzian inter band component. The utility of the model is demonstrated by application to platinum, a material of technical importance that also possesses the relevant intra- and interband characteristics. The model yields accurate estimates of the temperature-dependent spectral directional radiative properties over the wavelength range from 1.5 to 16 gm, and the temperature range from 0 to 1400 K. Results indicate that when computing the total normal, directional, or hemispherical properties, the model can be used for accurate extrapolation over the entire Planck-weighted spectrum. High-fidelity reproduction of the directional properties validates the inverse extrapolated estimates of the complex-refractive index. This indicates that the model can be interfaced with alternative Fresnel frameworks, such as those used to characterize surfaces that have been systematically or randomly roughened. A MATLAB code is provided as supplemental material for reproducibility and convenient implementation of the model. (C) 2019 Elsevier Ltd. All rights reserved.