An Improvement on the Prediction of Optical Constants and Radiative Properties by Introducing an Expression for the Damping Frequency in Drude Model

A method for predicting the optical constants and the radiative properties of metals and heat mirror films, by introducing an expression for the damping frequency in the Drude model, is described. The directional emissivity of aluminum predicted by this method agrees well with the classical experimental values given by Schmidt and Eckert. The prediction of the normal emissivity of indium–tin–oxide (ITO) heat mirror films is in agreement with our measured results. The directional emissivity of copper predicted using this method is reported. The calculated result of the spectrum normal emissivity of copper at 4 m and 20°C is also given, which supports the measured result. The values for the directional emissivity of aluminum calculated by using various methods based on the Hagen–Rubens relation are reported, and the values do not agree with the experimental results.