Direct Proof of the Effect of Temperature on the Conduction Electrons of a Metal

Abstract

IT has been recognized for some time that the structure of the K-, L-, etc., emission spectra of the metals in the soft X-ray region (about 10–500 A.) can lead to direct information about the level system occupied by the conduction-electrons¹. For the radiation of a metal in this region consists wholly (or, in other cases, at least partly) of a band which represents transitions of the conduction-electrons themselves into an inner shell which has been ionized by electron-impact in the X-ray tube; and since the inner level is relatively sharp, the structure of the conduction electron level system is clearly reflected in the emitted radiation. The most characteristic feature is the sharp edge which forms the short wave-length end of such a band ; this evidently corresponds to the sharp surface to which the conduction-electrons of the metal fill up the continuum of possible levels. But, theoretically, this surface is only sharp at the absolute zero of temperature. As is well known, the conduction-electrons are subject to Fermi-Dirac statistics and this has the result that at a temperature T, the surface is slightly diffused.