Normal spectral emissivity of elements of the XI group of the periodic system

An experimental study of the normal spectral emissivity $\varepsilon_{\lambda n}$ of chemically pure copper, gold and silver in the solid polished and liquid phases of the state, near the melting point of the metal, was carried out. The measurement of $\varepsilon_{\lambda n}$ was carried out using fixed passbands of narrowband filters. The dependence of the metal $\varepsilon_{\lambda n}$ on the wavelength in the range of the radiation spectrum of 0.26–4.2 $\mu$m microns is obtained. A comparative analysis with the literary data of other authors is carried out. The results of the calculation of $\varepsilon_{\lambda n}$ in the claimed experimental wave range according to the classical electromagnetic theory are presented.