Temperature dependence of the normal integral emissivity of the alkali metal group

The results of an experimental study of the normal integral emissivity (NIE) of lithium, sodium, and potassium during melting and in the liquid state are presented. The research is realized by the radiation method. The experimental results are compared with the theoretical calculation of the NIE from the Foot approximation and analyzed. The behavior of the main thermophysical properties of metals in the melting point region is generalized for the position of alkali metals in the Periodic Table.